My understanding is that etherchannel uses a hash calculation on the destination and/or source mac address to determine which leg to send a packet on.
While I was reading IBM's etherchannel support in AIX I came upon a small item that stated you can change the policy to round-robin. THis would mean that one source/destination session would have it's packets sent over all legs of the etherchannel. There is a comment that this could cause some packets to be received out of order.
1) Does a filer support this type of etherchannel? My understanding is that replies are always sent from the same adapter the received packet came in on, even if the adapter is part of a etherchannel. It seems that a filer wouldn't card about this.
2) Do ethernet switches support this kind of etherchannel?
3) pro/con
I guess the question is - can this kind of etherchannel be used to make a true load balanced pipe either directly into a netapp or via network switches.
Thanks
It depends on what ethernet switch vendor you are using. From a Cisco article:
Another option, offered by a few vendors, is round-robin load
balancing,
which provides a much more equal spreading. This scenario may well generate out-of-order packets and, in an IP environment, requires the IP stack at the receiver to reorder the packets or request
retransmissions.
Unfortunately, it is not possible to quantify the impact on
performance
that this causes, and it is probably best to avoid this technique of load spreading, particularly in a high-traffic environment. In an environment where protocols other than IP (or IPX) are running, round-robin distribution may cause serious problems.
http://www.cisco.com/warp/public/cc/techno/media/lan/ether/channel/prodl it/faste_an.htm
YMMV, but in my experience going to a larger pipe has yielded better results than trying to do FEC. But, you need to use what you have :)
Alexei
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Richard L. Rhodes Sent: Thursday, January 03, 2002 10:29 AM To: toasters@mathworks.com Subject: Etherchannel
My understanding is that etherchannel uses a hash calculation on the destination and/or source mac address to determine which leg to send a packet on.
While I was reading IBM's etherchannel support in AIX I came upon a small item that stated you can change the policy to round-robin. THis would mean that one source/destination session would have it's packets sent over all legs of the etherchannel. There is a comment that this could cause some packets to be received out of order.
- Does a filer support this type of etherchannel? My understanding
is that replies are always sent from the same adapter the received packet came in on, even if the adapter is part of a etherchannel. It seems that a filer wouldn't card about this.
Do ethernet switches support this kind of etherchannel?
pro/con
I guess the question is - can this kind of etherchannel be used to make a true load balanced pipe either directly into a netapp or via network switches.
Thanks
My understanding is that etherchannel uses a hash calculation on the destination and/or source mac address to determine which leg to send a packet on.
While I was reading IBM's etherchannel support in AIX I came upon a small item that stated you can change the policy to round-robin. THis would mean that one source/destination session would have it's packets sent over all legs of the etherchannel. There is a comment that this could cause some packets to be received out of order.
- Does a filer support this type of etherchannel? My understanding
is that replies are always sent from the same adapter the received packet came in on, even if the adapter is part of a etherchannel. It seems that a filer wouldn't card about this.
It should. I'm not as familiar with AIX, but SunTrunking has the same option, and I've successfully used it with a Sun<->Filer connection using 4 100Mb ports.
- Do ethernet switches support this kind of etherchannel?
Don't know.
- pro/con
I guess the question is - can this kind of etherchannel be used to make a true load balanced pipe either directly into a netapp or via network switches.
I've used it to sustain 300+ Mb/s into a backup box from a filer. That was without any real tuning of the sun or the network. No switches were involved in that setup.