From: huan@huanlan.com
Date: Fri Jul 18 2008 - 19:52:40 ART
This is a back to fundamental question. Traffic forwarding between R1 & R2
uses their Fa0/1 MAC as source/destination. They then do IP lookup to forward
further to the final host destinations (using the orignal PC's host MAC as
destination MAC).
--- On Fri, 7/18/08, John <jgarrison1@austin.rr.com> wrote:
From: John <jgarrison1@austin.rr.com>
Subject: Re: Etherchannel load-balance
To: "Huan Pham" <Huan.Pham@peopletelecom.com.au>, "Joseph Saad"
<joseph.samir.saad@gmail.com>, "Cisco certification" <ccielab@groupstudy.com>
Date: Friday, July 18, 2008, 11:01 PM
Huan,
If the routers strip the source mac. How does traffic know where to go in
either direction.?
----- Original Message -----
From: "Huan Pham" <Huan.Pham@peopletelecom.com.au>
To: "Joseph Saad" <joseph.samir.saad@gmail.com>; "Cisco
certification"
<ccielab@groupstudy.com>
Sent: Thursday, July 17, 2008 6:17 PM
Subject: RE: Etherchannel load-balance
> This is an interesting question!
>
> I do not think that Joseph's solution answers the question. This is
> because:
>
> For this particular example, as VLAN A is behind R1, SW2 only sees a
> single MAC of R1--Fa0/1, and not all MAC of PC in VLAN A. Therefore, it
> can not (effectively) do load-balancing based on destination MAC, nor
> can it do load-balancing based on source IP (traffic from server in VLAN
> C only have one single source IP). Note that switches can only influence
> (load-balance) traffic going out, and not traffic coming back.
>
> Similarly, SW1 can not do load-balance based on source MAC, although it
> can do load-blance based on source IP.
>
> So my solution is:
>
> SW1: load-balance based on source IP (or source-destination IP)
> SW2: load-balance based on destination IP (or source-destination IP)
>
> BTW, Joseph, how do you configure SW1 with both source Mac and Source IP
> (assuming you only have IP traffic)?
>
> Regards,
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Joseph Saad
> Sent: Monday, 7 July 2008 2:24 AM
> To: Cisco certification
> Subject: Re: Etherchannel load-balance
>
> in this particular scenario I'd configure
>
> SW1 with source Mac (or Source IP or both)
> SW2 with destination Mac (or Source IP or both)
>
> The simple rule is:
> You configure the switch "sending out the traffic to the
etherchannel"
> in a way to suit the destination SW connected hosts.
>
> HTH,
> Joseph.
>
> On Fri, Jul 4, 2008 at 7:49 PM, Cisco Addicted
> <cisco.addicted@gmail.com>
> wrote:
>
>> Dears,
>>
>> I want to know what is to consider when deciding the ether channel
>> load balancing if I may have the following scenario:
>>
>>
>>
>>
>>
>> VLANA-(Fa0/0--R1--Fa0/1)------ SW1 (3560)=== ===SW2 (3560)
>> ------(fa0/1-R2----fa0/0) ----- VLAN C
>>
>>
>>
>> And considering there is a many users in VLAN-A accessing server on
>> VLAN-C, and there is etherchannel trunk configured between SW1 &
SW2.
>>
>>
>>
>> Thanks in advance.
>>
>>
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