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

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

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

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

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

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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