Integrated IS-IS Commands

This chapter explains the function and syntax of the Intermediate System-to-Intermediate System (IS-IS) protocol commands. For more information about defaults and usage guidelines, see the corresponding chapter of the Cisco IOS IP and IP Routing Command Reference, Release 12.1.

area-password

To configure the Intermediate System-to-Intermediate System (IS-IS) area authentication password, use the area-password router configuration command. To disable the password, use the no form of this command.

area-password password

no area-password [password]

Syntax Description

password

Password you assign.

password	Password you assign.

default-information originate (IS-IS)

To generate a default route into an Intermediate System-to-Intermediate System (IS-IS) routing domain, use the default-information originate router configuration command. To disable this feature, use the no form of this command.

default-information originate [route-map map-name]

no default-information originate [route-map map-name]

Syntax Description

route-map map-name

(Optional) Routing process will generate the default route if the route map is satisfied.

route-map map-name	(Optional) Routing process will generate the default route if the route map is satisfied.

domain-password

To configure the Intermediate System-to-Intermediate System (IS-IS) routing domain authentication password, use the domain-password router configuration command. To disable a password, use the no form of this command.

domain-password password

no domain-password [password]

Syntax Description

password

Password you assign.

password	Password you assign.

ip router isis

To configure an Intermediate System-to-Intermediate System (IS-IS) routing process for IP on an interface and to attach an area designator to the routing process, use the ip router isis interface configuration command. Use the no form of the command to disable IS-IS for IP.

ip router isis area-tag

no ip router isis area-tag

Syntax Description

area-tag

Required for multiarea IS-IS configuration. Optional for conventional IS-IS configuration.

Defines a meaningful name for an area routing process. If not specified, a null tag is assumed. It must be unique among all IP router processes for a given router. The area-tag argument is used later as a reference to this area routing process.

Each area in a multiarea configuration should have a nonnull area tag to facilitate identification of the area.

area-tag	Required for multiarea IS-IS configuration. Optional for conventional IS-IS configuration. Defines a meaningful name for an area routing process. If not specified, a null tag is assumed. It must be unique among all IP router processes for a given router. The area-tag argument is used later as a reference to this area routing process. Each area in a multiarea configuration should have a nonnull area tag to facilitate identification of the area.

isis circuit-type

To configure the type of adjacency, use the isis circuit-type interface configuration command. To reset the circuit type to Level l and Level 2, use the no form of this command.

isis circuit-type {level-1 | level-1-2 | level-2-only}

no isis circuit-type

Syntax Description

level-1

A Level 1 adjacency may be established if there is at least one area address in common between this system and its neighbors. Level 2 adjacencies will never be established over this interface.

level-1-2

A Level 1 and Level 2 adjacency is established if the neighbor is also configured as level-1-2 and there is at least one area in common. If there is no area in common, a Level 2 adjacency is established. This is the default.

level-2-only

Level 2 adjacencies are established if the other routers are Level 2 or Level 1-2 routers and their interfaces are configured for Level 1-2 or Level 2. Level 1 adjacencies will never be established over this interface.

level-1	A Level 1 adjacency may be established if there is at least one area address in common between this system and its neighbors. Level 2 adjacencies will never be established over this interface.
level-1-2	A Level 1 and Level 2 adjacency is established if the neighbor is also configured as level-1-2 and there is at least one area in common. If there is no area in common, a Level 2 adjacency is established. This is the default.
level-2-only	Level 2 adjacencies are established if the other routers are Level 2 or Level 1-2 routers and their interfaces are configured for Level 1-2 or Level 2. Level 1 adjacencies will never be established over this interface.

isis csnp-interval

To configure the Intermediate System-to-Intermediate System (IS-IS) complete sequence number PDUs (CSNP) interval, use the isis csnp-interval interface configuration command. To restore the default value, use the no form of this command.

isis csnp-interval seconds {level-1 | level-2}

no isis csnp-interval {level-1 | level-2}

Syntax Description

seconds

Interval of time between transmission of CSNPs on multiaccess networks. This interval only applies for the designated router. The default is 10 seconds.

level-1

Configures the interval of time between transmission of CSNPs for Level 1 independently.

level-2

Configures the interval of time between transmission of CSNPs for Level 2 independently.

