Overview
MLPPP aggregates multiple physical links into a single logical bundle. More specifically, MLPPP bundles multiple link-layer channels into a single network-layer channel. Peers negotiate MLPPP during the initial phase of Link Control Protocol (LCP) option negotiation. Each system indicates that it is multilink-capable by sending the multilink option as part of its initial LCP configuration request.
The systems joined by the multilink each assign the same unique name to the bundle. A bundle can consist of multiple physical links of the same type—such as multiple asynchronous lines—or can consist of physical links of different types—such as leased synchronous lines and dial-up asynchronous lines.
Your E-series device treats MLPPP like another PPP network control protocol (NCP). Packets received with an MLPPP header are subject to fragmentation, reassembly, and sequencing. Packets received without the MLPPP header cannot be sequenced and can be delivered only on a first-come, first-served basis.
The NMC-RX implementation of MLPPP logically aggregates up to eight T1 or E1 connections into a single virtual connection, or bundle, to a given customer site, as shown in Table 75.
MLPPP allows you to bundle up to eight DS1s together to provide a service that offers greater than T1 but less than T3 bandwidth. This service provides bandwidth greater than DS1 service without the expense and infrastructure required for DS3 service. The NMC-RX application allows you to configure these bundles on your E-series device.
Table 75 compares the three modules that you can configure with MLPPP bundles.
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NOTE: The DS0s column indicates the number of DS0 bundle timeslots for each module type. DS1s are the basic units of MLPPP bundles. |
An MLPPP bundle is stacked on top of DS1s. If you select a DS1 that does not have a DS0 bundle created on it, then the NMC-RX application automatically creates a fully allocated DS0 bundle on that DS1. Also, if a DS0 bundle exists on a DS1 that you want to bind to an MLPPP bundle, the DS0 bundle must be fully allocated and cannot have anything created on top of it. Once a DS1 is associated with an MLPPP bundle, the NMC-RX application creates a PPP interface on the DS0 bundle on that DS1. You cannot create anything on the PPP interface. Also, you cannot delete a DS0 bundle or PPP interface on a DS1 that is associated with an MLPPP bundle.
Figure 18 illustrates the interface stacking with MLPPP.
