Windows Server 2008 R2 Backup Storage Support and Media Management

Windows Server Backup allows administrators to back up to locally attached disks, network shares, and DVD writable media. Tape devices are not supported by Windows Server Backup, and to back up to DVD media, the system requires a local writable DVD drive. Using Ntbackup.exe in previous versions of Windows Server editions, media management was one of the biggest challenges administrators faced. Tape media needed to be prelabeled if any logical media management was required for backups. Also, if disk-based file backups were used, the file could end up filling up the server disk if the media was configured to append instead of overwrite when new backups were performed. The other option for backup media was to overwrite the media when a backup was run, but that also relabeled the media and any stickers on the tape would no longer match. Media management was possible, but just very tedious.

Windows Server Backup greatly improves media management by taking full control of the media, including labeling, efficiently storing data, cataloging the backup media, and managing the free disk space. Performing backups using remote server shares or local volumes as backup destinations has the risk of filling up the destination volume. When local disks are dedicated for Windows Server Backup and the utilized disk space is nearing capacity, the backup system will overwrite the oldest backup data on the disk to keep the disk from filling and to keep the backup job from failing.


External Disks
Windows Server Backup supports backup data to be stored on locally attached disks and writable DVD media located in local writable DVD drives. Locally attached disks include internal disk drives, hot-swappable disk drives, and drives externally connected via USB 2.0 or IEEE 1394 interfaces. Also, SAN-attached disks can be used as backup destinations. Storing backups on SAN storage enables faster rotation or replication of backup disks volumes to other SAN storage without impacting Windows system performance.


CD/DVD Writer Drives
Windows Server 2008 R2 contains many features that can take advantage of DVD writer drives. These include the Windows Server Backup feature to capture backups to DVD and Windows Deployment Services, which can be used to create boot, capture, and discover images on DVD media. With regard to Windows Server Backup, a manual backup can be created to contain a volume or entire system backup, and might span multiple DVDs. This can be a valuable option as data from remote servers can be synchronized across the network using Distributed File System Replication, but creating a full system backup across a WAN link usually is not an option. Branch office administrators can be tasked with creating full system DVD backups monthly, quarterly, or more frequently to provide full system recovery options, and the media can easily be copied, archived, and shipped to offsite storage locations or to a central office.


Remote Shared Folder and Folder on Local Volume
Shares on remote servers or folders on local volumes can be designated as backup targets for manual and scheduled backup jobs. Designating a remote shared folder allows an administrator to create a backup not stored on media physically mounted in the system, and also allows for the backup of multiple servers to be stored on a central server. Choosing to back up using a folder on a local volume removes the restriction of having to dedicate an entire volume for backup usage. There are two very important catches to be aware of when using remote shared folders and folders on local volumes:

. When using a remote shared folder, only one copy of the backup can be stored within the folder, and each backup will perform a full overwrite backup.

. When a folder on a local volume is selected as a backup destination, the performance of that volume will be severely impacted during backup, which could cause poor system performance if any user data is stored and accessed on the same volume.


Tape Devices
Tape devices are not supported in Windows Server Backup. Administrators who want to back up data to tape will require Microsoft System Center Data Protection Manager or third-party backup applications, or they will be forced to create manual backups to disk and then copy the data to tape drives.

Source of Information : Sams - Windows Server 2008 R2 Unleashed

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Lync Server - Collaboration Benefits

In concert with Microsoft Office 2010 and Sharepoint 2010, Lync Server is the lynchpin to a successful enterprise collaboration strategy.


Improved Web Conferencing Experience
Possibly the most significant change to, and benefit of, the new collaboration tools in Lync Server is the deprecation of the live meeting client. Lync Server users can join and manage live meetings through their Communicator client. Help desk personnel no longer need to explain which client to use for what kind of call. Simple, tight integration of scheduling and managing conferences provides a huge confidence boost even for inexperienced users. With just a few clicks, users can schedule, manage, and provide content for a meeting. Conference invitees, who do not use Lync Server, can join Lync Server web conferences by using a new lightweight client, the Lync Server Attendee online client.

Administrators looking to provide limited communicator web access to non-Windows or remote users in OCS deployed Communicator web access (CWA). CWA was a dedicated
server role in OCS. In Lync Server, this role is deprecated and replaced with the
Communicator web app, which is a service running on the Front End Server.

This topology change benefits to administrators and users alike. Administratively speaking, eliminating this server role offers a reduced overall Lync Server server footprint and simplifies management responsibilities. Lync Server users accessing CWA can share their desktops, and manage inbound and outbound calls no matter what OS they used to access the CW application.

In previous versions of OCS, only Windows users could share their desktops; users could not receive calls. By bringing these additional options to the CWA experience, non Windows Lync Server users are provided with an improved experience.


Lobby Experience
With Lync Server, after joining a conference, it is possible to apply a new experience to attendees that enhances the meeting join experience. This is known as the lobby. When a nonpresenter joins a meeting that has not started, she is placed in the lobby until the presenter joins. In addition, the lobby mode can be used during a call to avoid the disturbance of people entering and exiting a conference. The presenter can control when lobby users are admitted to the conference. This enables a presenter to maintain control of a meeting, especially one with several attendees.


Multiple Language Support
Users at multinational enterprises benefit from this new Lync Server feature. Each Lync Server site can have its own language for meeting prompts. When users join a meeting, they hear prompts in the language of their site, regardless of the site of the organizer.


Simplified Join Experience
If you have ever had a difficult time getting users to connect a live meeting and were confused by the obfuscated meeting URI in previous versions, fear not. The new simplified meeting URIs make the meeting-join experience quicker and more reliable. System administrators can set a simple URL (for example, HTTP://meet.contoso.com) that will be used by all meetings. This simple URL cleans up the body of the default Outlook message so that even those unfamiliar with joining a live meeting can join easily.


Visual Conference Calls
Sometimes, a simple audio conference is all that is required for quick collaboration. If users frequently attend audio-only meetings in Lync Server, they will be presented with a familiar, clear, and concise listing of users who join their conference. Users can manage their audio conferences with confidence, using the same interface from which they make individual calls.


Mute All, DTMF, and Roll Call
Users conducting large conferences benefit from the mute all option. Using the simple, familiar Communicator interface, a meeting organizer can mute attendees to gain control of a meeting or conduct a press conference-type meeting. Meeting participants can control their meeting status using the dialpad. This also enables mobile users to have full control over their meeting experience. When conducting larger meetings, Lync Server meeting organizers can obtain an audio roll call of meeting participants. The recorded name or text-to-speech spoken name is played to only the organizer, enabling administrators to keep track of meeting participants.


Meeting Content Control
Collaboration power users can skip ahead in uploaded content shared in meetings. If you have ever been in a meeting where the presenter spent too much time on content you already knew about, you will appreciate this feature. A simple mouse click returns you to the content currently being shared.


Join from PBX
Users who are not Enterprise Voice–enabled can still participate in meetings with Lync Server Communicator. Users who have their extension homed to their corporate PBX phone can click the simple meet URL in a meeting invite. Communicator can be configured to call the meeting participants at their PBX number. This enables non-Enterprise Voice users to enjoy the benefits of Lync Server’s advanced UC features as well.

Source of Information : Pearson-Microsoft Lync Server 2010 Unleashed

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Lync Server - Client-Side Benefits

Lync Server takes huge strides to improve the client experience. Based on hours of user testing, the Microsoft team released an improved client in terms of functionality and usability.


Pre-Call and In-Call Quality Feedback
Lync Server users can determine, in advance, what kind of call quality to expect on a given call based on real-time feedback from within Communicator. Familiar bars icons, such as on a cell phone, tell users at a glance how their network is performing during a call. This provides, for example, a user currently connected through a public Wi-Fi network the knowledge that the available bandwidth might not provide a quality experience, enabling him or her to consider other options for the call.

With location services, Lync Server has the capability to determine whether multiple users are joining a conference call from the same physical location or a location that can cause poor conditions, including feedback. During a call, Lync Server alerts users, through a pop-up, that they might be causing call quality issues and suggests actions to resolve the problem, such as going on mute.

Lync Server users who need to confirm the quality of a call prior to initiating it can make a test call to an audio test service. This functionality is built into the client and provides users who deploy a new audio device or roam to an unknown network a chance to test their call by calling the test service, recording a short sentence, and playing the message back.


Private Lines
Lync Server users can have a private line for incoming calls. This enables calls from important business contacts and family members to be easily identified and receive priority handing. Calls to a user’s private number are uniquely identified on the incoming toast and with a distinct ring. Calls to private lines override DND and other redirection settings to ensure that they always route to the user.


Call Parking
Have you ever placed a call on hold and picked it up somewhere else, but didn’t transfer it because you knew you couldn’t get to the other phone in time? Well, that is a situation for which Call Park was invented. Now users can park a call in an orbit number and go to another client to retrieve it. By combining Call Park with a third-party overhead paging system, an attendant can answer a call, park it, and page the requested person. Enterprises that have mobile internal users, such as shop floor or manufacturing employees, have been using park-and-page for many years. Now Lync Server users can enjoy the same feature.


Common Area Phones
When considering a PBX replacement, not every existing phone location can have a PC.
Hallways, lobbies, and transient worker areas are locations that can benefit from the concept of common use phones. The expense of providing a Tanjay-type device and the access control requirements (domain account, and password or fingerprint) made OCS 2007 R2 ill-suited for this task.

