QOS - Policing example

vincehgov · ‎10-05-2010

Hi, thanks in advance for any help you could give me.

I'm trying to configure QoS between my US site and my UK site. Here are the details:

1. Leased line has a bandwidth of 3Mbps.

2. I have 5 queues: Voice (ef), Control protocols (af41), Video (af31), Citrix (af21), and default

Here's the relevant config. Tagging is done on the inbound interface and I'm only showing the outbound interface here.

The problem I am experiencing is that class-default traffic sometimes uses up all the bandwidth to the point that it affects the quality of the other traffic. Keep in mind that this link is the bottleneck. Everything else is gigabit.

class-map match-any AF41

match dscp af41

class-map match-any EF

match dscp ef

class-map match-any AF21

match dscp af21

class-map match-any AF31

match dscp af31

!

policy-map To_UK

class EF

priority 512

class AF41

bandwidth 256

class AF31

bandwidth 768

class AF21

bandwidth 1024

class class-default

policy-map To_UK_Shaper

class class-default

shape average percent 95

service-policy To_UK

!

interface FastEthernet0/0/0

description to SAVVIS UE to UK

bandwidth 3088

ip address 192.168.100.1 255.255.255.248

duplex full

speed 100

service-policy output To_UK_Shaper

!

Jerry Ye · ‎10-05-2010

I will change two thing in your configuration

policy-map To_UK

class EF

priority 512

class AF41

bandwidth 256

class AF31

bandwidth 768

class AF21

bandwidth 1024

class class-default

bandwidth percent 1 ! make the default to 1% during congestion

policy-map To_UK_Shaper

class class-default

shape average 3000000 ! shape the interface to 3Mb

service-policy To_UK

vincehgov · ‎10-05-2010

I'll try that and let you know. Thank you.

I thought that the 'bandwidth' statement guarantees a minimum bandwidth. I don't understand how this could work but I'll give it a shot and test it out.