IBM SC30-3681-08 manual Using the Multilink PPP Protocol, 509

Chapter 34. Using the Multilink PPP Protocol

This chapter describes how to use the Multilink PPP Protocol (MP). It includes the
following sections:
v	ªMP Considerationsº on page 510
v	ªMulti-Chassis MPº on page 511
v ªCon®guring a Multilink PPP Interfaceº on page 511
The Multilink PPP Protocol allows you to increase the bandwidth of:
v PPP leased lines, including channelized and I43x ISDN circuits
v PPP ISDN dial circuits
v	PPP V.25bis dial circuits
v	PPP V.34 dial circuits
v PPP Layer 2 Tunneling circuits
Increased bandwidth is accomplished by de®ning avirtual linkmade up of multiple
links. The bandwidth of the resulting MP bundle is almost equal to the sum of the
bandwidths of the individual links. The advantage is that large data packets
transmitted across a single link can now be fragmented, transmitted across multiple
links, and rebuilt at the receiving end station. MP uses both the Bandwidth
Allocation Protocol and the Bandwidth Allocation Control Protocol to dynamically
add and drop PPP dialcircuits to a virtual link. MP also uses Bandwidth-On-Demand
(BOD) to add ªdedicatedº MP dial links to an existing bundle.
There are two types of MP links: those that are dedicated and those that are simply
enabled. A dedicated MP link is an MP-enabled interface con®gured as a link to a
particular MP interface. If the link attempts to join another MP bundle, or if MP is
not negotiated at all, the software terminates the link. All PPP links except for
layer-2-tunneling interfaces can be con®gured as dedicated MP links. PPP leased
links must be con®gured as dedicated MP links.
PPP dial-circuits and Layer 2-Tunneling can be con®gured as MP enabled. An
MP-enabled link that is not dedicated can become a link in any MP bundle. If MP is
not negotiated, the link operates as an independent interface using the link's
con®gured protocols.
You can con®gure a Multilink PPP interface that consists of multiple PPP dial
circuits as part of the MP bundle.

There are also two types of MP interfaces: those that have a dedicated link and those that do not. An MP interface needs a dedicated link in any one of the following situations:

v The link is only for the MP interface

v The MP interface is con®gured for outbound calls. The dedicated link must then be con®gured with the destination phone number and caller identi®cation.

v The MP interface is con®gured to receive a particular inbound call. In this case, the dedicated link is con®gured with the inbound destination phone number and caller identi®cation.

v The MP interface needs to perform outbound authentication. In this case, all links use the same authentication name.

© Copyright IBM Corp. 1994, 1998 509