Media Port Range for Office Communications Server 2007 R2
Microsoft Office Communications Server 2007 and Microsoft Office Communications Server 2007 R2 will reach end of support on January 9, 2018. To stay supported, you will need to upgrade. For more information, see Resources to help you upgrade your Office 2007 servers and clients.
This section describes the minimum media port allocation requirements for the client and server.
The default UDP/TCP port range used by the Office Communicator 2007 R2 client is 1024-65535. The Real Time Media Communications stack in Office Communicator 2007 R2 allocates the media port dynamically in this range. To maintain an adequate level of performance, you can specify a smaller port range for Office Communicator 2007 R2 to use.
To control the specific range of ports that need to be open on a firewall, a registry key setting is provided to force the media stack to reduce the range of port values that can be used for real-time media communications. On the Office Communicator client, the port range registry settings are as follows:
HKLM\Software\Policies\Microsoft\Communicator\PortRange\Enabled
HKLM\Software\Policies\Microsoft\Communicator\PortRange\MaxMediaPort
HKLM\Software\Policies\Microsoft\Communicator\PortRange\MinMediaPort
By default none of these registry keys is set.
Minimum Number of Ports
If you use the port range registry key settings to reduce the ports that can be used for media, it is recommended that you do so according to the minimums described in this section.
For client endpoints, the port range should not be reduced to the point where it can compromise the ability of the media stack to negotiate audio, video, and desktop sharing communication ports during session setup or during a call. More specifically, for an Office Communicator 2007 R2 client, the minimum port range is 40. A smaller range of ports can result in errors during call transfer and conference escalation scenarios.
By configuring a minimum of 40 ports, you enable the client to evaluate the candidate transport addresses that it can use to stream audio, video, and desktop sharing to another client, as described in the Internet Engineering Task Force (IETF) Interactive Connectivity Establishment (ICE) protocol. Candidate addresses include a local address and an address on the A/V Access Edge server. A minimum of 40 ports in the port range will also accommodate any escalations from a peer-to-peer call to a conference.
Note
An escalation of a peer-to-peer call to a conference triggers a temporary doubling of the ports in use.
Different call scenarios can dictate whether to deliver by using User Datagram Protocol (UDP) or Transmission Control Protocol (TCP). However, whenever UDP can be used to deliver media, it will be used instead of TCP.
Note
Secure Real-Time Transport Protocol (SRTP) and Secure Real-Time Transport Control Protocol (SRTCP) streams are multiplexed over TCP but are delivered separately in the case of UDP. UDP connections are more resilient to packet loss than TCP. When a UDP packet is lost, there is no transport impact to subsequent packets. When packet loss occurs over TCP, all subsequent packets are held at the transport level to ensure a reliable stream of data. As a result, overall latency in the media delivery chain may increase over TCP.
The following set of tables show the detailed port requirements for call setup:
Table 1.0 Port Requirements for Call Setup
| Voice ICE v6 UDP RTP | Voice ICE v6 UDP RTCP | Voice ICE v6 TCP RTP+ RTCP | Voice ICE v19 UDP RDP | Voice ICE v19 UDP RTCP | |
|---|---|---|---|---|---|
ICE Local Candidate |
1 |
1 |
1 |
1 |
1 |
ICE A/V Edge Server Candidate |
