Ethernet Module testing (using Ixia)

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Mar 19th, 2009
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Hi all,

Pls advice if you have experience performing ethernet load testing

What i was planning to do was to have ethernet modules (NM-16ESW and HWIC-9ESW) loaded on a 2811 and 3845 and provide performance results based on ethernet loads.

Qtns that i was hoping for clarifications

-what's the best way to fully load all 16/9 ports with traffic through the use of Ixia.

-Would it be easier to have all ports configured under a single VLAN and have ixia flood traffic throughout a single broadcast domain or have each port connected to a dedicated layer 3 switch and have ixia flood traffic over a subnet range.

appreciate your inputs

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Overall Rating: 3.3 (3 ratings)
Giuseppe Larosa Fri, 03/20/2009 - 00:33
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Hello Clive,

I would keep all ports in the same vlan so that no external devices are introduced.

Remember to define flows so that there is not unicast flooding:

each MAC destination has to be also a source MAC address of traffic in another port.

Hope to help


echelon360 Mon, 03/23/2009 - 16:18
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Hello Giuseppe, just a quick qtn pls.

I'm setting up the cabling now and at present, i've connected 16 ports from the 3750 to the 3845 (NM-16ESW).

Is there a significant difference if i test using a single broadcast domain as opposed to having ports configured as native ports and flooding traffic via independent broadcast domains?

Giuseppe Larosa Tue, 03/24/2009 - 01:56
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Hello Clive,

until routing is not needed: if flows are confined in a single broadcast domain you can use multiple vlans / broadcast domains

Hope to help


echelon360 Thu, 04/02/2009 - 16:57
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Hello Giuseppe,

I have setup the test build as attached in this message.Could you please advice if i'm approaching this correctly.

-cabled up 9 LAN cables between the 3750 and 2811

-created vlan 900 on both switch and router. Assigned all ports to this vlan

I'm stuck with the Ixia part of it as i'm not entirely sure how to proceed.

Should i create 9 flows based on the number of ports connected?

Giuseppe Larosa Thu, 04/02/2009 - 23:42
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Hello Clive,

first of all if the 9 ports module in the 2811 has a GE uplink you need to connect it to a second ixia GE port.

in this way you can create bidirectional traffic and you can measure forwarding performances.

ixia:port1 --- C3750 == 9 links == c2811 --- ixia:port2

The second problem is that if when STP is running only one FE link will be active all other will be blocked.

Possible solutions for this are:

creating a bundle of 9 FE ports (etherchannel) but it is unlikely that can be supported by the lan module.

second solution:

the two uplink ports to/from IXIA become L2 802.1Q trunk ports carrying 9 vlan tags.

each port is placed on both ends in a different vlan:

900 - 908

in this way all ports are in STP forwarding state.

Note: Now, that I see the drawing I changed mind and I think this second solution using 9 vlans is better.

On the IXIA you need to generate on each port at least 9 flows including the 802.1Q tag and you need to use for the vlan-id field the vlan-ids defined on the switches: 900 -908.

Doing so makes not important the MAC addresses that you use it is just enough they are not made only of 0s.


It looks like the module has no GE uplink.

in this case you need to do the following:

leave 5 FE links between C3750 and the the C2811, find a way to connect the other 4 ports to a third external switch with a GE uplink and close it on the second IXIa port.

Hope to help


echelon360 Tue, 04/07/2009 - 14:58
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Hello Giuseppe, thanks for responding.

I was looking through the ixia docs and the best approach to take is to assign each port to a vlan and have a stream assigned to it.

the link between ixia and the 3750 is a trunk fibre port.

Let me look more into this and try the configurations.


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