Issue 3.4.1 June 2005
311
Quality of Service guidelines
This chapter contains guidelines for deploying Quality of Service (QoS) for an IP Telephony
network. This chapter begins with an overview of Class of Service (CoS) versus QoS.
Class of Service refers to mechanisms that tags traffic in such a way that the traffic can be
differentiated and segregated into various classes. Quality of Service refers to what the network
does to the tagged traffic to give higher priority to specific classes. If an endpoint tags its traffic
with Layer 2 802.1p priority 6 and Layer 3 Differentiated Services Code Point (DSCP) 46, for
example, the Ethernet switch must be configured to give priority to value 6, and the router must
be configured to give priority to DSCP 46. The fact that certain traffic is tagged with the intent to
give it higher priority does not necessarily mean it will receive higher priority. CoS tagging does
no good without the supporting QoS mechanisms in the network devices.
Topics covered in this section include:
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CoS
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Layer 2 QoS
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Layer 3 QoS
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IEEE 802.1 p/Q
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DiffServ
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RSVP
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Queuing methods
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Traffic shaping and policing
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Fragmentation
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RTP
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Examples of QoS implementation
CoS
IEEE 802.1p/Q at the Ethernet layer (Layer 2) and DSCP at the IP layer (Layer 3) are two
standards-based CoS mechanisms that are used by Avaya products. These mechanisms are
supported by the IP Telephone, the S8300 Media Server, and the C-LAN and MedPro circuit
packs. Although TCP/UDP source and destination ports are not CoS mechanisms, they can be
used to identify specific traffic, and can be used much like CoS tags. Other non-CoS methods to
identify specific traffic are to key in on source and destination IP addresses and specific
protocols, such as RTP. The MedPro circuit pack and IP Telephones use RTP to encapsulate
audio.
Содержание Application Solutions
Страница 1: ...Avaya Application Solutions IP Telephony Deployment Guide 555 245 600 Issue 3 4 1 June 2005 ...
Страница 20: ...About This Book 20 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 21: ...Issue 3 4 1 June 2005 21 Section 1 Avaya Application Solutions product guide ...
Страница 22: ...22 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 74: ...Avaya Application Solutions platforms 74 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 106: ...Call processing 106 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 124: ...Avaya LAN switching products 124 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 139: ...Issue 3 4 1 June 2005 139 Section 2 Deploying IP Telephony ...
Страница 140: ...140 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 186: ...Traffic engineering 186 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 204: ...Security 204 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 214: ...Voice quality network requirements 214 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 228: ...Avaya Integrated Management 228 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 239: ...Reliability Issue 3 4 1 June 2005 239 Figure 69 S8700 Media Server in a high reliability configuration ...
Страница 274: ...Reliability and Recovery 274 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 275: ...Issue 3 4 1 June 2005 275 Section 3 Getting the IP network ready for telephony ...
Страница 276: ...276 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 350: ...Implementing Communication Manager on a data network 350 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 356: ...Network recovery 356 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 366: ...Network assessment offer 366 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 367: ...Issue 3 4 1 June 2005 367 Appendixes ...
Страница 368: ...Appendixes 368 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 394: ...Access list 394 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 414: ...DHCP TFTP 414 Avaya Application Solutions IP Telephony Deployment Guide ...