[j-nsp] Set 802.1p bits for DHCP packets generated from the routing-engine

[Alex D.]

Hi Saku,
> You should be able to set forwarding-class for inject packets through
> lo0.0 egress filter. Rewrite filter on interface would then set
> appropriate CoS bits.
i tried that, but as mentioned, it didn't work. For testing purposes, i 
configured a "log all" as first term:
term log-all-re-traffic {
     then log;
}
DHCP packets from routing-engine to the DHCP-server and DHCP packets 
from client to the router are logged as expected. But mysteriously, I 
don't see DHCP packets from routing-engine towards the clients (behind 
the ONT) and thus setting a forwarding-class with this term also doesn't 
work. Did you already see such a behaviour?
I will do some further troubleshooting in our lab asap.

> However it is not entirely obvious to me why would you want to inject
> anything else but NC from control-plane, it seems like unnecessary
> complexity. Sure maybe it's not important that your SFTP of core file
> out from router is NC, but it's not like it's going to congest your NC
> and kill your LDP/BGP/IGP.
>
yes sure, i could inject management-traffic as NC, but as i implemented 
CoS in our Backbone initally, i decided to have it in an own 
forwarding-class. But problem for RE-generated DHCP-traffic would 
remain, because there is a strange problem with some GPON ONT types. 
They discard DHCP traffic, if DHCPOFFER has not the same 802.1p value as 
the respective DISCOVER/REQUEST. On our ONTs, we hand over three 
services separated by VLANs. Each VLAN is hardwired with a specific 
802.1p-Bit (VoIP=5, HSI=0,...) on our OLT and therefore the 
DHCPREQUEST/DHCPDISCOVER arrive with different p-bits.

I hope I could bring a little light into the dark ;-)

Regards,
Alex