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Cisco IOS IP Command Reference, Volume 2 of 4: Routing Protocols, Release 12.3 T
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IP Routing Protocol Commands: T Through V
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Introduction
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IP Routing Protocol Commands: A
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IP Routing Protocol Commands: B
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IP Routing Protocols Commands: C through H
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IP Routing Protocols Commands: ignore lsa mospf through ip ospf transmit-delay
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IP Routing Protocol Commands: ip policy route-map through is-type
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IP Routing Protocols Commands: K through M
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IP Routing Protocols Commands: N
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IP Routing Protocols Commands: O through R
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IP Routing Protocols Commands: send-lifetime through set-overload-bit
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IP Routing Protocols Commands: show bgp nsap through show ip bgp update-group
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IP Routing Protocols Commands: show ip cache policy through show ip local policy
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IP Routing Protocol Commands: show ip ospf through synchronization
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Table Of Contents
set ip next-hop verify-availability
send-lifetime
To set the time period during which an authentication key on a key chain is valid to be sent, use the send-lifetime command in key chain key configuration mode. To revert to the default value, use the no form of this command.
send-lifetime start-time {infinite | end-time | duration seconds}
no send-lifetime [start-time {infinite | end-time | duration seconds}]
Syntax Description
Defaults
Forever (the starting time is January 1, 1993, and the ending time is infinite)
Command Modes
Key chain key configuration
Command History
Usage Guidelines
Specify a start-time value and one of the following values: infinite, end-time, or duration seconds.
We recommend running Network Time Protocol (NTP) or some other time synchronization method if you intend to set lifetimes on keys.
If the last key expires, authentication will continue and an error message will be generated. To disable authentication, you must manually delete the last valid key.
Examples
The following example configures a key chain called trees. The key named chestnut will be accepted from 1:30 p.m. to 3:30 p.m. and be sent from 2:00 p.m. to 3:00 p.m. The key named birch will be accepted from 2:30 p.m. to 4:30 p.m. and be sent from 3:00 p.m. to 4:00 p.m. The overlap allows for migration of keys or discrepancies in the set time of the router. There is a 30-minute leeway on each side to handle time differences.
interface ethernet 0ip rip authentication key-chain treesip rip authentication mode md5!router ripnetwork 172.19.0.0version 2!key chain treeskey 1key-string chestnutaccept-lifetime 13:30:00 Jan 25 1996 duration 7200send-lifetime 14:00:00 Jan 25 1996 duration 3600key 2key-string birchaccept-lifetime 14:30:00 Jan 25 1996 duration 7200send-lifetime 15:00:00 Jan 25 1996 duration 3600Related Commands
set as-path
To modify an autonomous system path for BGP routes, use the set as-path command in route-map configuration mode. To not modify the autonomous system path, use the no form of this command.
set as-path {tag | prepend as-path-string}
no set as-path {tag | prepend as-path-string}
Syntax Description
Defaults
Autonomous system path is not modified.
Command Modes
Route-map configuration
Command History
Usage Guidelines
The only global BGP metric available to influence the best path selection is the autonomous system path length. By varying the length of the autonomous system path, a BGP speaker can influence the best path selection by a peer further away.
By allowing you to convert the tag into an autonomous system path, the set as-path tag variation of this command modifies the autonomous system length. The set as-path prepend variation allows you to "prepend" an arbitrary autonomous system path string to BGP routes. Usually the local autonomous system number is prepended multiple times, increasing the autonomous system path length.
Examples
The following example converts the tag of a redistributed route into an autonomous system path:
route-map set-as-path-from-tagset as-path tag!router bgp 100redistribute ospf 109 route-map set-as-path-from-tagThe following example prepends 100 100 100 to all the routes advertised to 10.108.1.1:
route-map set-as-pathmatch as-path 1set as-path prepend 100 100 100!router bgp 100neighbor 10.108.1.1 route-map set-as-path outRelated Commands
set automatic-tag
To automatically compute the tag value, use the set automatic-tag command in route-map configuration mode. To disable this function, use the no form of this command.
set automatic-tag
no set automatic-tag
Syntax Description
This command has no arguments or keywords.
Defaults
This command is disabled by default.
Command Modes
Route-map configuration
Command History
Usage Guidelines
You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.
Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all the match criteria of a route map are met. When all match criteria are met, all set actions are performed.
Examples
The following example configures the Cisco IOS software to automatically compute the tag value for the Border Gateway Protocol (BGP) learned routes:
route-map tagmatch as path 10set automatic-tag!router bgp 100table-map tagRelated Commands
set comm-list delete
To remove communities from the community0 attribute of an inbound or outbound update, use the set comm-list delete command in route-map configuration mode. To negate a previous set comm-list delete command, use the no form of this command.
set comm-list community-list-number | community-list-name delete
no set comm-list community-list-number | community-list-name delete
Syntax Description
Defaults
No communities are removed.
