From: Kenneth Wygand (KWygand@customonline.com)
Date: Sun May 23 2004 - 02:55:56 GMT-3
Joe,
There are two strategies you can employ, and your statements mesh two of them together in a way that it doesn't make logical sense, so in that way, you are correct!
When you use the token bucket (policing in this case) algorithm, each packet passing through the algorithm is considered to "conform", "exceed" or "violate" the restrictions (depending on which form of policing you are using - "rate-limit" uses only the "conform" and "exceed" actions while "class-based policing" uses all three of the restrictions.)
For arguments sake, lets say you are using the "rate-limit" command so all traffic can either "conform" or "exceed" the traffic contract you configure. For the traffic that exceeds, there are two strategies you can employ; you can send the traffic at a lower priority or you can drop the traffic completely. The first method, sending traffic at a lower priority, _will_ allow you to exceed the CIR, but will ensure that all traffic that does exceed the CIR has its priority marked down. This way, if congestion occurs at a later router, that router will know which traffic has already exceeded a particular traffic contract and can selectively drop that traffic first.
The other option, simply dropping the traffic completely, will always conform to the CIR, but will never send unconforming traffic.
Hope this helps!
Ken
-----Original Message-----
From: nobody@groupstudy.com on behalf of Joe Chang
Sent: Sat 5/22/2004 7:35 PM
To: ccielab@groupstudy.com
Cc:
Subject: Traffic Shaping question
QoS is a real popular topic here!
Does anyone know what happens to packets that are queued as a result of being
rejected by the token bucket algorithm? At what point are these packets
forwarded onto the transmit ring? Two streams result from the token bucket
function - one that conforms and one that doesn't. How and when can the
unconforming stream be sent without defeating the objective of traffic shaping
- keeping the average rate under the CIR?
TIA
_______________________________________________________________________
Please help support GroupStudy by purchasing your study materials from:
http://shop.groupstudy.com
Subscription information may be found at:
http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Wed Jun 02 2004 - 11:12:15 GMT-3