seconds	Interval of time between transmission of CSNPs on multiaccess networks. This interval only applies for the designated router. The default is 10 seconds.
level-1	Configures the interval of time between transmission of CSNPs for Level 1 independently.
level-2	Configures the interval of time between transmission of CSNPs for Level 2 independently.

isis display delimiter

To make output from multiarea displays easier to read by specifying the delimiter to use to separate displays of information, use the isis display delimiter global configuration command. This command displays the output from different areas as a string or additional white space. To disable this output format, use the no form of this command.

isis display delimiter [return cnt | char cnt]

no isis display delimiter [return cnt | char cnt]

Syntax Description

return

(Optional) Delimit with carriage returns.

cnt

(Optional) Number of carriage returns or length of string to use for delimiter.

char

(Optional) Character to use for delimiter string.

return	(Optional) Delimit with carriage returns.
cnt	(Optional) Number of carriage returns or length of string to use for delimiter.
char	(Optional) Character to use for delimiter string.

isis hello-interval

To specify the length of time between hello packets that the Cisco IOS software sends, use the isis hello-interval interface configuration command. To restore the default value, use the no form of this command.

isis hello-interval seconds {level-1 | level-2}

no isis hello-interval {level-1 | level-2}

Syntax Description

seconds

An integer value. By default, a value three times the hello interval seconds is advertised as the holdtime in the hello packets sent. (That multiplier of 3 can be changed by specifying the isis hello-multiplier command.) With smaller hello intervals, topological changes are detected faster, but there is more routing traffic. The default is 10 seconds.

level-1

Configures the hello interval for Level 1 independently. Use this on X.25, Switched Multimegabit Data Service (SMDS), and Frame Relay multiaccess networks.

level-2

Configures the hello interval for Level 2 independently. Use this on X.25, SMDS, and Frame Relay multiaccess networks.

seconds	An integer value. By default, a value three times the hello interval seconds is advertised as the holdtime in the hello packets sent. (That multiplier of 3 can be changed by specifying the isis hello-multiplier command.) With smaller hello intervals, topological changes are detected faster, but there is more routing traffic. The default is 10 seconds.
level-1	Configures the hello interval for Level 1 independently. Use this on X.25, Switched Multimegabit Data Service (SMDS), and Frame Relay multiaccess networks.
level-2	Configures the hello interval for Level 2 independently. Use this on X.25, SMDS, and Frame Relay multiaccess networks.

isis hello-multiplier

To specify the number of Intermediate System-to-Intermediate System (IS-IS) hello packets a neighbor must miss before the router should declare the adjacency as down, use the isis hello-multiplier interface configuration command. To restore the default value, use the no form of this command.

isis hello-multiplier multiplier {level-1 | level-2}

no isis hello-multiplier {level-1 | level-2}

Syntax Description

multiplier

Integer value from 3 to 1000. The advertised holdtime in IS-IS hellos will be set to the hello-multiplier times the hello-interval. Neighbors will declare an adjacency to this router down after not having received any IS-IS hellos during the advertised holdtime. The holdtime (and thus the hello-multiplier and the hello-interval) can be set on a per interface basis, and can be different between different routers in one area.

Using a smaller hello-multiplier will give fast convergence, but can result in more routing instability. Increment the hello-multiplier to a larger value to help network stability when needed. Never configure a hello-multiplier lower then the default value of 3.

level-1

Configures the hello multiplier independently for Level 1 adjacencies.

level-2

Configures the hello multiplier independently for Level 2 adjacencies.

multiplier	Integer value from 3 to 1000. The advertised holdtime in IS-IS hellos will be set to the hello-multiplier times the hello-interval. Neighbors will declare an adjacency to this router down after not having received any IS-IS hellos during the advertised holdtime. The holdtime (and thus the hello-multiplier and the hello-interval) can be set on a per interface basis, and can be different between different routers in one area. Using a smaller hello-multiplier will give fast convergence, but can result in more routing instability. Increment the hello-multiplier to a larger value to help network stability when needed. Never configure a hello-multiplier lower then the default value of 3.
level-1	Configures the hello multiplier independently for Level 1 adjacencies.
level-2	Configures the hello multiplier independently for Level 2 adjacencies.

isis lsp-interval

To configure the time delay between successive Intermediate System-to-Intermediate System (IS-IS) link state packet transmissions, use the isis lsp-interval interface configuration command. To restore the default value, use the no form of this command.

isis lsp-interval milliseconds

no isis lsp-interval

Syntax Description

milliseconds

Time delay between successive link state packets, in milliseconds.

