Topic Last Modified: 2010-07-18
The network adapter card of each server in the Microsoft Communications Server 2010 topology must support at least 1 gigabit per second (Gbps). In general, you should connect all server roles within the Communications Server 2010 topology using a low latency and high bandwidth local area network (LAN). The size of the LAN is dependent on the size of the topology:
- In Standard Edition topologies, servers should be in a network
that supports 1 Gbps Ethernet or equivalent.
- In Enterprise pool topologies, most servers should be in a
network that supports more than 1 Gbps, especially when supporting
audio/video conferencing and application sharing.
For PSTN integration, you can integrate by using either T1/E1 lines or SIP trunking.
Audio/Video Network Requirements
Key network requirements for audio/video in a Communications Server 2010 deployment include the following:
- The external firewall can be configured as a NAT (whether the
site has only a single Edge Server deployed or has multiple Edge
Servers deployed). For details about this requirement, see Determining Firewall and
50k Port Range Requirements.
- If your organization uses a Quality of Service (QoS)
infrastructure, the media subsystem is designed to work within this
- If you use IPsec, we recommend disabling IPsec over the port
ranges used for audio and video traffic. For details, see IPsec
To ensure optimal media quality, do the following:
- Provision your network links to support throughput of 45
kilobits per second (Kbps) per audio stream and 300 Kbps per video
stream, if enabled, during peak usage periods. A bidirectional
audio or video session consists of two streams.
- To cope with unexpected spikes in traffic above this level and
increased usage over time, Communications Server media endpoints
can adapt to varying network conditions and support loads of three
times the throughput (see previous paragraph) for audio and video
while still retaining acceptable quality. However, do not assume
that this adaptability will support an under-provisioned network,
because this will reduce the ability of the Communications Server
media endpoints to dynamically deal with varying network
conditions, such as temporary high packet loss.
- For network links where provisioning is extremely costly and
difficult, you may be forced to consider provisioning for a lower
volume of traffic and let the elasticity of the Communications
Server media endpoints absorb the difference between that traffic
volume and the peak traffic level, at the cost of some reduction in
the voice quality, but also of a decrease in the headroom otherwise
available to absorb sudden peaks in traffic.
- For links that cannot be correctly provisioned in the short
term, for example a site with very poor WAN links, consider
disabling video for certain users.
- Provision your network to ensure a maximum end to end delay
(latency) of 150 milliseconds (ms) under peak load. Latency is the
one network impairment that Communications Server media components
cannot reduce, and it is important to find and eliminate the weak
Web Conferencing Network Requirements
Bandwidth utilization for meeting content downloaded from the IIS server depends on the size of the content which is uploaded. The user model defines average content sizes that have been tested.