WAN QoS

[n.oneill]

Hi

I have been asked to configure our ATM WAN routers to prioritise Voice traffic. The White paper on QoS I have found was last updated 30/6/2001. Is there anything more up to date than this? Specifically I am looking at VoIP over ATM using a single data PVC only.

Many thanks in advance.

[adahan]

Hi,

You can use the following example, it works for me just fine:

class-map match-any VoIP-Control

match access-group 101

class-map match-any VoIP-RTP

match access-group 100

!

!

policy-map QoS-Policy

class VoIP-Control

bandwidth percent 10

class VoIP-RTP

bandwidth percent 50

class class-default

fair-queue

interface ATM1/0.37 point-to-point

description ### ATM to Texas ###

ip address 10.0.10.2 255.255.255.252

pvc 0/37

protocol ip 10.0.10.1 broadcast

ubr 4000

encapsulation aal5snap

service-policy output QoS-Policy

access-list 100 permit udp any any range 16384 32767

access-list 100 permit ip any any precedence critical

access-list 100 permit ip any any dscp ef

access-list 101 permit tcp any any range 2000 2002

access-list 101 permit tcp any any eq 1720

access-list 101 permit udp any any eq 2427

access-list 101 permit ip any any dscp af31

Hope it helps, Avi.

[jklute]

Although with a fat ATM pipe it might not matter, it may be prudent to use PQ for the media traffic -- "priority percent 50" instead of "bandwidth percent 50".

[allan.thomas]

Further consideration needs to be made with regards to prioritising SQL and LDAP replication, especially in a distributed CCM environment.

class-map match-all CallManager_SQL_LDAP

match access-group 100

access-list 100 permit tcp any any eq 445

access-list 100 permit tcp any any eq 102

[jcmartin]

And depending on the PVC speed, you may need to set up LFI. ATM does this by default with seperate PVCs, but over a single PVC, you will need to change your encapsulation to MLPPPoATM to accomplish this.