[c-nsp] Catalyst 6524 rate limit per port/vlan

[John Gill]

Mohammad,
The ES ports on the ME3750 are different than the other ports.  Which 
kind are yo using?

For ES ports you can use average rate shaping (class-based):
http://www.cisco.com/en/US/docs/switches/metro/catalyst3750m/software/release/12.2_50_se/configuration/guide/swqos.html#wp1282429

For non-ES ports, you can use "srr-queue bandwidth limit" to shape an 
entire interface to a rate, configurable at integer percentages - this 
is a great command but lacks in granularity.  For example,  you can set 
a gigabit port to 80% bandwidth, and you may see "show mls qos interface 
gi1/0/1" will say the bandwidth limit is 81.75.  If you set the 
bandwidth to 81%, you may see the limit has not actually changed, or 
perhaps it's now 82.03.  Just making up some examples, but basically you 
will see the actual hardware implementation of that command when you 
check it.  The downside is that this command affects the whole port and 
is not a true CIR, so it works well for handing off to a provider that 
charges you overage but not great if you are using it for a customer 
that you guarantee a certain burst.  When using bandwidth limit, you are 
relying on the egress buffers to handle the burst, so as you allocate 
more buffer for a given queue, you will see better performance in 
congestion.

Regards,
John Gill
cisco


On 5/30/11 9:19 PM, Mohammad Khalil wrote:
>
> Hi
>
> i am facing the same issue with Cisco ME3750
> and the traffic i want to limit is the outbound traffic
>
>> Date: Sun, 29 May 2011 23:34:20 +0200
>> From: paveldimow at gmail.com
>> To: mtinka at globaltransit.net
>> CC: cisco-nsp at puck.nether.net
>> Subject: Re: [c-nsp] Catalyst 6524 rate limit per port/vlan
>>
>> Hi Mark,
>>
>> thank you for your suggestion. I still can't figure out whats so
>> specific and difficult about egress rate limit?
>> Everyone seams to offer ingress rate limit but egress is very rare and
>> results vary.
>>
>>
>> Maybe someone from Cisco can shed a little light on this? :)
>>
>>
>> On Wed, May 25, 2011 at 3:48 AM, Mark Tinka<mtinka at globaltransit.net>  wrote:
>>> On Saturday, May 21, 2011 05:32:24 AM Pavel Dimow wrote:
>>>
>>>> I'am thinking of using CAT6524 as access switches for our
>>>> pure l2vpn customers. I have started reading about rate
>>>> limiting capabilities of those switches but it I can't
>>>> find a way to do a per port or per vlan rate limit. With
>>>> MQC I can limit the speed in inbound but not in outbound
>>>> direction. Is there any better way to do it? I don't
>>>> understand what is the problem with
>>>> outbound rate limit for Cisco (and Juniper) switches? Is
>>>> it architecture or something else and how come that
>>>> there is no problem for rate limit on routers (even the
>>>> smallest one).
>>>
>>> I would look at Cisco's ME3600X/3800X for this deployment. I
>>> wouldn't waste my time on an ME6524, given the capabilities
>>> and price of the ME3600X/3800X.
>>>
>>> Note that egress policing in this platform is not yet
>>> available in the software (but the hardware is built to
>>> support it). This should be out towards the end of 2011.
>>>
>>> Cheers,
>>>
>>> Mark.