From: Jason Sinclair (sinclairj@xxxxxxxxxxxxxxx)
Date: Mon Mar 18 2002 - 23:11:29 GMT-3
Jason,
With regards to ATM, the NNI spec allows for more VPI's than the UNI spec.
This is helpful in a provider environment. With regards to Frame Relay, the
advantage of NNI is the ability to pass control messages across network
borders.
I don't think doing away with NNI is a good idea, but I guess we could ditch
UNI in favour of NNI!!!!
Cheers,
Jason Sinclair
Manager, Network Support Group
POWERTEL
Ground Level, 55 Clarence Street,
SYDNEY NSW 2000
AUSTRALIA
office: + 61 2 8264 3820
mobile: + 61 416 105 858
* sinclairj@powertel.com.au
-----Original Message-----
From: Jason Wydra [mailto:jasonwydra@yahoo.com]
Sent: Tuesday, 19 March 2002 08:25
To: ccielab@groupstudy.com
Subject: Frame Relay UNI or NNI
Could someone tell me the difference between a UNI and NNI
in Frame Relay. I understand that UNI is used between the CPE and the
provider switch and that NNI is used between two different provider
switches. My question is, what is actually different in the frame packet or
what signaling techniques are used to differ the two? I understand that
adding ANSI annex D allows both devices at either end to both initiate and
respond to status messages/keepalives simultaneously. So why not just run
UNI with Annex D everywhere and forget about having NNI altogether. Do we
need to put a label on frame connections so that we know which one is a link
between a CPE and switch and which one is a link between two switches? Am I
way off base????
Furthermore - The only difference I see between an ATM UNI
and NNI is the GFC field and and extended VPI field. Big deal? Why have two
separate specifications?
Thanks,
Jason (NP,DP)
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