1. The QoS service offered by the ISP allows for control of how traffic is prioritised and bandwidth is reserved, with three queues available (multimedia – VoIP, critical data and normal data). Packets must be remarked with the following values to be classified on a each queue:
2. Thus, before sending the packets to the ISP router, the packets must be remarked with the EF value for VoIP 1)http://www.cisco.com/c/en/us/td/docs/ios/solutions_docs/qos_solutions/QoSVoIP/QoSVoIP.html and with AF11 for critical applications. Other traffic that are not being remarked will be forwarded to the normal data queue, with best effort processing.
3. The first step towards traffic remarking will be defining ACLs for traffic classification:
acl number 3121 description From_Priority_Application rule 0 permit tcp source 10.109.7.121 0 source-port eq 443 acl number 3500 description VoIP_Traffic rule 0 permit udp destination-port range 16384 32767 rule 5 permit tcp destination-port eq 1720
4. Configure traffic-classifiers using the defined ACLs.
traffic classifier From_Priority_Application operator and if-match acl 3121 traffic classifier voip operator and if-match acl 3500
5. Configure traffic-behaviors and inform the values to remark the packets.
traffic behavior voip-behavior remark dscp ef traffic behavior Marking_Priority_Application remark dscp af11
6. Configure the qos-policy to match each traffic-classifier to the desired traffic-behavior.
qos policy Remote-Locations classifier From_Priority_Application behavior Marking_Priority_Application classifier voip behavior voip-behavior
7. Apply the defined qos-policy to the port where the ISP router is connected.
interface Gigabit-Ethernet 4/0/5 qos apply policy Remote-Locations outbound
8. To verify the results, use the command:
display qos policy interface
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