Reference Guide

Intermediate System to Intermediate System | 485

Intermediate System to Intermediate System

Intermediate System to Intermediate System is supported on the e and platforms.

IS-IS is supported on the E-Series ExaScale platform with FTOS 8.1.1.0 and later. It is supported on the

with FTOS 8.3.10.0.

Intermediate System to Intermediate System (IS-IS) protocol is an interior gateway protocol (IGP) that

uses a shortest-path-first algorithm. Dell Force10 supports both IPv4 and IPv6 versions of IS-IS, as it is

detailed in this chapter.

• Protocol Overview on page 485

• IS-IS Addressing on page 486

• Multi-Topology IS-IS on page 487

• Graceful Restart on page 488

• Implementation Information on page 489

• Configuration Information on page 490

• IS-IS Metric Styles on page 509

• Sample Configuration on page 513

IS-IS protocol standards are listed in the Chapter 56, Standards Compliance chapter.

Protocol Overview

The intermediate-system-to-intermediate-system (IS-IS) protocol, developed by the International

Organization for Standardization (ISO), is an interior gateway protocol (IGP) that uses a shortest-path-first

algorithm.

IS-IS is organized hierarchally into routing domains, and each router or system resides in at least one area.

In IS-IS, routers are designated as Level 1, Level 2 or Level 1-2 systems. Level 1 routers only route traffic

within an area, while Level 2 routers route traffic between areas. At its most basic, Level 1 systems route

traffic within the area and any traffic destined for outside the area is sent to a Level 1-2 system. Level 2

Note: This protocol supports routers passing both IP and OSI traffic, though the Dell Force10

implementation supports only IP traffic.