From: Godswill Oletu (oletu@inbox.lv)
Date: Tue Mar 10 2009 - 06:18:19 ARST
> Did you have a closer look at the 'show policy-map interface' output?
> It clearly shows "bandwidth percent 70" resulting in a 70,000kbps
> bandwidth allocation to the class.
You will get an output similar to what you stated above, if you change the
maximum reserved bandwith from the default of 75% to 100%
see some example
!
policy-map test
class test1
bandwidth percent 70
class test2
bandwidth percent 30
!
interface FastEthernet0/0
max-reserved-bandwidth 100
service-policy output test
!
!
BR1#sh policy-map interface fa0/0
FastEthernet0/0
Service-policy output: test
Class-map: test1 (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: protocol imap
Queueing
Output Queue: Conversation 265
Bandwidth 70 (%)
Bandwidth 70000 (kbps)Max Threshold 64 (packets)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
Class-map: test2 (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: protocol snmp
Queueing
Output Queue: Conversation 266
Bandwidth 30 (%)
Bandwidth 30000 (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)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: any
BR1#
<changing the reserved bandwidth back to its default of 75%>
!
interface FastEthernet0/0
service-policy output test
!
BR1#sh policy-map interface fa0/0
FastEthernet0/0
Service-policy output: test
Class-map: test1 (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: protocol imap
Queueing
Output Queue: Conversation 265
Bandwidth 70 (%)
Bandwidth 52500 (kbps)Max Threshold 64 (packets)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
Class-map: test2 (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: protocol snmp
Queueing
Output Queue: Conversation 266
Bandwidth 30 (%)
Bandwidth 22500 (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)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: any
!
In both cases my 100% allocation to the policy-map yield different real
bandwidth to the policy-maps, depending on the max reserved bandwidth
configured on the interface.
Godswill Oletu
CCIE #16464 (R&S)
----- Original Message -----
From: "Dale Shaw" <dale.shaw@gmail.com>
To: "Godswill Oletu" <oletu@inbox.lv>
Cc: "karim jamali" <karim.jamali@gmail.com>; "Cisco certification"
<ccielab@groupstudy.com>
Sent: Tuesday, March 10, 2009 4:01 AM
Subject: Re: max-reserved-bandwidth
> Hi,
>
> On Tue, Mar 10, 2009 at 6:48 PM, Godswill Oletu <oletu@inbox.lv> wrote:
>> Though you have allocated 95% in your policy statements; you are actually
>> only using 95% of 75% of the interface bandwidth (or around 71.24% of
>> 100%
>> of the interface bandwidth).
>> <assuming max reseved bandwidth is left at its default of 75%>
>
> Hmmm..
>
>> If you reduce or increase the max reserved bandwitdth under the
>> interface;
>> the real bandwith allocated to each of your class maps will be
>> recalculated
>> and change accordingly.
>
> Did you have a closer look at the 'show policy-map interface' output?
> It clearly shows "bandwidth percent 70" resulting in a 70,000kbps
> bandwidth allocation to the class.
>
>> So, the answer to your question is no.
>
> I think the key may be found in the IOS the original poster is running.
>
> From:
> http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6558/white_paper_c11-481499.html
>
> "max-reserved-bandwidth Command
> The max-reserved-bandwidth command no longer affects the amount of
> bandwidth available to a service policy. Any policy-map can allocate
> up to 100% of the bandwidth without the need of the
> max-reserved-bandwidth command. The max-reserved-bandwidth command was
> used in previous IOS releases in order to overcome the restriction of
> allocating 75% of the bandwidth to user-defined classes. In HQF, that
> restriction does not exist anymore."
>
> And, for reference, here's Pavel Bykov's research from the archives:
> http://www.boxoid.org/cisco/MAX-RESERVED-BANDWIDTH-AND-CBWFQ.pdf
>
> cheers,
> Dale
Blogs and organic groups at http://www.ccie.net
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