[c-nsp] QoS on an Ethernet Sub-interface

[Justin Shore]

Pelle wrote:
> Not sure about this "one side" and "my side", but when you use a
> sub-rate Ethernet service you should apply a HQoS policy (parent
> shaper + child queues) on both ends of the link. There is no point
> sending egress traffic at 100Mbps (or even 1000Mbps) speed on your
> "full interface" 2821 when the actual pipe is just 3Mbps wide.

Unfortunately I don't admin the remote end of the link.  I'll send them 
my config and ask them to change it on their side.  I agree that 
line-rate traffic shouldn't be stuffed into a sub-rate queue on the 
transport provider's side.  That's asking for trouble.

> If your Ethernet provider support Ethernet CoS you could also "set cos
> X" on the interface where you use 802.1q encapsulation. Unfortunately
> this is not possible on regular Ethernet interfaces. Some SP's do
> support DSCP for classification of Ethernet frames, so you might be
> safe any way.

I don't believe they do.  Currently the L2 path isn't 1Q but it may be 
possible to change that.  I'll have to make some inquires.

> This policy should be attached both on the main interface on one end,
> and the sub-interface at the other end.

Right.  That's essentially what we've got.  They just had a free port on 
their 2821 when they set up their end.  On our end we had to bring it 
into a switch and trunk it up to the router.  I'm planning on moving the 
core routing over to the 3560E switch soon to get rid of the 
router-on-a-stick we have now.

> Note: There has been major improvement in HQoS and LLQ in 12.4(20)T,
> see the thread:
> https://puck.nether.net/pipermail/cisco-nsp/2008-August/053616.html

I was reading about that.  I would have loaded it the other night but my 
CF card was too small.  I'll have to try that in a later window.

Thanks for the info
  Justin