From: Radoslav Vasilev (deckland@gmail.com)
Date: Sun Sep 17 2006 - 10:13:33 ART
Hi Group,
While re-testing some QoS sections, I came accross this lab task, which
solution I consider partially wrong.
This will revive an old discussion about exactly this task (CAR to MQC
configuration transition).
I won't copy the whole CAR configuration, as I have problems with the
following part of it only:
existing rate-limit:
[...]
rate-limit input access-group 102 256000 4000 8000 conform-action transmit
exceed-action set-prec-transmit 0
access-list 102 permit tcp any any
This has to become a CB Policing congiguration with the IEWB solution being:
policy-map MQC-CAR
[...]
class TCP
police cir 256000 bc 4000 be 8000
conform-action transmit
exceed-action set-prec-transmit 0
I consider the solution incorrect as:
CAR and CB Policing have multiple differences, one of which is that CAR has
two actions (conform, exceed) and CBP has thee (conform, exceed, violate).
This is true when Be>0, which is the case in this task.
Now, what CAR achieves with the configuration above is that traffic will
still conform even when additional tokens should be borrowed from Bucket2(Be
bucket). In case when Be is used, the packets Precende won't be override.
With the proposed IEWB MQC solution, the packet's IP Precedence will be
override when Be extra tokes have to be used (bursts of traffic when Be can
cover). Therefore the suggested solution in my opinion is not entirely
correct.
My solution:
class TCP
police cir 256000 bc 4000 be 8000
conform-action transmit
exceed-action transmit
violate-action set-prec-transmit 0
Could you guys comment the solutions?
Rado
This archive was generated by hypermail 2.1.4 : Sun Oct 01 2006 - 16:55:40 ART