Subject: Protocol Action: Signalling of Modem-On-Hold status in Layer 2 Tunneling Protocol (L2TP) to Proposed Standard

From: The IESG <[email-masked]>
Date: Fri, 04 Apr 2003 18:06:42 -0500

The IESG has approved the Internet-Draft 'Signalling of Modem-On-Hold
status in Layer 2 Tunneling Protocol (L2TP)' 
<draft-ietf-l2tpext-v92-moh-05.txt> as a Proposed Standard. This 
document is the product of the Layer Two Tunneling Protocol Extensions
Working Group. The IESG contact persons are Thomas Narten and Erik
Nordmark.

Technical Summary
   
The Layer 2 Tunneling Protocol (L2TP) defines a mechanism for
tunneling Point-to-Point Protocol (PPP) sessions. It is common for
these PPP sessions to be established using modems connected over the
public switched telephone network.

One of the standards governing modem operation is the ITU-T
Recommendation V.92, which defines procedures that enable a client
modem to put the call on hold and later, re-establish the modem link
with minimal delay and without having to redial. While the modem
call is on hold, the client phone line can be used to place or
receive other calls.

The L2TP base protocol does not provide any means to signal these
events from the L2TP Access Controller (LAC), where the modem is
physically connected, to the L2TP Network Server (LNS), where the PPP
session is handled.

This document describes a method to let the LNS know when a client
modem connected to a LAC has placed the call on hold.
   
Working Group Summary
   
There was support for this extension in the WG and no issues were
raised during the Last Call.
   
Protocol Quality
   
This document has been reviewed for the IESG by Thomas Narten.