Examples of QoS implementation
Issue 3.4.1 June 2005
329
Figure 85: High-quality service across a congested WAN link
CB-WFQ/LLQ is a priority-aware queuing strategy that has a strict priority queue for voice
packets, and does round-robin queuing for other types of traffic. Non-prioritized traffic is still
forwarded, however, so this should not interfere with a customer’s data network. Use weighted
random early detect to manage the fair queue.
The actual router configuration used for this testing follows. First, set the endpoints to tag
interesting traffic as DSCP 46. Cisco routers support DiffServ in IOS 12.0 and later. Next, set up
a class map to match traffic that is marked with DSCP 46. Once traffic is defined by the class
map, set policies for it using a policy map. For the policy map to take effect, it has to be applied
to an interface. Queue packets on the outgoing interface. In the sample configuration, 768 K of
bandwidth is reserved for RTP. This value should be set at or above the maximum bandwidth to
be used for IP Telephony. In our case, 768 K supports 9 calls using G.711, or 31 calls using
G.729. This example should work well in most cases using Cisco routers with point-to-point
WAN links. Networks that use Frame Relay might need additional steps.
Assumptions for Example 1
Suppose all endpoints are capable of tagging with DSCP 46, which is the default for audio. This
would be true in a Communication Manager system with TN799DP C-LAN circuit packs running
firmware v5 or later. Previous firmware versions and the TN799C circuit pack cannot tag at
Layer 2 or Layer 3. A matching set of configurations is applied to both routers.
Summary of Contents for Application Solutions
Page 1: ...Avaya Application Solutions IP Telephony Deployment Guide 555 245 600 Issue 3 4 1 June 2005 ...
Page 20: ...About This Book 20 Avaya Application Solutions IP Telephony Deployment Guide ...
Page 21: ...Issue 3 4 1 June 2005 21 Section 1 Avaya Application Solutions product guide ...
Page 22: ...22 Avaya Application Solutions IP Telephony Deployment Guide ...
Page 106: ...Call processing 106 Avaya Application Solutions IP Telephony Deployment Guide ...
Page 124: ...Avaya LAN switching products 124 Avaya Application Solutions IP Telephony Deployment Guide ...
Page 139: ...Issue 3 4 1 June 2005 139 Section 2 Deploying IP Telephony ...
Page 140: ...140 Avaya Application Solutions IP Telephony Deployment Guide ...
Page 186: ...Traffic engineering 186 Avaya Application Solutions IP Telephony Deployment Guide ...
Page 204: ...Security 204 Avaya Application Solutions IP Telephony Deployment Guide ...
Page 228: ...Avaya Integrated Management 228 Avaya Application Solutions IP Telephony Deployment Guide ...
Page 274: ...Reliability and Recovery 274 Avaya Application Solutions IP Telephony Deployment Guide ...
Page 275: ...Issue 3 4 1 June 2005 275 Section 3 Getting the IP network ready for telephony ...
Page 276: ...276 Avaya Application Solutions IP Telephony Deployment Guide ...
Page 356: ...Network recovery 356 Avaya Application Solutions IP Telephony Deployment Guide ...
Page 366: ...Network assessment offer 366 Avaya Application Solutions IP Telephony Deployment Guide ...
Page 367: ...Issue 3 4 1 June 2005 367 Appendixes ...
Page 368: ...Appendixes 368 Avaya Application Solutions IP Telephony Deployment Guide ...
Page 394: ...Access list 394 Avaya Application Solutions IP Telephony Deployment Guide ...
Page 414: ...DHCP TFTP 414 Avaya Application Solutions IP Telephony Deployment Guide ...