From: Swan, Jay (jswan@sugf.com)
Date: Mon Jun 25 2007 - 17:04:23 ART
Yes, if you don't provision it, it will end up in class-default.
Depending on your queuing mechanism, the treatment of class-default
might vary.
Another thing to consider here is that in some designs you might have
control traffic inside GRE or IPSec tunnels. Packets in tunnels won't be
given pak_priority, so you might have to deal with that issue.
I just checked Szigeti's book; it says that IGPs (including IS-IS), PPP
keepalives, HDLC keepalives, ATM OAM & ARP cells, and FR LMI messages
are given pak_priority. BGP is not (but it's marked with CS6
automatically). IS-IS can be matched with NBAR if necessary with "match
protocol clns_is".
Jay
#17783
-----Original Message-----
From: Gregory Gombas [mailto:ggombas@gmail.com]
Sent: Monday, June 25, 2007 1:41 PM
To: Swan, Jay
Cc: Group study
Subject: Re: CBWFQ and pak_priority
Thanks Jay.
So if you forget to allocate the 3% for control traffic will the
control traffic end up in class default?
What part does max-reserved-bandwidth play in all this?
Isn't 25% of the available bandwidth already reserved for control
traffic?
Thanks again,
Greg
On 6/25/07, Swan, Jay <jswan@sugf.com> wrote:
> I believe the current QoS SRND recommends allocating 3% of link
> bandwidth to CS6 control traffic.
>
> On most platforms I think pak_priority should take care of IGPs, but
it
> doesn't provide for BGP or other control-type stuff like RSVP.
>
> IS-IS is also a special case since it's not IP traffic, and thus
doesn't
> have a DSCP value.
>
> Jay
> #17783
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Gregory Gombas
> Sent: Monday, June 25, 2007 11:03 AM
> To: Group study
> Subject: CBWFQ and pak_priority
>
> I was wondering if you need to specify a seperate class-map for
> routing protocols.
>
> According to the following doc:
>
http://www.cisco.com/en/US/tech/tk543/tk544/technologies_tech_note09186a
> 0080094612.shtml
>
> On some platforms you need to specifically assign to a queue:
> "In other words, on the Cisco 7500 series, if an output service-policy
> is attached to the interface, then the packets are classified with
> respect to the classes in that policy, and the pak_priority packet is
> placed at the end of the chosen class queue. If the pak_priority
> packet does not match any user defined class, then it is placed at the
> tail of the class-default queue.".
>
> What is the rule of thumb regarding routing protocol QOS?
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