How do you schedule traffic that exits via a bridge-domain?

Question

I've got a single MX router connected to two physical interfaces on an SRX chassis cluster - each interface being a member of a reth interface.

In order to make this work, on the MX side I have the interface from each SRX node connected into a bridge-domain, which in turn has an irb configured on it for the L3 interface. This all works fine.

I now want to schedule egress traffic from the MX (received and classified on another interface) into an appropriate forwarding class, however the MX (currently) does not support applying a scheduler to an irb interface.

Has anyone come across a way of doing this on the MX?

Answer 1

So I just came up with a hideous hack that gives the desired result:

firewall {
    family inet {
        filter DSCP-CLASSIFIER {
            term MATCH-EF {
                from {
                    dscp ef;
                }
                then {
                    forwarding-class VOICE-FC;
                    accept;
                }
            }
            term MATCH-ALL {
                then {
                    forwarding-class BE-FC;
                    accept;
                }
            }
        }
    }
}
interfaces {
    irb {
        unit 100 {
            family inet {
                filter {
                    output DSCP-CLASSIFIER;
                }
                address 192.168.88.3/31;
            }
        }
    }
}

bdale@lab-mx80a> show interfaces queue ge-1/0/4.100
  Logical interface ge-1/0/4.100 (Index 334) (SNMP ifIndex 850)
Forwarding classes: 16 supported, 5 in use
Egress queues: 8 supported, 5 in use
Burst size: 0
Queue: 0, Forwarding classes: BE-FC
  Queued:
    Packets              :                176357                     0 pps
    Bytes                :              21939946                     0 bps
  Transmitted:
    Packets              :                176357                     0 pps
    Bytes                :              21939946                     0 bps
    Tail-dropped packets :                     0                     0 pps
...
Queue: 1, Forwarding classes: VOICE-FC
  Queued:
    Packets              :                    69                     1 pps
    Bytes                :                  8694                   896 bps
  Transmitted:
    Packets              :                    69                     1 pps
    Bytes                :                  8694                   896 bps
    Tail-dropped packets :                     0                     0 pps
...

This works because the traffic that I’m sending is already pre-marked with DSCP; even though it is being classified by an EXP classifier on an ingress MPLS interface and that’s what we should really be using to determine forwarding-class on the egress interface, but obviously because it’s a non-mpls interface, we don’t see the EXP on egress.

It bugs me that the box is clearly capable of scheduling egress traffic from an irb in this manner, but doesn’t support it in the more traditional (and saner) way through the CoS stanza.

If you’ve got any better ideas, I’m all ears!