[c-nsp] Link/Line Testing

[Jeff Kell]

On 6/11/2011 3:07 PM, James Bensley wrote:
> OK, so now lets say you have a 24 x 100Mb port switch at the access
> layer and you have an EtherChannel over ports 23 + 24 to give 200 Mbps
> up to the distribution layer, how can you test that each end device is
> capable of pushing the 200Mbs over the EtherChannel?

To begin with, you can't just throw 200Mbps at the problem, as a
"port-channel" of 2(x) bandwidth doesn't mean you get 2(x) throughput,
your maximum speed for any ONE connection is going to be 1(x) if you are
talking about any of the Catalyst line of switches.  You would have to
push data that is particularly crafted for your switch load-balance
algorithm.

At layer-3, on a router, you can play with per-packet load balancing on
multiple equal cost paths (an old T1 bonding game), but as the speeds
increase you are likely to cause more layer-3 issues on the endpoints
with out-of-order packets, not to mention the load on the routers.

Or you can do flows over multiple equal cost paths with EIGRP and get
some traffic-load-based load balancing per flow.

But generically calling any aggregation of N*X links as providing N*X
bandwidth is best left to the marketing department :)

Jeff