From: Joseph Saad (joseph.samir.saad@gmail.com)
Date: Thu Jan 03 2008 - 07:11:58 ARST
R1 ---- SW1 -- (PO1) --- SW2 --- R2
R1 is connected to SW1.
SW1 is connected to SW2 via PO1 (encomapssing range fa1/7-9)
SW2 is connected to R2.
showing the mac-address-table as below concludes (with high degree of
certainty) that the load-balance algorithm on the receiving switch will be
in use while sending "return traffic".
The entry in mac-address-table (the learnt one) is pointing to PO1 and not a
specific interface which constitutes the bundles.
Rack1SW1#sh mac-address-table
Destination Address Address Type VLAN Destination Port
------------------- ------------ ---- --------------------
cc06.0888.0000 Self 1 Vlan1
cc00.0888.0000 Dynamic 1 FastEthernet1/1
cc01.0888.0000 Dynamic 1 Po1
Rack1SW2#sh mac-address-table
Destination Address Address Type VLAN Destination Port
------------------- ------------ ---- --------------------
cc07.0aa4.0000 Self 1 Vlan1
cc01.0888.0000 Dynamic 1 FastEthernet1/2
cc02.0888.0000 Dynamic 1 Po1
On Jan 3, 2008 12:49 PM, Darren Johnson <dazza_johnson@yahoo.co.uk> wrote:
> 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.
> >> > >> > > > > http://www.searchgamesbox.com
> >> > >> > > > >
> >> > >> > > > >
> >> > >> > >
> >> > >>
> >> >
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> >> > >> >
> >> > >> >
> >> > >> >
> >> > >> > --
> >> > >> > Shiran Guez
> >> > >> > MCSE CCNP NCE1
> >> > >> > http://cciep3.blogspot.com
> >> > >> > http://www.linkedin.com/in/cciep3
> >> > >> >
> >> > >> >
> >> >
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