Table Of Contents

offset-list (EIGRP)

offset-list (RIP)

output-delay

partition avoidance

passive-interface

prc-interval

protocol shutdown

redistribute (BGP to ISO IS-IS)

redistribute (IP)

redistribute (ISO IS-IS to BGP)

redistribute dvmrp

redistribute isis

redistribute maximum-prefix

redistribute maximum-prefix (EIGRP)

route-map

router bgp

router eigrp

router isis

router odr

router ospf

router rip

router-id

routing dynamic

offset-list (EIGRP)

To add an offset to incoming and outgoing metrics to routes learned via Enhanced Interior Gateway Routing Protocol (EIGRP), use the offset-list command in router configuration mode. To remove an offset list, use the no form of this command.

offset-list {access-list-number | access-list-name} {in | out} offset [interface-type interface-number]

no offset-list {access-list-number | access-list-name} {in | out} offset [interface-type interface-number]

Syntax Description

access-list-number | access-list-name	Standard access list number or name to be applied. Access list number 0 indicates all access lists. If the offset value is 0, no action is taken. For IGRP, the offset is added to the delay component only.
in	Applies the access list to incoming metrics.
out	Applies the access list to outgoing metrics.
offset	Positive offset to be applied to metrics for networks matching the access list. If the offset is 0, no action is taken.
interface-type	(Optional) Interface type to which the offset list is applied.
interface-number	(Optional) Interface number to which the offset list is applied.

Defaults

This command is disabled by default.

Command Modes

Router configuration

Command History

Release	Modification
10.0	This command was introduced.
10.3	The interface-type and interface-number arguments were added.
11.2	The access-list-name argument was added.

Usage Guidelines

The offset value is added to the routing metric. An offset list with an interface type and interface number is considered extended and takes precedence over an offset list that is not extended. Therefore, if an entry passes the extended offset list and the normal offset list, the offset of the extended offset list is added to the metric.

Examples

In the following example, the router applies an offset of 10 to the delay component of the router only to access list 21:

offset-list 21 out 10

In the following example, the router applies an offset of 10 to routes learned from Ethernet interface 0:

offset-list 21 in 10 ethernet 0

offset-list (RIP)

To add an offset to incoming and outgoing metrics to routes learned via Routing Information Protocol (RIP), use the offset-list command in router configuration mode. To remove an offset list, use the no form of this command.

offset-list {access-list-number | access-list-name} {in | out} offset [interface-type interface-number]

no offset-list {access-list-number | access-list-name} {in | out} offset [interface-type interface-number]

Syntax Description

access-list-number	Standard access list number to be applied. Access list number 0 indicates all access lists. If offset is 0, no action is taken. For IGRP, the offset is added to the delay component only.
access-list-name	Standard access list name to be applied.
in	Applies the access list to incoming metrics.
out	Applies the access list to outgoing metrics.
offset	Positive offset to be applied to metrics for networks matching the access list. If the offset is 0, no action is taken.
interface-type	(Optional) Interface type to which the offset list is applied.
interface-number	(Optional) Interface number to which the offset list is applied.

Defaults

This command is disabled by default.

Command Modes

Router configuration

Command History

Release	Modification
10.0	This command was introduced.
10.3	The interface-type and interface-number arguments were added.
11.2	The access-list-name argument was added.

Usage Guidelines

The offset value is added to the routing metric. An offset list with an interface type and interface number is considered extended and takes precedence over an offset list that is not extended. Therefore, if an entry passes the extended offset list and the normal offset list, the offset of the extended offset list is added to the metric.

Examples

In the following example, the router applies an offset of 10 to the delay component of a router only to access list 21:

offset-list 21 out 10

In the following example, the router applies an offset of 10 to routes learned from Ethernet interface 0:

offset-list 21 in 10 ethernet 0

output-delay

To change the interpacket delay for Routing Information Protocol (RIP) updates sent, use the output-delay command in router configuration mode. To remove the delay, use the no form of this command.

output-delay delay

no output-delay

Syntax Description

delay

Delay between packets in a multiple-packet RIP update (in milliseconds). The range is from 8 to 50. The default is 0.

Defaults

0 milliseconds

Command Modes

Router configuration

Command History

Release	Modification
10.0	This command was introduced.
12.2(33)SRA	This command was integrated into Cisco IOS Release 12.2(33)SRA.

