When there are no QOS polices applied on a network, there is equal priority for all traffic passing through the network. This is when congestion occur. Configuring QOS helps select a specific traffic to be prioritized, which makes this traffic to be delivered on time and thus improving the performance.

In this blog we can see how we can mark the VOIP traffic with a DSCP value and send this traffic through the network with priority. We have taken two ways of Prioritizing.

1) Prioritizing using ACL:

Create your access list according to your network, based on the VOIP traffic. For eg: If the VOIP traffic will be from a particular Ip address or IP range. Create an Access group with the concerned IP address or the IP range. Consider we have given an Access group name Voip-group.

Now we can create a class-map with the name Voip-Traffic and add the ACL, class-map Voip-Traffic match access-group Voip-group set ip dscp ef

Next step will be to create a policy-map, here we have shown steps to create a policy-map with name voip_policy. Configure the class-map to