Subject: wiretaping , streams and topology

From: Shlomo Kabaz ECItelecom <[email-masked]>
Date: Sun, 4 Feb 2001 13:29:02 +0200

Hi , all !

I  asked  a question on wiretapping and  a conversation started on that
subject , but sorry to be left still
with the simple trechnical  questions unanswered  :

     If   t1  and  t2  are terminations conected bothways , and i want to
do wiretap the stream recived by t2 ,
     then according to your suggestion i will add an ephemeral termination
t3 that will be described in a topology
     descriptor as:  t2,t3,oneway .
     And the questions are :

       a. Does termination t2 have to have to streams ?!?!?!?   or only one
? after adding t3 ?

       b. A question to  brian: You said it can be doen by adding a
termination that is oneway without topology .
           How it is possible according to the present spec , in a
termination as i understand the only way to control
           stream direction is by it's mode , but the mode refers to the
direction of the stream regarding element
           outside the gateway ???

    regards  , Shlomo .

---

From: Tom Taylor <[email-masked]>
Date: Sun, 4 Feb 2001 17:07:06 -0500

Replies below.

>        a. Does termination t2 have to have to streams ?!?!?!?   or only one
[PTT]
First point: a stream has two directions of flow.  In Megaco/H.248 terms, the
flow t2 receives comes from t1, and the flow t2 sends goes to t2.  Using that
terminology, you probably meant to say that you want to direct the flow sent by
t2 to t3 as well as to t1.

> direction of the stream regarding element
[PTT]
Again, a stream has two directions, characterized at a given termination by
Local for the received flow and Remote for the transmitted flow.  What Brian is
saying is that if the context does the necessary bridging and it's a voice
conversation you are tapping, you could do it by setting the Mode of t3 to
RecvOnly and not bothering with topology.

---

From: Matt Holdrege <[email-masked]>
Date: Mon, 5 Feb 2001 08:10:32 -0800

Is there not a basic wiretapping requirement that the field technicians
cannot know about the wiretap? If so, then you cannot tell the MG about the
wiretap since the field tech's will easily be able to discover it. Am I wrong?