Usage Guidelines

Consider using this command if you have a high-end router that is sending at high speed to a low-speed router that might not be able to receive at the high speed. Configuring this command will help prevent the routing table from losing information.

Examples

The following example sets the interpacket delay to 10 milliseconds:

router rip

 output-delay 10

partition avoidance

To cause an 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 command in router configuration mode. 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

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

Defaults

This command is disabled by default.

Command Modes

Router configuration

Command History

Release	Modification
12.0(5)T	This command was introduced.

Usage Guidelines

When the partition avoidance command is enabled, a multiarea router withdraws a Level 1 area prefix from the Level 2 backbone when it no longer has any active adjacencies to that Level 1 area. This withdrawal prevents the Level 1 area from appearing to be partitioned within the Level 2 backbone.

In International Standards Organization (ISO) CLNS networks using a redundant topology, it is possible for an area to become "partitioned" when full connectivity is lost between a Level 1-2 border router, all adjacent Level 1 routers, and end hosts. In such a case, multiple Level 1-2 border routers advertise the Level 1 area prefix into the backbone area, even though any one router can reach only a subset of the end hosts in the Level 1 area.

When enabled, the partition avoidance command prevents this partitioning by causing the border router to stop advertising the Level 1 area prefix into the Level 2 backbone. This command displays the output from different areas as a string or additional white space.

Other cases of connectivity loss within the Level 1 area itself are not detected or corrected by the border router, and this command will have no effect.

Examples

The following example causes the routing process named Finance to stop advertising the prefix for the area named area1 when the router no longer has any active adjacencies to area1:

router isis Finance

 partition avoidance area1

Related Commands

Command	Description
is-type	Configures the routing level for an instance of the IS-IS routing process.
router isis	Enables the IS-IS routing protocol and specifies an IS-IS process.

passive-interface

To disable sending routing updates on an interface, use the passive-interface command in router configuration mode. To reenable the sending of routing updates, use the no form of this command.

passive-interface [default] {interface-type interface-number}

no passive-interface interface-type interface-number

Syntax Description

default	(Optional) All interfaces become passive.
interface-type	Interface type.
interface-number	Interface number.

Defaults

Routing updates are sent on the interface.

Command Modes

Router configuration

Command History

Release	Modification
10.0	This command was introduced.
12.0	The default keyword was added.

Usage Guidelines

If you disable the sending of routing updates on an interface, the particular subnet will continue to be advertised to other interfaces, and updates from other routers on that interface continue to be received and processed.

The default keyword sets all interfaces as passive by default. You can then configure individual interfaces where adjacencies are desired using the no passive-interface command. The default keyword is useful in Internet service provider (ISP) and large enterprise networks where many of the distribution routers have more than 200 interfaces.

For the Open Shortest Path First (OSPF) protocol, OSPF routing information is neither sent nor received through the specified router interface. The specified interface address appears as a stub network in the OSPF domain.

For the Intermediate System-to-Intermediate System (IS-IS) protocol, this command instructs IS-IS to advertise the IP addresses for the specified interface without actually running IS-IS on that interface. The no form of this command for IS-IS disables advertising IP addresses for the specified address.

---

Note For IS-IS you must keep at least one active interface and configure the interface with the ip router isis command.

---

Enhanced Interior Gateway Routing Protocol (EIGRP) is disabled on an interface that is configured as passive although it advertises the route.

Examples

The following example sends EIGRP updates to all interfaces on network 10.108.0.0 except Ethernet interface 1:

router eigrp 109

 network 10.108.0.0

 passive-interface ethernet 1

The following configuration enables IS-IS on Ethernet interface 1 and serial interface 0 and advertises the IP addresses of Ethernet interface 0 in its link-state protocol data units (PDUs):

router isis Finance

 passive-interface Ethernet 0

interface Ethernet 1

 ip router isis Finance

interface serial 0

 ip router isis Finance

The following example sets all interfaces as passive, then activates Ethernet interface 0:

router ospf 100

passive-interface default

no passive-interface ethernet0

network 10.108.0.1 0.0.0.255 area 0

prc-interval

To customize IS-IS throttling of partial route calculations (PRC), use the prc-interval command in router configuration mode. To restore default values, use the no form of this command.

prc-interval prc-max-wait [prc-initial-wait prc-second-wait]

no prc-interval

Syntax Description

prc-max-wait	Indicates the maximum interval (in seconds) between two consecutive PRC calculations. Value range is 1 to 120 seconds. The default is 5 seconds.
prc-initial-wait	(Optional) Indicates the initial PRC calculation delay (in milliseconds) after a topology change. The range is 1 to 120,000 milliseconds. The default is 2000 milliseconds.
prc-second-wait	(Optional) Indicates the hold time between the first and second PRC calculation (in milliseconds). The range is 1 to 120,000 milliseconds. The default is 5000 milliseconds (5 seconds).

