[c-nsp] Link/Line Testing

[Keegan Holley]

2011/5/31 James Bensley <jwbensley at gmail.com>

> Hi list,
>
> Is there any way from either a router or L3 switch I can saturate a
> line/link? I don't want to use a computer or external device.
>

Network appliances just don't have the chops to generate line rate data.
 You need an external device to get anything accurate.  Even the high end
platforms have only PIII cpu's most of which is dedicated to something other
than packet generation.  I wouldn't trust any results based on packets
generated from a router.

>
> Lets pretend that $provider has given me a 1Gbps up-link to a device
> which terminates various 100 Mbps links, so having a pc with software
> to pump out 1Gbps would be no good.


You could have a pc with software pump out 100M to match your CIR.  iperf
and other tools are pretty simple.  Then there are ethernet test sets that
will generate realistic traffic rates and patterns based on standards link
IMIX.  I've also generated traffic in the past by causing a contained
bridging loop somewhere.


> Since most people have up links
> many times faster that most other ports on their routers/switches how
> can I test the up link throughput from the device.
>

Just set the test parameters to match the CIR/rate-limit and not the port
speed.

>
> If for what ever reason I had 1Gbps access ports with a 1Gbps up link
> I could use a pc/hardware traffic generator and test the link and for
> example routers ability to policy route and filter at 1Gbps but I just
> want to test the physical link its self for its top end throughput.
>

Which top end the physical 1G or the logical 100M?  Again, I'd use some sort
of load generation software or an ethernet test set.  Even if you had a CRS
or something to generate the data I doubt it could generate 1Gbps from the
processor without keeling over.

HTH,

Keegan