By: Jonathan Kang (johnbk.delete@this.gmail.com), September 25, 2007 8:10 am
Room: Moderated Discussions
Michael S (already5chosen@yahoo.com) on 9/25/07 wrote:
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>Aaron Spink (aaronspink@earthlink.net) on 9/24/07 wrote:
>---------------------------
>>Michael S (already5chosen@yahoo.com) on 9/24/07 wrote:
>>---------------------------
>>>I don't know whether it is blocking or not, but pass-through routing fall out of
>>>favor in high-speed network infrastructure equipment a long time ago. I'd guess
>>>there were reasons for preferring store-and-forward implementations over pass-through
>>>probably related to corner cases in error recovery. So I expect that at least first
>>>few generation of CSI would avoid path-through.
>>>
>>
>>Many high performance networks today are designed to MAXIMIZE pass-through routing
>>via means of virtual cut-through mechanisms.
>>
>
>Not in GBE switching. I didn't check recently, but 2-3 years ago all popular switches
>were store-and-forward. On the other hand, older 100BaseT switches are mostly pass-through.
This is most likely because 100BaseT networks were broadcast networks where the medium was shared. It made sense to pass-through as the switch basically acted as a physical medium.
The move to GBE spawned point-to-point physical connections which is much easier to maintain if it is stored and forwarded. My memory isn't always accurate but I believe carrier sensing was pretty much eliminated with GBE.
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>Aaron Spink (aaronspink@earthlink.net) on 9/24/07 wrote:
>---------------------------
>>Michael S (already5chosen@yahoo.com) on 9/24/07 wrote:
>>---------------------------
>>>I don't know whether it is blocking or not, but pass-through routing fall out of
>>>favor in high-speed network infrastructure equipment a long time ago. I'd guess
>>>there were reasons for preferring store-and-forward implementations over pass-through
>>>probably related to corner cases in error recovery. So I expect that at least first
>>>few generation of CSI would avoid path-through.
>>>
>>
>>Many high performance networks today are designed to MAXIMIZE pass-through routing
>>via means of virtual cut-through mechanisms.
>>
>
>Not in GBE switching. I didn't check recently, but 2-3 years ago all popular switches
>were store-and-forward. On the other hand, older 100BaseT switches are mostly pass-through.
This is most likely because 100BaseT networks were broadcast networks where the medium was shared. It made sense to pass-through as the switch basically acted as a physical medium.
The move to GBE spawned point-to-point physical connections which is much easier to maintain if it is stored and forwarded. My memory isn't always accurate but I believe carrier sensing was pretty much eliminated with GBE.
