RFC 3573 (rfc3573) - Page 1 of 13
Signalling of Modem-On-Hold status in Layer 2 Tunneling Protocol (L2TP)
Alternative Format: Original Text Document
Network Working Group I. Goyret
Request for Comments: 3573 Lucent Technologies
Category: Standards Track July 2003
Signaling of Modem-On-Hold status
in Layer 2 Tunneling Protocol (L2TP)
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
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 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.
Goyret Standards Track