The Router Option card is easily configured using the management terminal connected to the Echo LANlink from either end of the link, or through Telnet at a relevant workstation either LAN.

1.1Functional Overview

The Router Option card supports both transceiver connection (AUI port) and hub (10BASE-T port) connection to a 10MHz Ethernet LAN. Ethernet frames are transported to/from the remote LAN using some or all of the main communications link bandwidth. The bandwidth is allocated in 64Kbps timeslots amongst the various functions of the multiplexer as required by the user. Up to 1984Kbps free bandwidth is available on an E1 link, 64Kbps is permanently assigned for E1 frame synchronisation and signalling.

The router supports both the popular Internet Protocol (IP) and Internetwork Packet Exchange (IPX) protocols. Many other protocols may be used encapsulated by these as required: e.g. TCP, UDP, and NetWare.

The router maintains dynamic routing tables so that Ethernet frames are routed to their correct destination. This capability is performed automatically by the router as it “learns” routes and addresses available in the network. The router will also broadcast its own routing information to other devices on the network. Inoperative routes will time-out and be removed from the routing tables so that alternative routes may be used in the event a communications circuit failure.

A data compression algorithm is used when transporting Ethernet frames through the communications link to increase the throughput of data.

Comprehensive filtering options are available so the router may act as a sophisticated firewall to give added security for the LAN.

1.2Typical Applications

The simplest application for the Router Option is to link two LANs as shown in Figure 1. In this example, the Branch Office is linked to the Headquarters via the Echo LANlinks and users at the Branch office will be able to access the General Servers as if they were on the same network.

Further use of the router functionality can give sophisticated security for network elements. Restrictive firewalls are easily built using subnet masking. Entire subnets can be isolated from the network by simply entering appropriate configurations – see Figure 2. In this example the Salesperson in

Echo LANlink Router Option User Manual

Issue 1.0 04 December 1997 Page 7 of 59

Page 7
Image 7
Echo EN55022 manual Functional Overview, Typical Applications