Subject: Transport address --- TCP SESSIONS

From: LDP Hello <[email-masked]>
Date: Mon, 23 Jul 2001 08:54:01 -0700 (PDT)

Hi ; My question is regarding the Transport address in the LDP hello
...

Is it reasonable for a router to add its ROUTER ID into the Transport
TLV of hello... 
consider 
                       b1 > a1, b2 > a2, b3 > a3 
       
      _______                       ________
     |LSR A  |a1 <---L1-------> b1 |LSR B   |
     |ID:a1  |a2 <---L2-------> b2 |  ID:b1 |
     |_______|a3 <---L3-------> b3 |________|

Say LSR A always send ITS routerID (a1)  as the transport TLV in Hello
instead of its Interface IP addresses... TCP session will be
established properly on LINK L1 

Now trasport Address in Hellos on L2 & L3 is a1 and LSR B will try to
establish TCP session with address a1 for interfaces b2 & b3 and that
will be through link L1 again ...   LINKS L2 & L3 will never be
utilized ... 

So my question is IS IT VALID/ACCEPTABLE to use ROUTER ID as the
TRANSPORT ADDRESS INSTEAD of INterface address ...???

Thanks ... 

__________________________________________________
Do You Yahoo!?
Make international calls for as low as $.04/minute with Yahoo! Messenger
http://phonecard.yahoo.com/

---

From: "chetan kumar s" <[email-masked]>
Date: Tue, 24 Jul 2001 08:56:33 +0530 (IST)

On Mon, 23 Jul 2001, LDP Hello wrote:

Hi,
	The fact that need to considered here is that, two LSR can have
multiple LDP hello adjecencies for a label space, but only *one* TCP
session(for a label space). Thus in ur case the links L2 & L3 *will* be
unutilized..

Thanks
Chetan S

> __________________________________________________ Do You Yahoo!? Make
> international calls for as low as $.04/minute with Yahoo! Messenger

---

From: Abhijit Gadgil <[email-masked]>
Date: Tue, 24 Jul 2001 10:30:41 +0530 (IST)

cks>>
cks>> Hi ; My question is regarding the Transport address in the LDP hello
cks>> ...
cks>>
cks>> Is it reasonable for a router to add its ROUTER ID into the Transport
cks>> TLV of hello...
cks>> consider
cks>>                        b1 > a1, b2 > a2, b3 > a3
cks>>
cks>>       _______                       ________
cks>>      |LSR A  |a1 <---L1-------> b1 |LSR B   |
cks>>      |ID:a1  |a2 <---L2-------> b2 |  ID:b1 |
cks>>      |_______|a3 <---L3-------> b3 |________|
cks>>
cks>>
cks>> Say LSR A always send ITS routerID (a1)  as the transport TLV in Hello
cks>> instead of its Interface IP addresses... TCP session will be
cks>> established properly on LINK L1
cks>>
cks>> Now trasport Address in Hellos on L2 & L3 is a1 and LSR B will try to
cks>> establish TCP session with address a1 for interfaces b2 & b3 and that
cks>> will be through link L1 again ...   LINKS L2 & L3 will never be
cks>> utilized ...

Not necessarily they should go out of link L1. They may go out of link L2,
L3 (Perhaps what u r refering here is loopback router address - which
typically would be router id, but not necessarily.)  And it depends more
upon the implementation of the TCP/IP stack in Box A.

So the answer to the question below is Yes!

cks>> So my question is IS IT VALID/ACCEPTABLE to use ROUTER ID as the
cks>> TRANSPORT ADDRESS INSTEAD of INterface address ...???

-abhijit