QoS and control traffic

[dbass]

Can anyone please explain how control traffic (routing protocols, HSRP, L2 signaling, etc) is handled by a router in conjunction with a QoS policy?  I'm looking for specific references please .  I can't seem to find anything that is clear about the subject.

My understanding is that this traffic is marked by the router as prec 6, and is queued in to a seperate queue other than the user defined ones, so it does not need to be addressed within your QoS policy even if you are allocating 100% of bandwidth.  In older routers you did have to allocate bandwidth or else you could starve out that traffic, but I think that was fixed post 12.1 or 12.2 code and on all newer hardware.  That is just my understanding though, and I don't have any documentation that supports it...

Thanks for the help!

[Eugene Lau]

G'day,

This could help you get started for a conceptual overview:

SPD Selective Packet discard

http://www.cisco.com/web/about/security/intelligence/spd.html

Which is discussing it at the router/architecture layer.

I'm not sure what you are referring to in terms of the QoS policy and control traffic but here's another good doc

Enterprise QoS Solution Reference Network Design guide.

http://www.cisco.com/en/US/docs/solutions/Enterprise/WAN_and_MAN/QoS_SRND/QoS-SRND-Book.html

HTH get you started

Eugene.