871
Configuring IP Unicast Routing
Configuring ISO CLNS Routing
Configuring ISO CLNS Routing
The International Organization for Standardization (ISO) Connectionless Network Service (CLNS) protocol is a standard
for the network layer of the Open System Interconnection (OSI) model. Addresses in the ISO network architecture are
referred to as network service access point (NSAP) addresses and network entity titles (NETs). Each node in an OSI
network has one or more NETs. In addition, each node has many NSAP addresses.
When you enable connectionless routing on the switch by using the
clns routing
global configuration command, the
switch makes only forwarding decisions, with no routing-related functionality. For dynamic routing, you must also enable
a routing protocol. The switch supports the Intermediate System-to-Intermediate System (IS-IS) dynamic routing
protocols for ISO CLNS networks. This routing protocol supports the concept of
areas
. Within an area, all routers know
how to reach all the system IDs. Between areas, routers know how to reach the proper area. IS-IS supports two levels
of routing:
station routing
(within an area) and
area routing
(between areas).
The key difference between the ISO IGRP and IS-IS NSAP addressing schemes is in the definition of area addresses.
Both use the system ID for Level 1 routing (routing within an area). However, they differ in the way addresses are specified
for area routing. An ISO IGRP NSAP address includes three separate fields for routing: the
domain
,
area
, and
system ID
.
An IS-IS address includes two fields: a single continuous
area
field (comprising the domain and area fields) and the
system ID
.
For more detailed information about ISO CLNS, see the ISO CLNS documents listed in the
Configuring IS-IS Dynamic Routing
IS-IS is an ISO dynamic routing protocol. Enabling IS-IS requires that you create an IS-IS routing process and assign it
to a specific interface, rather than to a network. You can specify more than one IS-IS routing process per Layer 3 switch
or router by using the multiarea IS-IS configuration syntax. You then configure the parameters for each instance of the
IS-IS routing process.
Small IS-IS networks are built as a single area that includes all the routers in the network. As the network grows larger,
it is usually reorganized into a backbone area made up of the connected set of all Level 2 routers from all areas, which
is in turn connected to local areas. Within a local area, routers know how to reach all system IDs. Between areas, routers
know how to reach the backbone, and the backbone routers know how to reach other areas.
Routers establish Level 1 adjacencies to perform routing within a local area (station routing). Routers establish Level 2
adjacencies to perform routing between Level 1 areas (area routing).
A single Cisco router can participate in routing in up to 29 areas and can perform Level 2 routing in the backbone. In
general, each routing process corresponds to an area. By default, the first instance of the routing process configured
performs both Level 1and Level 2 routing. You can configure additional router instances, which are automatically treated
as Level 1 areas. You must configure the parameters for each instance of the IS-IS routing process individually.
For IS-IS multiarea routing, you can configure only one process to perform Level 2 routing, although you can define up
to 29 Level 1 areas for each Cisco unit. If Level 2 routing is configured on any process, all additional processes are
automatically configured as Level 1. You can configure this process to perform Level 1 routing at the same time. If Level 2
routing is not desired for a router instance, remove the Level 2 capability using the
is-type
global configuration
command. Use the
is-type
command also to configure a different router instance as a Level 2 router.
This section briefly describes how to configure IS-IS routing. For more detailed information about IS-IS, see the IS-IS
documents listed in the
.
This section includes the following topics:
Default IS-IS Configuration, page 872
Nonstop Forwarding Awareness, page 872
Содержание IE 4000
Страница 12: ...8 Configuration Overview Default Settings After Initial Switch Configuration ...
Страница 52: ...48 Configuring Interfaces Monitoring and Maintaining the Interfaces ...
Страница 108: ...104 Configuring Switch Clusters Additional References ...
Страница 128: ...124 Performing Switch Administration Additional References ...
Страница 130: ...126 Configuring PTP ...
Страница 140: ...136 Configuring CIP Additional References ...
Страница 146: ...142 Configuring SDM Templates Configuration Examples for Configuring SDM Templates ...
Страница 192: ...188 Configuring Switch Based Authentication Additional References ...
Страница 244: ...240 Configuring IEEE 802 1x Port Based Authentication Additional References ...
Страница 274: ...270 Configuring SGT Exchange Protocol over TCP SXP and Layer 3 Transport Configuring Cisco TrustSec Caching ...
Страница 298: ...294 Configuring VLANs Additional References ...
Страница 336: ...332 Configuring STP Additional References ...
Страница 408: ...404 Configuring DHCP Additional References ...
Страница 450: ...446 Configuring IGMP Snooping and MVR Additional References ...
Страница 490: ...486 Configuring SPAN and RSPAN Additional References ...
Страница 502: ...498 Configuring Layer 2 NAT ...
Страница 559: ...555 Configuring Network Security with ACLs How to Configure Network Security with ACLs Creating a Numbered Extended ACL ...
Страница 770: ...766 Configuring IPv6 MLD Snooping Related Documents ...
Страница 930: ...926 Configuring IP Unicast Routing Related Documents ...
Страница 956: ...952 Configuring IPv6 Unicast Routing Configuring IPv6 network 2010 AB8 2 48 network 2010 AB8 3 48 exit address family ...
Страница 976: ...972 Configuring Cisco IOS IP SLAs Operations Additional References ...
Страница 978: ...974 Dying Gasp ...
Страница 990: ...986 Configuring Enhanced Object Tracking Monitoring Enhanced Object Tracking ...
Страница 994: ...990 Configuring MODBUS TCP Displaying MODBUS TCP Information ...
Страница 996: ...992 Ethernet CFM ...
Страница 1030: ...1026 Working with the Cisco IOS File System Configuration Files and Software Images Working with Software Images ...
Страница 1066: ...1062 Using an SD Card SD Card Alarms ...