Defaults

prc-max-wait: 5 seconds
prc-initial-wait: 2000 milliseconds
prc-second-wait: 5000 milliseconds

Command Modes

Router configuration

Command History

Release	Modification
12.1	This command was introduced.

Usage Guidelines

PRC is the software's process of calculating routes without performing an SPF calculation. This is possible when the topology of the routing system itself has not changed, but a change is detected in the information announced by a particular IS or when it is necessary to attempt to reinstall such routes in the RIB.

The following description will help you determine whether to change the default values of this command:

•The prc-initial-wait argument indicates the initial wait time (in milliseconds) before generating the first LSP.

•The prc-second-wait argument indicates the amount of time to wait (in milliseconds) between the first and second LSP generation.

•Each subsequent wait interval is twice as long as the previous one until the wait interval reaches the prc-max-wait interval specified, so this value causes the throttling or slowing down of the PRC calculation after the initial and second intervals. Once this interval is reached, the wait interval continues at this interval until the network calms down.

•After the network calms down and there are no triggers for 2 times the prc-max-wait interval, fast behavior is restored (the initial wait time).

Examples

The following example configures intervals for SPF calculations, PRC, and LSP generation:

router isis

 spf-interval 5 10 20

 prc-interval 5 10 20

 lsp-gen-interval 2 50 100

protocol shutdown

To disable the Intermediate System-to-Intermediate System (IS-IS) protocol so that it cannot form any adjacency on any interface and will clear the IS-IS link-state packet (LSP) database, use the protocol shutdown command in router configuration mode. To reenable the IS-IS protocol, use the no form of this command.

protocol shutdown

no protocol shutdown

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values

Command Modes

Router configuration

Command History

Release	Modification
12.3(4)T	This command was introduced.
12.2(25)S	This command was integrated into Cisco IOS Release 12.2(25)S.

Usage Guidelines

The protocol shutdown command allows you to disable the IS-IS protocol for a specific routing instance without removing any existing IS-IS configurations parameters. When you enter the protocol shutdown command, the IS-IS protocol will continue to run on the router, and you can use the current IS-IS configuration, but IS-IS will not form any adjacencies on any interface, and it will also clear the IS-IS LSP database.

If you want to disable the IS-IS protocol for a specific interface, use the isis protocol shutdown command.

Examples

The following example disables the IS-IS protocol for a specific routing instance:

Router(config)# router isis area1

Router(config-router)# protocol shutdown

Related Commands

Command	Description
isis protocol shutdown	Disables the IS-IS protocol so that it cannot form adjacencies on a specified interface and places the IP address of the interface into the LSP that is generated by the router.

redistribute (BGP to ISO IS-IS)

To redistribute routes from a Border Gateway Protocol (BGP) autonomous system into an International Organization for Standardization (ISO) Intermediate System-to-Intermediate System (IS-IS) routing process, use the redistribute command in router configuration mode. To remove the redistribute command from the configuration file and restore the system to its default condition where the software does not redistribute routes, use the no form of this command.

redistribute protocol as-number [route-type] [route-map map-tag]

no redistribute protocol as-number [route-type] [route-map map-tag]

Syntax Description

protocol	Source protocol from which routes are being redistributed. It must be the bgp keyword. The bgp keyword is used to redistribute dynamic routes.
as-number	The autonomous system number of the BGP routing process.
route-type	(Optional) The type of route to be redistributed. It can be one of the following keywords: clns or ip. The default is ip. The clns keyword is used to redistribute BGP routes with network service access point (NSAP) addresses into IS-IS. The ip keyword is used to redistribute BGP routes with IP addresses into IS-IS.
route-map map-tag	(Optional) Identifier of a configured route map. The route map should be examined to filter the importation of routes from this source routing protocol to IS-IS. If not specified, all routes are redistributed. If the keyword is specified, but no route map tags are listed, no routes will be imported.

Defaults

Route redistribution is disabled.

protocol: No source protocol is defined.
route-type: ip
route-map map-tag: If the route-map argument is not entered, all routes are redistributed; if no
     map-tag value is entered, no routes are imported.