milliseconds	Time delay between successive link state packets, in milliseconds.

isis mesh-group

To optimize link-state packet (LSP) flooding in nonbroadcast multiaccess (NBMA) networks with highly meshed, point-to-point topologies, use the isis mesh-group interface configuration command. To remove a (sub)interface from a mesh group, use the no form of this command.

isis mesh-group [num | blocked]

no isis mesh-group [num | blocked]

Syntax Description

num

(Optional) A number identifying the mesh group of which this interface is a member.

blocked

(Optional) Keyword specifying that no LSP flooding will take place on this (sub)interface.

num	(Optional) A number identifying the mesh group of which this interface is a member.
blocked	(Optional) Keyword specifying that no LSP flooding will take place on this (sub)interface.

isis metric

To configure the metric for an interface, use the isis metric interface configuration command. To restore the default metric value, use the no form of this command.

isis metric default-metric {level-1 | level-2}

no isis metric {level-1 | level-2}

Syntax Description

default-metric

Metric assigned to the link and used to calculate the cost from each other router via the links in the network to other destinations. You can configure this metric for Level 1 or Level 2 routing. The range is from 0 to 63. The default value is 10.

level-1

This metric should be used only in the SPF calculation for L1 (intra-area) routing.

level-2

This metric should be used only in the SPF calculation for L2 (interarea) routing.

default-metric	Metric assigned to the link and used to calculate the cost from each other router via the links in the network to other destinations. You can configure this metric for Level 1 or Level 2 routing. The range is from 0 to 63. The default value is 10.
level-1	This metric should be used only in the SPF calculation for L1 (intra-area) routing.
level-2	This metric should be used only in the SPF calculation for L2 (interarea) routing.

isis password

To configure the authentication password for an interface, use the isis password interface configuration command. To disable authentication for Intermediate System-to-Intermediate System (IS-IS), use the no form of this command.

isis password password {level-1 | level-2}

no isis password {level-1 | level-2}

Syntax Description

password

Authentication password you assign for an interface.

level-1

Configures the authentication password for Level 1 independently. For Level 1 routing, the router acts as a station router only.

level-2

Configures the authentication password for Level 2 independently. For Level 2 routing, the router acts as an area router only.

password	Authentication password you assign for an interface.
level-1	Configures the authentication password for Level 1 independently. For Level 1 routing, the router acts as a station router only.
level-2	Configures the authentication password for Level 2 independently. For Level 2 routing, the router acts as an area router only.

isis priority

To configure the priority of designated routers, use the isis priority interface configuration command. To reset the default priority, use the no form of this command.

isis priority value {level-1 | level-2}

no isis priority {level-1 | level-2}

Syntax Description

value

Sets the priority of a router and is a number from 0 to 127. The default value is 64.

level-1

Sets the priority for Level 1 independently.

level-2

Sets the priority for Level 2 independently.

value	Sets the priority of a router and is a number from 0 to 127. The default value is 64.
level-1	Sets the priority for Level 1 independently.
level-2	Sets the priority for Level 2 independently.

isis retransmit-interval

To configure the amount of time between retransmission of each Intermediate System-to-Intermediate System (IS-IS) link-state packet (LSP) on a point-to-point link, use the isis retransmit-interval interface configuration command. To restore the default value, use the no form of this command.

isis retransmit-interval seconds

no isis retransmit-interval seconds

Syntax Description

seconds

Time in seconds between retransmission of each LSP. It is an integer that should be greater than the expected round-trip delay between any two routers on the attached network. The default is 5 seconds.

seconds	Time in seconds between retransmission of each LSP. It is an integer that should be greater than the expected round-trip delay between any two routers on the attached network. The default is 5 seconds.

isis retransmit-throttle-interval

To configure the amount of time between retransmissions on each Intermediate System-to-Intermediate System (IS-IS) link-state packet (LSP) on a point-to-point interface, use the isis retransmit-throttle-interval interface configuration command. To restore the default value, use the no form of this command.

isis retransmit-throttle-interval milliseconds

no isis retransmit-throttle-interval

Syntax Description

milliseconds

Minimum delay (in milliseconds) between LSP retransmissions on the interface.

milliseconds	Minimum delay (in milliseconds) between LSP retransmissions on the interface.

is-type

To configure the routing level for an instance of the Intermediate System-to-Intermediate System (IS-IS) routing process, use the is-type router configuration command. To reset the default value, use the no form of this command.

