From: Darren Johnson (dazza_johnson@yahoo.co.uk)
Date: Thu Jan 03 2008 - 06:49:01 ARST
Im interested to see how this tests out, however, having slept it seems I
overlooked something...
If the source sends to a destination, ASSUMING that the destination is not
currently learned (as per standard source mac-address learning), then the
configured load-balancing would be used - in our case destination-mac.
However, the receiving switch would 'learn' the source mac address of the
sender, so would traffic back to it use the same link using the mac-address
forwarding table? Does a switch learn mac address received over an
etherchannel with the etherchannel as the receiving interface, or the actual
physical interface that participates in the etherchannel? What Im basically
saying is, one of two things happen for the return frame:
1) The switch sends back to the 'original' source using the mac address
table
OR
2) The switch sends back to the 'original' source using the etherchannel
load-balancing method of choice.
Hmmmmm. Any thoughts?
-----Original Message-----
From: Gary Duncanson [mailto:gary.duncanson@googlemail.com]
Sent: 03 January 2008 00:33
To: Joseph Saad
Cc: ccielab@groupstudy.com; Darren Johnson
Subject: Re: port-channel load-balance for 3550/3560
Thanks Joseph,
Any chance you can test this? I shall have a look myself when I get a chance
as port-channel load balancing is next on my list of things to do.. From the
sounds of things you would also asserting that it is the receiving switch
configuration which determines which of it's ports it will egress it's
replies to regardless of what is configured at the 'sending' side. My
question then is does a reply need to go out the same port as it is received
on in a port-channel bundle for the L2 load balancing to work or will the
switch not care much really? You mentioned L3 load balancing. I understand
with BGP peering policies between directly connected AS's it should be
possible to configure a way to come back the same way as they go out.
Regards
Gary
----- Original Message -----
From: "Joseph Saad" <joseph.samir.saad@gmail.com>
To: "Cisco certification" <ccielab@groupstudy.com>
Sent: Wednesday, January 02, 2008 7:04 PM
Subject: Re: port-channel load-balance for 3550/3560
> so, let's assume that I want to use the same path for the traffic back and
> forth.
>
> I'd configure the sending switch with dest-mac and other switch with
> source-mac (I am taking the simple assumption that the MAC addressess are
> simply swapped in the response).
>
> HTH,
> Joseph.
>
> On Jan 2, 2008 11:02 PM, Joseph Saad <joseph.samir.saad@gmail.com> wrote:
>
>> What I simply mean is that: load balancing in a specific direction
>> depends
>> on the "Sending" switch.
>>
>> So, let's say you want to load balance the traffic always to be based on
>> destination MAC. then, I would ask in which direction?
>>
>> It's important to draw a quick L2 for such questions.
>>
>> It is similar to a router load balancing traffic between 2 links ... It
>> always depends on the router "sending" the traffic. the other router
>> returning the response, could completely use a different path and it
>> never
>> depends on how the information was received.
>>
>> Difficult to test, but I fail to see how a switch configuration can
>> control how the traffic is "received" by it.
>>
>> Joseph.
>>
>>
>> On Jan 2, 2008 10:52 PM, Gary Duncanson < gary.duncanson@googlemail.com>
>> wrote:
>>
>> > Joseph,
>> >
>> > This is interesting. Do you mean that the reply path is a done deal
>> > because
>> > the of the source mac used by the inbound frame?
>> >
>> > Incidently are you saying it needs to be port-channel load-balance
>> > dest-mac
>> > at both ends? It seems so.
>> >
>> > Regards
>> > Gary
>> > ----- Original Message -----
>> > From: "Joseph Saad" < joseph.samir.saad@gmail.com>
>> > To: "Cisco certification" <ccielab@groupstudy.com>
>> > Sent: Wednesday, January 02, 2008 6:09 PM
>> > Subject: Re: port-channel load-balance for 3550/3560
>> >
>> >
>> > > Darren, the return traffic will need to have port-channel
>> > > load-balance
>> > > dest-mac also but on the other switch. load balancing is determined
>> > > by
>> > the
>> > > "Sending" switch. don't you think?
>> > >
>> > > On Jan 2, 2008 5:42 PM, Darren Johnson <dazza_johnson@yahoo.co.uk>
>> > wrote:
>> > >
>> > >> To load-balance from source at SW1 to destinations at SW2, you will
>> > need
>> > >> to
>> > >> configure the etherchannel as:
>> > >>
>> > >> port-channel load-balance dest-mac
>> > >>
>> > >> Obviously, the return traffic would need the opposite
>> > (source-mac)....
>> > >>
>> > >> Check it out.