Command Modes

Router configuration

Command History

Release	Modification
12.2(8)T	The clns keyword was added.

Usage Guidelines

The clns keyword must be specified to redistribute NSAP prefix routes from BGP into an ISO IS-IS routing process. This version of the redistribute command is used only under router configuration mode for IS-IS processes.

Examples

The following example configures NSAP prefix routes from BGP autonomous system 64500 to be redistributed into the IS-IS routing process called osi-proc-17:

router isis osi-proc-17

 redistribute bgp 64500 clns

Related Commands

Command	Description
network (BGP and multiprotocol BGP)	Specifies the list of networks for the BGP routing process.
route-map (IP)	Defines the conditions for redistributing routes from one routing protocol into another.
show route-map	Displays all route maps configured or only the one specified.

redistribute (IP)

To redistribute routes from one routing domain into another routing domain, use the redistribute command in router configuration mode. To disable redistribution, use the no form of this command.

redistribute protocol [process-id] {level-1 | level-1-2 | level-2} [as-number] [metric {metric-value | transparent}] [metric-type type-value] [match {internal | external 1 | external 2}]
[tag tag-value] [route-map map-tag] [subnets]

no redistribute protocol [process-id] {level-1 | level-1-2 | level-2} [as-number] [metric {metric-value | transparent}] [metric-type type-value] [match {internal | external 1 | external 2}] [tag tag-value] [route-map map-tag] [subnets]

Syntax Description

protocol	Source protocol from which routes are being redistributed. It can be one of the following keywords: bgp, connected, eigrp, isis, mobile, ospf, static [ip], or rip. The static [ip] keyword is used to redistribute IP static routes. The optional ip keyword is used when redistributing into the Intermediate System-to-Intermediate System (IS-IS) protocol. The connected keyword refers to routes that are established automatically by virtue of having enabled IP on an interface. For routing protocols such as Open Shortest Path First (OSPF) and IS-IS, these routes will be redistributed as external to the autonomous system.
process-id	(Optional) For the bgp or eigrp keyword, this is an autonomous system number, which is a 16-bit decimal number. For the isis keyword, this is an optional tag value that defines a meaningful name for a routing process. You can specify only one IS-IS process per router. Creating a name for a routing process means that you use names when configuring routing. For the ospf keyword, this is an appropriate OSPF process ID from which routes are to be redistributed. This identifies the routing process. This value takes the form of a nonzero decimal number. For the rip keyword, no process-id value is needed.
level-1	Specifies that for IS-IS Level 1 routes are redistributed into other IP routing protocols independently.
level-1-2	Specifies that for IS-IS both Level 1 and Level 2 routes are redistributed into other IP routing protocols.
level-2	Specifies that for IS-IS Level 2 routes are redistributed into other IP routing protocols independently.
as-number	(Optional) Autonomous system number for the redistributed route.
metric metric-value	(Optional) When redistributing from one OSPF process to another OSPF process on the same router, the metric will be carried through from one process to the other if no metric value is specified. When redistributing other processes to an OSPF process, the default metric is 20 when no metric value is specified.
transparent	(Optional) Causes RIP to use the routing table metric for redistributed routes as the RIP metric.
metric-type type-value	(Optional) For OSPF, the external link type associated with the default route advertised into the OSPF routing domain. It can be one of two values: •1—Type 1 external route •2—Type 2 external route If a metric-type is not specified, the Cisco IOS software adopts a Type 2 external route. For IS-IS, it can be one of two values: •internal—IS-IS metric that is < 63. •external—IS-IS metric that is > 64 < 128. The default is internal.
match {internal | external 1 | external 2}	(Optional) For the criteria by which OSPF routes are redistributed into other routing domains. It can be one of the following: •internal—Routes that are internal to a specific autonomous system. •external 1—Routes that are external to the autonomous system, but are imported into OSPF as Type 1 external route. •external 2—Routes that are external to the autonomous system, but are imported into OSPF as Type 2 external route.
tag tag-value	(Optional) 32-bit decimal value attached to each external route. This is not used by OSPF itself. It may be used to communicate information between Autonomous System Boundary Routers (ASBRs). If none is specified, then the remote autonomous system number is used for routes from Border Gateway Protocol (BGP) and Exterior Gateway Protocol (EGP); for other protocols, zero (0) is used.
route-map	(Optional) Route map that should be interrogated to filter the importation of routes from this source routing protocol to the current routing protocol. If not specified, all routes are redistributed. If this keyword is specified, but no route map tags are listed, no routes will be imported.
map-tag	(Optional) Identifier of a configured route map.
subnets	(Optional) For redistributing routes into OSPF, the scope of redistribution for the specified protocol.

