Subject: RE: From whence they came?

From: [email-masked]
Date: Fri, 11 May 2001 20:13:02 +0530

Hello Tom,
     Does that mean that from a host with IP1 as the IP address, a Megaco
message
can be sent to the peer with an MId as IP2? Should the receiving entity not
compare the
source IP address and the IP address in the message header (assuming the mID is
represented by IP address)?

Regards,
Vivek

"Tom-PT Taylor" <[email-masked]> on 05/11/2001 06:13:14 PM

To:   "'Paul Long'" <[email-masked]>, megaco <[email-masked]>
cc:    (bcc: Vivek Bansal/HSS)

Subject:  RE: From whence they came?

Basically, yes.  It's probably better to use a domain name rather than an
address as an mID tag.

-----Original Message-----
From: Paul Long [mailto:[email-masked]]
Sent: Thursday, May 10, 2001 8:28 PM
To: megaco
Subject: RE: From whence they came?

Tom,

Hmmm... Taking a closer look at the spec, I see that the mID in the message
prolog is just used by the receiver as a logical identifier for the sender
and that, in particular, the IP-address forms just have syntactical
value--they are never used as IP addresses, per se. It looks like these mIDs
are only used when paired up with transaction identifiers to uniquely
identify transactions, scoped to the receiver. Is this correct? Scary
thought, but, as long as the sender takes care by using an IP address that
another sender will not use, it appears that the IP address in a message mID
doesn't have to have any relationship to the actual network interface of the
sender. Am I right?

Paul Long
ipDialog, Inc.

-----Original Message-----
From: Tom-PT Taylor [mailto:[email-masked]]
Sent: Thursday, May 10, 2001 5:56 PM
To: 'Paul Long'; megaco
Subject: RE: From whence they came?

It's partly the difference between a physical and a logical unit in a
load-sharing architecture where the separate units have different addresses.
There's also the possibility that a single physical unit has multiple
network interfaces.  Using the address as received in the header is
important because it gives a beter chnace of the response getting back
through any intervening firewall.

-----Original Message-----
From: Paul Long [mailto:[email-masked]]
Sent: Thursday, May 10, 2001 5:40 PM
To: megaco
Subject: RE: From whence they came?

Tom,

Okay, then, and this may be a stupid question, but what is the difference
between "the peer in an association" and the source of a message? IOW, under
what circumstances might they be different? The reason I was confused was
probably because in H.323 the source of a message is of absolutely no
consequence.

Paul Long
ipDialog, Inc.

---

From: "Paul Long" <[email-masked]>
Date: Fri, 11 May 2001 09:55:22 -0500

Vivek,

Let Tom answer of course but, if I understand it correctly now, yes, only
use the mID to _logically identify_ the source of the message. Never treat
it like an IP address in any way. The mID is really only used to scope the
transaction identifiers. The only reason why IP addresses in particular are
allowed is apparently because they guarantee some uniqueness and not because
they provide the actual network location of the sender. It's just a
coincidence that they often (always? sometimes?) are the same as the actual
transport address from which the message was sent.

Paul Long
ipDialog, Inc.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Friday, May 11, 2001 9:43 AM
To: Tom-PT Taylor
Cc: 'Paul Long'; megaco
Subject: RE: From whence they came?

Hello Tom,
     Does that mean that from a host with IP1 as the IP address, a Megaco
message
can be sent to the peer with an MId as IP2? Should the receiving entity not
compare the
source IP address and the IP address in the message header (assuming the mID
is
represented by IP address)?

Regards,
Vivek

-----Original Message-----
From: Paul Long [mailto:[email-masked]]
Sent: Thursday, May 10, 2001 8:28 PM
To: megaco
Subject: RE: From whence they came?

Tom,

Paul Long
ipDialog, Inc.