Example: PPP to ATM TCC Configuration

In Figure 1, 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/SDH interface.

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.

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.

Verifying Your Work

To verify your TCC connection, use the show connections command on Router B:

CCC and TCC connections [Link Monitoring On]
  Legend for status (St)              Legend for connection types
  UN -- uninitialized                 if-sw:  interface switching
  NP -- not present                   rmt-if: remote interface switching
  WE -- wrong encapsulation           lsp-sw: LSP switching
  DS -- disabled
  Dn -- down                          Legend for circuit types
  -> -- only outbound conn is up      intf -- interface
  <- -- only inbound  conn is up      tlsp -- transmit LSP
  Up -- operational                   rlsp -- receive LSP
Connection/Circuit                  Type    St  Time last up     # Up trans
PPP-to-ATM                          if-sw   Up  Nov 30 08:57:53           1
  at-1/1/0.32                         intf  Up
  so-0/0/0.0                          intf  Up