Example: PPP to ATM TCC Configuration
In Figure 31, Router A uses PPP to connect with Router B, while Router C connects with Router B through ATM. Router B acts as the Layer 2 virtual switch and transparently connects Router A to Router C.
On Router A, configure basic PPP encapsulation and any desired Layer 3 protocol families on the SONET interface.
Router A
[edit]
interfaces {
so-0/1/0 {
description "to Router B so-0/0/0";
unit 0 {
encapsulation ppp;
family inet {
address 1.1.1.1/30;
}
}
}
}
Router B acts as the virtual Layer 2 switch. Here you configure the appropriate TCC encapsulations on the corresponding interfaces. In this case, encapsulation ppp-tcc is bound to physical interface so-0/0/0, and encapsulation atm-tcc-vc-mux is placed on VC 32 of interface at-1/1/0. Because the switching occurs at Layer 2, you cannot configure IP addresses or other Layer 3 family information on these interfaces.
You also need to configure MPLS and establish the cross-connect by adding the necessary interfaces to the interface-switch statement at the [edit protocols connections] hierarchy level.
Router B
[edit]
interfaces {
so-0/0/0 {
description "to Router A so-0/1/0";
encapsulation ppp-tcc;
unit 0 {
}
at-1/1/0 {
description "to Router C at-0/3/0";
atm-options {
vpi 0 maximum-vcs 2000;
}
unit 32 {
vci 32;
encapsulation atm-tcc-vc-mux;
}
}
}
protocols {
mpls {
interface so-0/0/0.0;
interface at-1/1/0.32;
}
connections {
interface-switch PPP-to-ATM {
interface so-0/0/0.0;
interface at-1/1/0.32;
}
}
}
On Router C, the encapsulation option used to connect to the TCC-encapsulated ATM interface on Router B is atm-vc-mux. Since this ATM connection is switched at Layer 2 to reach the PPP link, it is transparent to Layer 3 addressing. As a result, the IP address must be configured in the same address space as Router A's so-0/1/0 interface.
Router C
[edit]
interfaces {
at-0/3/0 {
description "to Router B at-1/1/0";
atm-options {
vpi 0 maximum-vcs 2000;
}
unit 32 {
vci 32;
encapsulation atm-vc-mux;
family inet {
address 1.1.1.2/30;
}
}
}
}