LAN issues
Issue 3.4.1 June 2005
285
A duplex mismatch condition results in a state where one side perceives a high number of
collisions, while the other side does not. This results in packet loss. Although it degrades
performance in all cases, this level of packet loss might go unnoticed in a data network because
protocols such as TCP retransmit lost packets. In voice networks, however, this level of packet
loss is unacceptable. Voice quality rapidly degrades in one direction. When voice quality
problems are experienced, duplex mismatches are the first thing to look for.
VLANS
VLANS are an often-misunderstood concept. This section begins by defining VLANS, and then
addresses configurations that require the Avaya IP Telephone to connect to an Ethernet switch
port that is configured for multiple VLANs. The IP Telephone is on one VLAN, and a personal
computer that is connected to the telephone is on a separate VLAN. Four sets of configurations
are given: Avaya Cajun P330 v3.2.8 and later, Avaya Cajun P330 pre-3.2, Cisco CatOS, and
some Cisco IOS.
Table 67: Speed/duplex matrix
Device 1
configuration
Device 2
configuration
Result
Autonegotiate
Autonegotiate
100/full expected and often achieved, but not
always stable. Suitable for user PC connections,
but not suitable for server connections or uplinks.
May be suitable for a single IP Telephony call,
such as with a Softphone. Not suitable for multiple
IP Telephony calls, such as through a MedPro
circuit pack.
Autonegotiate
100/half
100/half stable. Device 1 senses the speed, and
matches accordingly. Device 1 senses no duplex
negotiation, so it goes to half duplex.
Autonegotiate
10/half
10/half stable. Device 1 senses the speed and
matches accordingly. Device 1 senses no duplex
negotiation, so it goes to half duplex.
Autonegotiate
100/full
Device 1 goes to 100/half, resulting in a duplex
mismatch, which is undesirable. Device 1 senses
the speed, and matches accordingly. Device 1
senses no duplex negotiation, so it goes to half
duplex.
100/full
100/full
100/full stable. Typical configuration for server
connections and uplinks.
10/half
100/half
10/half
100/half
Stable at respective speed and duplex. Some
enterprises do this on user ports as a matter of
policy for various reasons.
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 ...