[c-nsp] IRB and 802.1q subinterfaces - How to set COS?

[Herro91]

Hi,

A few ideas - don't know if they will work for you:

1) Have you considered or verified if local switching is available on this
router/IOS? This would allow you to "connect" the two interfaces together -
essentially bridging them, though I believe there is no mac learning with
local switching, so it would just forward the packets, not learn destination
macs.

2) Regarding the QoS - I've seen some cases where you need to put the
policy-map on the main interface. This was on a GSR and a particular
linecard - but may be worth a try. It could just be it won't work properly
with the way your doing bridging.

3) Have you done any debugs?




On Wed, May 4, 2011 at 7:11 PM, Robert Johnson <fasterfourier at gmail.com>wrote:

> IOS 12.4 advanced enterprise on a 3745. I have two fast ethernet
> interfaces, each with a set of 802.1q subinterfaces. Each subinterface
> has a bridge-group assigned to it so that select VLANS on each FE port
> are bridged. I'd like to apply a policy-map to one of the outbound
> subinterfaces that looks at the DSCP value of outbound IP packets and
> sets an 802.1p COS according to the DSCP value found. Here's the
> relevant part of the configuration:
>
>
> class-map match-all assure
>  match ip dscp af31
> class-map match-all critical
>  match ip dscp cs6
> class-map match-all expedite
>  match ip dscp ef
> !
> policy-map output-cos
>  class expedite
>  set cos 6
>  class assure
>  set cos 5
>  class critical
>  set cos 7
> !
> interface FastEthernet1/0
>  description Trunk to switch 1
>  no ip address
>  full-duplex
> !
> interface FastEthernet1/0.500
>  encapsulation dot1Q 500
>  bridge-group 100
>  service-policy output output-cos
> !
> interface FastEthernet2/0
>  description trunk to cheverly-md-s1b
>  no ip address
>  full-duplex
> !
> interface FastEthernet2/0.500
>  description Customer access
>  encapsulation dot1Q 500
>  bridge-group 100
>  service-policy output output-cos
> !
> interface BVI100
>  ip address x.x.x.x y.y.y.y
>  ip verify unicast reverse-path
> !
> bridge 100 protocol ieee
> bridge 100 route ip
>
>
> The policy-map can't be applied to the BVI since it's not handling
> VLAN tagging. However, the above configuration doesn't pick up any of
> the traffic marked with the DSCPs specified in the class-map:
>
> #sho policy-map int f1/0.500
>  FastEthernet1/0.500
>
>  Service-policy output: output-cos
>
>    Class-map: expedite (match-all)
>      0 packets, 0 bytes
>      5 minute offered rate 0 bps, drop rate 0 bps
>      Match: ip dscp ef (46)
>      QoS Set
>        cos 6
>          Packets marked 0
>
>    Class-map: assure (match-all)
>      0 packets, 0 bytes
>      5 minute offered rate 0 bps, drop rate 0 bps
>      Match: ip dscp af31 (26)
>      QoS Set
>        cos 5
>          Packets marked 0
>
>    Class-map: critical (match-all)
>      0 packets, 0 bytes
>      5 minute offered rate 0 bps, drop rate 0 bps
>      Match: ip dscp cs6 (48)
>      QoS Set
>        cos 7
>          Packets marked 0
>
>    Class-map: class-default (match-any)
>      4380 packets, 297206 bytes
>      5 minute offered rate 0 bps, drop rate 0 bps
>      Match: any
>
> Also, the class-default class does not seem to be counting in tune
> with the actual traffic flowing across the subinterface.
>
> This configuration works if the BVI is removed and IP addresses are
> assigned directly to the subinterfaces. Unfortunately this is not a
> practical solution due to other design considerations.
>
> Ideas? TIA.
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