[j-nsp] Using QoS to ensure BGP bandwidth

Jason J. W. Williams jasonjwwilliams at gmail.com
Mon Apr 23 12:56:17 EDT 2007

Hi Guys,

I was hoping to use an egress filter to make sure BGP traffic got top
priority. The issue that occurred is that we accepted a flood of large
messages from Hotmail, which was alright on the inbound because the
Internet acted as speed buffer. However, when we went to deliver them
it saturated our line outbound going from our LAN to WAN connection,
which interrupted the BGP healthchecks. We've put some outbound
bandwidth restrictions on our delivery servers, however I was hoping
to also put BGP into a higher priority queue than all other traffic to
ensure the connection stayed up. Thank you in advance for your help.


On 4/23/07, Guy Davies <aguydavies at gmail.com> wrote:
> Hi All,
> It's worth pointing out that there is no implicit link between Q0 and
> a particular scheduler or behaviour.  If you want to use Q0 for
> control traffic, then do that.  Just make sure that all non-control
> traffic gets put into a different queue.  That's not particularly
> difficult if you put a MF classifier at all the ingress points to your
> network and default all traffic into Q3, for example.
> Rgds,
> Guy
> On 22/04/07, Thomas Mangin <thomas.mangin at exa-networks.co.uk> wrote:
> > Alex wrote:
> > > Jason,
> > > Locally originated BGP traffic is classified into Q0 by default (except BGP
> > > retransmissions)
> > > http://www.juniper.net/techpubs/software/junos/junos82/swconfig82-cos/html/cos-hardware4.html#1197876
> > > --and AFAIK, it is impossible to override this behaviour. So, in an essence,
> > > you can guarantee bandwidth to
> > > BGP traffic _through_ the router but not to locally-originated BGP traffic.
> > >
> > Never tried, just a mad idea.
> >
> > If using trunking to switches : create two vlan, one for control one
> > traffic. Use the control vlan for BGP traffic but make the next hop the
> > IP of the traffic interface ? This way you can limit the bandwidth on
> > the customer vlan and be sure that some is left on the "control" one. No
> > idea if you can apply the same idea to your IGP as well.
> >
> > Thomas
> > PS: I do not pretend it is a sane idea neither.
> > _______________________________________________
> > juniper-nsp mailing list juniper-nsp at puck.nether.net
> > https://puck.nether.net/mailman/listinfo/juniper-nsp
> >

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