1 |
1 |
1 |
1 |
1 |
Voice Maximum Number of Ports |
4 |
4 |
4 |
4 |
4 |
Consultative Call Transfer, Number of Additional Ports |
4 |
4 |
4 |
4 |
4 |
Total Audio Maximum Number of Ports |
8 |
8 |
8 |
8 |
8 |
Audio Video Maximum Number of Ports |
16 |
16 |
16 |
16 |
16 |
Consultative Call Transfer Maximum Number of Ports |
16 |
16 |
16 |
16 |
16 |
Total Audio Video Maximum Number of Ports |
32 |
32 |
32 |
32 |
32 |
Audio Video Desktop Sharing Maximum Number of Ports |
16 |
16 |
16 |
16 |
16 |
Consultative Call Transfer Maximum Number of Ports |
16 |
16 |
16 |
16 |
16 |
Total Audio Video Desktop Sharing Maximum Number of Ports |
32 |
32 |
32 |
32 |
32 |
Table 1.1 Port Requirements for Call Setup
| Voice ICE v19 TCP RTP+ RTCP | CIF/VGA/HD Video ICE v6 UDP RTP | CIF/VGA/HD Video ICE v6 UDP RTCP | CIF/VGA/HD Video ICE v6 TCP RTP+ RTCP | |
|---|---|---|---|---|
ICE Local Candidate |
1 |
1 |
1 |
1 |
ICE A/V Edge Server Candidate |
1 |
1 |
1 |
1 |
Voice Maximum Number of Ports |
4 |
N/A |
N/A |
N/A |
Consultative Call Transfer, Number of Additional Ports |
4 |
N/A |
N/A |
N/A |
Total Audio Maximum Number of Ports |
8 |
N/A |
N/A |
N/A |
Audio Video Maximum Number of Ports |
16 |
16 |
16 |
16 |
Consultative Call Transfer Maximum Number of Ports |
16 |
16 |
16 |
16 |
Total Audio Video Maximum Number of Ports |
32 |
32 |
32 |
32 |
Audio Video Desktop Sharing Maximum Number of Ports |
16 |
16 |
16 |
16 |
Consultative Call Transfer Maximum Number of Ports |
16 |
16 |
16 |
16 |
Total Audio Video Desktop Sharing Maximum Number of Ports |
32 |
32 |
32 |
32 |
Table 1.2 Port Requirements for Call Setup
| CIF/VGA/HD Video ICE v19 UDP RTP | CIF/VGA/HD Video ICE v19 UDP RTCP | CIF/VGA/HD Video ICE v19 TCP RTP+ RTCP | Desktop Sharing TCP RTP+ RTCP | |
|---|---|---|---|---|
ICE Local Candidate |
1 |
1 |
1 |
2 |
ICE A/V Edge Server Candidate |
1 |
1 |
1 |
1 |
Voice Maximum Number of Ports |
N/A |
N/A |
N/A |
N/A |
Consultative Call Transfer, Number of Additional Ports |
N/A |
N/A |
N/A |
N/A |
Total Audio Maximum Number of Ports |
N/A |
N/A |
N/A |
N/A |
Audio Video Maximum Number of Ports |
16 |
16 |
16 |
N/A |
Consultative Call Transfer Maximum Number of Ports |
16 |
16 |
16 |
N/A |
Total Audio Video Maximum Number of Ports |
32 |
32 |
32 |
N/A |
Audio Video Desktop Sharing Maximum Number of Ports |
16 |
16 |
16 |
16 |
Consultative Call Transfer Maximum Number of Ports |
16 |
16 |
16 |
16 |
Total Audio Video Desktop Sharing Maximum Number of Ports |
32 |
32 |
32 |
32 |
The following set of tables show the detailed port requirements for escalation during a call:
Table 2.0 Port Requirements for Escalation During a Call
| Voice ICE v6 UDP RTP | Voice ICE v6 UDP RTCP | Voice ICE v6 TCP RTP+ RTCP | Voice ICE v19 UDP RDP | Voice ICE v19 UDP RTCP | |
|---|---|---|---|---|---|
Established P2P or Conference |
1 |
1 |
1 |
1 |
1 |
Escalation From P2P to Conference |
1 |
1 |
1 |
1 |
1 |
Total Audio Maximum Number of Ports |
4 |
4 |
4 |
4 |
4 |
Total Audio Video Maximum Number of Ports |
16 |
16 |
16 |
16 |
16 |
Total Audio Video Desktop Sharing Maximum Number of Ports |
16 |
16 |
16 |
16 |
16 |
Table 2.1 Port Requirements for Escalation During a Call
| Voice ICE v19 TCP RTP+ RTCP | CIF/VGA/HD Video ICE v6 UDP RTP | CIF/VGA/HD Video ICE v6 UDP RTCP | CIF/VGA/HD Video ICE v6 TCP RTP+ RTCP | |
|---|---|---|---|---|
Established P2P or Conference |
1 |
1 |
1 |
1 |
Escalation From P2P to Conference |
1 |
1 |
1 |
1 |
Total Audio Maximum Number of Ports |
4 |
N/A |
N/A |
N/A |
Total Audio Video Maximum Number of Ports |
16 |
16 |
16 |
16 |
Total Audio Video Desktop Sharing Maximum Number of Ports |
16 |
16 |
16 |
16 |
