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Old 06-18-2007, 03:47 AM   #1
vishamr2000
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Info about switches that do per-packet load balancing!!


Hi to all,

Does anyone know of hardware switches (Cisco or others) that do per-packet load balancing?

Warm regards,
Visham
 
Old 06-18-2007, 04:11 AM   #2
acid_kewpie
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what does "per packet" load balancing mean to you? loadbalancing isn't generally done on a per packet basis, but per mac pair of ip pair hash. it's possible to round robin packets if wanted, but this is generally a pretty poor way to do load balancing, even if the 50/50 split looks like on a graph.
 
Old 06-18-2007, 05:13 AM   #3
vishamr2000
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By "per packet" load balancing I mean to say that the packets forming part of one particular connection are forwarded to different machines, in a round-robin manner as you rightly pointed out.
Quote:
loadbalancing isn't generally done on a per packet basis, but per mac pair of ip pair hash
That's right..this is done to maintain session persistence, that is, all packets belonging to the same connection go through the same server or firewall. But I wanted to know if a per-packet load balancer or switch which functions as I described, exists.
Quote:
but this is generally a pretty poor way to do load balancing, even if the 50/50 split looks like on a graph.
Why is it a poor way of doing load balancing? I have read that it allows a more equal usage of the links or paths along which load balancing is taking place. Can you also tell me what does this 50/50 split mean? I didn't understand this.

Many thx for the reply..

Warm regards,
Visham
 
Old 06-18-2007, 07:39 AM   #4
rossonieri#1
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hi vishamr2000,

if you are talking about gateway load balancing (GLBP) maybe you can do per packet basis (although I hardly found that ). but if you are talking about SLB - hmmmm... how can a backend server response to the request if it only had a partial amount of information?

but anyway -- you are talking about packet - so you are talking about routing/router (not application aware switches).

acid_kewpie 50/50 means that equal/fair balancing for any remote-end.

if you have any info on this -- pls let me know

HTH,

Cheers.

Last edited by rossonieri#1; 06-18-2007 at 07:43 AM.
 
Old 06-18-2007, 08:09 AM   #5
acid_kewpie
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i've read this as link load balancing, e.g. etherchannel, IEEE802.3ad as seen on cisco catalyst switches. is that right? or are you looking at applciationlevel loadbalacning where multiple servers are handling requests?
 
Old 06-20-2007, 12:43 PM   #6
vishamr2000
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To rossonieri#1:

Quote:
but anyway -- you are talking about packet - so you are talking about routing/router (not application aware switches).
I was actually thinking of hardware load balancers and cisco routers/switches that do per-packet load balancing without any hashing method. Just using plain round-robin or wieghted round-robin. I know that load balancers use the hash method of per-packet load balancing.

To acid_kewpie:
Quote:
i've read this as link load balancing, e.g. etherchannel, IEEE802.3ad as seen on cisco catalyst switches. is that right? or are you looking at applciationlevel loadbalacning where multiple servers are handling requests?
I thought about this one too. Actually what I want to know whether routers/switches/load balancers do perform the kind of per-packet load balancing i'm talking about, that is, one in which we do not care about connection tracking or session persistence.

I have worked this type of per-packet load balancing. Have a look at this.
http://www.wcl.ee.upatras.gr/csndsp/...tion/A12.3.PDF

Warm regards,
Visham
 
Old 06-21-2007, 03:09 AM   #7
rossonieri#1
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hi vishamr2000,

you've forgot my previous post :
check this out on cisco's website.

Quote:
Originally Posted by rossonieri#1

if you are talking about gateway load balancing (GLBP) maybe you can do per packet basis (although I hardly found that ).
BTW - etherchannel is a trunk - it doesnt know any balancing method.
GLBP is cisco's prop in providing clients "config-free" gateway balancing.

..and nice work the document you have there
i wish i can write like that..

HTH.

Last edited by rossonieri#1; 06-21-2007 at 03:11 AM.
 
Old 06-21-2007, 03:21 AM   #8
acid_kewpie
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of course etherchannel uses load balancing, how else do you thing is makes use of multiple connections effectively? luck?

etherchannel itself seems to be a pretty vague term. AIX systems do "etherchannel" to and DO use a round robin method, no idea if that contravenes 802.3ad or what...

i guess we're still at odds over what kind of load balancing were even talkign about.

Last edited by acid_kewpie; 06-21-2007 at 03:23 AM.
 
Old 06-21-2007, 04:01 AM   #9
rossonieri#1
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hi acid_kewpie,

since i'm not an IEEE engineer - then i dont have any picture how to describe it. but your explanation is very logic.
people said that it was more like an access-multiplexer (electric regulator) rather than software emulation.

cheers.
 
  


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