[rbak-nsp] propagate qos to l2tp

[Jim Tyrrell]

Does the propogate QoS to L2TP only propogate from/to the 3 most 
significant bits of the DSCP?

I have subscribers within an MPLS context and I want to propogate the 
users DSCP to the L2TP packet, in particular EF 46, but the outgoing 
L2TP is always marked as 40.  It seems that only the 3 most significant 
bits are set so it can not be marked as EF - is this correct?

Here is an example of my config:

context local
  router mpls
   propagate qos from mpls

context testnetwork
  l2tp-peer unnamed local 192.168.10.110
   function lns-only
   lns card selection priority
   lns card 2 preference 1
   propagate qos to l2tp class-map qos-to-l2tp

qos class-map qos-to-l2tp ip out
  qos 40 to ip 46

And a packet capture:
17:13:23.069910 IP (tos 0xa0, ttl 255, id 5450, offset 0, flags [none], 
proto: UDP (17), length: 102) 192.168.10.110.1701 > 
192.168.10.104.1701:  l2tp:[](34233/55764) {IP (tos 0xb8, ttl 253, id 
28458, offset 0, flags [none], proto: ICMP (1), length: 64) 10.88.50.7 > 
10.88.50.150: ICMP echo request, id 7369, seq 99, length 44}

The outgoing packet correctly has 0xb8 in the subscriber packet, but the 
outer L2TP is 0xa0.  If I change the qos mapping I can alter the 
outbound to one of the other priorities (ie 0,8,16,24,32,40,56) but not 
the 3 less significant bits for the drop priority.   I need to mark the 
outbound L2TP as 46 EF if the subscriber packet is EF, is this possible?

Thanks.

Jim.