Table 2.2 Port Requirements for Escalation During a Call
| CIF/VGA/HD Video ICE v19 UDP RTP | CIF/VGA/HD Video ICE v19 UDP RTCP | CIF/VGA/HD Video ICE v19 TCP RTP+ RTCP | Desktop Sharing TCP RTP+ RTCP | |
|---|---|---|---|---|
Established P2P or Conference |
1 |
1 |
1 |
2 |
Escalation From P2P to Conference |
1 |
1 |
1 |
1 |
Total Audio Maximum Number of Ports |
N/A |
N/A |
N/A |
N/A |
Total Audio Video Maximum Number of Ports |
16 |
16 |
16 |
N/A |
Total Audio Video Desktop Sharing Maximum Number of Ports |
16 |
16 |
16 |
16 |
The following set of tables show the detailed overall requirements for ports:
Table 3.0 Overall Requirements for Ports
| Voice ICE v6 UDP RTP | Voice ICE v6 UDP RTCP | Voice ICE v6 TCP RTP+ RTCP | Voice ICE v19 UDP RDP | Voice ICE v19 UDP RTCP | |
|---|---|---|---|---|---|
Minimum Ports Required for Audio |
16 |
16 |
16 |
16 |
16 |
Minimum Ports Required for Audio Video |
32 |
32 |
32 |
32 |
32 |
Minimum Ports Required for Audio Video Desktop Sharing |
32 |
32 |
32 |
32 |
32 |
ALL * |
32 |
32 |
32 |
32 |
32 |
Table 3.1 Overall Requirements for Ports
| Voice ICE v19 TCP RTP+ RTCP | CIF/VGA/HD Video ICE v6 UDP RTP | CIF/VGA/HD Video ICE v6 UDP RTCP | CIF/VGA/HD Video ICE v6 TCP RTP+ RTCP | |
|---|---|---|---|---|
Minimum Ports Required for Audio |
16 |
N/A |
N/A |
N/A |
Minimum Ports Required for Audio Video |
32 |
32 |
32 |
32 |
Minimum Ports Required for Audio Video Desktop Sharing |
32 |
32 |
32 |
32 |
ALL * |
32 |
32 |
32 |
32 |
Table 3.2 Overall Requirements for Ports
| CIF/VGA/HD Video ICE v19 UDP RTP | CIF/VGA/HD Video ICE v19 UDP RTCP | CIF/VGA/HD Video ICE v19 TCP RTP+ RTCP | Desktop Sharing TCP RTP+ RTCP | |
|---|---|---|---|---|
Minimum Ports Required for Audio |
N/A |
N/A |
N/A |
N/A |
Minimum Ports Required for Audio Video |
32 |
32 |
32 |
N/A |
Minimum Ports Required for Audio Video Desktop Sharing |
32 |
32 |
32 |
32 |
ALL * |
32 |
32 |
32 |
32 |
Note
- 8 additional ports required to accommodate any third party applications. At least 40 ports needed for allocating ports in the same range at the same time.
As described in the tables, the minimum number of ports that must be allocated on a client platform is 40. During a normal call, the number of ports used will not exceed 2, 4, or 5 depending on whether audio, audio/video, or audio/video/Desktop sharing are streamed.
Server Port Allocation
Changing the default port range on the server is not recommended. However, if your organization has a need to establish port ranges on the server, you can use the following WMI settings to configure the port range:
MSFT_SIPPoolConfigSetting
MSFT_SIPDataMCUSetting
MSFT_SIPMediationServerConfigSetting
For an A/V Conferencing Server as well as all other server components terminating Audio/Video media (for example, Front-Ends hosting Conferencing Attendant, Response Group Service), the port range must be at least six times the maximum number of concurrent call legs that can be supported on the server (that is, two ports for the RTP and RTCP traffic for each modality – audio, video, and panoramic video).
For an A/V Access Edge server, the port range must be at least twelve times the maximum number of outside user calls that can be supported on the server (two ports for the RTP and RTCP traffic for each modality – audio, video and panoramic video, or audio, video, and desktop sharing for ICE v6 and ICE v19.
For a Mediation Server, the port range must be at least eight times the maximum number of concurrent calls that can be supported on the server (that is, two ports for the RTP and RTCP traffic for audio multiplied by two because the Mediation Server is a back-to-back User Agent for ICE v6 and also for ICE v19).