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New Member

QoS on Egress TCP Traffic

Hi,

What is the best way to achieve QoS on a TCP traffic? For eg I want to achieve a throughput of 10Mb. As we are a service provider we apply rate limit at our end. So if we have to do shaping on egress traffic it takes buffer for each customer and the router may run short of memory. If we have to do in CPE then we will be overutilizing the link to the customer. I we apply policing it starts dropping the packets due to its saw tooth nature.

I want to achieve this only for Egress traffic like internet or ftp download to the customer.

Thanks,

Silju

2 REPLIES
Cisco Employee

Re: QoS on Egress TCP Traffic

Hi Silju,

Why don't you configure the class base qos by which I mean classify the traffic based on tcp port number using extended ACL and then apply some action or police the traffic on classfied traffic.

For an example just have a look at this link and read the classffication section

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat3750/12225see/scg/swqos.htm#wp1196344

HTH

Ankur

New Member

Re: QoS on Egress TCP Traffic

Hi Ankur,

Policing will not help to achieve the desired throughput for TCP because of its saw tooth nature.

http://www.cisco.com/en/US/tech/tk543/tk545/technologies_tech_note09186a00800a3a25.shtml

But with shaping we can achieve the throughput but the device require enough buffers to store the data or we may have to implement WRED to randomly drop the traffic.

As we are a service provider there are lot of customers on one box so the device require enoough buffer size to store the excess traffic.

Regards,

Silju

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