QOS on 3550 for SIP and RTP

Unanswered Question
Nov 27th, 2007
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Hi

I need to configure QOS for SIP and RTP on our LAN switches. We have approximately 60 hosts connected to 2 x 3550-SMI switches that talk directly to 6 x PBX's on the same switches (30 hosts and 3 PBX's per switch). The hosts are PC's that run a voice application. They are also used for normal data. We have been experiencing some lost SIP initiation packets and dropped calls.


Any suggestions on how to prioritise SIP and RTP on the LAN?


Thanks

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davidbuit Mon, 12/03/2007 - 04:46
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Please see the config below. Would this achieve the desired result of prioritising SIP and RTP traffic?


I haven't been able to test it because I can't get down time scheduled on the switch.


Thanks



mls qos map policed-dscp 24 26 46 to 0

mls qos map cos-dscp 0 8 16 26 32 46 48 56

mls qos min-reserve 5 170

mls qos min-reserve 6 85

mls qos min-reserve 7 51

mls qos min-reserve 8 34

mls qos


#RTP

access-list 100 permit udp any any range 16384 32767


#SIP

access-list 110 permit udp any any eq 5060

!

class-map match-all voip-rtp

match access-group 100

!

class-map match-all voip-control

match access-group 110

!


policy-map qos-voip

class voip-rtp

set dscp 46

police 320000 8000 exceed-action policed-dscp-transmit

class voip-control

set dscp 24

police 32000 8000 exceed-action policed-dscp-transmit

!

And then on all ports that connect to terminals as well as the gateway servers

!

int fast 0/XX

switchport mode dynamic desirable

service-policy input qos-voip

mls qos trust cos

wrr-queue bandwidth 10 20 70 1

wrr-queue min-reserve 1 5

wrr-queue min-reserve 2 6

wrr-queue min-reserve 3 7

wrr-queue min-reserve 4 8

wrr-queue cos-map 1 0 1

wrr-queue cos-map 2 2 4

wrr-queue cos-map 3 3 6 7

wrr-queue cos-map 4 5

priority-queue out


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