SIP in higher education

["Bauer, Steven J." <>]

Would there be an automated method to fall back to the normal pstn
provided the VoIP connection didn't work for some reason?  

Also, would these numbers, (ITAD * number) work for use use in the
current ENUM as a sip destination?  

Steve


-----Original Message-----
From: John Todd 
[mailto:]
 
Sent: Thursday, August 04, 2005 8:18 PM
To: Ed Guy; 

Subject: Re: [sip.edu] ITAD-based numbering, an alternative proposal

7) I am unconvinced that e.164 numbers should be forbidden as part of 
the identifier, regardless of if the "*" or run-length value is used 
as an ITAD delimitation method.  It may be good practice to actually 
go out of one's way to _include_ the e.164 numbers as an alias 
identifier for a domain.
   Let's say I have Penny's business card with -only- her e.164 number 
on it (16095551212), and I know that Penny is a professor at Banzai 
University (BU).  Because I often communicate with other staff at BU, 
I happen to know that the ITAD for the BU is 1984.  Or perhaps I 
looked up BU's ITAD in the on-line ITAD directory.  If the 
administrator at BU has been clever and followed the hypothetical 
best practices document, then for every e.164 number that BU is 
allocated from various PSTN providers is _also_ mapped in an internal 
system on BU's SIP proxies.  So, I could guess and dial 
16095551212*1984 and it would map to a device which would reach 
Penny.  Recall that these directory listings do NOT pollute the true 
ENUM root nor should they cause any confusion, because they are 
essentially local requests within the entity.  Of course, every 
entity needs to maintain that list however they see fit - there can 
be as many or as diverse a set of aliases as would be deemed 
appropriate for that enterprise.  Perhaps 
5551212@1984
 maps to Penny, 
as does 
1212@1984.
  Other numbers which are not part of previous 
e.164 mappings may also map to Penny - this is totally up to the 
local administrator, and it may make sense for some entities to 
install full e.164 mappings in their tables to make "guess-able" 
transitions possible even if only the e.164 number and organization 
is known by a caller.  Some sites might use it, some might not, but 
why limit the obvious mappings?

JT