Understanding E&M Interfaces

This section describes the process of transparently transmitting E&M data through an MPLS tunnel.

As shown in Figure 10-1, the E&M data transceiver connects to the E&M terminal in wired or wireless mode and connects to the remote data processing center through the IP/MPLS network.

RouterA connects to the data processing center through an E&M interface, and RouterB connects to the E&M data transceiver through an E&M interface. RouterA and RouterB have set up an MPLS tunnel between them.

Figure 10-1 Transparent transmission of E&M data through the MPLS tunnel

When the data processing center needs to transmit data to the E&M terminal, the E&M data is transparently transmitted through the MPLS tunnel as follows:

1. The E&M interface of RouterA receives E&M data from the data processing center.
2. RouterA encapsulates E&M data into a PWE3 packet.
3. RouterA transparently transmits the PWE3 packet to RouterB through the MPLS tunnel.
4. RouterB parses E&M data from the PWE3 packet and transmits the E&M data through the E&M interface to the E&M data transceiver.
5. The E&M data transceiver transmits the E&M data to the E&M terminal in wired or wireless mode.

The process of transmitting data from the E&M terminal to the data processing center is the reverse of the preceding process.