Modular QoS (low latency queueing) on SHDSL bridged config

What router and software are you using?

  1. Since you have TAC then just keep beating them until they fix it.

  1. I have spent a lot of time on this trying to get it to work and to understand it and I have not really succeeded.

I did get it to work I think by doing the following.

pvc 0/38 vbr-nrt 240 240 !

Reply to
Bod43
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Got an issue where I am trying to apply a policy map on an outbound SHDSL interface.

The SHDSL is configured via a BVI so you can't apply CBWFQ on that, nor the ATM interface nor the subinterface. But you CAN apply it to the pvc within the ATM subinterface config.

However when I apply it, it doesn't mark the outbound packets properly - everything appears to be caught in the default class.

I have confirmed the config is correct because

a.) exact same policy map works on multiple different routers using variety of different WAN connections b.) I write a 'test' policy map using the same class maps, except the only action I perform is to mark DSCP. When I apply this test policy map to the LAN side ingress queue, it correctly classifies the traffic.

I have actually escalated this to Cisco TAC who suggested changing the shdsl config to use vbr-nrt instead of the previous mode ubr , but no dice.

Anyone seen this before?

Reply to
Johann Lo

Yeah that was our general consensus at work as well (i.e. bridged = L2 hence L3 marking and classification won't work).

I tried applying a policy map to the BVI already, no dice. I don't have a dialer as its using IRB (ATM subinterface part of bridge group, then you route/address on the BVI interface). Sorry I don't know much about ATM/SHDSL (they don't even cover this stuff properly in CCNP Remote Access module, its a shame really as there is so much SHDSL out there and there's only going to be more and more wanting to carry voice).

TAC'S SOLUTION - not really a solution but educational!

TAC's reply is that CBWFQ is not supported using Integrated Bridging and Routing which is how this particular router is configured (there is a bridge irb command in there somewhere). I think your solution is working because you're using ADSL so its going to be PPPoE or PPPoA hence its encapsulated (Route Bridging Encapsulated) not directly bridged.

I'm going to keep at this problem to see if there is a solution short of asking the carrier to change how this link is delivered / putting in a router behind the current one just for QoS queueing (e.g. back to back serial cable, dial down the clock rate to match the WAN link speed and apply LLQ to the outbound interface).

Reply to
Johann Lo

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