With Lync Server, endpoint devices are available that provide simple calling features by being plugged in and provisioned by an administrator. These phones retrieve parked calls and make internal calls without users signing in to Lync Server.

On recovering from a power failure or being unplugged, common-use phones automatically reregister with the registrar. Calling rules for default behavior can be set using the same management tools that other CS users are managed. Common-use phones have their own domain accounts in Lync Server.


Hot Desking
For transient areas, common use phones can be logged in to with a standard user’s account, enabling the user to make and receive calls wherever logged in. By using a PIN code or pairing the phone with a PC, transient workers can have all the benefits of a fully functional Lync Server endpoint wherever they need it. By signing into a phone designated as a hot-desking location, a Lync Server user gets a contact list, recent calls, and other contact-related information where he or she signs in. Hot-desking phones revert back to their common-use configurations based on a configurable timeout, allowing for a touchless user experience. Hot-desking options are easily managed by group policy settings similar to all other CS users.

Source of Information : Pearson-Microsoft Lync Server 2010 Unleashed

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Enterprise Voice Benefits

Perhaps some of the most tangible, new, and exciting benefits of Lync Server are those related to the Enterprise Voice set of features. With the new release, Lync Server competes with the voice features provided by traditional PBXs. In fact, at VoiceCon 2010, Lync Server won the Voice RFP competition competing against the major PBX manufacturers.


Mediation Server Role Collocation
In prior versions of OCS, the Mediation Server was a dedicated role and required a one one relationship between the server and the gateway. OCS configuration enabled only a single, next-hop configuration from the Mediation Server to the media gateway (PBX, PSTN, and so on). Although certain gateway manufacturers were able to load-balance calls from the gateway to OCS, OCS was limited to only the single next hop. In Lync Server, the mediation role now runs on the Front End Server as a service. This concept of mediation server collocation provides tangible benefits from a topology, administrative, and user perspective.

With Lync Server, each Front End Server can have its own mediation service, enabling pools to route to gateways instead of the mediation servers. This enables multiple mediation servers to route to the same gateway or multiple gateways to route to a single mediation service.

This capability provides tremendous flexibility to design engineers and enterprises with a large number of PBX/PSTN trunks at a single site or many smaller sites. In previous versions of OCS, these scenarios required a mediation server at each location. In addition to a tangible reduction in servers, this topology change provides greater resiliency, more flexible routing choices, and more options for media flow.


Media Bypass
One of original roles of the mediation server was to transcode between RealTime audio (RTAudio) and G.711 to integrate with standards-based media gateways and PBXs. With Lync Server, calls can be sent using G.711 directly to a supported gateway or PBX. Although low bandwidth signaling (SIP) still traverses the mediation service role, higher bandwidth media (RTP) flows directly from a Lync Server endpoint to the GW/PBX, bypassing the Mediation Server role.

This change provides several benefits, including
. Removes a potential single point of failure that a mediation server introduced
. Reduces the overall server footprint of OCS
. Reduces the number of hops a media stream takes

In addition, in scenarios where a branch appliance is deployed, calls from PBX users at a branch to Lync Server users at the same branch, media now remains at the branch. Prior to Lync Server, an extra mediation server at the branch was required to enable similar call flow.


Optional Dedicated A/V Conferencing Role
In scenarios that require heavy conferencing resources, or MCUs, the A/V Conferencing role can be split off from the Front End Server role. Multiple A/V servers can be placed in a pool and this A/V pool can be designated as the conferencing resource for many other pools. This topology offers a distinct advantage enabling conference-centric enterprises the capability to provide a highly available conferencing resource to the users, but also keeping this resource-intensive application isolated from the day-to-day IM presence and telephony services. Additionally, this enables an enterprise to virtualize basic telephony services while providing physical hardware for A/V services.


Call Admission Control and DiffServ
Although RTAudio is a flexible payload codec, many larger enterprises believe that Lync Server should support call admission control, or CAC, as well. Already a fixture in many
VoIP communications servers, call admission control is now configurable in Lync Server. With Lync Server, network managers can control the amount of bandwidth voice and video calls consume on a given link. By configuring the bandwidth policy service to control a specific site, calls can be rejected or rerouted to the PSTN when sufficient bandwidth is not available to complete the call. This ensures quality audio or video sessions. Enterprises can garner tremendous benefit from planning their CAC strategy prior to deployment.

Lync Server users benefit from its capability to leverage the concept of differential services code points (Diffserv—or DSCP) for audio and video traffic. By separating port ranges for audio and video, Lync Server enables network administrators to provide different per-hop behaviors (for example, EF or expedited forwarding) for these streams. This enables latency sensitive traffic to route ahead of web or other non-real-time traffic. Windows 7 and Vista desktops can leverage Windows-based QoS. This enables them to be provisioned to apply DSCP markings to packets based exclusively on application and port ranges.

By combining CAC, DSCP, and Windows-based QoS policies, network administrators can rely on Lync Server to adhere to the policies they create and deploy on their network to enable all packets to arrive as required and ensure a quality user experience.


E911
Primarily developed for North America, enhanced 911 (E911) allows for additional information to be presented to the public service answering point (PSAP) that enables emergency personnel to obtain details about the specific location of an emergency call. These additional attributes are a building number, mailstop, cubicle number, or any other specific attribute that can save precious seconds in an emergency situation. Because VoIP is mobile, simply relying on a telephone number is not suitable for IP communications. The new location information service (LIS) role in Lync Server enables network identifiers such as switch ports, subnets, and wireless BSSID information to be matched up with location information and transmitted to the PSAP when setting up a 911 call. In addition to regulatory compliance benefits, e911 allows for a safer telephony environment. With Lync Server’s E911 service, end users trust that calls made to a 911 service will provide the vital details to emergency personnel.

Location can be set through the policy or manually. Visual indication of the current location is presented directly in the Lync Server client. E911 can also be configured to enable other onsite users to be automatically conferenced into an emergency call, enabling corporate first responders to be aware of 911 calls as they happen, which coordinates with police, fire, and other emergency services as they arrive.


Malicious Call Trace
When a Lync Server user receives a call that she deems is harassing or threatening, she can flag it in the call database. By alerting system administrators of this fact, they can quickly determine the source of the call and trace it back to its origin for evaluation by security personnel.


Caller ID Controls
Lync Server allows for a user’s caller ID to be modified dynamically based on the destination of the call—internal or external. This enables an enterprise to maintain full reverse name lookup to the corporate directory for internal calls, but provide a uniform departmental or location number to be presented when making external calls. This is used in certain situations such as outbound call centers, support desks, or any other situation where it is necessary to block caller ID digits to external parties. This can be set at a user level or by policy.


Anonymous Agents
Lync Server response group agents can be placed in anonymous groups. This feature enables help desk personnel to participate in a response group without providing a name and number to internal users. Prior to Lync Server, users calling a response group saw the agent they were connected to in their Communicator client and frequently then bypassed the response group on subsequent calls, defeating the purpose of the group by failing to leverage the available pool of agents. Lync Server response groups in anonymous mode are suitable for use in scenarios where the agent’s number needs to be kept private.


On-Net and Off-Net Voice Routing
For an enterprise to benefit from a large geographically dispersed voice network with many PSTN egress points, the capability to route calls through these points is crucial. However, when the points are located in different cities or countries, each point can require different dialing formats, prefixes, or other access codes. This can add tremendous complexity to a corporate dialing plan. Fortunately, Lync Server provides central alternative routes and number-formatting changes to manipulate the dialed number prior to routing to a PBX or the PSTN.


Media Gateway Certification
Beginning with OCS 2007, Microsoft developed the open interoperability program (OIP) for PBX and gateway vendors to enable enterprises to determine whether a particular piece of hardware or software version is certified to work with OCS. Beginning with Lync Server, audio quality and performance testing is included in OIP certification. This enables systems engineers to design a solution that will perform properly for all communication modalities.

Source of Information : Pearson-Microsoft Lync Server 2010 Unleashed

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Benefits for Lync Server Users

UC solution begins with the end-user experience. Lync Server’s newly designed Communicator client provides a concise, seamless, and logical view to enable users easy access to all communications modalities.


Contacts
Lync Server provides many new, yet familiar, ways to interact, learn about, and communicate with colleagues. The clear view of many data streams enables the user to choose the proper modality to communicate with another user. Users can save time when locating resources because they can search for others using keywords as well as names. Even with incomplete information, users can locate and communicate with others.

Lync Server also leverages the concept of social networks. Live contact cards, photos, and spoken names enable users to recognize and discover more about the people in their social network that matter to them most.

Users can save time and be more granular when searching, thanks to SharePoint skill search with address book service web queries (ABS-WQ). By simply placing a mouse over a contact, the hover card provides a consistent view of vital user data across all Office products, including Lync Server, enabling users to be more productive and save time by not switching applications as often.

Users that are part of a large enterprise might be overwhelmed by team-level or corporate wide changes by having users’ photos and their spoken name populating the OCS contact list. In this way, users can become familiar with their evolving social network. Users can become better corporate citizens by learning how a new colleague’s name is pronounced prior to meeting or speaking with him or her. You can now quickly see updates from all your contacts in a single concise view, called the Activity Feed.

