Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
New Member

3550-12G Useless??

Actually, I love the 3550s. I'm wondering why the 3550-12G doesn't support CAR. We want to use this for some metro access, but I can't rate limit the port. What gives? What are other people using in this capacity of low cost, GBIC dense boxes?


Re: 3550-12G Useless??

As far as I know, Cat Os don't support CAR. CAR is only for L-3 packets and supports in IOS of routers. Other alternatives, to use QoS queueing techniques like WRR.

I hope this following link helps...


New Member

Re: 3550-12G Useless??

The 3550s don't use CatOS. They use IOS and are an L3 switch. However, I did do some research and came up with a QoS config that polices the traffic and drops any out of profile in conjunction with the time-based ACLs. It could have been a lot simpler with CAR support.


Re: 3550-12G Useless??

The 3550 does support policing using command "policer" in policy-map config, and also "mls qos aggregate-policer" in global config. You can specify certain rate and limit traffic to that rate, and drop traffic exceeding that rate. See example below:

class-map match-all data

match ip dscp 18



policy-map policer

class data

police 128000 80000 exceed-action drop

int gi0/1

service-policy output policer

Do this help?? I believe this should solve your purpose.



New Member

Re: 3550-12G Useless??

You are correct and that is a good egress policy. I ended up with an ingress policy because I needed to match an ACL that was referencing time ranges. I haven't decided yet if there is going to be a need to also throw on an egress policy. Thanks for your reply. However, I'm sorry to see that I can't apply these policies to VLAN interfaces.

CreatePlease to create content