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Linear topology - QoS sugestion

Answered Question
Aug 12th, 2013
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  • Bronze, 100 points or more

Hi, I need to configure a topology and I would like some sugestion for QoS config.


The topology is like below. The distances are more than 20km. Please, don't suggest new topology as it's not possible. They are linked by optic fiber.

All the routers have a local lan and 2 WAN links, one to the left and one to the right. (except R1 and R11)



           Lan2                       Lan4........

              |                             |

R1------R2-------R3--------R4--------R5----------R6--------R7-------R8-------R9-------R10--------R11

|                            |                             |

Lan1                   Lan3                  Lan5......



Considering all links are 1Gb and all the server are at R11.     

My thought is, when R1 get to R2 it will share the traffic from "LAN1" and LAN2 on the link "R2-R3". So Lan1 will have 500Mb and Lan2 will have 500Mb.

So the bandwidth share will always be devided by 2 on each hop. (Lan1 on R4-R5 link will have 250Mb, on R5-R6 will have 125Mb.. and so on)



My idea so far is:

Devide 1Gb by 10(the number of links) = 100Mb.

Apply a policy that will set DSCP to 2 on traffic up to 100Mb on each site. exceed and violate traffic will have DSCP to 0.

On all links configure fair-queue.



I would like to hear any thoughts or sugestions.


Thanks

Correct Answer by Joseph W. Doherty about 4 years 6 days ago

Disclaimer


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


3560s don't support FQ.  Their QoS feature set is limited.  Enabling QoS on them can also be adverse to your traffic unless you've very carefully thought out (and fully understand) how to use their QoS features for your traffic.  (Paolo's earlier [?] comment, to first try to not use QoS, has merit on these platforms.  If you search these forums, you'll find quite a few posts about performance issues when [default] QoS is enabled on 3560s/3750s.)

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guibarati Mon, 08/12/2013 - 17:42
User Badges:
  • Bronze, 100 points or more

They are actually 3560 switches with ip services IOS.
The devices didn't arrive yet, so I'm not sure what version exactly.
I am still on the planning phase.

Thanks,


Sent from Cisco Technical Support iPhone App

Correct Answer
Joseph W. Doherty Mon, 08/12/2013 - 18:44
User Badges:
  • Super Bronze, 10000 points or more

Disclaimer


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


3560s don't support FQ.  Their QoS feature set is limited.  Enabling QoS on them can also be adverse to your traffic unless you've very carefully thought out (and fully understand) how to use their QoS features for your traffic.  (Paolo's earlier [?] comment, to first try to not use QoS, has merit on these platforms.  If you search these forums, you'll find quite a few posts about performance issues when [default] QoS is enabled on 3560s/3750s.)

guibarati Thu, 08/15/2013 - 11:49
User Badges:
  • Bronze, 100 points or more

Thanks Joseph,


I will do more research before enabling it.

Do you have any suggestion link for reading about it?

Joseph W. Doherty Thu, 08/15/2013 - 19:45
User Badges:
  • Super Bronze, 10000 points or more

Disclaimer


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



http://www.cisco.com/en/US/products/hw/switches/ps5023/products_tech_note09186a0080883f9e.shtml

https://supportforums.cisco.com/docs/DOC-8093

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