From: gladston@br.ibm.com
Date: Sat May 07 2005 - 10:07:43 GMT-3
Would you interpret the following statement:
=======================
quoted
Note CQ was modified in Cisco IOS Release 12.1. When the queue is depleted early, or the last packet from the queue does not exactly match the configured byte count, the amount of deficit is remembered and accounted for the next time the queue is serviced. Beginning with Cisco IOS Release 12.1, you need not be as accurate in specifying byte counts as you did when using earlier Cisco IOS releases that did not take deficit into account.
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fqos_c/fqcprt2/qcfconmg.htm#1003648
======================
as if we do not know the size of the packets for, for example, telnet, www and ftp, "deficit remembered" will correct this. Just use any value for all protocols.
For example, using 1500 bytes, 20% for www, 10% for telnet, 30% for ftp:
20/1500 , 10/1500 , 30/1500
0.013 , 0.007 , 0.02
normalizing -> 1.86 , 1 , 2.86
round up the numbers --> 2 , 1, 3
www byte count is 3000
telnet byte count is 1500
ftp byte count is 4500
If the real size of www was 1500, telnet 700 was and ftp was 600, would the new CQ correct the differences in bandwidth use?
Do you think the following Cisco statement was cancelled by the previous? (change on 12.1)
=================================
quoted
For example, suppose one protocol has 500-byte packets, another has 300-byte packets, and a third has 100-byte packets. If you want to split the bandwidth evenly across all three protocols, you might choose to specify byte counts of 200, 200, and 200 for each queue. However, this configuration does not result in a 33/33/33 ratio. When the router services the first queue, it sends a single 500-byte packet; when it services the second queue, it sends a 300-byte packet; and when it services the third queue, it sends two 100-byte packets. The effective ratio is 50/30/20
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fqos_c/fqcprt2/qcfconmg.htm#1003648
==================================
So the new CQ after 12.1 would really get an effective ration of 33/33/33 in this Cisco example.
This archive was generated by hypermail 2.1.4 : Fri Jun 03 2005 - 10:11:57 GMT-3