From: Cisco study (groupstudy@btinternet.com)
Date: Mon Nov 27 2006 - 08:07:50 ART
Gents,
Ref: Voice traffic
I have a scenario, a call is made to site Y from site X which will be routed via the WAN.
The WAN SP router classifies VoIP RTP streams based on DSCP 46 within the IP header. It then maps this to a PHB EF within the WAN Class of service on the outgoing WAN interface.
Based on this the WAN engineer (third party) would expect to see sustainable input packets being picked up by the policy, unfortunately he does not. He does see signalling however (DSCP40/CS5 - AF3), and can replicate DSCP46 traffic in order to confirm QoS configuration.
This leads the WAN engineer to the conclusion that RTP packets are being marked incorrectly or are being marked down before hitting the WAN SP router.
The physical setup is as follows:
WAN service provider router
|
Cisco Express 500 Switch (Layer 2)
|
PIX 515 firewall
|
LAN switch (WS-4507R)
On the LAN the following is configured:
1) Voice payload is set to DSCP value EF (46)
2) Voice signaling is set to DSCP value AF31 (26)
LAN Switch:
X_sw01#show run
Building configuration...
!
Current configuration : 33510 bytes
version 12.2
hostname X_sw01
!
qos dbl
qos map dscp 24 25 26 27 28 29 30 31 to tx-queue 4
qos map dscp 32 33 34 35 36 37 38 39 to tx-queue 4
qos map cos 3 to dscp 26
qos map cos 5 to dscp 46
qos
!
policy-map autoqos-voip-policy
class class-default
dbl
!
interface FastEthernetX/1-48
description *** TLAN ***
switchport access vlan 702
switchport mode access
service-policy output autoqos-voip-policy
qos trust cos
auto qos voip trust
tx-queue 3
priority high
shape percent 33
spanning-tree portfast
!
interface Vlan1
no ip address
shutdown
!
interface Vlan702
description *** TLAN_Tel ***
ip address X.X.X.X SM.SM.SM.SM
no ip redirects
.
.
<config omitted>
X_sw01#
Does anyone know what IOS commands I can use to check on the PIX firewall or the LAN switch if the voice traffic is hitting the WAN router?
It appears the PIX firewall is blocking the voice traffic but not the signalling, how can I verify this?
Many thanks,
Jo
This archive was generated by hypermail 2.1.4 : Fri Dec 01 2006 - 08:05:48 ART