CS7 is applied without any bandwidth restriction

[kb.choudhury]

Please advise me.

my client insisting to set a dscp value of 56  (= CS7 , the highest priority) for their video packet without any bandwith restriction in the input of fast ethernet port and PPP Multilink serial output port of the 7513 router. Please tell me what will be the outcome at time of video streaming and video conference ?  As this dscp value CS7 is the highest priority and reserved for network only.we are using ospf routing (some of the network is connected through this multilink port via ospf routing), also this ethernet is connected to various statice routed ip network via cisco asa and cisco 4507. The keep alive ospf neighbour router will be  lost or not?

[Peter Paluch]

Hello,

You indeed risk the possibility of the video traffic being prioritized over routing protocols and other possible important inter-device traffic. I strongly recommend avoiding this scenario if possible.

Moreover, the customer is using inappropriate marking. Video traffic should not be marked as CS7 at all. Cisco recommends using AF41 for video traffic:

http://www.cisco.com/en/US/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND/QoSIntro.html

http://www.cisco.com/en/US/technologies/tk543/tk759/technologies_white_paper0900aecd80295aab.pdf

As marking the video priority as CS7 may hurt your network as well as the customer's network, I would personally recommend reasoning with your customer and try to persuade him to start marking the packets with AF41. However, if that is not possible, I do not recommend carrying the customer's video traffic through your network just so, as it may negatively impact its operation. You could perhaps remark the DSCP of the customer's traffic to AF41 as it enters your network and optionally rewrite it back if the traffic is sent towards another location of the same customer.

Best regards,

Peter

[kb.choudhury]

Dear Peter,

Thanks for your reply, I totally agreed with you, with CS7 the network will be totally at the mercy of video bandwidth consumption, routing and ncp, ipcp everything will be effected.

Is anyone ever done any such configuration with CS7 ? I am very much egar to know what was his experiences.

Thanks again & Regards,

kb choudhury