raghujindia at gmail
Jan 7, 2009, 9:44 PM
Post #5 of 5
(2312 views)
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Bryan.,Thanks for explaining the vpi/vci concept with a simple phone
number example. :-)
Now I have got an idea of vp/vc.
Thanks a lot.
On Mon, Jan 5, 2009 at 9:58 PM, Bryan Campbell <bbc [at] misn> wrote:
> Let's make this a bit more simple.
>
> VPI/VCI is kinda like a phone number.
>
> Imagine the phone number 22-333-444-5555.
>
> A call to that number can be switched at country code (22), area code
> (333), exchange (444), or end customer digits (5555). The only difference
> is that ATM is not native voice traffic. It is ATM cell traffic. And, the
> traffic can have switching treatment by VPI, VCI, or both, that is applied
> at layer 2 or layer 3 by the ATM network.
>
> The most comparable data technology is Q-in-Q vlan tagging.
>
> And, if you don't understand VPI-VCI now, you should read "Essentials of
> ATM Networks and Services" by Oliver C. Ibe.
>
> Enjoy!
>
>
>
>
>
> raghuram chary wrote:
>
>> Doug Thanks for the reply.But I couldnt understant what you are saying.
>>
>>
>> On Sat, Jan 3, 2009 at 1:23 AM, Doug McIntyre <merlyn [at] geeks <mailto:
>> merlyn [at] geeks>> wrote:
>>
>> On Fri, Jan 02, 2009 at 08:05:35PM +0530, raghuram chary wrote:
>> > Hi all,I'm unable to understand/imagine the VP and VC concept in ATM
>> > technology.Can anyone explain the concept in detail?Any website
>> pointers or
>> > animated videos will also be appreciated.
>>
>> Its much like a DLCI in frame relay or a VLAN tag in ethernet
>> networks..
>>
>> An identifier to mark this cell/packet/frame/whatever is identified
>> with this number and we differentiate that from other cells that could
>> be for other things.
>>
>> As to the reason for splitting the identifier into two seperate ones,
>> ATM allows you to do path switching as well as VPI switching. You can
>> take everything within the same VPI and push it out a different port
>> than another.
>>
>> You could have all of customers X traffic on VPI 10, and all of
>> customer Y's traffic on VPI 11. Now, no matter how many VPI's customer
>> X lights up, your switching setup continues to work without additional
>> setup on your switching gear.
>>
>> There's reserved VCI's so that also comes into play (ie. why the first
>> PVC may be on 0/32 instead of 0/0 like you'd expect).
>>
>>
>>
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>>
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>
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