Mark it's own BGP packets with QoS

[DarkStorm007]

Been looking the answer to this.

Between two routers I am seeing that applying some marking to the packets apply to the incoming packets from some source to the router. But, what about marking the BGP packets the router generates and then send it to the BGP peer? It is that possible?

[Seb Rupik · Accepted solution]

Hi there,

It is default behaviour of cisco routers to mark IGP and BGP packets with a DSCP value of CS6, the highest possible priority.

https://tools.ietf.org/html/rfc2474

cheers,

Seb.

[DarkStorm007]

Now I proved that by getting TCP 179 opened in my windows and see a BGP packet from my router, it says CS6 or IPP 6 (if I do not get wrong in the second one).

The question then would be that why I loss connectivity when I full use the internet connection even if the BGP have higher ToS and all other traffic is without treatment? (no QoS has been applied on other than BGP)

I did the test and my BGP goes down. After aplying some EF QoS to incoming packet from the tunnel I have to my BGP peer (using the internet link) it is not happening anymore.

[Seb Rupik]

Hi there,

The packet will be marked correctly as you have seen, but it is up to you to configure both trust and QoS policing/ shaping to ensure that it is prioritised along the links toward the destination BGP peer.

cheers,

Seb.

[Joseph W. Doherty]

As Seb notes, although, by default, Cisco BGP packets are marked with DSCP CS6, also by default, routers don't have QoS policies.