Subject: [Megaco] RE: Please Clear This Doubt

From: "Kevin Boyle" <[email-masked]>
Date: Mon, 13 Sep 2004 09:52:59 -0400

Comments inline. [KJBII]

Kevin

-----Original Message-----
From: Vijaya Kumar [mailto:[email-masked]] 
Sent: Monday, September 13, 2004 6:24 AM
To: [email-masked]
Subject: Please Clear This Doubt

Hi,

   I have doubt regarding TCP Connection establishement between MGC and MG.
See the following senario.

DOUBT 1 :

1. MGC is listening on TCP Port 8000
2. MG opens tcp socket where local port is 9000 3. MG Cold boot:
         a. MG Connects(TCP) to MGC
         b. MG Sends ServcChg command to MGC
         
In the above scenario is ServcChgAddr=9000  must? Without this parameter,
MGC can detect from which port it has received request.
[KJBII] If the MGC is known to be listening on that port, then it seems to
me that the MG will not have to explicitly indicate that the port is the
desired on for transmission.  Note, however, that the defaults ports are
2944 for text and 2945 for binary -- I would imaging that most
implementations would ignore traffic from other ports in order to cut down
on network noise and overhead.

DOUBT 2:

1. MGC is listening on TCP Port 8000
2. MG opens tcp socket where local port is 9000 3. MG Cold boot:
         a. MG Connects(TCP) to MGC
         b. MG Sends ServcChg command to MGC 4. Assume that after some
transaction MG want to
     change its local port to 9001
      a. So it sends ServcChg Command with method RESTART and ServcChgAddr =
9001
      b. MG receives ServcChg Reply

In the above scenario

  1. when should MG open socket with port 9001? Before sending ServcChg 
command or
or after receiving reply.
[KJBII] After receiving the reply.  Remember that responses must go back to
their source address.

  2. Who initiates connect MG or MGC? if MGC hast to initiates 
Connection,  Then
MGC connect to MG. In that case MG has to open socket with 9001(Before 
Sending ServcChg command)
and hast to listen on that port till MGC connects. 
If MG has to initiate connection then when it initiates connection? 
Before sending ServcChg command
or after receiving Reply.
[KJBII] MGCs NEVER initiate connections.  The MG will open the new port once
the MGC has replied and given it permission to do so.  It is entirely
possible that the MGC could reject the proposed port change.

I have so many doubts like above. Draft is not telling what to in this 
type of cases.
Anybody know answer to these doubts?

Bye

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