Configuring IS-IS Protocol - DMC Cisco Networking Academy

102 Pages·2002·1.31 MB·English

BSCI
Configuring IS-IS Protocol
Version 1.2 – Module 7

Student Guide
Copyright  2002, Cisco Systems, Inc. All rights reserved.
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2 Building Scalable Cisco Internetworks (BSCI) v1.2 Copyright  2002, Cisco Systems, Inc.
Configuring IS-IS Protocol
Overview
This lesson provides an overview of Intermediate System-to-Intermediate System (IS-IS)
technology, and its structures and protocols, as well as basic configuration examples. The
lesson begins with Open System Interconnection (OSI) routing and then focuses on Integrated
IS-IS as a version that supports IP networks. Basic IS-IS and Integrated IS-IS router
configuration commands, examples, and some troubleshooting guidelines are presented at the
end of the lesson. The major part of this lesson is dedicated to an explanation of IS-IS concepts
and capabilities, including hierarchy and addressing of OSI-based networks.
Outline
The lesson includes these sections:
! Objectives
! Introduction to OSI Protocols and IS-IS Routing
! Operation of IS-IS
! IP and OSI Routing with Integrated IS-IS
! Basic Integrated IS-IS Router Configuration
! Modeling WAN Networks in Integrated IS-IS
! Summary
! Review Questions
Copyright  2002, Cisco Systems, Inc. Configuring IS-IS Protocol 3
Objectives
This section lists the lesson objectives.
Objectives
Upon completing this lesson, you will be able to:
• Explain basic OSI terminology and network layer
protocols used in OSI
(cid:127) Identify similarities and differences between
Integrated IS-IS and OSPF
(cid:127) Identify characteristics of an effective addressing
plan for IS-IS deployment
(cid:127) Explain how networks and interfaces are
represented in IS-IS
(cid:127) List the types of IS-IS routers and their role in IS-IS
area design
(cid:127) Describe the hierarchical structure of IS-IS areas
© 2002, Cisco Systems, Inc. All rights reserved. BSCI v1.2—7-3
! Explain basic OSI terminology and network layer protocols used in OSI
! Identify similarities and differences between Integrated IS-IS and OSPF
! Identify characteristics of an effective addressing plan for IS-IS deployment
! Explain how networks and interfaces are represented in IS-IS
! List the types of IS-IS routers and their role in IS-IS area design
! Describe the hierarchical structure of IS-IS areas
4 Building Scalable Cisco Internetworks (BSCI) v1.2 Copyright  2002, Cisco Systems, Inc.
Objectives (cont.)
Objectives (cont.)
(cid:127) Describe the concept of establishing adjacencies
(cid:127) Describe the concepts of routing traffic transport and
database synchronization
(cid:127) Explain the basic principles of area routing
(cid:127) Explain IS-IS NBMA (non-broadcast multi-access
network) modeling solutions in switched WAN
networks
(cid:127) Given an addressing scheme and other laboratory
parameters, identify the steps to configure Cisco
routers for proper Integrated IS-IS operation
(cid:127) Identify verification methods which ensure proper
operation of Integrated IS-IS on Cisco routers
© 2002, Cisco Systems, Inc. All rights reserved. BSCI v1.2—7-4
! Describe the concept of establishing adjacencies
! Describe the concepts of routing traffic transport and database synchronization
! Explain the basic principles of area routing
! Explain IS-IS nonbroadcast multiaccess (NBMA) network modeling solutions in switched
WAN networks
! Identify the steps to configure Cisco routers for proper Integrated IS-IS operation, given an
addressing scheme and other laboratory parameters
! Identify verification methods that ensure proper operation of Integrated IS-IS on Cisco
routers
Copyright  2002, Cisco Systems, Inc. Configuring IS-IS Protocol 5
Introduction to OSI Protocols and IS-IS Routing
OSI Protocols
ISO and OSI?
(cid:127) The International Organization for
Standardization (ISO) has been constituted to
develop standards for data networking.
(cid:127) The Open System Interconnection (OSI)
protocols represent an international
standardization program that facilitates
multivendor equipment interoperability.
© 2002, Cisco Systems, Inc. All rights reserved. BSCI v1.2—7-6
The OSI protocols are part of an international program to develop data-networking protocols
and other standards that facilitate multivendor equipment interoperability. The OSI program
grew out of a need for international networking standards and is designed to facilitate
communication between hardware and software systems despite differences in underlying
architectures.
