IPR 12-1
IP Routing Introduction
Chapter 12IP Routing

12.1 Introduction

This chapter provides information for the IP Router (IPR) function contained in the IMACS
200 platform.

12.2 IPR Description

12.2.1 IMACS 200 IPR

The IMACS 200 IPR port is an Ethernet interface port and uses a modular jack for a 10Base-T
connection (RJ48), and is labelled ENET on the rear panel of the IMACS 200.
The IMACS 200 IPR port is an IPR router that routes packets based on IP destination address.
IPR routes IP datagrams between Ethernet and Frame Relay PVCs. Frame Relay PVCs must
be associated with the Frame Relay port. IPR also has provisions to for ward IP p ackets to and
from the host (CPU) IP node of the IMACS 200 that IPR resides in. It automatically take s care
of all the IP fragmentation to and from the host (CPU) IP node.
The maximum number of bytes that an IPR can handle in a single packet is 1520 bytes
regardless whether a packet arrives from Et hernet or Frame Relay interface.
Currently, the IPR does not support SNMP, and will be available in a future release. It uses the
standard Ethernet encapsulation, utilizing 14 bytes Ethernet Header: Source Et hernet Address
(6 bytes), Destination Ethernet Address (6 bytes), and a Protocol Type (2 bytes). IPR supports
RIP (Routing Information Protocol, RFC 1058) for dynamically discovering IP routes from
adjacent IP routers on Frame Relay or Ethernet.
The IMACS 200 implementation of the IPR function does not contain provisions for the
bridging function. The WAN interface is sta ndard encapsulatio n of Ethernet over Frame Relay
(RFC 1490).