Priority queuing question

[Sandip Barot]

Hi ,

I want to establish QOS on our ASA firewall for VOIP traffic but have a question about its functioning.

5 Mbps internet connection ----> ASA  --->  LAN

If I apply it to outside interface (connected to 5 Mbps internet) , will priority queuing kicks in when 5Mbps bandwidth is saturated or when the actual physical Interface (100 Mbps) is saturated?

Thanks,

[Vivek Ganapathi]

Hi Sandip,

I would like to understand more on this,

1) Do you have an IPSEC tunnel running in from your ASA to some office ?

2) Do you have an agreement with your Internet service provider to carry your QoS Markings End-to-End?

Without an agreement with Service provider, you would never be able to achieve an end-to-end priority for your VoIP.

Regards

Vivek

[Sandip Barot]

Its an Internet leased line from provider and we used it for both voice and data traffic from LAN. There is 90% voice traffic

We just want to ensure that any heavy download from LAN client should not consume entire 5 Mbps bandwidth and prevent it from affecting voice quality.

We do not have any agreement with ISP but it is guaranteed 5 Mbps up/down bandwidth and there is no IPsec tunnel.

[Vivek Ganapathi]

Well in that case, i would suggest to speak to the ISP & get this clarified. In order for you to get a priority treatment of voice traffic, your service provider should carry those QoS markings end-to-end. This involves co-ordination by the ISP with other ISP vendors as well.

[Sandip Barot]

Hi Vivek,

thanks for your input.

With current scenario, Is there any other QOS technique which can help us to prevent voice traffic not affected by download from client? (i.e like reserving some bandwidth in-out from ASA for voice traffic or limiting http traffic to consume cettain bandwidth only)..

[Vivek Ganapathi]

Hi Sandip,

What is the router model on the internet edge?

Regards

Vivek

[Sandip Barot]

Its ASA 5510

[Vivek Ganapathi]

Yes, i think we can do something about your requirement here.  Solution would be configure Traffic Policing. Define the classes - VOIP  & HTTP/S etc. You would effectively be rate-limiting the traffic.  You can define the WEB traffic to be dropped if it goes beyond the  configure limit. Below is a link which may help.

http://blog.ine.com/2008/09/20/qos-on-the-pixasa-%E2%80%93-part-4traffic-shaping-and-traffic-policing/