Intermediate System To Intermediate System; Is-Is Protocol Overview - Dell C9000 Series Networking Configuration Manual

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Table of Contents

Intermediate System to Intermediate

The intermediate system to intermediate system (IS-IS) protocol that uses a shortest-path-first algorithm. Dell

Networking supports both IPv4 and IPv6 versions of IS-IS.

The IS-IS protocol standards are listed in the

IS-IS Addressing

Multi-Topology IS-IS

Graceful Restart

Implementation Information

Configuration Information

IS-IS Metric Styles

Configure Metric Values

Sample Configurations

IS-IS Protocol Overview

The IS-IS protocol, developed by the International Organization for Standardization (ISO), is an interior

gateway protocol (IGP) that uses a shortest-path-first algorithm.

This protocol supports routers passing both IP and OSI traffic, though the Dell Networking

implementation supports only IP traffic.

IS-IS is organized hierarchically 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 systems manage

destination paths for external routers. Only Level 2 routers can exchange data packets or routing information

directly with external routers located outside of the routing domains. Level 1-2 systems manage both inter-

area and intra-area traffic by maintaining two separate link databases; one for Level 1 routes and one for Level

2 routes. A Level 1-2 router does not advertise Level 2 routes to a Level 1 router.

To establish adjacencies, each IS-IS router sends different protocol data units (PDU). For IP traffic, the IP

addressing information is included in the IS-IS hello PDUs and the link state PDUs (LSPs).

Standards Compliance

Intermediate System to Intermediate System