[c-nsp] RSVP and CBWFQ

[Luan Nguyen]

Not sure if anyone answer this yet but the following is what I dig up from
CCO:
"RSVP works in conjunction with, not in place of, current queueing
mechanisms. RSVP requests the particular QoS, but it is up to the particular
interface queueing mechanism, such as WFQ or WRED, to implement the
reservation.  WFQ or WRED sets up the packet classification and the
scheduling required for the reserved flows. Using WFQ, RSVP can deliver an
integrated services Guaranteed Rate Service. Using WRED, it can deliver a
Controlled Load Service.  For RSVP, an application could send traffic at a
rate higher than the requested QoS, but the application is guaranteed only
the minimum requested rate. If bandwidth is available, traffic surpassing
the requested rate will go through if sent; if bandwidth is not available,
the exceeding traffic will be dropped."
Additional information here
http://www.cisco.com/en/US/partner/products/sw/iosswrel/ps1831/products_conf
iguration_guide_chapter09186a00800c60ce.html#78227
So to answer your question to the best of my knowledge...
RSVP is a signaling protocol much like IP precedence.  CBWFQ will use it as
it uses the TOS bit.
So you probably will have
Interface serial6/0
Ip rsvp bandwidth 10000 10000
Service-policy output RSVP
Class-map match-all RSVP
Match protocol rsvp (instead of match ip precendence 5..etc)
Policy-map RSVP
Class RSVP
*you probably don't need to use bandwidth percent here since cbwfq will use
the rsvp configure on the interface itself...not so sure what will happen if
you put bandwidth percent 33 or something like that here*
Class default
Fair-queue
Random detect
Then the above config will provide an absolute rate even in case of
conjestion - exceed traffic will be dropped in case bandwidth is not
available -if available everything will go through

I am running some CBWFQ tests tomorrow using some fancy tools like IXIA and
netIQ chariot if have some time will test this out for sure.

Luan




-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Temkin, David
Sent: Thursday, August 12, 2004 7:52 PM
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] RSVP and CBWFQ

Anyone know how the two interact?
If I reserve a percentage of interface bandwidth with "bandwidth
percent" but also use RSVP to reserve, say, 10mbit of bandwidth on a
ds-3, does the default class get 35mbit minus whatever the percent was?
Or does it oversubscribe, or, finally, does  it take the bandwidth
reservation in a certain order

Any info anyone has would be great...

-Dave

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