Contact management is simpler thanks to the unified contact store. Lync Server now utilizes Exchange 2010 for its contact list, so users save time by not having to manage contacts in both Lync Server and Exchange. When the Outlook Social connector is deployed, users can search across their entire social network, such as Facebook from within Communicator.

Users now have easy access to the history of their communication with a particular contact, enabling them to easily determine the context of a conversation and eliminate the need to catch up on a conversation, for example, when usually just a simple IM can answer a question. Similarly, when starting new conversations, a user can easily provide context to a session to further streamline communications.


Managing Communications
Although there are many ways to initiate a call to a contact, users that are transitioning to Lync Server from traditional PBXs will benefit from having an easily accessible dialpad. In the previous version of OCS, the dialpad existed but was not easy to find.

Lync Server users migrating from simple instant messaging and presence on previous versions of OCS to Enterprise Voice on Lync Server will benefit from being able to conduct communications using any modality from a familiar, consistent interface.

When coupled with exchange unified messaging, users can now have a simple-to-view visual representation of each voicemail message. Lync Server users save time by easily managing voicemails within Communicator.


Panoramic Mode
Lync Server clients can leverage the panoramic video of roundtable devices, allowing for a more comfortable face-to-face video experience. This emulates a telepresence environment that integrates well with commodity desktop hardware.


Activity Feed
Users of common current social networks (Twitter, LinkedIn, Facebook, and so on) will immediately recognize and be comfortable with the new activity feed in the Lync Server Communicator client. With a simple glance, you can receive updates (notes) and pictures from those in your social network.


Privacy and Presence Enhancements
Executive users benefit most from the new privacy enhancements in Lync Server. By adding enhanced privacy to a pool, users added to a contact list appear as offline until granted permission by the added contact to see their presence updates. This is valuable, for example, to create ethical walls between departments or divisions. Even if this setting is applied to a pool, users can opt out, enabling all others to see their presence.


Audio and Video to MSN PIC Contacts
Although public instant messaging communication (PIC) has always been a benefit of OCS, Lync Server takes the PIC story a bit further by enabling one-to-one audio and video exclusively to PIC contacts that are homed to the MSN service. This change enables corporate users with a strong MSN presence outside of work to reduce the need to run a separate client on their corporate workstation, yet maintain a robust communications experience.

Source of Information : Pearson-Microsoft Lync Server 2010 Unleashed

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Brief History of UC

Before Voice over IP (VoIP), voice calls were sent over a dedicated network. Each call passed through a dedicated circuit and was switched from one point to the other, hence the term circuit-switched. Although this guaranteed a quality connection, it required dedicated processing power and physical connectivity. For example, the wire that went from your home telephone to the central office (CO) connected you to a physical port on the CO telephone switch. The processor of the CO switch had to constantly monitor each port to determine whether a particular phone (port) made a request to dial a number or access a feature, such as call forwarding.

With a telephone connected to a dedicated network, either the public switched telephone network (PSTN) or an enterprise class private branch exchange (PBX) network, it was difficult for outside influences to affect the quality of a connected call. Although having this separate network held numerous advantages, most notably quality and reliability, individual PBX or CO switches used proprietary protocols limiting interoperability and feature expansion. It also meant, for example, that if you wanted to access your PBX voicemail box from your email client, you were subject to the whim of the PBX voicemail vendor’s decision as to what you could and couldn’t do and what standards were supported.


Using LANs and Packet-Switched Networks
As more and more communications began using LANs and packet-switched networks (the Internet is just a huge packet-switched network), the voice networks were forced to open up and connect to other networks. Unified messaging was probably the first mainstream attempt at UC. Accessing voicemail from your email client and unifying your inbox gave users the potential of true UC. In fact, some traditional phone vendors still consider unified voice messaging the equivalent to UC. Of course, anyone who has shared a desktop with a single click, made a call without dialing a phone number, or created a conference using only the mouse certainly knows that is not the case.

The capability to leverage a database of phone numbers to make calls using the phone was also an early attempt at UC. Anyone who attempted to deploy this type of integration, even as recently as a decade ago, knows that it’s not for the faint of heart and was generally implemented only in narrow cases, such as when a huge database of contacts were dialed by large calling centers. The average enterprise had neither the expertise nor the time and money to implement such a system.


VoIP Becomes Mainstream
When VoIP finally became mainstream, again, the promise of truly UC was presented to the enterprise community. In theory, now that the voice packets were riding the same network as the data packets, how difficult could it be to unify them? A lot harder than it looked.

Although VoIP brought the capability to easily perform day-to-day administrative tasks such as moves, adds, and changes, little was done to unify the communications. Users’ identities were still synched from, and stored outside of, the VoIP PBX, voicemail systems still use proprietary interfaces, and now the quality of the voice call was subject to influences outside of the PBX administrator’s hands. It seemed that, aside from adding complexity to the building of a communications system, VoIP didn’t add that much value overall.

As a new technology, most of the effort in deploying VoIP was put into the actual engineering and the proper deployment of the technology, not in the leveraging of the endless possibilities that existed. In addition, VoIP was initially positioned as a replacement end state for the traditional TDM infrastructure. Enterprises that saw cost savings over dedicated point-to-point (T1) links saw value in VoIP-compatible PBXs, but just replacing the line cord that went into the desktop phone with an Ethernet patch cord didn’t alter the user experience much.

Users still had to remember phone numbers, dial a multitude of phone numbers to reach someone, leave and retrieve voicemail messages using the handset, check multiple voicemail inboxes, and so on. Communications were unified simply because they were using a VoIP-based communications system.

To truly unify communications, begin with a central repository of user attributes at the core of your strategy. This repository should be easily updated, secure, and extensible so that as new features are created, the required attributes can be easily added. If an enterprise has deployed a Windows server infrastructure, it already has a repository in place: Active Directory.

Unlike other solutions, Microsoft’s UC architecture directly uses Active Directory and does not rely on a separate data feed for synchronization. Unlike previous versions, Lync Server now utilizes a Central Management Store (CMS) for all settings and configuration details. This store is replicated to all servers so that servers are now survivable.

Source of Information : Pearson-Microsoft Lync Server 2010 Unleashed

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Overview of Unified Communications

Since the first time a call was placed to a phone that did not answer, users of communications devices needed unified communications (UC). However, ask 1,000 IT professionals what UC means, and you’ll likely get close to that number of answers. This is due to that fact that unlike Voice over IP (VoIP), where there is a tangible description of what a technology is or does, UC is s bit more difficult to qualify. Is it collaboration? Is it the capability to see someone’s presence? Is it instant messaging? Is it all of these in a single client? The answer is yes... and no. Without realizing it, as we attempt to collaborate on a more granular and contextual level, we have been unifying our communications slowly and steadily for years.

The truth is that UC more closely defines how humans interact in person. For example, how did you communicate with someone who was having a conversation on a mobile phone? Without thinking about it, you updated his presence to busy in a call. If it wasn’t important, you would probably just wait. However, if you really needed to communicate with someone, you would most likely make eye contact, and, if he signaled to you that he could accept communication from you, you would either use a gesture or speak to him.

This is nearly the same way you communicate when using a UC solution. Utilizing tools such as instant messaging, presence, voice, video, and screen sharing, you are able to interact with others in near real-time, using a familiar interface to provide the same clues and info you get when you interact with someone face to face.


Software-Powered Communication
As computer-processing power has dramatically increased (compare even a low-end workstation of today to the high-end workstations of less than a decade ago), the communications industry has realized that software-powered communication servers allow for dramatic changes in the way both enterprises and consumers interact with one another.

No matter how you define UC, the desire to reduce the latency in user-to-user communication should be a primary goal of any UC strategy. For example, how many times have you been involved in an email thread that stretched out over days or weeks due to time zones or some other reason that could have been solved with a quick, real-time audio conference call?

Enabling users to communicate in the method that best suits their needs at any particular moment, while relaying their willingness and availability to communicate, goes a long way towards reducing the human latency inherent in attempts at collaboration and communications today.

Source of Information : Pearson-Microsoft Lync Server 2010 Unleashed

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Lync Server Integration with Other Microsoft Applications

One of the greatest strengths of a Microsoft product is that it is guaranteed to integrate with other Microsoft applications. Not only does it integrate in the sense that applications work with each other, Microsoft actually hooks the Lync Server technologies into other applications. This means that rich presence information can be shared with other applications and that one doesn’t necessarily have to switch to the Communicator client to interact with other users on the system. Not only do these integration points give other applications access to Lync Server, but in some cases, it also gives Lync Server access to information stored in other systems such as SharePoint or Exchange.

Integration with Exchange
Probably the coolest of the new integrations with Exchange is that Exchange 2010 Outlook Web App (OWA) now has Presence and IM integration built in. This provides useful features such as

. Presence for internal and federated Lync Server contacts

. The capability to start and maintain chat sessions directly from OWA

. Lync Server contact list integration, including adding and removing contacts and groups

. The capability to control the presence state from OWA

Lync Server also integrates into the meeting creation process, enabling you to create a voice and/or video conference at the time of the meeting creation. This gives users a onestop shop to service meeting needs. Lync Server also integrates with the Unified Messaging role in Exchange that enables Lync Server to use Exchange as the storage for voice mail messages.

