Rate Limiting Switch port Egress Traffic

[jschweng]

I have 3750G-12TS-S   fiber siwtch with 12  1000Mbs fiber ports and need to rate limit  the traffic leaving the swtich on several ports down to 25M

ios version 12.2.50SEB3

I know srr-que can be applied to the interface for outbound traffic and its in 10% increments of the total bandwidth so don't think that will work

And I think I can rate limit the inbound traffic using a qos policy.

Is there any way to restrict the outbound traffic to 25M.

Thanks

jeff

[Latchum Naidu]

Hi jeff,

See the below two individual steps may help in your scenario.
You can change some parameters based on at how much bandwidth you want restrict.

STEP-1:

Apply rate-limit on each L3 vlan interface in your 2851
Example (for 1024kbits for vlan 2):

Router# conf t
Router(config)# int vlan 2
Router(config-if)#rate-limit input 1000000 187500 375000 conform-action transmit exceed-action drop
Router(config-if)#rate-limit output 1000000 187500 375000 conform-action transmit exceed-action drop

STEP-2:

Policy a specific VLAN number on VLAN interface.

class-map vlan5
match vlan 5
match class-map class-default

policy-map vlan5-limit
class vlan5
police 2000000 250000 exceed-action drop

int vlan5
service-policy input vlan5-limit

After you apply this configuration, the traffic with VLAN 5 coming from any will be policed at 2Mbps.
Hope this will help you.

HTH
Please click on the correct answer if this answered your question.
Regards,
Naidu.

[jschweng]

thanks Naidu

The second STEP-2 is similar to what I was using to what I was using to rate limit traffic entering the swtich.  Except that I was applying the servvice-policy tp specific ports.   I need to rate limit traffic on specific ports as it leaves the switch.  I dont think its an option to apply a service policy as  "service-policy output policy-map"  - I could only apply as an input.

The first STEP-1 I havent tried.   I have one vlan 650 with several gig ports on the switch.   The exitnig traffic on each port needs to be rate-limited to 25M.  If I apply:

Router(config)# int vlan 650

Router (config)# rate-limit output 25000000 2000000 1000000 conform-action transmit exceed-action drop

Then doesnt that mean that if I have several ports (4 for example) all transmitting data which are all on Vlan650, that the total 25M will be what is allowed to leave out of Vlan650 and so the aggregate rate will be split between the 4 ports.  And if only one port is transmitting at any given time then the switch will allow 25M out that port?

if so is there any way to speciify output rate-limiting on specific ports?