Re: [Sip] Re: URI comparison rules

Vijay K. Gurbani wrote:
> Michael Thomas wrote:
>> Doesn't this sort of slide down the slippery slope of understanding 
>> the semantics of the URI for comparison? For example, why can't you
>> make the same kind of argument for www.example.com and example.com
>> since they're pretty much synonymous these days? And for that matter
>> what about comparing example.com and, oh say, its A(AAA) record?
>> They're the "same", FSVO "same".
>
> Mike: Our domain is restricted to SIP URIs.  In other words,
> while DNS-wise, www.example.com = example.com, this does not carry
> into SIP; i.e., sip:user@sip.example.com != sip:user@example.com.
>
> I suppose the rules for SIP URI comparisons are a bit more stringent
> than DNS equivalence of names, aliases, and their resulting addresses.
>

This of course leads us into the mysterious rat hole of what constitutes
"same", but...
>> Maybe I missed the first post, but is it realistic that something(s) 
>> producing URI's for the same target would create their name in 
>> different manners?
>
> No, not realistic, but entirely probable.
>
>> And if it is, why wouldn't it be as much of a problem with the IP
>> address name and a real fqdn?
>
> Because, SIP URI wise, sip:user@example.com != sip:user@192.0.2.128
> even though DNS_lookup("example.com") = "192.0.2.128".

Well, that's sort of my point: if you have something(s) writing URI's
for the same entity in different ways, it seems just as likely that they
might write them as sip:user@example.com and 192.0.2.128 as
they would by writing different representations of IPv6 addresses.
Here's another corner case: try multi-homed servers.

Let me put it another way: if there is something dire that happens if
two different representations of the same identity can't be compared
as equal, then your problem runs much deeper than the special IPv6
case.

       Mike

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Re: [Sip] Re: URI comparison rules - IPv6 addresses