Quality of Service guidelines
318 Avaya Application Solutions IP Telephony Deployment Guide
Figure 83: Differentiated Services (DiffServ) TOS byte
A DiffServ Code Point (DSCP) of 46 (101110), referred to as expedited forwarding (EF), is
suggested for the proper treatment of voice and signaling packets. However, with
Communication Manager, one can set any DSCP value as desired to work with a company’s
QoS scheme. Some common DiffServ Code Points are defined in RFCs 2474 and 2475.
Although DSCPs are specified in IETF RFCs, the treatment of packets that are tagged with
DiffServe is implementation- dependent.
Note that older routers might require a DSCP setting of 40 (101000), which is backward
compatible to the original TOS byte definition of critical. But again, Avaya products and software
allows users to set any of the 64 possible DSCP values to work with your voice quality policy.
The TOS byte is an OSI model Layer 3 solution, and works on IP packets on the LAN and
possibly the WAN, depending upon the service provider.
Table 74: Original TOS specification
Bit
description
Value
Use
Bits 0-2IP
precedence
000
001
010
011
100
101
110
111
Routine
Priority
Immediate
Flash
Flash Override
CRITIC/ECP
Internetwork control
Network control
Bit 3
delay
0
1
Normal
Low
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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 ...