Tagging for QOS

[tahequivoice]

I have a problem that I think QOS may help resolve. A T1 at a site is bursting and causing Citrix clients to drop. There is an existing QOS policy for voip giving 70% bandwidth for EF packets.  On the core router where the Citrix servers reside I created an ACL to mark the servers with DSCP 46 and applied it to the policy. This part is working, however, I dont think return packets from the clients will get marked properly. 

If I create an ACL on the client side routers source client network destination host server IP, will the packet be tagged properly for just packets destined for those servers, or will the internal IP's get tagged then for all traffic?

I ran into a problem recently trying to do this for NAT, and found that once an IP is NAT it then NAT's everything. Will I see the same results?

[Marwan ALshawi]

Marking with this acl is fine

But make sure it will not get changed in path

With nat if if you are applying the acl in the inside interface of the nat then no issue as in this case the acl and policy map of qos will be done before the nat

HTH

If helpful rate

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[tahequivoice]

Since we control all the network between sites the tags will remain, and this one isn't in a NAT environment, the NAT was an example of somethgin that didn't work as I had thought it would .

I'll give this a try and see how it goes.

[Joseph W. Doherty]

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Posting

As Marwanshawi already noted, the ACL should work fine.

However, strongly suggest you don't place Citrix class into same queue as VoIP (LLQ?).  It would be better to define another class for it with an adequate bandwidth allocation.

(NB: Cisco recommends not using more than about a 1/3 of a link's bandwidth for VoIP, this to allow sufficient bandwidth for other traffic.  I.e., you might want to review the 70% bandwidth allocation for VoIP.)

BTW, Citrix supports more than just "screen scraping".  Later versions of NBAR can identify the different Citrix traffic types (if using the later Citrix protocol) allowing you to only give precedence to the "screen scraping" traffic.