SIP.edu

Just sat in on a good session about SIP.edu. In particular, there was good discussion about numbering plans (i.e. how do we identify and dial) especially considering the “legacy” devices with 12-key interfaces that are difficult to use with the email address paradigm that’s what SIP.edu 1.0 focused on. A popular proposal seems to be to use what’s called the ISN (ITAD Subscriber Number, where ITAD = Internet Telephony Administrative Domain). Basically, there is an RFC that is was not widely used that set up a number (ranging from 256 up to 10^32 – 1) that would be used sort of like a domain name in conjunction with a locally defined number. There is the character ‘*’ used as the separator between the ITAD and the local number (local number comes first) so that if an organization had ITAD 256, then “phone” 12345 in that organization (not location!) would be 12345*256. This would use a bit of DNS configuration through an NAPTR record to rewrite to a SIP extenstion at a given gateway. Seems like a quite workable scheme…

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