Command Default

Route redistribution is disabled.
protocol: No source protocol is defined.
process-id: No process ID is defined.
metric metric-value: 0
metric-type type-value: Type 2 external route
match internal | external: Internal, external 1, external 2
external: Internal
tag tag-value: If no value is specified, the remote autonomous system number is used for routes from BGP and EGP; for other protocols, the default is 0.
route-map map-tag: If the route-map keyword is not entered, all routes are redistributed; if no map-tag value is entered, no routes are imported.
subnets: No subnets are defined.

Command Modes

Router configuration
Address family configuration

Command History

Release	Modification
10.0	This command was introduced.
12.0(5)T	Address family configuration mode was added.
12.0(22)S	Address family support under EIGRP was added in Cisco IOS Release 12.0(22)S.
12.2(15)T	Address family support under EIGRP was added in Cisco IOS Release 12.2(15)T.
12.2(18)S	Address family support under EIGRP was added.
12.2(27)SBC	This command was integrated into Cisco IOS Release 12.2(27)SBC.
12.2(33)SRA	This command was integrated into Cisco IOS Release 12.2(33)SRA.

Usage Guidelines

Changing or disabling any keyword will not affect the state of other keywords.

A router receiving a link-state protocol with an internal metric will consider the cost of the route from itself to the redistributing router plus the advertised cost to reach the destination. An external metric only considers the advertised metric to reach the destination.

Routes learned from IP routing protocols can be redistributed at Level 1 into an attached area or at Level 2. The level-1-2 keyword allows both Level 1 and Level 2 routes in a single command.

Redistributed routing information must be filtered by the distribute-list out router configuration command. This guideline ensures that only those routes intended by the administrator are passed along to the receiving routing protocol.

Whenever you use the redistribute or the default-information router configuration commands to redistribute routes into an OSPF routing domain, the router automatically becomes an ASBR. However, an ASBR does not, by default, generate a default route into the OSPF routing domain.

When routes are redistributed into OSPF from protocols other than OSPF or BGP, and no metric has been specified with the metric-type keyword and type-value argument, OSPF will use 20 as the default metric. When routes are redistributed into OSPF from BGP, OSPF will use 1 as the default metric. When routes are redistributed from one OSPF process to another OSPF process, Autonomous system (AS) external and not-so-stubby-area (NSSA) routes will use 20 as the default metric. When intra-area and inter-area routes are redistributed between OSPF processes, the internal OSPF metric from the redistribution source process is advertised as the external metric in the redistribution destination process. (This is the only case in which the routing table metric will be preserved when routes are redistributed into OSPF.)

When routes are redistributed into OSPF, only routes that are not subnetted are redistributed if the subnets keyword is not specified.

Routes configured with the connected keyword affected by this redistribute command are the routes not specified by the network router configuration command.

You cannot use the default-metric command to affect the metric used to advertise connected routes.

---

Note The metric value specified in the redistribute command supersedes the metric value specified using the default-metric command.

---

Default redistribution of IGPs or EGP into BGP is not allowed unless the default-information originate router configuration command is specified.

Examples

The following example shows how OSPF routes are redistributed into a BGP domain:

router bgp 109

 redistribute ospf

The following example causes Enhanced Interior Gateway Routing Protocol (EIGRP) routes to be redistributed into an OSPF domain:

router ospf 110

 redistribute eigrp

The following example causes the specified EIGRP process routes to be redistributed into an OSPF domain. The EIGRP-derived metric will be remapped to 100 and RIP routes to 200.

router ospf 109

 redistribute eigrp 108 metric 100 subnets

 redistribute rip metric 200 subnets

The following example configures BGP routes to be redistributed into IS-IS. The link-state cost is specified as 5, and the metric type will be set to external, indicating that it has lower priority than internal metrics.

router isis

 redistribute bgp 120 metric 5 metric-type external

In the following example, network 172.16.0.0 will appear as an external link-state advertisement (LSA) in OSPF 1 with a cost of 100 (the cost is preserved):

interface ethernet 0

 ip address 172.16.0.1 255.0.0.0

 ip ospf cost 100

interface ethernet 1

 ip address 10.0.0.1 255.0.0.0

!

