Patton electronic IM2RC/I-100B Transparent bridging between two routers over a serial link

Figure 2. Cisco router with serial interface, configured as PPP Half Bridge

For example, the customer site is assigned the addresses 192.168.1.1 through 192.168.1.254. The address 192.168.1.1 is also the default gateway for the remote network. The above settings remove any routing/ forwarding intelligence from the CPE. The associated Cisco configura- tion will set serial interface (s0) to accommodate half bridging for the above example.

Authentication is optional under PPP. In a point-to-point leased-line link, incoming customer facilities are usually fixed in nature, therefore authen- tication is generally not required. The IM2RC/I-100B does not require authentication. It also does not respond to authentication requests.

Some networking systems do not define network numbers in packets sent out over a network. If a packet does not have a specific destination network number, a router will assume that the packet is set up for the local segment and will not forward it to any other sub-network. However, in cases where two devices need to communicate over the wide-area, bridging can be used to transport non-routable protocols.

Figure 3 illustrates transparent bridging between two routers over a serial interface (s0). Bridging will occur between the two Ethernet Inter- faces on Router A (e0 and e1) and the two Ethernet Interfaces on Router B (e0 and e1).

Figure 3. Transparent bridging between two routers over a serial link.

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