How does one bond two interfaces together to share bandwidth?

[Michael Smith]

Hello:

On Dec 13, 2006, at 5:13 PM, Dan Nelson wrote:

> In the last episode (Dec 13), N. Harrington said:
>>  I am trying to figure out how to bond or combine 2 interfaces
>> together. Such that they each share traffic.
>>
>>  I have tried one way, however when I use it I seem to have an odd
>> broadcast occuring on my switch. Such that I am seeing incoming
>> traffic hit some other ports on the switch.  Can someone confirm if I
>> am doing it correctly? Perhaps I have a switch issue? Do I also need
>> to bond the ports together on the switch? Sadly the switch they are
>> connected to does not support port bonding. Does that matter? I have
>> not seen any mention of that being required.
>
> If the remote switch doesn't support it, only outgoing traffic will be
> split across both ports.  Incoming traffic will probably come in on  
> the
> first port that came up, or the switch may decide that there's a
> routing loop (or other misconfiguration) because the same MAC address
> is seen on both ports, and disable one of the ports (or even both).
> Most managed switches should support it; they may call it trunking.

Both sides need to support EtherChannel which is 802.3ad (although  
Cisco does have a proprietary variant (go figure)).  If only one side  
is set to channel and the other side is not, the non-channeled side  
will detect a loop and set one of the ports into blocking state; that  
is, if it's Spanning Tree aware.  If it's a consumer-grade switch or  
hub, the network will do the functional equivalent of a Bill the Cat  
face and fall over most dramatically.

Regards,

Mike