[c-nsp] etherchannel load-balancing and unpredictability

[David Prall]

Typically the first port on one will return via the first port on the other.
The hash is based on src and dst, so they hash to the same link. Test
etherchannel will show you what the actual hash is for a given source and
destination, run it for some randomly chosen traffic. If you are only
looking for redundancy, and don't want spanning-tree, you can run LACP with
max-bundle configured. Then you will only use 1 of the interfaces in the
port-channel even though you have 2. 

David

--
http://dcp.dcptech.com


> -----Original Message-----
> From: Steven Pfister [mailto:SPfister at dps.k12.oh.us]
> Sent: Wednesday, July 20, 2011 9:11 AM
> To: David Prall; 'Keegan Holley'
> Cc: cisco-nsp at puck.nether.net
> Subject: RE: [c-nsp] etherchannel load-balancing and unpredictability
> 
> Yes, that's correct. Either content filter should be able to handle all
> of the load if it needed to.  The goal was mainly redundancy.
> 
> If we swap the links so interface 1 on one switch goes to interface 2
> on the other and vice versa, would that help?
> 
> Steve Pfister
> Network Engineer
> Office of Information Technology
> Dayton Public Schools
> 115 S Ludlow St
> Dayton, OH 45402-1812
> Phone: 937-542-3149
> Cell: 937-673-6779
> spfister at dps.k12.oh.us <mailto:spfister at dps.k12.oh.us>
> 
> 
> >>> "David Prall" <dcp at dcptech.com> 7/19/2011 8:48 PM >>>
> Keegan,
> I think he isn't worried about it being unpredictable load wise. He's
> more
> interested in it being predictable that a source .1 to .2 on the inside
> switch goes over link 1, and that the .2 to .1 on the outside switch
> returns
> over link 1.
>