From: Edwards, Andrew M (andrew.m.edwards@boeing.com)
Date: Tue Aug 02 2005 - 14:44:36 GMT-3
2. There is a big difference between priority and police
First look at the basic MQC traffic classes.
Within a defined traffic class, traffic is serviced FIFO. As an added
benefit, you can enable congestion avoidance techniques such as WRED
within a traffic class. But the Congestion Management mechanism
mechanism is FIFO within the class.
You can define a bandwidth and a que depth to each class. If you define
a class to be given a bandwidth value, this value becomes the minimum
amount of guaranteed BW that will be available when there is congestion
on the outbound interface. By default the minimum que depth is 64.
This can be adjusted to affect tail-drop. As specified earlier, if you
desire other than tail drop you can implement WRED to the class instead
of the que depth.
Now, using the priority feature implements low latency queueing for
CBWFQ; versus police which implements a rate-limiting function to the
class.
Priority - places that class of traffic into a low latency que for
immediate transmission. Another affect of the priority command is that
it will police traffic of that class to the specified rate when there is
congestion; without congestion no police action. You can specify
multiple classes to be part of the low latency que. Each will be placed
into the low latency que and policed to their individual class rates
when congestion occurs.
Police - traffic is queued FIFO within traffic class. Otherwise, like
CAR, it rate limits (no buffer) the traffic class. Like CAR you can set
conform and exceed parameters. Unlike CAR there is an added violate
option for dual rate policing (optional).
CBWFQ info:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/
fqos_c/fqcprt2/qcfconmg.htm#1001203
Regarding question 1, your other option is really Custom Queueing.
CQ allows you to specify a relative BW by adjusting the byte-count
allocated to each que.
EX.
Queue-list 1 protocol ip 2 tcp www < if you want to be more specific
use the list option instead >
Queue-list 1 default 3
Queue-list 1 que 2 byte-count 4000
Queue-list 1 que 3 byte-count 6000
Int x/y
Custom 1
The list option just specifies an access list number to match traffic.
Make sure you define the ACL for ALL web traffic.
HTH,
andy
-----Original Message-----
From: buesink@fma.nl [mailto:buesink@fma.nl]
Sent: Tuesday, August 02, 2005 8:25 AM
To: ccielab@groupstudy.com
Subject:
Hi Guys,
I have a question, maybe someone can help me
1]
Let's say we have a www server in a certain vlan.
Give all www traffic to this server a bandwidth of 40% of the total
But you can't use policy maps.. Is this possible.. so doing it without
the
class-map policymap servicepolicy thing.
2] Could somebody give me the difference between MQC priority command
and police command.
Thanks in advance
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