Integration with SharePoint
Lync Server has taken an interesting approach to its integration with SharePoint. Like older versions of Communications Server, Lync Server displays Presence information anywhere a contact is shown in SharePoint and enables users to start an IM or audio conference with a click on the Presence icon.

What’s new is that Lync Server can read information from SharePoint to allow users totally new functionality. Probably the best example of this is the concept of a skills-based search. A Communicator user can search a company for “anyone who knows Exchange” as an example, and then Lync Server looks at data stored in SharePoint about users and identifies those who list that particular skill. It returns a list of users who do have that skill. This type of bidirectional integration opens up a whole world of possibilities for making it easier for users to connect with each other in a productive manner. Imagine being a new employee and having the option to ask Lync Server to show you a list of people in HR who deal with vacation requests and that are currently online and not busy. This is better than looking at a company intranet, searching for the HR pages, digging through documents to see who handles vacation requests, looking up the numbers, and then trying each of them until you finally get through to someone.


Integration with Office
Lync Server also integrates with some functions in Office 2010, including Backstage, a mechanism in Office 2010 that enables an unlimited number of people to concurrently edit a common document. Lync Server provides Presence information about other people working in the document, providing quick and easy IM collaboration between editors of the document.

Source of Information : Pearson-Microsoft Lync Server 2010 Unleashed

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Lync Server Related Acronyms

. Call Admission Control (CAC)—A method of preventing oversubscription of VoIP networks. Unlike QoS tools, CAC is call-aware and acts as a preventive congestion control by attempting to route calls across other media before making a determination to block a call rather than impacting the quality of existing calls.

. Call Detail Records (CDR)—A record produced by a phone system containing details of calls that have passed through it. They track information such as the number of the calling party, the number of the called party, the time of call initiation, the duration of the call, the route by which the call was routed, and any fault condition encountered. These records might be used for cross billing, for tracking of an employee’s usage of the system, or for monitoring system uptime and issues.

. Client Access License (CAL)—A software license that entitles a user to access specific systems or specific features in a system. Usually these come in two flavors: Standard and Enterprise.

. Common Intermediate Format (CIF)—A format used to standardize the vertical and horizontal resolutions in video signals, often in video conferencing systems.

. Communicator Web Access (CWA)—The browser-based Communicator client provided by Lync Server.

. Direct Inward Dialing (DID)—A service offered by telephone companies wherein one or more trunk links is provided to a customer for connection to the customer’s PBX. Incoming calls are routed to internal destination numbers at the PBX. This enables a company to have significantly more internal lines than it does external lines.

. Dual-tone multi-frequency (DTMF)—A method for providing telecommunication
signaling over analog telephones lines in the voice frequency band. DTMF is also
referred to as Touch Tone. This technology enables users to initiate events in the
phone system by simply pressing a button on a keypad.

. Extensible Markup Language (XML)—A set of rules for encoding documents in a
machine-readable format. The goal of XML is to be a simple and open standard for
representing arbitrary data structures, most often in web services.

. Extensible Messaging and Presence Protocol (XMPP)—An open, XML-based protocol designed to provide near real-time extensible IM and presence information. It has since expanded into VoIP and file transfer signaling.

. Hardware Load Balancing (HLB)—A method of distributing a workload across multiple computers to optimize resource utilization, increase throughput, and provide a level of redundancy through the use of an external hardware device.

. IM—A form of real-time, direct, text-based communication between multiple parties. IM is sometimes referred to as online chat.

. Interactive Voice Response (IVR)—A technology that enables a system to detect voice and dual-tone multifrequency inputs. IVR is often used in telecommunications for automated decision trees. This technology powers concepts such as “press 1 for English” when providing for call routing.

. Mean Opinion Score (MOS)—In multimedia, MOS provides a numerical indication of the perceived quality of a call after compression and/or transmissions. MOS is expressed as a single number ranging from 1 to 5 where 1 is the lowest perceived audio quality and 5 is the highest perceived audio quality.

. Network Address Translation (NAT)—A method of modifying network address information when packets pass through a traffic routing device. This effectively remaps a packet from one IP space to another. NAT is common in home usage where multiple computers with a private IP addressing site behind a router or firewall that holds a publically routable address. NAT maps a port back to the initiating internal host and reroutes responses back to the originating host.

. Network Load Balancing (NLB)—A method of distributing a workload across multiple computers to optimize resource utilization, increase throughput, and provide a level of redundancy through the use of software running in the operating system.

. Personal Identification Number (PIN)—A secret numeric password shared between a user and a system that is used to authenticate the user to the system.

. PSTN—The network of the world’s public circuit-switched telephone networks. The first company to provide PSTN services was Bell Telephone.

. Plain Old Telephone Service (POTS)—Another term for a PSTN.

. Private Branch Exchange (PBX)—A telephone system that serves a particular business or office as opposed to a common carrier or a system for the general public. This is what traditionally provides voice services to companies that are connected to the local exchange to provide external connectivity for telephone calls.

. Quality of Experience (QoE)—A subjective measure of a customer’s experiences with a vendor or service.

. Quality of Service (QoS)—A mechanism to control resource reservation in a system; typically, it is a method to prioritize various traffic types to ensure a minimum level of performance for a particular type of traffic.

. Real Time Protocol (RTP)—A standardized packet format for delivering audio and video over the Internet. RTP’s claim to fame is the capability to deal with large amounts of packet loss before the impact on the call becomes noticeable.

. Remote Call Control (RCC)—A method of utilizing a phone resource on one system with a resource on another. Typically, in the context of Lync Server, this is the capability to use a Communicator client to place a call through a desk phone that is controlled by a PBX rather than by Lync Server.

. SIP—An Internet Engineering Task Force (IETF) defined protocol used for controlling multimedia communications sessions. The goal of SIP is to provide a common signaling and call setup protocol for IP-based communications.

. SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE)—An open standard protocol suite that provides for the registration of presence information and the receipt of presence status notifications.

. Survivable Branch Appliance (SBA)—A combination of Registrar, Mediation Server, and PSTN gateway that is designed to maintain most voice services for a site that has lost connectivity to the main Lync Server site.

. Role Based Access Control (RBAC)—An approach to restricting system access to authorized users by granting the rights based on the role served by the user. This normally results in granular permissions with an eye toward granting the minimum level of rights needed to perform a task.

. Transmission Control Protocol (TCP)—Generally considered one of the core protocols of the Internet. TCP is a protocol that provides reliable ordered delivery of a stream of packets from one device to another. TCP has the reliability advantage of performing an acknowledgement of receipt of a packet back to the sender. This acknowledgement, however, comes at a performance price and ultimately limits the scalability of TCP.’

. Uniform Resource Identifier (URI)—A string of characters used to identify a name or a resource on the Internet. This allows interaction with representations of the resource over a network, often the Internet, using various protocols.

. User Datagram Protocol (UDP)—Another method of delivering a stream of packets from one device to another. UDP does not attempt to order or verify delivery of packets, nor does it need to first initiate a conversation with a destination host via a handshake. This behavior makes it faster and more scalable than TCP, but ultimately, it is less reliable.

. Virtual Private Network (VPN)—A method of passing packets across a public network in a secured and authenticated manner. VPNs enables users to access their private corporate networks through connections to the public Internet.

. Voice over IP (VoIP)—A generic term for transmission technologies that deliver voice communications over IP-based networks. Also referred to as IP Telephony or Internet Telephony.

Source of Information : Pearson-Microsoft Lync Server 2010 Unleashed

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Evaluating Different Disaster Scenarios

Before a backup and disaster recovery plan can be formulated, IT managers and administrators should meet with the business owners to discuss and decide on which types of failures or disasters should be planned for. This section of the chapter provides a high-level description of common disaster scenarios to consider. Of course, planning for every disaster scenario is nearly impossible or, more commonly, will exceed an organization’s backup and recovery budget, but discussing the likelihood of each scenario and evaluating how the scenario can impact the business is necessary.


Physical Disaster
A physical disaster is anything that can keep employees or customers from reaching their desired office or store location. Examples include natural disasters such as floods, fires, earthquakes, hurricanes, or tornadoes that can destroy an office. A physical disaster can also be a physical limitation, such as a damaged bridge or highway blockage caused by a car accident. When only physical access is limited or restricted, a remote access solution could reestablish connectivity between users and the corporate network.


Power Outage or Rolling Blackouts
Power outages can occur at any time unexpectedly. Some power outages are caused by bad weather and other natural disasters, but other times they can be caused by high power consumption that causes system overloads. When power systems are overloaded, rolling blackouts may occur. A rolling blackout is when a power company shuts off power to certain power subscribers or areas of service, so that it maintains power to critical services, such as fire departments, police departments, hospitals, and traffic lights. The rolling part of rolling blackouts is that the blackout is managed; after a predetermined amount of the time, the power company will shut down a different power grid and restore power to a previously shutdown grid. Of course, during power outages, many businesses are unable to function because the core of their work is conducted on computers or even telephone systems that require power to function.


Network Outage
Organizations that share data and applications between multiple offices and require access to the Internet as part of their daily business operations are susceptible to network outages that can cause severe loss of employee productivity and possibly revenue. Network outages can affect just a single computer, the entire office, or multiple offices depending on the cause of the outage. IT staff must take network outages into consideration when creating the backup and recovery plans.


