1. Instant Messaging and Presence
Although instant messaging (IM) and Presence
are two different functions, together they form the most basic
functionality available in Lync. In fact, it is not possible to deploy
one without the other. IM describes the now-ubiquitous function of
engaging in a conversation with another user using simple text-based
messaging. In addition to enabling IM for users within an organization,
Lync Server supports public IM connectivity (PIC) with several of the
more popular IM providers, including AOL, Skype, and Google Talk. In
addition, Lync Server allows organizations to federate with other
organizations that are also using Lync, extending the IM capabilities
beyond corporate borders.
Federation effectively sets up a
connection between multiple implementations of Lync or Office
Communications Server, allowing both sides to selectively share
Presence information with one another, and use the core features of
Lync for communication. This is an especially useful feature for
business partners who are required to frequently and quickly contact
one another. Rather than the inherent delays involved in sending single
sentence or short emails to one another, federated partners can simply
exchange instant messages in real time.
Note
Although this might seem like a small
distinction in methods of communications, administrators who manage
email systems are quite satisfied to offload communications to
alternate methods such as IM. This is largely due to the realization
that a large percentage of the data stored in mail systems consists of
nonessential conversations along the lines of “Where do you want to
meet for lunch?”
Although on the surface it might seem minor,
being informed as to a user’s availability and willingness to
communicate can be useful for both parties. For example, often a user
won’t bother to call another individual if it is evident that the other
person is not likely to answer the call. At other times, a user might
choose to intentionally call someone who is listed as not available so
that the user can simply leave a quick message and avoid a lengthy
conversation. These examples are common uses of Presence and illustrate
the usefulness of this feature.
These are some of the more commonly used Presence states within Lync:
• Available
• Offline
• Away
• Busy
• Do Not Disturb
Lync can update a
user’s Presence status based on information available in other
applications. One of the most useful examples of this is the
client-side integration between Lync and Microsoft Outlook. If
Microsoft Outlook is installed on the same client workstation as the
Lync client, Lync will automatically update the user’s Presence status
based on information in the user’s Outlook calendar.
2. Peer-to-Peer Audio
Peer-to-peer audio is a core feature
of all Lync Server deployments, and is very simple to configure and
support, since it doesn’t involve integration with any other systems.
Much like IM, P2P audio involves a point-to-point conversation between
Lync endpoints; however, in this case the network communications
include audio codecs rather than simple text. This audio communication
requires more bandwidth than IM and is also much more sensitive to
network latency. However, P2P audio still generally requires relatively
little in the way of system resources. Because P2P audio communications
traverse the data network only, generally good quality can be expected
even across a wide area network (WAN) or the Internet.
3. Web, Audio, and Video Conferencing
Lync Server 2013 includes a comprehensive set
of conferencing capabilities as an important core feature of the
product. Web conferencing provides users with document collaboration
and application sharing, along with whiteboard, remote control, session
recording, and other useful collaboration tools. These features,
combined with audio and video conferencing, provide a powerful set of
features, all of which are made available via the Lync client software.
Meetings can be either scheduled or ad-hoc, and through automatic
integration with Microsoft Outlook they can be scheduled using a single
click. All the Lync conferencing capabilities can be leveraged
seamlessly in an on-demand fashion without interrupting a meeting and
without requiring separate software, resulting in a conferencing
experience that is extremely user-friendly.
Note
Web, audio, and video conferencing
features are available with all Lync deployments and do not require
additional components beyond the Lync Front End Server. However,
dial-in conferencing, which allows users to join a conference using a
PSTN phone, requires a PSTN gateway along with the Lync Mediation
Server role before it can be used.
4. Enterprise Voice
Enterprise Voice describes the set of
features that allow Lync Server to be leveraged as a complete telephony
solution for an organization. This includes connectivity to the PSTN,
as well as PBX and IP-PBX systems using media gateways and Session
Initiation Protocol (SIP) trunks. It also includes voice features that
are common to many voice platforms, such as call forwarding, hold,
transfer, call parking, enhanced 9-1-1, call admission control, branch
office survivability, distinctive ringing, and many more. Traditional
voice management functions are also included, such as dial plans, call authorization, and call detail records.
The Enterprise Voice features included with
Lync Server are on par with and in many cases exceed the functionality
provided by a traditional PBX system. For this very reason, Lync Server
can be considered a viable replacement for PBX systems, which can be
accomplished either through attrition or via a greenfield replacement.
Note
As was the case with previous versions of the
product, in Lync Server 2013 remote call control (RCC) will continue to
be supported as a coexistence option. RCC allows integration between
Lync and a PBX, such that RCC-enabled users can use the Lync interface
to control calls on their PBX phone. This can be a particularly
attractive option for organizations that want to evaluate Lync Server
while maintaining their existing telephony investment, or as an
effective method of gradually introducing Lync into the environment
while retiring an older voice platform.
