shaping policy

Unanswered Question
Jul 21st, 2009
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Hi ,

Between two of our sites, i have gathered below data in terms of traffic across these.Both links are connected by 8M Cloud.

Inbound -

- from proxy servers 60%

- from an application server (port 80) 10%

- from another server (port1599) 9%

- from email servers 8%

-rest to other traffic

Outbound -

- to proxy server 30%

- to server (port 80) 11%

- to another server (port1494) 9%

- to mail server 27%

- Rest is for rest of small traffic

I need to apply shaping on both sides.Please advise how much % of shaping bandwidth should i allocate to each class for efficient use. & what is the best way to determine so?

If am not wrong, shaping would slow down the drop rate of packets during high congestion.


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Joseph W. Doherty Tue, 07/21/2009 - 04:06
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Assuming you have more than 8 Mbps physical connections to the "cloud" at your two sites, and assuming within such "cloud" it either polices your traffic to 8 Mbps or has global FIFO congestion (for your traffic), and assuming there's only these two sites in communication, then shaping could be of much benefit. Most shapers implement (W?)FQ, so if you just shape for "8M" (BTW, you might need to allow for L2 overhead), on both sites outbound, you might not need to do anything more.

If such approach doesn't work well enough for you, you might want to implement a hierarchical service policy rather than shaping different classes of traffic.

suthomas1 Tue, 07/21/2009 - 04:27
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Thanks, if we implement a hierarchial policy, how would be the shape "bandwidth" assignments for each class ( like server , proxy etc) be based on the results.

like proxy server - shape 300000 so on.

Joseph W. Doherty Tue, 07/21/2009 - 04:43
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I'm not sure that you can, i.e. nested shapers.

Within a hierarchial policy, normally you shape for the available bandwidth, then you provision how you want your classes to share this bandwidth. (I.e. you don't shape per class.) In most cases this would be a better approach since classes can use bandwidth unused by other classes yet are guaranteed some bandwidth.


policy-map parent

class class-default

shape average #

service-policy child

policy-map child

class email

bandwidth percent 5

class proxy

bannwidth percent 10



interface (WAN)

service-policy output parent


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