[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: noid and applications (generic requirements from applications)



On 2003-11-17, at 13.41, Brian E Carpenter wrote:

In NOID the transport layer and above aren't aware that the locator
is rewritten. So I don't see that part of your concern.

Good. I just wanted someone else to say so, because when I read the noid draft that was not clear to me.


More fundamentally, you say

Today, the idea is that the IP address as well as the FQDN is globally
unique

Unfortunately that certainly isn't true of addresses today and we still have to
fight hard for it to be true of IPv6 addresses tomorrow. It's a dangerous
assumption. However, there's no reason FQDNs should be non-unique.

Let me rephrase myself.


In the real world, this is of course not true, BUT, protocols we have (FTP, SIP etc) believe it is true.

If the noid identifier is "more globally unique" than IPv4 addresses, then I can see not objection from apps people but very strong support for noid.

paf

Brian

Patrik Fältström wrote:

On 2003-11-13, at 14.48, Tony Li wrote:


That is going to be exceedingly difficult.  As long as we
are using IP addresses in applications and we are hiding
the actual reachability of the address from the application,
we are guaranteed to be allowing an application to pass along
an unreachable address.

Note that this is a result of the layering violation of
passing around an IP address in the application.  Asking us
to warp the world to support architectural mistakes strikes
me as suboptimal.

The reason I ask is because I want to know what we will get at the end of the day with the noid proposal.

Today, the idea is that the IP address as well as the FQDN is globally
unique and have the properties described.

|    (A=B) and (B=C) gives (A=C) where '=' is "can communicate with"
|
|  and
|
|    (A->B) gives (B->A) where '->' is "can send data to"

What I understood from the noid draft is that what we today call IP
addresses (what is above L2, used in the arp requests etc) can be
rewritten and because of this doesn't have the properties above.

My question was whether the new identifier will have the properties
above, so an application instead of doing layering violations on
FQDN+IP should do the same kind of violations on FQDN+Identifier?

Else it will be extremely hard to "fix" protocols like ftp and
everything which controls RTP streams.

I think the discussion whether those protocols are designed in a
correct or wrong way will not help, as you and myself possibly have the
same view -- even though there are rumors there are differences in how
hot it is in hell.


IF the above properties are valid for at least one of the identifier
"layers" in noid, fixing applications and protocols we have today will
be much easier.

paf