The OSI specifications were conceived and implemented by two international standards
organizations: the International Organization for Standardization (ISO) and the International
Telecommunication Union Telecommunication Standardization Sector (ITU-T).
The world of OSI internetworking includes various network services with these characteristics:
! Independence of underlying communications infrastructure
! End-to-end transfer
! Transparency
! Quality of service (QoS) selection
! Addressing
6 Building Scalable Cisco Internetworks (BSCI) v1.2 Copyright  2002, Cisco Systems, Inc.
OSI Protocols (cont.)
The OSI protocol suite supports:
(cid:127) Numerous standard protocols at each layer of
the OSI reference model
(cid:127) OSI network-layer
hierarchical addressing
(cid:127) Two routing protocols at the
network layer
© 2002, Cisco Systems, Inc. All rights reserved. BSCI v1.2—7-7
The OSI protocol suite supports numerous standard protocols at the physical, data-link,
network, transport session, presentation, and application layers.
OSI network-layer addressing is implemented by using two types of hierarchical addresses:
network service access point (NSAP) addresses and network-entity titles. An NSAP is a
conceptual point on the boundary between the network and the transport layers. The NSAP is
the location at which OSI network services are provided to the transport layer. Each transport-
layer entity is assigned a single NSAP, which is individually addressed in an OSI internetwork
using NSAP addresses.
The OSI protocol suite specifies two routing protocols at the network layer: End System-to-
Intermediate System (ES-IS) and Intermediate System-to-Intermediate System (IS-IS). In
addition, the OSI suite implements two types of network services: connectionless service and
connection-oriented service.
Copyright  2002, Cisco Systems, Inc. Configuring IS-IS Protocol 7
OSI Protocols—Terminology
Terminology used in OSI
(cid:127) End system (ES) is any nonrouting
network nodes (host)
(cid:127) Intermediate system (IS) is a router
(cid:127) An area is a logical entity
–Formed by a set of contiguous routers, hosts,
and the data links that connect them
(cid:127) Domain is a collection of connected areas
© 2002, Cisco Systems, Inc. All rights reserved. BSCI v1.2—7-8
In an OSI network four significant architectural entities exist: hosts, areas, a backbone, and a
domain. A domain is any portion of an OSI network that is under a common administrative
authority. Within any OSI domain, one or more areas can be defined. An area is a logical
entity; it is formed by a set of contiguous routers and the data links that connect them. All
routers in the same area exchange information about all the hosts that they can reach. The areas
are connected to form a backbone. All routers on the backbone know how to reach all areas.
The term “end system” (ES) refers to any nonrouting host or node; “intermediate system” (IS)
refers to a router. These terms are the basis for the OSI ES-IS and IS-IS protocols.
8 Building Scalable Cisco Internetworks (BSCI) v1.2 Copyright  2002, Cisco Systems, Inc.
OSI Protocol Suite and its Mapping to the OSI
Reference Model
© 2002, Cisco Systems, Inc. All rights reserved. BSCI v1.2—7-9
The OSI protocol suite supports numerous standard protocols at each of the seven OSI layers.
The figure here illustrates the entire OSI protocol suite and its relation to the layers of the OSI
reference model.
Copyright  2002, Cisco Systems, Inc. Configuring IS-IS Protocol 9
OSI Network Services—
What to Route in OSI Environment?
Two types of OSI network-layer services are
available to the OSI transport layer:
(cid:127) Connectionless Network Service (CLNS)
–CLNS performs datagram transport
(cid:127) Connection-Mode Network Service (CMNS)
–CMNS requires explicit establishment
of paths between communicating transport-
layer entities
© 2002, Cisco Systems, Inc. All rights reserved. BSCI v1.2—7-10
Connectionless Network Service (CLNS) uses a datagram data transfer service and does not
require a circuit to be established before data is transmitted. In contrast, Connection-Mode
Network Service (CMNS) requires a circuit to be established before transmitting data. While
CLNS and CMNS define the actual services provided to the OSI transport layer entities that
operate immediately above the network layer, Connectionless Network Protocol (CLNP) and
Connection-Oriented Network Protocol (CONP) name the protocols that these services use to
convey data at the network layer. CLNP is the OSI equivalent of IP.
10 Building Scalable Cisco Internetworks (BSCI) v1.2 Copyright  2002, Cisco Systems, Inc.