router ospf 1

 network 10.0.0.0 0.255.255.255 area 0

 redistribute ospf 2 subnet

router ospf 2

 network 172.16.0.0 0.255.255.255 area 0

Related Commands

Command	Description
address-family ipv4 (BGP)	Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard IPv4 address prefixes.
address-family vpnv4	Places the router in address family configuration mode for configuring routing sessions such as BGP, RIP, or static routing sessions that use standard VPNv4 address prefixes.
default-information originate (BGP)	Allows the redistribution of network 0.0.0.0 into BGP.
default-information originate (IS-IS)	Generates a default route into an IS-IS routing domain.
default-information originate (OSPF)	Generates a default route into an OSPF routing domain.
distribute-list out (IP)	Suppresses networks from being advertised in updates.
route-map (IP)	Defines the conditions for redistributing routes from one routing protocol into another, or enables policy routing.
show route-map	Displays all route maps configured or only the one specified.

redistribute (ISO IS-IS to BGP)

To redistribute routes from an International Organization for Standardization (ISO) Intermediate System-to-Intermediate System (IS-IS) routing process into a Border Gateway Protocol (BGP) autonomous system, use the redistribute command in address family or router configuration mode. To remove the redistribute command from the configuration file and restore the system to its default condition where the software does not redistribute routes, use the no form of this command.

redistribute protocol [process-id] [route-type] [route-map [map-tag]]

no redistribute protocol [process-id] [route-type] [route-map [map-tag]]

Syntax Description

protocol	Source protocol from which routes are being redistributed. It can be one of the following keywords: isis or static. The isis keyword is used to redistribute dynamic routes. The static keyword is used to redistribute static routes.
process-id	(Optional) When IS-IS is used as a source protocol, this argument defines a meaningful name for a routing process. The process-id argument identifies from which IS-IS routing process routes will be redistributed. Routes can be redistributed only from IS-IS routing processes that involve Level 2 routes, including IS-IS Level 1-2 and Level 2 routing processes. The process-id argument is not used when the protocol keyword is static.
route-type	(Optional) The type of route to be redistributed. It can be one of the following keywords: clns or ip. The default is ip. The clns keyword is used to redistribute Connectionless Network Service (CLNS) routes with network service access point (NSAP) addresses into BGP. The ip keyword is used to redistribute IS-IS routes with IP addresses into BGP.
route-map map-tag	(Optional) Identifier of a configured route map. The route map should be examined to filter the importation of routes from this source routing protocol to BGP. If no route map is specified, all routes are redistributed. If the route-map keyword is specified, but no map-tag value is entered, no routes will be imported.

Defaults

Route redistribution is disabled.

route-type: ip
route-map map-tag: If the route-map argument is not entered, all routes are redistributed; if no
     map-tag value is entered, no routes are imported.

Command Modes

Address family configuration (Cisco IOS 12.3(8)T and later releases)
Router configuration (T-releases after Cisco IOS 12.3(8)T)

Command History

Release	Modification
12.2(8)T	The clns keyword was added.
12.3(8)T	Beginning with Cisco IOS Release 12.3(8)T this version of the redistribute command should be entered under address family mode rather than router configuration mode.

Usage Guidelines

The clns keyword must be specified to redistribute NSAP prefix routes from an ISO IS-IS routing process into BGP. Beginning with Cisco IOS Release 12.3(8)T, this version of the redistribute command is entered only in address family configuration mode for BGP processes.

Examples

Cisco IOS Releases Prior to Release 12.3(8)T

The following example configures CLNS NSAP routes from the IS-IS routing process called osi-proc-6 to be redistributed into BGP:

Router(config)# router bgp 64352

Router(config-router)# redistribute isis osi-proc-6 clns

Cisco IOS Releases 12.3(8)T and Later Releases

The following example configures CLNS NSAP routes from the IS-IS routing process called osi-proc-15 to be redistributed into BGP:

Router(config)# router bgp 404

Router(config-router)# address-family nsap

Router(config-router-af)# redistribute isis osi-proc-15 clns

Related Commands

Command	Description
network (BGP and multiprotocol BGP)	Specifies the list of networks for the BGP routing process.
route-map (IP)	Defines the conditions for redistributing routes from one routing protocol into another.
show route-map	Displays all route maps configured or only the one specified.

redistribute dvmrp

To configure redistribution of Distance Vector Multicast Routing Protocol (DVMRP) routes into multiprotocol BGP, use the redistribute dvmrp command in address family or router configuration mode. To stop such redistribution, use the no form of this command.

redistribute dvmrp [route-map map-name]

no redistribute dvmrp [route-map map-name]

Syntax Description

route-map map-name

(Optional) Name of the route map that contains various BGP attribute settings.