Hardware Failures
Hardware failures seem to be the most common disaster encountered and coincidentally are the most common type of problem organizations plan for. Server hardware failures include failed motherboards, processors, memory, network interface cards, network cables, fiber cables, disk and HBA controllers, power supplies, and, of course, the hard disks in the local server or in a storage area network (SAN). Each of these failures can be dealt with differently, but to provide system- or server-level redundancy, key services should be deployed in a redundant cluster configuration, such as is provided with Windows Server 2008 R2, Enterprise Edition Failover Clustering, or Network Load Balancing (NLB).


Hard Drive Failure
Hard drives are indeed the most common type of computer- and network-related hardware failure organizations have to deal with. Windows Server 2008 R2 supports hot-swappable hard drives and two types of disks: basic disks, which provide backward compatibility, and dynamic disks, which allow software-level disk arrays to be configured without a separate hardware-based disk array controller. Also, both basic and dynamic disks, when used as data disks, can be moved to other servers easily to provide data or disk capacity elsewhere if a system hardware failure occurs and the data on these disks needs to be made available as soon as possible. Windows Server 2008 R2 also contains tools to provision, connect, and configure storage located on a SAN and can easily mount VHD files as operating system disks using Disk Manager or diskpart.


Software Corruption
Software corruption can occur at many different levels. Operating system files could be corrupted, antivirus software can interfere with the writing of a file or database causing
corruption, or a new application or driver installation could overwrite a critical file leaving a system unstable or in a failed state. Also, more commonly found in today’s networks, a security, application, or system update conflicts with an existing application or service causing undesirable issues.

Source of Information : Sams - Windows Server 2008 R2 Unleashed

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What Is Microsoft Lync Server?

Lync Server is the latest incarnation of a product line dating back to 2000. Microsoft has made a substantial commitment to providing a single integrated communications suite that enables users to communicate with each other more easily. Lync Server represents a fundamental shift in how telephony is handled. Lync Server attempts to remove telephony from dedicated systems such as Private Branch Exchanges (PBX) and places them in a software based infrastructure that can more easily adapt to changing needs and so they can be extended to provide new functionality as technologies change.

Picture a world in which users are no longer tied to a single device for their communication endpoint. They can choose to use a traditional style desk phone, a headset attached to a laptop, or a mobile device to place and receive calls. Not only do they have these choices, but these choices also don’t need to be static. Rather than being assigned a phone and a phone number, a user can log into any supported phone with his own identity and that phone becomes his phone. Calls to users are routed to this device or other devices that they have requested and ring at the same time. Rich presence information in the system enables a user to know whether another user is available even before picking up the phone to call the user.

Lync Server attempts to enable users to alter their forms of communications seamlessly as the situation demands without having to make drastic changes. For example, Andrew might have a question for Sean. Andrew looks at his Lync Server client and sees that Sean is listed as available. As such, Andrew sends Sean an Instant Message via Communications Server asking him whether he has a moment for a question. Sean replies, “Yes.” After a few messages, Sean determines that Andrew’s question is a little complicated to handle over IM and suggests they speak by phone. Andrew is able to convert the IM to a point-to-point voice chat with a single click. Now Andrew and Sean are able to speak directly. After a few minutes, Andrew determines that he still doesn’t quite understand what Sean is explaining and asks whether Sean could show him what he means. At this point, Andrew converts the call to a video conference with application sharing. Sean is able to draw out his explanation via his favorite application and explains it as he goes by simply talking.

In this scenario, everything can be accomplished by two people on beaches over laptops. Lync Server doesn’t require participants to reserve video conferencing resources ahead of time, to schedule conferences, or even to use specific hardware. Through these functions, Lync Server is able to make the world a much smaller place by enabling users to dynamically control their own communications and to be available almost anywhere at most any time.

Source of Information : Pearson-Microsoft Lync Server 2010 Unleashed

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Standardization in the Wireless World

The advent of next-generation mobile computing calls for open standards and platforms to enable interoperability. As has been discussed in this chapter, a full spectrum of wireless technologies is set to be integrated to allow roaming in on unprecedented levels. Proprietary technologies do not fit into this new era of convergence, as it would be difficult for them to gain ground to a great extent due to the limited number of vendors and compatible products. On the contrary, open, well-crafted standards for the technology will enable and encourage any interested business parties to engage in developing and manufacturing products or offering services that are guaranteed to be interchangeable or compatible. Open standards essentially provide a solid foundation of framework of a technology as well as design constraints, thereby boosting the spread and acceptance of the technology.

A standard is a specification or definition that has been approved by a recognized standards organization such as ITU, IEEE, and ETSI, or is generally accepted as a de facto model by the industry. In the context of computing, standards exist for computer hardware, communication protocols, programming languages, operating systems, and some applications. Network communications have a wide range of standards, such as IEEE 802.3 Ethernet standard for LANs, IEEE 802.11 and ETSI HIPERLAN for wireless LANs, GSM, and IS-95 and IS136.

In addition to communication standard bodies such as ITU, IEEE, and ETSI, some other standard bodies have been founded for specialized technological fields. The American
National Standards Institute (ANSI) is primarily responsible for software and programming language standardization; it has created ANSI C and C _ _ . HTML and XML have been adopted by the International Organization for Standardization (ISO) and the World Wide Web Consortium (W3C). The Internet Engineering Task Force (IETF) has released a number of requests for comments (RFCs) that serve as the basis of many network protocols. Many computer peripheral standards such as the PCMCIA, Universal Serial Bus (USB), and compact flash have been created by industrial forums or associations.


Cellular Standard Groups
The two standard bodies behind competing cellular technologies are the Third Generation
Partnership Project (3GPP) and Third Generation Partnership Project 2 (3GPP2). 3GPP is an international organization supporting the development of UMTS/WCDMA systems.
3GPP partners include ETSI of Europe, ATIS of the United States, ARIB and TTC of Japan, TTA of Korea, and CCSA of China. 3GPP has released two versions of UMTS standards, namely Release 99 and Release 2000. 3GPP2 is the parallel partnership project for cdma2000 technology. It consists of TIA of the United States, ARIB and TTC of Japan, TTA of Korea, and CCSA of China. ITU is a United Nations organization responsible for maintaining and extending worldwide coordination of different governments and private sectors and managing the radio-frequency spectrum. 3GPP and 3GPP2 are formed under ITU.


IEEE Standards
The Institute of Electrical and Electronic Engineers (IEEE) has been the key standards organization in promoting networking technologies for many years. For wireless technologies, IEEE has established several working groups, mainly under the 802 standard committee.

» IEEE 802.1: LAN/MAN architecture with emphasis on internet working and link security (inactive).
» IEEE 802.2: Logical link control, part of the data-link layer protocol of a LAN.
» IEEE 802.3: Ethernet, the dominating LAN technology.
» IEEE 802.4: Token bus, a LAN technology utilizing token rings over coaxial cables.
» IEEE 802.5: Token ring, another token ring LAN technology (inactive).
» IEEE 802.6: Metropolitan area networks, a specification of MANs using Distributed Queue Dual Bus (DQDB) (inactive).
» IEEE 802.7: Broadband TAG (Technical Advisory Group), a broadband LAN.
» IEEE 802.8: Fiberoptic TAG, a fiber-optic LAN standard (inactive).
» IEEE 802.9: Isochronous LAN, an Isochronous Ethernet (IsoEnet) (inactive).
» IEEE 802.10: Security, specifying key management, access control, and data integrity for LANs and WANs (inactive).
» IEEE 802.11: Wireless LAN, a set of protocols for wireless LANs operating on unlicensed 2.4-GHz and 5-GHz bands.
» IEEE 802.12: Demand priority, 100BaseVG-AnyLAN (inactive).
» IEEE 802.13: Not used (for some reason).
» IEEE 802.14: Cable data, a MAC layer specification for multimedia traffic over hybrid fiber and coaxial networks.
» IEEE 802.15: Wireless PAN, a set of protocols for short-range wireless networks, including Bluetooth (802.15.1).
» IEEE 802.16: Broadband wireless access, PHY and MAC layer protocols for PTM broadband wireless access; WiMax is based on 802.16.
» IEEE 802.17: Resilient packet ring (RPR), a protocol to improve resilience for packet data traffic over fiber rings.
» IEEE 802.20: Mobile Broadband Wireless Access, PHY and MAC layer protocols for mobile data access.


Standards War
Emerging innovational technologies usually imply huge business opportunities. Different groups of industry alliances always attempt to influence the standardization of these technologies in favor of their own business interests. This sometimes leads to serious conflicts within a standardization body which inevitably puts the technology in stalemate and affects the promotion of the underlying technology with respect to providing a unified, interoperable solution framework for interested parties. For instance, the IEEE standardization of UWB (802.15.3) has been deadlocked due to proposals from two rivalry groups: the MBOA Alliance (Intel and TI lead) and UWB Forum (Motorola leads). Each side claims its proposal is superior to the other. Seeing no immediate ratification of a standard, both groups are moving forward to advance their approaches in commercial developments, effectively creating a segmented UWB market. The evolution of cellular networks is another example of a standards war. The lack of a global standard of cellular networks has resulted in two dominating 2G GSM and CDMA systems and two ongoing 3G deployments: UMTS/WCDMA and cdma2000, backed up by two organizations, 3GPP and 3GPP2, respectively. If a united standard agreement cannot be reached by the different groups, it is very likely the market will make the final decision. The standards body will supposedly pick the approach that is the most popular in the marketplace. Interestingly and understandably, it is not always the technically superior approach or system that eventually wins the majority of the market. We have seen this happen with Betamax versus VHS, two competing videotape standards back in the 1990s. It would be interesting to see what will happen to those emerging wireless technology standards.

