From: Chris Lewis \(chrlewis\) (chrlewis@cisco.com)
Date: Tue Sep 06 2005 - 15:18:36 GMT-3
It can make CLI easier, but for the purposes of the exam, the usual
rules apply of needing to answer what is asked :)
Chris
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Edwards, Andrew M
Sent: Tuesday, September 06, 2005 12:46 PM
To: Chris Lewis (chrlewis); ccielab@groupstudy.com
Subject: RE: bandwidth remaining percentage
Chris,
Based upon what you are saying, it seems to me that using bandwidth
remaining percent might be a better implementation for any class of
traffic specified within a policy that uses LLQ.
So, put another way, it might just be better to use bandwidth remaining
percentage whenever there is a LLQ. Yes?
andy
-----Original Message-----
From: Chris Lewis (chrlewis) [mailto:chrlewis@cisco.com]
Sent: Thursday, September 01, 2005 7:26 PM
To: Edwards, Andrew M; ccielab@groupstudy.com
Subject: RE: bandwidth remaining percentage
Here is one example;
policy-map pm1
class traffic
bandwidth remaining percent 90
class voice
priority percent 20
class class-default
bandwidth remaining percent 10
The show policy-map output looks like this
Router1(config-if)#service-pol out pm1
Router1(config-if)#do sho policy-map int
Serial3/0
Service-policy output: pm1
Class-map: traffic (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: protocol ip
Queueing
Output Queue: Conversation 265
Bandwidth remaining 90 (%) Max Threshold 64 (packets)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
Class-map: voice (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: ip rtp 16383 16383
Queueing
Strict Priority
Output Queue: Conversation 264
Bandwidth 20 (%)
Bandwidth 308 (kbps) Burst 7700 (Bytes)
(pkts matched/bytes matched) 0/0
(total drops/bytes drops) 0/0
Class-map: class-default (match-any)
1 packets, 24 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: any
Queueing
Output Queue: Conversation 266
Bandwidth remaining 10 (%) Max Threshold 64 (packets)
(pkts matched/bytes matched) 1/365
(depth/total drops/no-buffer drops) 0/0/0
So voice gets 308K, which is 20% of 1544Kbits as expected, and we are
not told what the other classes get, which is in contrast to what we see
when we use bandwidth percent.
policy-map pm3
class voice
priority percent 20
class traffic
bandwidth percent 30
class class-default
bandwidth percent 25
Router1(config-if)#do sho policy-map int
Ethernet0/0
Service-policy output: pm3
Class-map: voice (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: ip rtp 16383 16383
Queueing
Strict Priority
Output Queue: Conversation 264
Bandwidth 20 (%)
Bandwidth 2000 (kbps) Burst 50000 (Bytes)
(pkts matched/bytes matched) 0/0
(total drops/bytes drops) 0/0
Class-map: traffic (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: protocol ip
Queueing
Output Queue: Conversation 265
Bandwidth 30 (%)
Bandwidth 3000 (kbps) Max Threshold 64 (packets)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
Class-map: class-default (match-any)
1 packets, 60 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: any
Queueing
Output Queue: Conversation 266
Bandwidth 25 (%)
Bandwidth 2500 (kbps) Max Threshold 64 (packets)
(pkts matched/bytes matched) 1/390
(depth/total drops/no-buffer drops) 0/0/0
The reason is that bandwidth remaining will allocate available bandwidth
in the percentage defined in the configuration, so in the example given,
the worst case for the class traffic is it gets 90% of 1544-308 (1112)
if the priority traffic fills the priority queue, if the priority
traffic uses less than that, class traffic gets something more than
1112, but only in the proportion of 90% of whatever the priority traffic
is not using.
In terms of wording, you could be asked to configure a given amount for
priority, then be told to use a percentage scheme for allocating
bandwidth to the other classes, where the allocation must total 100%
(which you could not do using just bandwidth percent). Maybe they would
reference something about the difference in the output of the show
policy map display, maybe showing you this policy map and telling you to
make the router display that (as they do with BGP tables sometimes).
Alternatively they could ask about unused bandwidth being assigned in
the proportion of its allotment, but that I think would be hard to word
precisely, but you never know :)
Chris
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Edwards, Andrew M
Sent: Thursday, September 01, 2005 6:12 PM
To: ccielab@groupstudy.com
Subject: Re: bandwidth remaining percentage
Anyone have a better explaination of when to use the remaining
percentage than CCO?
Explain it to me like a 5 year old? 8)
I know that it's the relative bandwidth available after LLQ, RSVP, and
ip rtp priority. But what type of example (wording) might lead you to
use it?
andy
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