>> > >>
>> > >>
>> > >>
http://www.cisco.com/en/US/docs/switches/lan/catalyst3550/software/release/1
>> >
>> > >> 2.2_25_see/configuration/guide/swethchl.html#wp1020011
>> > >>
>> > >> Dazzler
>> > >>
>> > >> -----Original Message-----
>> > >> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
>> > Of
>> > >> Frank CCIE
>> > >> Sent: 31 December 2007 03:29
>> > >> To: shiran guez
>> > >> Cc: WorkerBee; Herbert Maosa; mazhar minhas; ccielab@groupstudy.com
>> > >> Subject: Re: port-channel load-balance for 3550/3560
>> > >>
>> > >> Hi, Experts,
>> > >>
>> > >> If there is only one source at SW1 and many destination at SW2,
>> > >> and
>> >
>> > >> SW3 is between SW1 and SW2. SW3 is 3550.
>> > >>
>> > >> How to config load-balance in SW3?
>> > >>
>> > >> Thanks
>> > >>
>> > >> Frank
>> > >>
>> > >> On Dec 30, 2007 1:33 PM, shiran guez < shiranp3@gmail.com> wrote:
>> > >> > if there is only one source and one destination yes it doesn't
>> > meter
>> > >> > but
>> > >> if
>> > >> > there is one source and many destination it dose meter the
>> > direction of
>> > >> the
>> > >> > load balancing as if there is src-mac method on SW1 and SW1
>> > connected
>> > >> > to
>> > >> SW2
>> > >> > and behind SW2 there are many destination, then it doesn't meter
>> > all
>> > >> traffic
>> > >> > will be using one link and not really load balance on the
>> > ether-channel
>> > >> > bundle but if you set on SW1 dst-mac and the host on SW1 is
>> > >> > sending
>> > to
>> > >> many
>> > >> > destinations then there will be load balancing on the
>> > ether-channel.
>> > >> >
>> > >> > so it is important to know the ratio of the traffic source to
>> > >> destination,
>> > >> > if it is almost the same then you have of the 3560 src-dest-mac.
>> > >> >
>> > >> > so please Random is your worst enemy as Network Expert!
>> > >> >
>> > >> >
>> > >> >
>> > >> >
>> > >> >
>> > >> > On Dec 30, 2007 7:38 PM, WorkerBee < ciscobee@gmail.com> wrote:
>> > >> >
>> > >> > > Does it matters if the algo is different from both ends? It can
>> > be
>> > >> > > set
>> > >> > > differently at
>> > >> > > both ends and thins still work because at any one time, the
>> > traffic
>> > >> > > stream is send
>> > >> > > across only 1 link out of x links in that bundle.
>> > >> > >
>> > >> > > The switch will still receive the packets correctly. Randomness
>> > maybe
>> > >> the
>> > >> > > best
>> > >> > > form of load balancing..
>> > >> > >
>> > >> > > On Dec 30, 2007 10:47 PM, Herbert Maosa
>> > >> > > <asawilunda@googlemail.com
>> > >
>> > >> wrote:
>> > >> > > > It gets interesting when the port channel is between a 3550
>> > >> > > > and
>> > a
>> > >> 3560.
>> > >> > > >
>> > >> > > > :-)
>> > >> > > >
>> > >> > > > Herbert.
>> > >> > > >
>> > >> > > >
>> > >> > > > On Dec 30, 2007 1:33 PM, mazhar minhas < mmgnoc@hotmail.co.uk>
>> > >> > > > wrote:
>> > >> > > >
>> > >> > > >
>> > >> > > > > hi,
>> > >> > > > >
>> > >> > > > > EXPERTS,
>> > >> > > > >
>> > >> > > > > i have one Questions here.
>> > >> > > > >
>> > >> > > > > i m trying to configure load-balance between port-channels.
>> > >> > > > >
>> > >> > > > > Found 2 commands, and need to confirm if you guys can help
>> > please
>> > >> > > > > ======
>> > >> > > > > there are 2 differnet commands as for as i know .....
>> > >> > > > > according to my knowledge.....
>> > >> > > > > here they are
>> > >> > > > >
>> > >> > > > > port-channel load-balance src.mac (this is for 3550)
>> > >> > > > >
>> > >> > > > > por-chanel load-balance src-dst-ip (this is for 3560)
>> > >> > > > >
>> > >> > > > > can some one please confirm this....
>> > >> > > > >
>> > >> > > > > many thanks.
>> > >> > > > >
>> > >> > > > >
>> > >> > > > >
>> > >> > > > >
>> > _________________________________________________________________
>> > >> > > > > Free games, great prizes - get gaming at Gamesbox.
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>> > >> > >
>> > >>
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>> > >> >
>> > >> >
>> > >> > --
>> > >> > Shiran Guez
>> > >> > MCSE CCNP NCE1
>> > >> > http://cciep3.blogspot.com
>> > >> > http://www.linkedin.com/in/cciep3
>> > >> >
>> > >> >
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