Source of Information : Elsevier Wireless Networking Complete 2010

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ZigBee

One of the emerging applications of WSN is wireless monitoring and control. ZigBee is such an application that uses low-power and low-data-rate networked sensors. It was developed by the ZigBee Alliance, an industry association of semiconductor companies and network equipment companies such as Ember, Honeywell, Mitsubishi Electric, Motorola, Samsung, and Philips. It has to be noted that the term ZigBee refers to the silent communication between honeybees where the bee dances in a zig-zag pattern to tell others the location, distance, and direction of some newly found food. WSN communication somewhat resembles the ZigBee principle in that they must be simple and effective.

The idea is to take advantage of wireless sensors to monitor environments, objects, and human beings and control devices, appliances, and facilities. Wireless sensors make it possible to remotely and conveniently monitor or be notified of operational states or crucial state change of an object, such as a dying battery in a smoke detector and rapidly increasing temperature in a truck carrying frozen goods. WSNs in ZigBee are not designed to carry large data transfer due to the limited capability of wireless communication; however, these sensors are able to form a fully functional network, self-organize for efficient data routing and in-network processing, and self-heal in the case of node failure. The initial target markets of ZigBee products are home control, building control, industrial automation, personal healthcare, consumer electronics, PC and peripherals control, etc. Key specs of ZigBee include the following:

» Frequency bands: 868 MHz, 915 MHz, and 2.4 GHz;
» Data transfer rate up to 250 Kbps;
» Signal transmission range of 10 to 100 m, depending on the sensors being used;
» AES encryption of data;
» Various ZigBee applications can work with each other;
» Low power usage.

Unlike UWB or Bluetooth, ZigBee specifications do not define radio interface and data-link layer protocols; ZigBee simply uses the IEEE 802.15.4 physical radio standard. The ZigBee network application support layer and application profile are the major components that make up the ZigBee specification. Because ZigBee is a proprietary protocol rather than an open standard like those ratified by IEEE, its fate hinges on how it refines itself to become the de facto industry standard. To this end, standardization battles seem inevitable.

Source of Information : Elsevier Wireless Networking Complete 2010

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Self-Organized Networks

The physical layer of a WSN is nothing new: radio-frequency transmission at unlicensed bands. LOS is not required. The data-link layer monitors the channels and transmits frames only when the channel is idle. The network layer and transport layer require more discussion. Like ad hoc networks, the routing paths between each two nodes cannot be determined and configured prior to deployment because there is no predefined fixed infrastructure in WSNs. Sensor nodes have to discover multihop routes to relevant nodes themselves. This is often done via routing data dissemination, in which packets that contain the transmitter and the distance to the root are flooded in the network. A sensor node, upon receiving such packets, will be able to find a “ parent ” who is closer to the root; hence, a distribution tree can be generated. Data collection from sensor nodes can be routed back to the root following the distribution tree.

Task or query dissemination throughout a sensor network is data-centric in association with data aggregation, a routing scheme known as directed diffusion. Sensor nodes are not addressed uniformly using numeric identifications; instead, the addressing and naming schemes are correlated with the application. They are identified by “ attribute – value ” pairs in their data. A task in the form of some attribute inquiry is sent out from some nodes in the hope of obtaining relevant data from other nodes, and then all participating nodes form a routing gradient toward the originators. In the case where a WSN is used as a platform of the sensory database, the applications and underlying routing schemes must support declarative queries, thereby making the detail of in-network query processing and optimization transparent to the user. Power consumption is another crucial factor when it comes to in-network aggregation support of query processing. Sophisticated power-aware query processing and packet routing schemes have been devised to reduce the overall power consumption of a WSN.

Sensory data delivery can be performed in several ways. Sensor node can actively report readings periodically to its parent or only report when an event occurs. The delivery procedure can also be initiated by a user issuing a command that is diffused across the network. Depending on the design objectives, a WSN may apply different data delivery models to different sensor nodes. For example, some high-level roots in the distribution tree may employ a request-and-response mechanism for queries, whereas some low-level sensor nodes may simply report data continuously.

Compared with mobile ad hoc network, network communication over WSNs imposes additional constraints other than node mobility and power consumption. Sensors node are more prone to failure, and their computational capability and memory capacity are greatly limited. When designing a protocol stack of a WSN, these constraints have to be taken into account. Specifically, because complete raw data forwarding is not necessary in many circumstances, data aggregation may be conducted at various levels of the distribution tree to reduce the amount of data being transferred upward to the gateway while still providing sufficient information to other nodes. Furthermore, data aggregation can be combined with applications of the WSN to further improve the efficiency of data collection and dissemination schemes. This reflects one of the most important characteristics of WSNs: cross-layer design. The well-known sensor operating system is TinyOS, which is an open-source, event-based embedded operating system developed at the University of California, Berkeley. TinyOS provides a set of components for networking, memory management, and power management, as well as data acquisition and query processing tools. The programming language supported by TinyOS is nesC, a C-like language for embedded network system development.

Source of Information : Elsevier Wireless Networking Complete 2010

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Wireless Sensor Node

A sensor node is made up of four basic components: sensing unit, processing unit, transceiver unit, and power unit. The sensing unit usually consists of two components: a sensor and an analog-to-digital converter (ADC). The processing unit acts as a tiny computer: a microprocessor and some RAM. The processing unit runs an embedded operating system and executes WSN applications that control the operations of the sensor and communication between sensor nodes. The transceiver unit is a low-power radio operating on an unlicensed frequency band. The power unit is a battery for regular sensor nodes. Note that in most cases a WSN will have a special sensor node that acts as the gateway for other sensor nodes with respect to ultimate data delivery. The gateway node interfaces to computers via RS232 or Ethernet links. As a result, the gateway node is different from other regular nodes, in both size and processing functionality, thus requiring more power supply.

Following is a list of sensor node characteristics that affect the design of WSN system architectures and applications:

» Size: Sensor nodes are very small, due to advancements in semiconductor technologies.

» Low power: Sensor nodes are expected to operate for a long time before the battery drains out. In many cases, it is prohibitive to replace batteries.

» Autonomous, unattended operations: Once deployed, sensor nodes should selforganize to work as programmed. Remote reprogramming is sometimes possible.

» Inexpensive: Their low cost makes it possible to deploy a large number of sensor notes at a moderate cost.

» Adaptive to environments and themselves: Sensor nodes are able to adapt to environmental and status changes.

Source of Information : Elsevier Wireless Networking Complete 2010

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WSN Applications

The wide range of sensors and collective instrumental functionality of WSNs, coupled with the underlying wireless networks, make it possible to provide unprecedented levels of data access and associated intelligence, bringing about a new dimension of application for different industry sectors. WSN applications can be divided into three categories: monitoring space, including objects as part of the space; monitoring operation states of objects; and monitoring interactions between objects and space. The first category represents the most common and basic use of WSNs (dealing with physical environments), whereas the second is mainly concerned with a specific entity rather than its surroundings. The third category encompasses more sophisticated monitoring and control over communications and interactions between objects and between an object and its surroundings. Some pilot projects have explored WSNs for a number of different application scenarios. Many potential applications are being developed to leverage WSNs. Some examples are introduced as follows.


Environmental Sensing
Using a large number of sensor nodes deployed in a target geographic location, it is possible to derive useful patterns and trends based on datasets collected over time. Examples of environmental sensing are light sensing, microclimate monitoring, traffic monitoring, pollution level monitoring, indoor climate control, and habitat monitoring. Very often users are only concerned with independent characteristics of an entity, such as the number of vehicles passing by during a time period or the propagation speed of some contaminant in a river.


Object Sensing
Aside from environmental sensing, sensors can be attached to objects and collect data regarding motion, pressure, or any mechanical, electronic, or biological characteristics of the host. Object sensing is predominantly used in industrial control and maintenance. Examples include structural monitoring of buildings, bridges, vehicles, and airplanes; sensing machinery wear in a factory; industrial asset tracking in warehouses and stores; surveillance in parking lot and streets; crop monitoring; and military-related object sensing in battlefields. In particular, RFID, a scaled-down wireless sensing technology, utilizes small tags of very limited local computing power and storage to identify and inventory objects. Section 13 has presented a detailed introduction to RFID.


Sensing with Intelligence
More challenging application scenarios require embedded intelligence that goes beyond raw data sensing, thus requiring the simultaneous sensing of multiple related quantities and in-network processing so as to detect internal interactions between objects. Examples of this category are monitoring wildlife habitats, telemedicine sensing, context-aware pervasive computing using sensors, and disaster management. For instance, researchers at the University of California, Berkeley, and Intel have developed a successful experimental WSN to monitor petrels on an uninhabited island off the coast of Maine. The birds being observed are Leach’s store petrels, a type of tiny reclusive seabird that burrows in sandy soil and emerges only at night. To ornithologists, monitoring and understanding the comings and goings of these birds in a wild area are not simple tasks, as they would have to dig into the birds ’ burrows for more information. The WSN deployed on the island consists of 190 wireless sensor nodes called motes , some of which are located in burrows and others on the ground, and a solar-powered central computer station that collects sensory data from a gateway mote and reports back to a remote site in real-time via satellite links. Sensors on the motes monitor temperature, humidity, barometric pressure, and ambient light. The temperature reading within a burrow can be used to infer if a petrel is present or not. Other data also contribute to our understanding of the behavior of these petrels and their responses to changes in their surroundings.

