| This section details the network requirements for Microsoft Unified Communications on ProCurve switches.
4.1 Requirements for voice and video bandwidth
If possible, perform network analysis prior to deployment. Or you can use quality of experience (QoE) data to understand the network environment and the impact of any changes. When planning for bandwidth requirements it is important to:
- Understand any potential issues in the network environment.
- Consider not only the network, but the end devices as well. Consider the full end-to-end path.
- Know the user profile when planning. You should know what the type of calls (voice, video conferencing) the network will be supporting, as well as the call duration.
- In your calculations, take the voice or video codec into account. The following table shows the bandwidth impact of voice traffic using various codecs.
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4.1.1 Codec bandwidth
Here are the bandwidth impacts of voice traffic on the network using different codecs:
These are on-the-wire numbers, including Ethernet, IP, UDP, RTP and SRTP overhead; they are not raw codec numbers and do not include signaling such as media setup/tear-down, instant messaging (IM), presence state, etc. The values shown are for one-way circuits; since media are typically duplex, you need to consider this when calculating bandwidth requirements.
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4.1.2 Voice behavior and its effects
bandwidth. In a typical peer-to-peer voice conversation, only one person speaks at a time. In a typical conference, 80 percent of the time only one person speaks, while 7 percent of the time two persons are speaking. During 13 percent of the time, no one talks.
In a voice conference, only the speaker generates data; parties who are silent do not generate data. When a person is speaking the resulting data is a constant stream of varying size. For good voice quality, delay should be kept under 150 milliseconds and loss under 10 percent.
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4.1.3 Video behavior and its effects
In peer- to-peer conference, both persons typically send video. As a presenter you can select which video stream to see: the active speaker stream or a specific stream from a participant.
The presenter imposes his or her choice on all participants. The current active speaker sees the previous active
speaker stream.
The Multipoint Control Unit (MCU) controls video streams from participants and pauses unneeded streams at the
source. The MCU can receive up to four streams, and sends up to four streams out to all participants who desire video
in the meeting.
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4.2 Call scenarios
Here are some typical call scenarios employing Microsoft Unified Messaging and Office Communicator 2007 (OC
2007).
Scenario 1: Voice call using OC 2007 to OC 2007 or OC Phone Edition:
- Each user sends one audio stream and receives one audio stream.
- Codec: Realtime Audio
- Bandwidth requirements in each direction: 57 Kbps
Scenario 2: OC 2007 to OC 2007 video call:
- Each user sends and receives one audio and one video stream.
- Bandwidth requirements in each direction: 57 Kbps (voice) + 320 Kbps (video) = 377 Kbps total
Scenario 3: Video conference, with multiple OC 2007 to OCS 2007:
- Active speaker sends 368 Kbps and receives video from the previous active speaker. (Active speaker is talking, so he or she receives no audio.)
- Previous active speaker sends 320 Kbps of video and receives 368 Kbps from the active speaker (audio + video).
- Other listeners receive 368 Kbps from the active speaker.
Scenario 4: Video conference with round table (a Microsoft device that offers panoramic view):
- Participants send and receive video and audio as in scenario 3 above.
- In addition, each participant receives the panorama video from the active speaker.
- The active speaker receives the panorama video from the previous active speaker.
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4.3 Ports and port traffic
Inbound ports: For Microsoft Unified Communications, the router or firewall must have the following ports open for inbound traffic from the Internet:
Scenario 3: Video conference, with multiple OC 2007 to OCS 2007:
- Port 5061 – SIP/MTLS for signaling
- Port 443 – SIP/TLS (secure SIP)
- Port 8057 – PSOM
- Port 3478 – STUN
Inbound and outbound ports: Ports that must be open for inbound and outbound traffic are:
- Ports UDP 50000 to 59000 – Opening this entire range on the external firewall may appear to be a security
hole. However, the server will not listen on all these ports, only on the ones that are associated with voice
calls, so a hacker cannot discover this entire range.
To open ports on a ProCurve Secure Router:
- Log on to the router web interface: http://<router-ip-address>
- From the Menu list on the left launch the Firewall Wizard:
- At the next screen, select the Public Interface; that is, the interface connected to the Internet:
- At the next screen, select all private interfaces that require Internet access:
- Then define the services that must be available from the outside. Current services as Web, FTP, email or
Telnet server are already listed. Choose Other server to define a new service:
- To define a new service, enter the IP address of the private server, then the protocol (TCP or UDP) and ports
(choose from the list of well-known ports or define a port or a range of ports). For example, to use TCP 5061
for SIP:
- Open other services if needed. Otherwise, choose No at the next screen:
- At the final screen click Finish to implement the modifications.
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4.4 QoS requirements and configuration
Differentiated Services (DiffServ) is a computer networking architecture that specifies a mechanism for classifying, managing network traffic and providing Quality of Service (QoS) guarantees. Microsoft Unified Communications does not require DiffServ, but can work within a DiffServ environment and supports DiffServ marking.
Microsoft Unified Messaging supports DiffServ through Differentiated Services Code Point (DSCP) marking. DSCP marking can be performed by the end points, which by default mark all media for DiffServ. Marking is as follows:
- Audio: Marked for Expedited Forwarding
- Video: Marked for Class 3 of Assured Forwarding
DSCP marking can also be tuned through use of policy. Windows Vista® allows centralized policy enforcement.
ProCurve switches and routers can perform DSCP marking and prioritize traffic according to its values. The recommended configuration is to dedicate a VLAN to voice solutions; this a good solution for use with IP phones, but is more of an issue for Unified Communications when UC software may be installed in different VLANs on user PCs. Another possibility is to mark DSCP for a particular port (for example, TCP 5061 for SIP).
Examples of DSCP marking:
A DSCP value of 46 means that traffic will receive Expedited Forwarding. To assign a DSCP value of 46 on the traffic
of VLAN 10:
To assign a DSCP value of 46 to the traffic coming from source IP address 10.1.10.10:
To assign a DSCP value of 46 on port 5061:
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4.5. Interoperability of Microsoft Office Communicator with ProCurve switch protocols
- Power over Ethernet: Microsoft Office Communicator Phone Edition supports standard PoE (802.3af), which is also supported by ProCurve Switches 3500yl, 5400zl, 8212zl and 2610-PWR series.
- 802.1X: Microsoft Office Communicator Phone Edition is based on the Nortel 8540 IP Phone. This model does not support 802.1X.
- LLDP-MED: Neither CDP nor LLDP-MED are supported by Microsoft Office Communicator Phone Edition.
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