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Testing QoS policy by generating source UDP port traffic - is it possible

We have voice traffic that we are identifying and marking using an ACL

 

ip access-list extended voice
permit udp any range 16384 17683 any range 16384 17683

 

Then mark the traffic below with a DSCP of EF

policy-map wan-out
class realtime-1
set dscp ef

 

Policy Map wan-shaping-pri
Class class-default
Average Rate Traffic Shaping
cir 18730000 (bps)
service-policy wan-out

 

Then apply the policy-map to the WAN interface

 

service-policy output wan-shaping-pri

 

I'm looking for a way to generate EF marked traffic to check the service provider is honouring the marking which I believe isn't happening. We don't have any in-bound ACLs to check against.

 

As the ACL is checking both source and destination UDP ports I'm having trouble finding a way to generate test traffic that allows me to configure both source and destination UDP ports. Every tool or test I find only allows me to define the destination UDP which is no good for me as I need to define the source port for the ACL to match.

 

Any idea of tools out there without modifying the ACL to allow any source UDP port?

 

Cheers

Barry

7 Replies 7

Dennis Mink
VIP Alumni
VIP Alumni

iperf can do this, it allows you to generate trraffic with a certrain dscp value

 

https://iperf.fr/iperf-download.php

Please remember to rate useful posts, by clicking on the stars below.

Helo, iperf does not allow for the configuration of the source port and only allows destination port to be defined.

Barry,

 

what is it you are after exactly? simulate RTP traffic and see if the ef dscp value is honoured end to end?

 

cheers 

Please remember to rate useful posts, by clicking on the stars below.

Yes that's it. 

 

Trouble is all the ways I can find only allows you to define the destination UDP port and not the source. Trouble is our ACLs check for source and destination ports before it marks them with EF. 

 

Cheers

 

Barry

Hello Barry,

you can modify your ACL to match only on destination UDP ports for the time you make tests.

 

You should capture traffic on the workstation running iperf on the remote end and check if DSCP settings is still EF or not.

 

This is your target and you can modify your ACL to adapt to the limitations of the available traffic generator.

 

The service provider should honor = mantains your marking of DSCP. The ISP can have provided you what DSCP values it is going to accept from you and EF should be among these values.

Use packet size of 64 or 100 bytes to emulate VOIP packets.

 

Hope to help

Giuseppe

 

Hi, Sorry you seemed to have missed some of my wording to the question. 

 

I cannot modify the ACL easily to test.

 

The question IS. Are there any tools out that that allow me to generate some traffic where I can define the source AND destination UDP port.

 

Cheers

 

Barry

Hello Barry,

you can define an alternative ACL, an alternative class-map, and an alternative child policy-map for tests.

 

I don't see any great difficulty in doing this from a technical point of view.

 

You can explain to your manager that you need to adapt to what available traffic generators can do.

Otherwise you cannot make your tests.

 

Hope to help

Giuseppe

 

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