[c-nsp] Egress shaping/policing for bandwidth control on a 3750-ME

Brad Henshaw brad.henshaw at qcn.com.au
Mon Mar 9 19:59:19 EDT 2009


Frank Bulk - iName.com wrote:
 
> I have two Cisco 3750-ME (Metro) where we are trying to apply
> an 8 Mbps bandwidth limit to it.  
> We tried HQM shaping but got a lovely message that "Hierarchical
> service-policies are only supported on ES interfaces".

Frank,

The 3750ME can only do per-VLAN shaping on the ES ports.

You can shape standard ports (but not per-VLAN) in increments of 10% of
the port speed using the 'srr-queue bandwidth limit' command. To achieve
8Mbps with this you'd need to lock the [FastEthernet] port to 10Mbps and
set the limit to 80%. Buffering of packets is less than ideal.

The 3750ME supports hierarchical dual-level *ingress* policies on SVIs.
To use these you need to set 'mls qos vlan-based' on the port and may
or may not need to use a 'match input-interface' statement in the class
of a subpolicy. (I've never used these so can't comment with authority)

I'd provide an example but I'd just be ripping it from page 35-71 of
the 3750 Metro 12.2(46)SE Software Configuration Guide ;-)

I'm pretty sure neither SVIs nor standard ports support output policies
so you'd best do as much as you can on the ES ports on ingress from your
core.

Note that ingress service policies on 12.2(44)SE1 seem to be broken - 
This may also affect other versions. We never logged a bug because it's
fixed in 12.2(46)SE.

Overall I think the quality control on IOS releases for the 3750ME
leaves a BLOODY LOT to be desired.

Regards,
Brad


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