Topic Last Modified: 2010-07-18
This topology is for a small to medium organization with one central site. The exact topology in this diagram is for an organization of 15,000 users. Typically, the type of topology shown in this diagram would be recommended for organizations with 5,000 to 30,000 users, but it can support many more users than that.
|All capacity and performance numbers in this section pertain only to the Microsoft Communications Server 2010 (Beta Refresh) release, and are subject to change in future releases.|
- Active Directory Deployment—All Communications Server
deployments reside in a single Active Directory forest. For this
topology, the customer has Communications Server deployed in the
child domain, retail.contoso.com.
- To Accommodate More Users, Add More Front End
Servers—The exact topology in this diagram has two Front End
Servers, so it supports up to 16,000 users. If you have a single
central site and more users, you can simply add Front End Servers
to the pool. One Front End pool can have as many as 10 servers, so
a single Front End pool at a single site can support up to 80,000
However, the single site topology can support even more users by adding another Front End pool to the site. To support these extra users only another Front End pool needs to be added; just one pool each of A/V Conferencing Servers, Edge Servers, and Directors are still sufficient, although more servers may need to be added to these pools.
- A/V Conferencing Can Be Collocated in Smaller
Organizations—If this organization has 10,000 or fewer users,
you could decide to collocate A/V Conferencing Services with the
Front End Pool, instead of deploying a separate A/V Conferencing
Pool. Collocating these services is not recommended for
organizations with 10,000 or more users, for performance
- Monitoring Server Database Server Options—In this
topology, the Monitoring Server pool is using the same pair of
database servers that the Front End pool uses. A topology in which
the Monitoring Server pool has its own database servers is also
supported. In each case, we recommend more than one database server
in each pool, for high availability.
- High Availability for All Server Pools—In this example
organization with 15,000 users, just one Director server, Edge
Server and A/V Conferencing server would be sufficient for
performance. However, there are pools of two servers of each type
deployed to provide high availability for each feature.
- Branch Office Deployment Options—The organization in
this topology has Enterprise Voice deployed as their voice
solution. Branch Site 1 does not have a resilient WAN link to the
central site, so it has a Survivable Branch Appliance deployed to
provide telephone service in case the WAN link to the central site
goes down. Branch Site 2 however has a resilient WAN link, so only
a PSTN gateway is needed. The PSTN gateway deployed there supports
media bypass, so no Mediation Server is needed at Branch Site B.
For details about deciding what to install at a branch site, see
Branch-Site Voice Resiliency.
- DNS Load Balancing—The Front End pool, Edge Server pool,
and the Director pool have DNS load balancing for SIP traffic
deployed. This eliminates the need for hardware load balancers for
the internal interface of the Edge Servers, and significantly
lessens the setup and maintenance of the hardware load balancers
for the other pools, as the hardware load balancers are needed only
for HTTP traffic. For details about DNS load balancing, see
- Exchange UM Deployment—Each of the reference topologies
includes an Exchange UM Server, which runs Exchange, not
Communications Server. The Exchange UM routing functionality for
Communications Server runs on the Front End pool. For details about
Exchange UM, see Exchange Unified
- Edge Servers Recommended—Although deploying an Edge
Server is not required, it is recommended for any size of
deployment. You can maximize your Communications Server investment
by deploying an Edge Server to provide service to users currently
outside your organization’s firewalls. The benefits include the
- Your organization’s own users can use Communications Server
functionality, if they are working from home or are out on the
- Your users can invite outside users to participate in
- If you have a partner, vendor or customer organization that
also uses Communications Server, you can form a federated
relationship with that organization. Your Communications Server
deployment would then recognize users from that federated
organization, leading to better collaboration.
- Your users can exchange instant messages with users of public
instant messaging (IM) services, including any or all of the
following: Windows Live, AOL, and Yahoo!, as well as XMPP-based
providers and servers, such as Google Talk and Jabber. A separate
license might be required for public IM connectivity with Windows
Live, AOL, and Yahoo!
- Your organization’s own users can use Communications Server functionality, if they are working from home or are out on the road.