IP trunk on c-lan 2

[amateurope]

We have three pbx's connected with the clan cards over a cisco router network. Today the traffic on the WAN links are to high. To reduce the traffic we changed the codec on the c-lan from G.711 to G.729. The second thing we want to do is implement Qos on the router network.
To do this I have to filter the voice calls from the data packets. I read a lot of info on this but still I can not find the stream. A lot of info is about the PBX G3r9 but we use G3sir8. This means I can not make use of Diffserv and so I have to nail down the voice in a other way

Question : Who has build something like this or were can I find info on it???

 

[BuckWeet]

You need to classify the Packets at the router then..

With the Cisco devices you can setup a classmap using access-lists to say any traffic coming from this IP(s) to get tagged with IP TOS as 5 or whatever you desire.. and then set it up to give you your priority with the policy map..

Then you take an apply that policy to the WAN interfaces that you choose.


This is a good document for CBWFQ

http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120t/120t5/cbwfq.htm

BuckWeet

 

[amateurope]

The problem we expierence is how to define the voice packets. According to avaya voice packets are used in the UDP range 2048 - 65335. We do not see those packets when voice calls are made. When we want to define priority on those packets in the routers, we need to know which protocols are used. We have monitorred the LAN with Network Monitor which comes with SMS from Microsoft but only broadcasts from the medpro card are seen and not the actual voice packets.

any suggestions???

 

[whitera]

If the Switches are connected to dedicated switch ports, you can set a priority bit on all packets from that switch port. Then you need to configure all routers in the network to read the priority byte and handle the packet appropriately.

 

[BuckWeet]

don't worry about protocol, just do it by IP

do the access-list method like I said

access-list 99 permit 192.168.1.101
access-list 99 permit 192.168.1.100
access-list 99 permit 192.168.1.102
access-list 99 deny any

class-map match-any voice
match access-group 99

policy-map voice
class voice
priority 768
class class-default
fair-queue

interface s0/0
service-policy voice output

The access-list defines the IP's you want to give priority
the class-map matches this access-list

the policy map defines what the class does, in the case the voice class gets 768K of bandwidth, the rest gets fair-queued. last command applies it to the outbound que of s0/0

You can also set the IP TOS or DSCP bit if you want to, if you're going to be hopping around multiple routers, I would do that.. You need to make sure your IOS supports this feature though. Its a "set" command under the policy-map..

BuckWeet