Defaults

DVMRP routes are not redistributed into multiprotocol BGP.

Command Modes

Address family configuration

Router configuration

Command History

Release	Modification
11.1(20)CC	This command was introduced.
12.0(7)T	Address family configuration mode was added.

Usage Guidelines

Use this command if you have a subset of DVMRP routes in an autonomous system that you want to take the multiprotocol BGP path. Define a route map to further specify which DVMRP routes get redistributed.

Examples

The following router configuration mode example redistributes DVMRP routes to BGP peers that match access list 1:

router bgp 109

 redistribute dvmrp route-map dvmrp-into-mbgp

route-map dvmrp-into-mbgp

 match ip address 1

The following address family configuration mode example redistributes DVMRP routes to multiprotocol BGP peers that match access list 1:

router bgp 109

address-family ipv4 multicast

 redistribute dvmrp route-map dvmrp-into-mbgp

route-map dvmrp-into-mbgp

 match ip address 1

redistribute isis

To redistribute IS-IS routes specifically from Level 1 into Level 2 or from Level 2 into Level 1, use the redistribute isis command in router configuration mode. To disable the redistribution, use the no form of this command.

redistribute isis ip {level-1 | level-2} into {level-2 | level-1} [[distribute-list list-number] | [route-map map-tag]]

no redistribute isis ip {level-1 | level-2} into {level-2 | level-1}{[distribute-list list-number] | [route-map map-tag]}

Syntax Description

ip	Redistributes IS-IS IP routes (IS-IS CLNS routes are unaffected).
level-1 | level-2	Level from which and to which you are redistributing IS-IS routes.
into	Keyword that separates the level of routes being redistributed from the level into which you are redistributing routes.
distribute-list list-number	(Optional) Number of a distribute list that controls the IS-IS redistribution. You may specify either a distribute list or a route map, but not both.
route-map map-tag	(Optional) Name of a route map that controls the IS-IS redistribution. You may specify either a distribute list or a route map, but not both.

Defaults

There are no default values for this command.

Command Modes

Router configuration

Command History

Release	Modification
12.0(5)T	This command was introduced.
12.3(2)T	The route-map map-tag keyword and argument were added.

Usage Guidelines

Specify either level-l into level-2 or level-2 into level-1. You may optionally specify either a distribute list or a route map, but not both. You must also specify the metric-style wide command in order for the redistribute isis command to work.

In IS-IS, all areas are stub areas, which means that no routing information is leaked from the backbone (Level 2) into areas (Level 1). Level 1-only routers use default routing to the closest Level 1-Level 2 router in their area. This command enables you to redistribute Level 2 IP routes into Level 1 areas. This redistribution enables Level 1-only routers to pick the best path for an IP prefix to get out of the area. This is an IP-only feature, CLNS routing is still stub routing.

For more control and scalability, a distribute list or a route map can control which Level 2 IP routes can be redistributed into Level 1. This command allows large IS-IS-IP networks to use areas for better scalability.

Examples

In the following example, access list 100 controls the redistribution of IS-IS from Level 1 into Level 2:

router isis

 net 49.0000.0000.0001.00

 metric-style wide

 redistribute isis ip level-1 into level-2 distribute-list 100

access-list 100 permit ip 10.10.10.0 0.0.0.255 any

In the following example, the route map named "match-tag" controls the redistribution of IS-IS from Level 1 into Level 2 so that only routes tagged with 110 are redistributed:

router isis

 net 49.0000.0000.0001.00

 metric-style wide

 redistribute isis ip level-1 into level-2 route-map match-tag

route-map match-tag permit 10

 match tag 110

Related Commands

Command	Description
metric-style wide	Configures a router running IS-IS so that it generates and accepts only new-style Type, Length, and Value objects (TLVs).

redistribute maximum-prefix

To limit the number of prefixes redistributed into Open Shortest Path First (OSPF) or to generate a warning when the number of prefixes redistributed into OSPF reaches a maximum, use the redistribute maximum-prefix command in router configuration mode. To remove the values, use the no form of this command.

