QOS and Policy Map

Answered Question
Aug 17th, 2014
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Gentlemen,

I am just wondering if below qos and policy map configurations are correct or if there is anything that i am missing .... I would welcome any comments...

=====

class-map match-any b_classmap

match access-group name b_acl

class-map match-any g_classmap

match access-group name g_acl

class-map match-any s_classmap

match access-group name s_acl

class-map match-any class_default

match access-group name class-default_acl

=

=

policy-map qos_policymap

class g_classmap

priority percent 35

set ip dscp ef

class s_classmap

bandwidth remaining percent 65

set ip dscp af31

class b_classmap

bandwidth remaining percent 35

set ip dscp af21

class class-default

set ip dscp af11

===========

 

Thank you

 

 

Correct Answer by acampbell about 2 years 11 months ago

Hi,

I think this what Joseph is trying to alert you to

You are using the "remaining percent" command
That means you are allocating 35% to Gold -- 65% left

You are then trying to allocated 65% of the 65% (left) to Silver
That leave you a remaining 35% which you have then allocated to Bronze.

You have now starved the DEFAULT

What about re-writing the map like ths:-

policy-map qos_policymap
class g_classmap
priority percent 35
set ip dscp ef
class s_classmap
bandwidth percent 25
set ip dscp af31
class b_classmap
bandwidth percent 15
set ip dscp af21
class class-default
set ip dscp af11

In total I have allocated 35 + 25 + 15 = 75%
So that leave 25% for the DEFAULT

Regards
Alex

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Joseph W. Doherty Mon, 08/18/2014 - 06:43
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Posting

"Correct" depends on what your QoS goals are.  Not knowing those, cannot judge.

However, you usually don't define a class map for class-default, because it's just that, the default.

Also, you've allocated all remaining bandwidth to your S and B classes, so zero for class-default?

eandrcisco007 Fri, 08/29/2014 - 08:33
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Thank you, here I am just trying to tweak the current configuration,

At this point I am almost pretty sure that QOS has no impact on both incoming and outgoing traffic so i am trying to figure it out, troubleshoot and fine tune its configuration and limits.

Can you please update what would be the standard configuration? Considering the fact that Class Gold priority will stay @ 35 percent for sure but the rest (Silver/Bronze and default) can be changed and reconfigure. (Gold 35%, Silver 25%, Bronze 15% and Default remainder)

According to sh policy-map int ... command, the drop rate is all zero on all class maps and the queue limit is on (default) 64 packets.

Please let me know if you need further details.

 

Thank you

 

Joseph W. Doherty Fri, 08/29/2014 - 09:17
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The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

If you believe your current QoS has no impact - unsure what you're expecting to accomplish with "tweaking".

There really isn't a "standard" QoS configuration.  QoS depends on your service requirements and traffic.

You say you're sure Gold will stay at 35% but other classes can be changed.  Ok, why?  Again, unless you define your service goals, how would I know Gold should be 35% and what your other class should be?

PS:

BTW, QoS features are platform and IOS version dependent, so without knowing that, even if knew your QoS goals, I couldn't offer specific recommendations.

eandrcisco007 Fri, 08/29/2014 - 09:50
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Joseph,

Below are the numbers that we would like to accomplish per our goals.

(Gold 35%, Silver 25%, Bronze 15% and Default remainder)

and the IOS is 15.2 (4) M2

FYI. I dont see any output based on the current qos configureation and its logs, so i assume it doesnt have any impact and or the configuration is incorrect. ( i need to fugure it all out)

 

 

 

 

 

Correct Answer
acampbell Sat, 08/30/2014 - 16:21
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Hi,

I think this what Joseph is trying to alert you to

You are using the "remaining percent" command
That means you are allocating 35% to Gold -- 65% left

You are then trying to allocated 65% of the 65% (left) to Silver
That leave you a remaining 35% which you have then allocated to Bronze.

You have now starved the DEFAULT

What about re-writing the map like ths:-

policy-map qos_policymap
class g_classmap
priority percent 35
set ip dscp ef
class s_classmap
bandwidth percent 25
set ip dscp af31
class b_classmap
bandwidth percent 15
set ip dscp af21
class class-default
set ip dscp af11

In total I have allocated 35 + 25 + 15 = 75%
So that leave 25% for the DEFAULT

Regards
Alex

eandrcisco007 Mon, 09/01/2014 - 21:28
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Thank you Alex, I am going to check for sure.

Basically, I have not configured above configuration and it has been like that for a long time but i am trying to update/change and or modify its configuration  accordingly but in the meantime I am curious to know what the current configuration does to our outgoing interface traffic....i am going to send you some output and show commands .... to see if you could check and verify.

 

 

 

eandrcisco007 Tue, 09/02/2014 - 15:15
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Here is the output of sh policy-map interface gigabitEthernet ....

GigabitEthernet0/1

Service-policy output: qos_policymap

queue stats for all priority classes:

Queueing

queue limit 64 packets

(queue depth/total drops/no-buffer drops) 0/0/0

(pkts output/bytes output) 169520965/64449869603

Class-map: gold_classmap (match-any)

169520962 packets, 64449871325 bytes

5 minute offered rate 8000 bps, drop rate 0000 bps

Match: access-group name gold_acl

169520964 packets, 64449871180 bytes

5 minute rate 8000 bps

Priority: 35% (70000 kbps), burst bytes 1750000, b/w exceed drops: 0

QoS Set

dscp ef

Packets marked 169520969

Class-map: silver_classmap (match-any)

13440635 packets, 7617928250 bytes

5 minute offered rate 50000 bps, drop rate 0000 bps

Match: access-group name silver_acl

13440635 packets, 7617928250 bytes

5 minute rate 50000 bps

Queueing

queue limit 64 packets

(queue depth/total drops/no-buffer drops) 0/0/0

(pkts output/bytes output) 13440635/7617928250

bandwidth remaining 65%

QoS Set

dscp af31

Packets marked 13440635

Class-map: bronze_classmap (match-any)

18038596 packets, 6200868725 bytes

5 minute offered rate 57000 bps, drop rate 0000 bps

Match: access-group name bronze_acl

18038596 packets, 6200868725 bytes

5 minute rate 57000 bps

Queueing

queue limit 64 packets

(queue depth/total drops/no-buffer drops) 0/0/0

(pkts output/bytes output) 18038596/6200868725

bandwidth remaining 35%

QoS Set

dscp af21

Packets marked 18038596

Class-map: class-default (match-any)

60032394518 packets, 59606814921807 bytes

5 minute offered rate 102874000 bps, drop rate 0000 bps

Match: any

queue limit 64 packets

(queue depth/total drops/no-buffer drops) 0/0/0

(pkts output/bytes output) 60032394581/59606563114914

QoS Set

dscp af11

Packets marked 60031729916

======

 

Above is based on the current configuration and i have not made any changes per your suggestion.

I would like to know what impact current configuiration has before we make the chnages and i would like to be able to measure it if possible.

 

Please check the config. and let me know /thanks

 

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