redistribute

redistribute

Injects (redistributes) routes from one routing protocol domain to another.

Syntax: [no] redistribute protocol [process-id]{level-1 | level-2} [match {internal | external 1 | external 2}] [metric metric] [metric-type {1 | 2 | external | internal}] [route-map map-name]

protocol

Protocol from which routes are being redistributed. Valid values are: bgp, isis, ospf, static ip, connected.

static - redistribute IP static routes.

static ip - redistribute static IP routes into IS-IS.

connected - redistribute routes that have enabled IP on an interface. OSPF and IS-IS routes that are also connected are redistributed as external to the autonomous system.

process-id

For bgp: an autonomous system number.

For isis: defines an optional tag for route processing.

For ospf: identifies an OSPF process ID from which routes are redistributed. The ID identifies the routing process. Valid values are non-zero decimal numbers. Only one OSPF process per router is supported.

For static/static ip: no process-id value is required.

For connected: no process-id value is required.

level-1| level-2

For redistributing routes into IS-IS: Specifies at what level routes are redistributed into IS-IS from other protocols.

level-1 - routes are redistributed as Level-1

level-2 - routes are redistributed as Level-2.

For redistributing routes from IS-IS: Specifies the level of routes redistributed to other protocol domains.

match {internal | external 1 | external 2}

For redistributing routes into OSPF: Specifies how routes are redistributed into other routing domains. Valid values are:

internal - routes internal to a specified autonomous system.

external 1 - routes imported into OSPF as type 1 external routes, but are external to the autonomous system.

external 2 - routes imported into OSPF as type 2 external routes, but are external to the autonomous system.

For other protocols: matches the level of routes to redistribute.

metric metric

Metric included in the redistributed route. The default metric is 0 if no metric is defined using either the redistribute or default-metric commands.

metric-type

For redistributing routes into OSPF: specifies the type of external link associated with the default route advertised into the OSPF routing domain. Valid values are:

type 1 external route

type 2 external route

Default value is type 2 external route.

For redistributing routes into IS-IS: Valid values are:

internal - IS-IS metric less than 63.

external - IS-IS metric greater than 64 and less than 128.

Default value is internal.

route-map map-name

Apply the specified route map to filter incoming routes from the source protocol into the local protocol. If no route map is specified, no filtering occurs and all routes are redistributed. If the route-map keyword is included with no map-name, no routes are imported.

Description: Use the redistribute command to redistribute routes from one routing domain to another.

Use the no redistribute command to disable redistribution.

The redistribute command is used to inject routes from one routing domain into another routing domain. You can conditionally control the redistribution of routes between routing domains by defining route maps (see route-map).

The table below describes which routing protocols may be redistributed to other protocol domains:

Table 5-5. Redistribution Between Protocol Domains
TO Protocol

BGP

IS-IS

OSPF

FROM Protocol
BGP

n/a

Yes

Yes

IS-IS

Yes

n/a

No

OSPF

Yes

No

n/a

Static IP

Yes

Yes

Yes

Connected¹

Yes

Yes

Yes

1 The redistribute command does not redistribute the loopback interface.
Redistribution passes route information from your network into BGP. You must carefully filter this routing information to insure that only those routes that you want advertised are passed. Use the neighbor distribute-list out command to filter routing information.

Metric values defined by the default-metric command are overridden by the metric values defined by the redistribute command.

For OSPF: OSPF metrics are not preserved when routes are redistributed between OSPF processes. Routes redistributed into OSPF with no metric specified are assigned default metrics of 1 for BGP routes and 20 for all other protocols.

If you configure a router (using the redistribute or default-information commands) to redistribute routes into OSPF, that router becomes an Autonomous System Boundary Router (ASBR). ASBRs do not generate a default route into OSPF.

The metric specified by the default-metric command does not affect the metric used to advertise connected routes.

Factory Default: Route distribution is disabled. No source protocol is defined. No process ID is defined. OSPF criteria are not defined. No route map is defined. No map-name is defined. Network weight is not defined. Metric is 0.

Command Mode: Router configuration.

Example 1: In the following example, routes are redistributed from OSPF into BGP:

router(config)#router bgp 120

router(config-router)#redistribute ospf 100

The routes learned by OSPF are visible to BGP.

Example 2: In the following example, the redistribute command redistributes routes learned from BGP into IS-IS as Level-1 routes. The metric-type keyword specifies that the metric-type is set as external for those routes.

router(config)#router isis route_tag

router(config-router)#redistribute bgp 41 level-1 metric-type external

Related Commands: route-map
show route-map
router bgp
router isis
router ospf

protocol	Protocol from which routes are being redistributed. Valid values are: bgp, isis, ospf, static ip, connected. static - redistribute IP static routes. static ip - redistribute static IP routes into IS-IS. connected - redistribute routes that have enabled IP on an interface. OSPF and IS-IS routes that are also connected are redistributed as external to the autonomous system.
process-id	For bgp: an autonomous system number. For isis: defines an optional tag for route processing. For ospf: identifies an OSPF process ID from which routes are redistributed. The ID identifies the routing process. Valid values are non-zero decimal numbers. Only one OSPF process per router is supported. For static/static ip: no process-id value is required. For connected: no process-id value is required.
level-1\| level-2	For redistributing routes into IS-IS: Specifies at what level routes are redistributed into IS-IS from other protocols. level-1 - routes are redistributed as Level-1 level-2 - routes are redistributed as Level-2. For redistributing routes from IS-IS: Specifies the level of routes redistributed to other protocol domains.
match {internal \| external 1 \| external 2}	For redistributing routes into OSPF: Specifies how routes are redistributed into other routing domains. Valid values are: internal - routes internal to a specified autonomous system. external 1 - routes imported into OSPF as type 1 external routes, but are external to the autonomous system. external 2 - routes imported into OSPF as type 2 external routes, but are external to the autonomous system. For other protocols: matches the level of routes to redistribute.
metric metric	Metric included in the redistributed route. The default metric is 0 if no metric is defined using either the redistribute or default-metric commands.
metric-type	For redistributing routes into OSPF: specifies the type of external link associated with the default route advertised into the OSPF routing domain. Valid values are: type 1 external route type 2 external route Default value is type 2 external route. For redistributing routes into IS-IS: Valid values are: internal - IS-IS metric less than 63. external - IS-IS metric greater than 64 and less than 128. Default value is internal.
route-map map-name	Apply the specified route map to filter incoming routes from the source protocol into the local protocol. If no route map is specified, no filtering occurs and all routes are redistributed. If the route-map keyword is included with no map-name, no routes are imported.

**Table 5-5.** Redistribution Between Protocol Domains
		TO Protocol
		BGP	IS-IS	OSPF
FROM Protocol	BGP	n/a	Yes	Yes
IS-IS	Yes	n/a	No
OSPF	Yes	No	n/a
Static IP	Yes	Yes	Yes
Connected¹	Yes	Yes	Yes

router(config)#router bgp 120 router(config-router)#redistribute ospf 100

router(config)#router isis route_tag router(config-router)#redistribute bgp 41 level-1 metric-type external

   Source File Name: Routing_Pol.fm
    HTML File Name: Routing_Pol29.html
    Last Updated: 05/10/04 at 16:38:37

redistribute

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