RE: [nsp] two interfaces on the same LAN with same subnet

From: David Sinn (dsinn@microsoft.com)
Date: Wed Nov 21 2001 - 13:47:15 EST


This is only true of the early implementations of etherchannel in
switches (Cat5k series). The 6500 series will do EtherChannel
frame-distribution based on source/dest IP address, or MAC, depending on
your config. IP is the default, but you can revert to MAC if you need
for consistency sake.

David

> -----Original Message-----
> From: Dmitri Kalintsev [mailto:dek@hades.uz]
> Sent: Tuesday, November 20, 2001 3:14 PM
> To: cisco-nsp@puck.nether.net
> Subject: Re: [nsp] two interfaces on the same LAN with same subnet
>
>
> On Tue, Nov 20, 2001 at 04:22:17PM -0500, Yuval Ben-Ari wrote:
> > Niels,
> > According to following URL what you are saying is not configurable:
> >
> http://www.cisco.com/univercd/cc/td/doc/product/lan/cat5000/re
l_6_2/_con
> fig/channel.htm#23937
>
> "EtherChannel distributes frames across the links in a channel based
on
> the low-order bits of the source and destination Media Access Control
> (MAC) addresses of each frame. The frame distribution method is not
> configurable."
>
> It is possible, however, to manipulate MAC addresses.

FYI: etherchannel on *router* side would load-balance based on hash of
source/dest _IP_ address. It implies that if you run etherchannel
between
router and a switch (we're talking Cisco here), and most of the traffic
heading into router would be coming from one layer2 point (say, gateway
router), it will occupy one of etherchannel links, but return traffic
(from
router into switch) will load-balance. ;) Extremely useless. ;)

SY,

-- 
 CCNP, CCDP (R&S)                          Dmitri E. Kalintsev
 CDPlayer@irc               Network Architect @ connect.com.au
 dek @ connect.com.au    phone: +61 3 9674 3913 fax: 9251 3666
 http://-UNAVAIL-         UIN:7150410    cell: +61 414 821 382



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