Junos Enterprise Routing, 2nd Edition

Layer 2 Services

Layer 2 services are essentially the services that are enabled on a physical interface such as LFI (FRF.12), MLFR (FRF.15), user-to-network interface (UNI) NNI (FRF.16), MLPPP, and multiclass MLPPP.

Multilink PPP

MLPPP (RFC 1990) allows the router to combine multiple links together into one large logical bundle (as shown in Figure 9-1). This was originally created to bond multiple Integrated Services Digital Network (ISDN) bearer signals together, but it is now used for any two systems with multiple links between them. Multilink is negotiated during the initial Link Control Protocol (LCP) option negotiation. When configuring MLPPP on a Juniper router, you can combine into one bundle any eight PPP links of the same type on the chassis. To configure MLPPP, first create a logical bundle link:

lsq-0/0/0 {
    unit 0 {
        encapsulation multilink-ppp;
        family inet {
            address 166.8.67.30/30;
        }
    }
}

Figure 9-1. MLPPP bundle

Next, configure the physical interfaces to link the newly created link service interface. In the following example, interfaces t1-1/0/0 and t1-1/0/1 are linked to the logical bundle unit 0 on the lsq-0/0/0 interface:

t1-1/0/0 {
    unit 0 {
        family mlppp {
            bundle lsq-0/0/0.0;
        }
    }
}
t1-2/0/1 {
    unit 0 {
        family mlppp {
            bundle lsq-0/0/0.0;
        }
    }
}

When there are multiple links in your bundle, packets above the minimum maximum transmission unit/maximum received reconstructed unit ...