is-type {level-1 | level-1-2 | level-2-only}

no is-type {level-1 | level-1-2 | level-2-only}

Syntax Description

level-1

Router performs only Level 1 (intra-area) routing. This router only learns about destinations inside its area. Level 2 (interarea) routing is performed by the closest Level 1-2 router.

level-1-2

Router performs both Level 1 and Level 2 routing. This router runs two instances of the routing process. It has one link-state packet database (LSDB) for destinations inside the area (Level 1 routing) and runs an shortest path first (SPF) calculation to discover the area topology. It also has another link-state packet database (LSDB) with link-state packets (LSPs) of all other backbone (Level 2) routers, and runs another SPF calculation to discover the topology of the backbone, and the existence of all other areas.

level-2-only

Routing process acts as a Level 2 (interarea) router only. This router is part of the backbone, and does not communicate with Level 1-only routers in its own area.

level-1	Router performs only Level 1 (intra-area) routing. This router only learns about destinations inside its area. Level 2 (interarea) routing is performed by the closest Level 1-2 router.
level-1-2	Router performs both Level 1 and Level 2 routing. This router runs two instances of the routing process. It has one link-state packet database (LSDB) for destinations inside the area (Level 1 routing) and runs an shortest path first (SPF) calculation to discover the area topology. It also has another link-state packet database (LSDB) with link-state packets (LSPs) of all other backbone (Level 2) routers, and runs another SPF calculation to discover the topology of the backbone, and the existence of all other areas.
level-2-only	Routing process acts as a Level 2 (interarea) router only. This router is part of the backbone, and does not communicate with Level 1-only routers in its own area.

net

To configure an Intermediate System-to-Intermediate System (IS-IS) network entity title (NET) for the routing process, use the net router configuration command. To remove a NET, use the no form of this command.

net network-entity-title

no net network-entity-title

Syntax Description

network-entity-title

NET that specifies the area address and the system ID for an IS-IS routing process. This argument can be either an address or a name.

network-entity-title	NET that specifies the area address and the system ID for an IS-IS routing process. This argument can be either an address or a name.

partition avoidance

To cause an Intermediate System-to-Intermediate System (IS-IS) Level 1-2 border router to stop advertising the Level 1 area prefix into the Level 2 backbone when full connectivity is lost between the border router, all adjacent Level 1 routers, and end hosts, use the partition avoidance router configuration command. This command displays the output from different areas as a string or additional white space. To disable this output format, use the no form of the command.

partition avoidance area-tag

no partition avoidance area-tag

Syntax Description

area-tag

Required for multiarea IS-IS configuration. Optional for conventional IS-IS configuration. Required for multiarea IS-IS configuration.

Meaningful name for a routing process. If it is not specified, a null tag is assumed and the process is referenced with a null tag. This name must be unique among all IP or Connectionless Network Service Protocol (CLNS) router processes for a given router.

area-tag	Required for multiarea IS-IS configuration. Optional for conventional IS-IS configuration. Required for multiarea IS-IS configuration. Meaningful name for a routing process. If it is not specified, a null tag is assumed and the process is referenced with a null tag. This name must be unique among all IP or Connectionless Network Service Protocol (CLNS) router processes for a given router.

router isis

To enable the Intermediate System-to-Intermediate System (IS-IS) routing protocol and to specify an IS-IS process, use the router isis global configuration command. To disable IS-IS routing, use the no form of this command.

router isis area-tag

no router isis area-tag

Syntax Description

area-tag

Required for multiarea IS-IS configuration. Optional for conventional IS-IS configuration.

Meaningful name for a routing process. If it is not specified, a null tag is assumed and the process is referenced with a null tag. This name must be unique among all IP or Connectionless Network Service (CLNS) router processes for a given router.

area-tag	Required for multiarea IS-IS configuration. Optional for conventional IS-IS configuration. Meaningful name for a routing process. If it is not specified, a null tag is assumed and the process is referenced with a null tag. This name must be unique among all IP or Connectionless Network Service (CLNS) router processes for a given router.

set-overload-bit

To configure the router to signal other routers not to use it as an intermediate hop in their shortest path first (SPF) calculations, use the set-overload-bit router configuration command. To remove the designation, use the no form of this command.

set-overload-bit

no set-overload-bit

Syntax Description

This command has no arguments or keywords.

show isis database

To display the Intermediate System-to-Intermediate System (IS-IS) link state database, use the show isis database EXEC command.

show isis area-tag database [level-1] [level-2] [l1] [l2] [detail] [lspid]

Syntax Description

area-tag

Required for multiarea IS-IS configuration. Optional for conventional IS-IS configuration.