For many organizations, an important benefit
of using a VoIP system such as Lync Server is the ability to bypass
long-distance toll charges through the use of call routing, which is
also referred to as toll bypass. For example, if a company has offices
in San Francisco and New York, and these two locations are connected
via a WAN link, calls between the sites can be routed internally via
Lync Server, which makes the call effectively free since the data
network is being utilized.
If, on the other hand, a user in San
Francisco needs to call an external user in New Jersey, there are two
ways this call can be routed. Either the VoIP call from San Francisco
can directly exit the local PSTN gateway to the long-distance provider,
or the call can first traverse the WAN to the New York office and then
exit the PSTN gateway at that location. This would likely result in a
cost savings, since the toll charges for a call to New Jersey are
likely lower from New York than from San Francisco. Through the use of
effective dial plans and call routing, a Lync Server administrator can
leverage toll bypass to ensure that the least expensive call path is
used for a given scenario. These rules are typically configured based
on area codes so that the number of required rules remains manageable.
5. Persistent Chat
Persistent Chat is a Lync feature that allows
users to create chat rooms that contain persistent conversations based
on specific topics and categories. In contrast, a Lync IM conversation
between three or more users is considered an IM conference, however
when all parties leave the conversation, the content of that
conversation cannot be retrieved or reviewed. With Persistent Chat,
conversations remain even after all users involved in a conversation
leave the chat room. The persistent nature of the messages allows Lync
users to view ongoing conversations at their leisure, and also search
for information within the chat rooms. Many organizations find that
ongoing persistent conversations provide a valuable and effective tool
for collaboration that can be leveraged by teams of users.
Note
Persistent Chat was available as a
server role with previous versions of the product, but was known as
Group Chat. With Lync Server 2013, this feature will likely find more
widespread adoption than ever before, primarily due to the
architectural changes that have been introduced with this version. For
example, it is now supported to collocate the Persistent Chat server
role with a Lync 2013 Standard Edition Front End server, and the
Persistent Chat databases can now be collocated on the same SQL server
with the rest of the Lync databases. Another significant improvement is
that the Persistent Chat features are now included in the base Lync
client, and therefore no additional client software is required to
leverage this feature.
6. Lync Server Terms and Acronyms
In the world of unified communications, there
are many terms and acronyms that are routinely used that might be
unfamiliar to those new to the Lync product line.
• 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. Ultimately, the result of a properly
implemented CAC configuration is that the quality of existing calls is
preserved, even when bandwidth is scarce.
• Call detail records (CDR)—A
record produced by a phone system containing details of calls that have
passed through it. Each record includes 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 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. A CAL is typically offered 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.
• Direct Inward Dialing (DID)—A
service offered by phone carriers wherein a block of telephone numbers
is provided to a customer for connection to the customer’s internal
phone system (including Lync Server or a traditional PBX). Incoming
calls to the DID block are routed to internal destination numbers,
which allows an organization to have significantly more internal lines
than 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, and it is most often used 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. XMPP has more recently 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.
• Instant messaging (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 as an
input for automated decision trees. For example, IVR technology is used
behind the scenes with voice menu prompts that are frequently heard,
such as “press 1 for English.”
• 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, with 1 being the
lowest perceived audio quality and 5 being the highest perceived audio
quality.
• Network Address Translation (NAT)—A
method of modifying network address information when packets pass
through a traffic routing device. NAT effectively remaps a packet from
one IP space to another, and is common in home usage when there are
multiple computers with a private IP addressing site behind a router or
firewall that holds a publicly 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 Windows operating
system.
• Plain Old Telephone Service (POTS)—Another term for PSTN.
• Public Switched Telephone Network (PSTN)—The
global network consisting of the world’s public circuit-switched
telephone systems. The first company to provide PSTN services was Bell
Telephone.
• 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. A PBX is what
traditionally provides voice services to companies that are connected
to a local exchange, and provides external connectivity to the PSTN for
users in that organization.
• 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.
• Realtime Transport Protocol (RTP)—A
standardized format for delivering audio and video over the Internet. A
noted advantage of RTP is its ability to handle 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 Lync client to place a call through a desk phone
that is controlled by a PBX rather than by Lync Server.
• 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 the goal of granting the minimum level of
rights needed to perform a task.
• Session Initiation Protocol (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
physical appliance that combines the Lync Registrar, Mediation Server,
and PSTN gateway services in one compact unit; it is designed to
maintain most voice services for a branch site that has lost
connectivity to the main Lync Server site.
• Transmission Control Protocol (TCP)—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 advantage of sending an acknowledgment of receipt
of a packet back to the sender, resulting in increased reliability.
This acknowledgment, however, comes at a performance price and can
therefore serve to limit 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
one of the core protocols of the Internet, UDP delivers a stream of
packets from one device to another, but does not attempt to order or
verify delivery of packets. UDP also does not 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 enable 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. VoIP is also referred to as IP Telephony or Internet Telephony.
