Re: identity persistence and comparison issues

On 14 jun 2004, at 12:12, Joe Touch wrote:

>     a) are two IDs comparable within the same app over time?
>         i.e., can an ID change? if so, can the old ID be used?

>     b) can two IDs on different apps on the same node be compared?

>     c) can two IDs on different nodes be compared?

During the meeting there was some talk about per-session identifiers. 
Wouldn't such identifiers be pretty much useless?

What I want from an identifier is be able to set up sessions towwards 
it, the same way I can now with a FQDN or IP address. If this isn't 
possible, what use are these identifiers? In this situation an 
identifierless solution would be better. And if there are ephemeral 
values that are used internally somewhere, we should probably avoid 
calling them "identifiers".

In the good old days it would have been possible to presume that if two 
FQDN or IP address values are identical, they point to the same host. 
However, in these days of load balancers this is no longer true, 
although it's usually safe to make this assumption in applications 
because the different hosts would be providing the same service.

In the design team # 1 we had some discussions on the FQDN <-> ID <-> 
locator relationship and I think we agreed that the ID should be tied 
to a single host, even if the FQDN is shared between more than one 
host.

Obviously it must be possible to change identifiers. This means it must 
be possible to have more than one at the same time or operators will 
revolt. Another reason to have more than one ID at one point in time is 
for privacy reasons, this would be similar to RFC 3041.