Cisco IOS - QOS Configuration Example on Metro Ethernet Link

Test Scenario:

• We have 5 Mbps point-to-point Metro Ethernet connection to an ISP
• All voip and video traffic should be prioritized to prevent delay and jitter
• ISP classifies our voice/video traffic according to dscp value of ef and they prioritized this traffic in their IP/MPLS backbone
• Lets make the configuration on branch site:

Firstly, voip-video traffic should be classified and marked:

In our example, Voip and Video packets are classified by their IP addresses(they can also be marked by lots of matching criteria)

ip access-list extended voip-video-acl

permit ip 10.10.11.0 0.0.0.255 any

class-map match-any voip-video-marking

match access-group voip-video-acl

policy-map Qos-Marking

 class voip-video-marking

  set ip dscp ef

Packets are marked when entering the router from the LAN side:

interface G0/0

service-policy input Qos-Marking

Then these packets will be prioritized:

class-map match-any voip-video

match dscp ef

policy-map QOS-child

class voip-video

priority percent 50

class class-default

fair-queue

random-detect dscp-based

Traffic shaping should be enabled according the CIR value in Ethernet WAN connections.In our case this value is 5Mbps.We are doing prioritizing in shaping queues:

policy-map QOS-parent

class class-default

shape average 5000000

service-policy QOS-child

Then we attached this policy-map to our WAN interface.

interface G0/1

service-policy output Qos-parent

Note: Similar QOS configurations should be done at remote side.