Source of Information : Elsevier Wireless Networking Complete 2010

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Wireless Sensor Networks

Data communication continues to expand in both scope and complexity, from internal communication among the hardware components of an individual computer to intercomputer network communication via wired or wireless BANs, PANs, LANs, MANs, and WANs. At the same time, computers are becoming more closely related to the physical world and human beings, gathering, monitoring, processing, and analyzing data to allow instrumentation and automation and to facilitate decision-making. Wireless sensor networks (WSNs) represent networks that are embedded into our physical environments. A sensor is a tiny electronic device that can respond to a physical stimulus and convert it into numeric data. A WSN is composed of many low-power, low-cost, autonomous sensor nodes interconnected with wireless communication of sensory data. A myriad of measurements can be done by sensors, including environmental properties such as temperatures, humidity, and air pressure; presence, vibration, and motion detection of objects; chemical properties; radiation levels; GPS; light; and acoustic and seismic activities. Data gathering is conducted intermittently at a specified frequency. A sensor node in a WSN possesses sufficient computing power to process sensory data gathered locally or transmitted from other sensor nodes via wireless links. Furthermore, sensor nodes in a WSN self-organize into a network topology, thereby improving robustness and reducing maintenance costs.

Source of Information : Elsevier Wireless Networking Complete 2010

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Satellite

Global wireless communication comprises two elements: terrestrial communication and satellite communication. Cellular networks are primarily terrestrial-based, consisting of a vast number of base stations across heavily populated areas. In some circumstances, such as research laboratories established in the Antarctic, satellite communication is the only means of communication. Some other applications of satellite communication include military satellite espionage, global television broadcast, satellite radio, meteorological satellite imaging, and GPS. In addition, satellites complement cellular networks in reaching far rural areas and have been integrated into worldwide GSM and CDMA systems.


Satellite Communication
Despite the advantage of providing global coverage, satellite communication is known to have significant drawbacks. For one thing, satellite links introduce greater propagation latency than fiber-optic links due to the much longer distance a signal must travel back and forth between a terminal and a satellite. A delay of even half a second when using a geostationary satellite phone is noticeable. Bandwidth is another downside of satellite communication compared to terrestrial wired or wireless communications. Although a single satellite may cover a large geographical area (known as the “ footprint ” ), the cost of the entire system remains extremely high, making its acceptability by the general public economically impossible.


Satellite Systems
Satellites orbit the Earth at different heights in various periods. The higher the satellite, the longer the period of the satellite will be. The orbits can be circles or eclipses. Earlier satellites were composed of transponders that received signals on one frequency and transmitted them on another. Digital technologies were introduced later to allow improved quality of the signals and more reliable communication. Signals transmitted from a satellite to the Earth attenuate proportional to the square of the distance. A variety of atmospheric conditions also influence satellite signal transmission, such as rain absorption and meteors in the space.

Communication satellites can be divided into four categories based on the orbit of the satellite in space: geostationary (GEO) satellite, medium Earth orbit (MEO) satellite, and low Earth orbit (LEO) satellite.

GEO satellites remain relatively stationary at a height of about 36,000 km. Three of them are required to cover the entire surface of the Earth. The frequency bands allocated for GEO satellite communication by the ITU are L band (1.5-GHz downlink, 1.6-GHz uplink, 15-MHz bandwidth), S band (1.9-GHz downlink, 2.2-GHz uplink, 70-MHz bandwidth), C band (4.0-GHz downlink, 6.0-GHz uplink, 500-MHz bandwidth), Ku band (11-GHz downlink, 14-GHz uplink, 500-MHz bandwidth), and Ka band (20-GHz downlink, 30-GHz uplink, 3500-MHz bandwidth). GEO satellite systems are primarily used for television broadcasting, such as Direct TV and Dish Networks, and mobile communications. The newest member of this family is satellite digital radio, which provides CD-quality music over more than 1000 channels.

MEO satellites orbit the Earth at heights of around 10,000 to 20,000 km. GPS systems use MEO satellites to provide precise location identifi cation with a range of several meters. 24 GPS satellites operated by U.S. Department of Defense orbit the Earth twice a day at a height of about 19,320 km. The civilian use of GPS operates at 1575.42 MHz, part of the L band. A GPS receiver must communicate with at least three GPS satellites in order to compute a specific two-dimensional location via triangulation. With four or more signals from GPS satellites, the receiver is able to calculate a three-dimensional location.

LEO satellites are much closer to the surface of the Earth than MEO and GEO satellites.
Their period can be as short as 1 or 2 h. Because of the considerably shorter distance between LEO satellites and receivers, propagation latency is reduced down to about 10 msec; however, to offer global coverage, many more satellites are needed. For example, the Iridium system was originally designed to have 77 satellites in space (element 77 is iridium). The Teledesic project planed to launch 840 LEO satellites. These numbers had to be scaled back in order to keep costs under control. Aimed at reducing the cost of satellites, another system, Globalstar, has 48 satellites and a large number of ground base stations. (It must be noted that Iridium went bankrupt in 1999 as a result of a small user base and high operational cost.) The data rate offered by LEO satellite systems varies from kilobits per second to megabits per second, depending on the target applications.

Source of Information : Elsevier Wireless Networking Complete 2010

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WiMax

The WiMax Forum harmonizes IEEE 802.16 and ETSI HIPERMAN into a WiMax standard. The core components of a WiMax system include the subscriber station (SS), also known as the customer premise environment (CPE), and the base station (BS). A BS and one or more CPEs can form a cell with a point-to-multipoint (PTM) structure, in which the BS acts as central control over participating CPEs. The WiMax standard specifies the use of licensed and unlicensed bands within the 2- to 11-GHz range, allowing non-LOS (NLOS) transmission, which is highly desired for wireless service deployment, as NLOS does not require high antennas in order to reach remote receivers, which reduces site interference and the deployment cost of CPE. NLOS raises multipath transmission issues such as signal distortion and interference. WiMax employs a set of technologies to address these issues:

» OFDM : As discussed earlier in this chapter, OFDM uses multiple orthogonal narrowband carriers to transmit symbols in parallel, effectively reducing ISI and frequency-selective fading.

» Subchannelization : The subchannelization of WiMax uses fewer OFDM carriers in the upstream link of a terminal, but each carrier operates at the same level of the base station. Subchannelization extends the reach of upstream signals from a terminal and reduces its power consumption.

» Directional antennas : Directional antennas are advantageous in fi xed wireless systems because they are more powerful in picking up signals than are omnidirectional antennas; hence, a fixed CPE typically uses a directional antenna, while a fixed BS may use directional or omni directional antennas.

» Transmit and receive diversity : WiMax may optionally employ a transmit and receive
diversity algorithm to make use of multipath and refl ection using MIMO radio systems.

» Adaptive modulation : Adaptive modulation allows the transmitter to adjust modulation schemes based on the SNR of the radio links. For example, if the SNR is 20 dB, 64 QAM will be used to achieve high capacity. If the SNR is 16 dB, 16 QAM will be used, and so on. Other NLOS schemes of WiMax, such as directional antenna and error correction, are also used.

» Error-correction techniques : WiMax specifi es the use of several error-correction codes and algorithms to recover frames lost due to frequency-selective fading or burst errors. These codes and algorithms are Reed Solomon FEC, convolutional encoding, interleaving algorithms, and Automatic Repeat Request (ARQ) for frame retransmission.

» Power control : In a WiMax system, a BS is able to control power consumption of CPEs by sending power-control codes to them. The power-control algorithms improve overall performance and minimize power consumption.

» Security : Authentication between a BS and an SS is based on the use of X.509 digital certificates with RSA public key authentication. Traffi c is encrypted using Counter Mode with Cipher Block Chaining Message Authentication Code Protocol (CCMP) which uses Advanced Encryption Standard (AES) for transmission security and data integrity authentication. WiMax also supports Triple Data Encryption Standard (3DES).

Initially, the WiMax Forum has focused on fi xed wireless access for home and business users using outdoor antennas (CPEs), and indoor fi xed access is under development. A base station may serve about 500 subscribers. WiMax vendors have begun to test fi xed wireless broadband access in metropolitan areas such as Seattle. Due to its relatively high cost, the major targets of this technology are business users who want an alternative to T1, rather than residential home users. A second goal of the forum is to address portable wireless access without mobility support, and another is to achieve mobile access with seamless mobility support (802.16e). Recall that a Wi-Fi hotspot offers wireless LAN access within a limited coverage of an AP; the WiMax Forum plans to build MetroZones that allow portable broadband wireless access. A MetroZone comprises base stations connected to each other via LOS wireless links, and 802.16 interfaces for laptop computers or PDAs that connect to the 「 best 」 base station for portable data access. This aspect of WiMax seems more compelling in terms of potential data rate compared with 3G cellular systems.