redistribute maximum-prefix maximum [threshold] [warning-only | withdraw]

no redistribute maximum-prefix

Syntax Description

maximum	The maximum number of IP prefixes that are allowed to be redistributed into OSPF, or sets a number of prefixes allowed to be redistributed into OSPF before the system logs a warning message, depending on whether the warning-only keyword is present. •There is no default value for the maximum argument. •If the warning-only keyword is also configured, this value does not limit redistribution; it is simply the number of redistributed prefixes that, when reached, causes a warning message to be logged.
threshold	(Optional) Percentage of the value set for maximum number of redistributed prefixes that, when reached, causes a warning message to be logged. •The threshold value defaults to 75 percent.
warning-only	(Optional) Causes a warning to be logged when the number of routes defined by the maximum argument have been redistributed. Additional redistribution is not prevented.
withdraw	(Optional) Prevents additional redistribution when the number of routes defined by the maximum argument have been redistributed. Also, IS-IS rebuilds link-state PDUs (LSPs) without the external (redistributed) IP prefixes.

Defaults

threshold: 75 percent

Command Modes

Router configuration

Command History

Release	Modification
12.0(25)S	This command was introduced.
12.2(18)S	This command was integrated into Cisco IOS Release 12.2(18)S.
12.3(4)T	This command was integrated into Cisco IOS Release 12.3(4)T.

Usage Guidelines

If someone mistakenly injects a large number of IP routes into IS-IS, perhaps by redistributing Border Gateway Protocol (BGP) into IS-IS, the network can be severely flooded. Limiting the number of redistributed routes prevents this potential problem.

When the redistributed maximum-prefix command is configured, if the number of redistributed routes reaches the maximum value configured, no more routes will be redistributed (unless the warning-only keyword was configured).

The redistribution limit applies only to external IP prefixes. Default routes and summarized routes are not limited.

The limit is tracked separately for each not-so-stubby-area (NSSA) because redistribution to NSSAs is done independently for each NSSA and independently of all other regular areas.

Select a maximum value based on your knowledge of how many prefixes are redistributed on the router to the OSPF process.

Examples

Examples for IS-IS Protocol

This example sets a maximum of 600 prefixes that can be redistributed into IS-IS. If the number of prefixes redistributed reaches 75 percent of 600 (450 prefixes), a warning message is logged.

router isis

 redistribute maximum-prefix 600

This example sets a maximum of 1200 prefixes that can be redistributed into IS-IS. If the number of prefixes redistributed reaches 80 percent of 1200 (960 prefixes), a warning message is logged.

router isis

 redistribute maximum-prefix 1200 80

This example allows two warning messages to be logged, the first if the number of prefixes redistributed reaches 85 percent of 600 (510 prefixes), and the second if the number of redistributed routes reaches 600. However, the number of redistributed routes is not limited.

router isis 

 redistribute maximum-prefix 600 85 warning-only

This example sets a maximum of 2000 prefixes that can be redistributed into OSPF process 1. If the number of prefixes redistributed reaches 75 percent of 2000 (1500 prefixes), a warning message is logged. Another warning is logged if the limit is reached, and no more routes are redistributed.

Examples for OSPF Routing Protocol

router ospf 1

 network 10.0.0.0 0.0.0.255 area 0

 redistribute eigrp 10 subnets

 redistribute maximum-prefix 2000

This example sets a maximum of 1200 prefixes that can be redistributed into OSPF process 1. If the number of prefixes redistributed reaches 80 percent of 1200 (960 prefixes), a warning message is logged. Another warning is logged if the limit is reached, and no more routes are redistributed.

router ospf 1

 network 10.0.0.0 0.0.0.255 area 0

 redistribute eigrp 10 subnets

 redistribute maximum-prefix 1200 80

This example allows two warning messages to be logged, the first if the number of prefixes redistributed reaches 85 percent of 600 (510 prefixes), and the second if the number of redistributed routes reaches 600. However, the number of redistributed routes is not limited.

router ospf 1

 network 10.0.0.0 0.0.0.255 area 0

 redistribute eigrp 10 subnets

 redistribute maximum-prefix 600 85 warning-only

redistribute maximum-prefix (EIGRP)

To limit the number of prefixes redistributed into an Enhanced Interior Gateway Routing Protocol (EIGRP) process, use the redistribute maximum-prefix command in address-family configuration mode. To disable this function, use the no form of this command.

redistribute maximum-prefix maximum [threshold] [[dampened] [reset-time minutes] [restart minutes] [restart-count