Hello, first of all thank you very much for answer.
Well now I will describe my network scenario.
I have SIP (Linksys SPA) adapter which is connected with its WAN port on to LAN port in the Cisco ASA, than Cisco ASA is connected to the internet via a ZyXel Bridge. The Cisco ASA have Static WAN ip address. All needed ports are opened in the ASA for SIP traffic.
So nex hop from my ASA is ofcourse ISP provider CORE router, than via my ISP provider this SIP adapter connect to the SIP server in another town.
Now my problems are :
When I am uploading the files from our network, and if someone is than tolking via SIP tha he get bad sound with noises, latency etc... So therfore I`ll try to configure the QOS for SIP traffic.
What you mean, will this config above you wrote help me ?? or I need to call my ISP too and as them to create the priority on their interface on the CORE router too ?? is this what you mean ????
Thank You !! waiting for answer from you before I do anything.
Best regards
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by: oletuPosted on 2007-12-16 at 08:33:31ID: 20480884
It is will be very difficult to give you a precise answer, because your topology is not quite clear.
e.g. where is the SIP server and where is the SIP phone in your network, also remember that for Voice QoS to be effective it has to be end-to-end, ie if you give Voice traffic a high priority in within your network and send it to a SIP server somewhere on the internet, do not expect your ISP to abide by that priority that you have assigned to SIP. Your ISP will combine the Voice traffic & Data traffic into one single stream and treat them as the same.
This is different if you have IP/MPLS and you have purchased a higher priority service from your ISP, in that case you will be able to achieve a true end-end QoS for your voice path from the SIP phone to the SIP server.
That said, let try to do what you have control over which is the traffic within your network and exit out of your network into the ISP cloud.
Your configure above assume that the SIP traffic has been marked as EF, but what is the SIP phone has not been marked or what if the SIP phone is using another type of marking eg some phone mark their traffic as EF & AF31, others also utilize the CS3 marking. If you are not sure of the marking that your SIP phone is doing or if your SIP phone is not doing any marking at all, you have to take it upon yourself to mark the traffic, before assigning it to a strict priority queue.
We know that SIP by default uses port 5060, so back to your routers:
!
#access-list 101 permit tcp any any eq 5060
#access-list 101 permit udp any any eq 5060
#access-list 101 permit tcp any eq 5060 any
#access-list 101 permit udp any eq 5060 any
!
Class-map match-any SIP
match access-group 101
!
Policy-map SIP
Class SIP
set dscp ef
priority percent 10
!
Interface serial 0/0
description outside
service-policy output SIP
!
I have done multiple things above, I have use access-list 101 to capture all SIP traffics, and have given it 10% of the bandwidth on Serial0/0. You also see that I have remarked the SIP traffic with EF.
The importance of this remarking is that, if your SIP traffic passes through multiple devices in your network, you have to log into each of those routers and keep giving SIP a priority (remember QoS is an end-end thing, if router-1 gives priority to SIP, that does not means router-2 will, you must log into router-2 and tell it to give priority to SIP, else router-2 will treat SIP as a regular traffic), since we have already re-marked the SIP traffic, you do not need the ACL in the other routers, all you need is...a class map, matching 'ef'
If can adapter this method for any plateform, my example above is using Cisco IOS, but the method is the same even for Firewall, Cat OS, Catalys IOS, etc.
If you have a problem adaptering itfor your specific platform, let me know.
If you stick this into your last router before the ISP, this configure will only help the router to give priority to SIP traffic as they leave the router into your ISP network, since the ISP will not trust it by default, when the traffic gets into their network, the markings are not obeyed. And SIP traffic from the ISP to you will be sent just like regular traffic with no priority.
But since upload bandwidth are normally smaller than download bandwidth, this might help your situation.
On the other hand, if the path between the SIP phone & the SIP server is under your control, you can implement end to end QoS and you will certain that SIP will be treated as king from one end of the network to the other.