Like the Wi-Fi forum, the WiMax forum aims at providing certifi cation of WiMax products in order to guarantee interoperability. In March 2005, Alvarion, Airspan, and Redline began to conduct the industry's fi rst WiMAX interoperability test. WiMax chips for fixed CPEs and base stations developed by Intel will be released in the second half of 2005, and WiMax chips for mobile devices will be released in 2007. At the time of this writing, some WiMax systems were expected to go into trial operation in late 2005.

Source of Information : Elsevier Wireless Networking Complete 2010

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Wireless Broadband: IEEE 802.16

The most noticeable technological development in wireless MANs and wireless WANs are embodied by the IEEE 802.16, 802.20, and ETSI HIPERMAN standards. Based on the open IEEE 802.16 and HIPERMAN, a commercialized technology called WiMax has been devised. The WiMax Forum, an industry consortium of over 100 companies, has been formed to promote the technology and provide certified, interoperable WiMax products. IEEE 802.16 specifies the PHY and MAC layers. It will support higher network layers and transport layer protocols such as ATM, Ethernet, and IP.

It is noteworthy that the frequency band of 10 to 66 GHz specified by the initial 802.16 standard requires LOS transmission. Some other frequency bands are also specified in later versions of the standard in order to provide indoor wireless access. The MAC layer portion of 802.16 addresses QoS by introducing a bandwidth request and grant scheme. Terminals can be polled or actively signal the required bandwidth, which is based on traffic QoS parameters. 802.16 employs a public-key infrastructure in conjunction with a digital certificate for authentication.

Extensions of IEEE 802.16 include:

• 802.16a, which specifies a data rate up to 280 Kbps per base station over the 2- to 11-GHz frequency band reaching a maximum of 50 km and mesh deployment.

• 802.16b, which addresses QoS issues surrounding real-time multimedia traffic.

• 802.16c, which defines system profiles that operate at 10 – 66 GHz for interoperability.

• 802.16d, which represents system profile for 802.16a devices.

• 802.16e, which standardizes handoff across base stations for mobile data access.

The ETSI HIPERMAN standard is similar to 802.16a. It has been developed in very close cooperation with IEEE 802.16, such that the HIPERMAN standard and IEEE 802.16a standard can work together seamlessly. As a result, many of the characteristics of 802.16 are available in HIPERMAN, such as QoS support, adaptive modulation, and strong security. HIPERMAN supports both PTM and mesh network configurations. The differences between HIPERMAN and 802.16 are primarily on the PHY layer. In order to create a single interoperable standard for commercialization, as well as product testing and certification, several leaders in the wireless industry formed the WiMax Forum. Another IEEE working group, called IEEE 802.20 Mobile Broadband Wireless Access (MBWA), uses the 500-MHz to 3.5-GHz frequency band for mobile data access, an application also targeted by 802.16e; however, 802.20 does not have as strong industry support as 802.16 does.

Source of Information : Elsevier Wireless Networking Complete 2010

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Wireless Metropolitan Area Networks

Wireless MANs refer to a set of wireless data networks that provide wireless data access in a metropolitan area. The principal advantage of building wireless MANs for data access as opposed to establishing a wired network infrastructure is the cost of copper-wire or fiber optic cable, installation, and maintenance. In rural areas and developing countries where telephone lines and cable televisions are not in place, a wireless data access solution is more cost effective than a wired network solution. Depending on how wireless technologies are used in the infrastructure, wireless MANs can be categorized into the following types:

• Wireless “ last mile ” (fixed broadband wireless access),
• Wireless data access for mobile terminals,
• Wireless backbones or wireless mesh.

The first type is still based on a wired network infrastructure; that is, base stations connect directly to a backend wired network. PTM wireless communication replaces wired network communication between a base station and the end-user’s computer, the so-called “ last mile. ” Telephone-line-based last-mile access allows dial-up data access and ADSL (with necessary modems), whereas cable-television-based last-mile access permits higher bandwidths and an always-on connection. Dedicated T1 is commonly used by businesses. For the general public, these Internet service providers coined the terms “ broadband Internet ” or “ high-speed Internet access ” in order to differentiate high-speed data access services such as ADSL and cable television from traditional dial-up service. In fact, one of the driving forces behind the wireless last-mile technology is that the broadband Internet access of ADSL and cable has grown rapidly in recent years.

The second type of wireless MANs targets mobile data access. In a sense, 2.5G and 3G cellular networks could be considered wireless MANs or wireless WANs as they have provided wide-area mobile data access for cell phone users. On the other hand, it would be natural to speculate on extending wireless LANs to cover a larger area and to allow roaming across areas covered by these base stations. Still, this type of wireless MAN relies on a wired network infrastructure to function, as the base stations connect directly to a wired network. Many proprietary wireless MANs have been in operation for years. They mainly target a very narrow business market such as mobile professionals, rather than the general public.

The third type of MAN is a pure wireless network, in which backbones as well as the means of access are both wireless. Base stations are not connected to a backend wired network; instead, they coordinate with adjacent base stations, forming a mesh for data forwarding over a wide area. This is a significant development with regard to providing data access services to underdeveloped areas where no fixed networks exist.

Source of Information : Elsevier Wireless Networking Complete 2010

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Creating an NLB Cluster

Before an NLB cluster can be created, a few bits of information are required. The NLB cluster is actually clustering based on a defined IP address, the DNS name, and the TCP/IP ports that will be used. Each NLB cluster node can also be configured with multiple network cards. Each card can be associated with a different NLB cluster and a single card can support multiple clusters, but each cluster must have a different DNS name and IP address(es). One configuration that cannot be performed is creating a single NLB cluster that uses multiple network adapters in a single node. To designate multiple adapters for a single NLB cluster, third-party network teaming software must be loaded prior to configuring the NLB cluster; the cluster will use the Virtual Team Network adapter and the teamed physical adapters should not be configured with NLB. For this example, a new NLB cluster will be created for the name www.companyabc.com using the IP address of 192.168.206.50. To create an NLB cluster, perform the following steps:

1. Log on to a Windows Server 2008 R2 system with an account that has local administrator rights and that has the NLB feature already installed.

2. Click Start, click All Programs, click Administrative Tools, and select Network Load Balancing Manager.

3. When the Network Load Balancing Manager console opens, click the Cluster menu, and select New to create a new cluster.

4. When the New Cluster window opens, type in the name of the first server that will be added to the new NLB cluster, and click Connect. If the server is a remote system and cannot be contacted, ensure that the Inbound Remote Administration exception has been enabled in the remote system’s firewall.

5. When the server is contacted, each of the network adapters will be listed, select the adapter that will be used for the NLB cluster, as shown in Figure 29.16, and click Next.

6. On the Host Parameters page, accept the defaults of giving this first server the Host ID of 1 and select the dedicated IP address that will be used when communication is received for the NLB cluster IP address, which will be specified next. Click Next to continue.

7. On the Cluster IP Addresses page, click the Add button to specify an IPv4 address and subnet mask or an IPv6 address to use for the NLB cluster, and click OK. For our example, we will use the IPv4 configuration of 192.168.206.50/255.255.255.0.

8. Back on the Cluster IP Addresses page, add additional cluster IP addresses as required, and click Next to continue.

9. On the Clusters Parameters page, enter the fully qualified DNS name that is associated with the IP address specified on the previous page, and select whether it will be used for Unicast traffic, Multicast traffic, or IGMP Multicast. This choice depends on the network communication of the service or application that will be used in this NLB cluster. For this example, we are creating an NLB cluster for standard web traffic, so we will use www.companyabc.com as the Internet name and select Unicast as the cluster operation mode.

10. If multiple IP addresses were defined on the previous page, the IP address can be chosen from the IP address drop-down list, and the Internet name and cluster operation mode can be defined for each additional address. When all the IP addresses have had their properties defined, click Next to continue.

11. On the Port Rules page, a default rule is precreated that allows all traffic on all ports to be load-balanced across the NLB cluster between the cluster IP address and the dedicated IP address of the local server’s dedicated IP address. Select this rule and click the Remove button to delete it.

12. Click the Add button to create a new port rule.

13. When the Add/Edit Port Rule window opens, type in the starting and ending port range, for example 80 and 80 for a single HTTP port rule, but do not close the window.

14. Under protocols, select the TCP option button, but do not close the window.

15. In the Filtering Mode section, select Multiple Host, and select Single Affinity, but do not close the window.

16. Finally, review the settings, and click OK to create the port rule.

17. Back on the Port Rules page, click the Add button to create an additional port rule.

18. Specify the starting port as 0 and the ending port as 79, select Both for the protocol’s configuration, select the Disable This Port Range Filtering mode, and click OK to create the rule.

19. Back in the Port Rules page, click the Add button to create one more port rule.

20. Specify the starting port as 81 and the ending port as 65535, select Both for the protocol’s configuration, select the Disable This Port Range Filtering mode, and click OK to create the rule.

21. Back on the Port Rules page, review the list of port rules and if the rules look correct, click Finish.

22. Back in the Network Load Balancing Manager window, the cluster will be created and brought online. The cluster IP addresses are automatically added to the TCP properties of the designated network adapter. Close the NLB Manager and log off of the server.

Source of Information : Sams - Windows Server 2008 R2 Unleashed (2010)

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