Meaningful name for a routing process. This name must be unique among all IP or Connectionless Network Service (CLNS) router processes for a given router. If an area tag is not specified, a null tag is assumed and the process is referenced with a null tag. If an area tag is specified, output is limited to the specified area.

level-1

(Optional) Displays the IS-IS link state database for Level 1.

level-2

(Optional) Displays the IS-IS link state database for Level 2.

l1

(Optional) Abbreviation for the option level-1.

l2

(Optional) Abbreviation for the option level-2.

detail

(Optional) When specified, the contents of each LSP are displayed. Otherwise, a summary display is provided.

lspid

(Optional) Link-state PDU identifier. When specified, the contents of a single LSP is displayed by its ID number.

area-tag	Required for multiarea IS-IS configuration. Optional for conventional IS-IS configuration. Meaningful name for a routing process. This name must be unique among all IP or Connectionless Network Service (CLNS) router processes for a given router. If an area tag is not specified, a null tag is assumed and the process is referenced with a null tag. If an area tag is specified, output is limited to the specified area.
level-1	(Optional) Displays the IS-IS link state database for Level 1.
level-2	(Optional) Displays the IS-IS link state database for Level 2.
l1	(Optional) Abbreviation for the option level-1.
l2	(Optional) Abbreviation for the option level-2.
detail	(Optional) When specified, the contents of each LSP are displayed. Otherwise, a summary display is provided.
lspid	(Optional) Link-state PDU identifier. When specified, the contents of a single LSP is displayed by its ID number.

show isis spf-log

To display how often and why the router has run a full shortest path first (SPF) calculation, use the show isis spf-log user EXEC command.

show isis area-tag spf-log

area-tag	Required for multiarea IS-IS configuration. Optional for conventional IS-IS configuration. Meaningful name for a routing process. This name must be unique among all IP or Connectionless Network Service (CLNS) router processes for a given router. If an area tag is not specified, a null tag is assumed and the process is referenced with a null tag. If an area tag is specified, output is limited to the specified area.

show isis topology

To display a list of all connected routers in all areas, use the show isis topology EXEC command.

show isis area-tag topology

area-tag	Required for multiarea IS-IS configuration. Optional for conventional IS-IS configuration. Meaningful name for a routing process. This name must be unique among all IP or Connectionless Network Service (CLNS) router processes for a given router. If an area tag is not specified, a null tag is assumed and the process is referenced with a null tag. If an area tag is specified, output is limited to the specified area.

summary-address (IS-IS)

To create aggregate addresses for Intermediate System-to-Intermediate System (IS-IS) or Open Shortest Path First (OSPF), use the summary-address router configuration command. Use the no form of the command to restore the default.

summary-address address mask {level-1 | level-1-2 | level-2} prefix mask

no summary-address address mask {level-1 | level-1-2 | level-2}

Syntax Description

address

Summary address designated for a range of addresses.

mask

IP subnet mask used for the summary route.

level-1

Only routes redistributed into Level 1 are summarized with the configured address/mask value.

level-1-2

The summary router will be applied both when redistributing routes into Level 1 and Level 2 IS-IS, and when L2 IS-IS advertised Level 1 routes reachable in its area.

level-2

Routes learned by Level 1 routing will be summarized into the Level 2 backbone with the configured address/mask value, and redistributed routes into Level 2 IS-IS will be summarized also.

prefix

IP route prefix for the destination.

mask

IP subnet mask used for the summary route.

address	Summary address designated for a range of addresses.
mask	IP subnet mask used for the summary route.
level-1	Only routes redistributed into Level 1 are summarized with the configured address/mask value.
level-1-2	The summary router will be applied both when redistributing routes into Level 1 and Level 2 IS-IS, and when L2 IS-IS advertised Level 1 routes reachable in its area.
level-2	Routes learned by Level 1 routing will be summarized into the Level 2 backbone with the configured address/mask value, and redistributed routes into Level 2 IS-IS will be summarized also.
prefix	IP route prefix for the destination.
mask	IP subnet mask used for the summary route.

Table of Contents

Integrated IS-IS Commands