Command Modes
Route-map configuration
Command History
Usage Guidelines
This set route-map configuration command removes communities from the community attribute of an inbound or outbound update using a route map to filter and determine the communities to be deleted. Depending upon whether the route map is applied to the inbound or outbound update for a neighbor, each community that passes the route map permit clause and matches the given community list will be removed from the community attribute being received from or sent to the Border Gateway Protocol (BGP) neighbor.
Each entry of a standard community list should list only one community when used with the set comm-list delete command. For example, in order to be able to delete communities 10:10 and 10:20, you must use the following format to create the entries:
ip community-list 500 permit 10:10 ip community-list 500 permit 10:20The following format for a community list entry, while acceptable otherwise, does not work with the set comm-list delete command:
config ip community-list 500 permit 10:10 10:20When both the set community community-number and set comm-list delete commands are configured in the same sequence of a route map attribute, the deletion operation (set comm-list delete) is performed before the set operation (set community community-number).
Examples
In the following example, the communities 100:10 and 100:20 (if present) will be deleted from updates received from 172.16.233.33. Also, except for 100:50, all communities beginning with 100: will be deleted from updates sent to 172.16.233.33.
router bgp 100 neighbor 172.16.233.33 remote-as 120 neighbor 172.16.233.33 route-map ROUTEMAPIN in neighbor 172.16.233.33 route-map ROUTEMAPOUT out ! ip community-list 500 permit 100:10 ip community-list 500 permit 100:20 ! ip community-list 120 deny 100:50 ip community-list 120 permit 100:.* ! route-map ROUTEMAPIN permit 10 set comm-list 500 delete ! route-map ROUTEMAPOUT permit 10 set comm-list 120 deleteRelated Commands
set community
To set the BGP communities attribute, use the set community route map configuration command. To delete the entry, use the no form of this command.
set community {community-number [additive] [well-known-community] | none}
no set community {community-number [additive] [well-known-community]}
Syntax Description
Defaults
No BGP communities attributes exist.
Command Modes
Route-map configuration
Command History
Usage Guidelines
You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.
Use the route-map global configuration command, and the match and set route map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route map configuration commands specify the redistribution set actions to be performed when all of the match criteria of a route map are met. When all match criteria are met, all set actions are performed.
Examples
In the following example, routes that pass the autonomous system path access list 1 have the community set to 109. Routes that pass the autonomous system path access list 2 have the community set to no-export (these routes will not be advertised to any external BGP [eBGP] peers).
route-map set_community 10 permitmatch as-path 1set community 109route-map set_community 20 permitmatch as-path 2set community no-exportIn the following similar example, routes that pass the autonomous system path access list 1 have the community set to 109. Routes that pass the autonomous system path access list 2 have the community set to local-as (the router will not advertise this route to peers outside the local autonomous system.
route-map set_community 10 permitmatch as-path 1set community 109route-map set_community 20 permitmatch as-path 2set community local-asRelated Commands
set dampening
To set the BGP route dampening factors, use the set dampening route map configuration command. To disable this function, use the no form of this command.
set dampening half-life reuse suppress max-suppress-time
no set dampening
Syntax Description
Defaults
This command is disabled by default.
Command Modes
Route-map configuration
Command History
Usage Guidelines
Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
When a BGP peer is reset, the route is withdrawn and the flap statistics cleared. In this instance, the withdrawal does not incur a penalty even though route flap dampening is enabled.
Examples
The following example sets the half life to 30 minutes, the reuse value to 1500, the suppress value to 10000; and the maximum suppress time to 120 minutes:
route-map tagmatch as path 10set dampening 30 1500 10000 120!router bgp 100neighbor 172.16.233.52 route-map tag inRelated Commands
set default interface
To indicate where to output packets that pass a match clause of a route map for policy routing and have no explicit route to the destination, use the set default interface command in route-map configuration mode. To delete an entry, use the no form of this command.
set default interface type number [...type number]
no set default interface type number [...type number]
Syntax Description
type
Interface type, used with the interface number, to which packets are output.
number
Interface number, used with the interface type, to which packets are output.
Defaults
This command is disabled by default.
Command Modes
Route-map configuration
Command History
11.0
This command was introduced.
12.3(7)T
This command was updated for use in configuring IPv6 policy-based routing (PBR).
Usage Guidelines
An ellipsis (...) in the command syntax indicates that your command input can include multiple values for the type and number arguments.
Use this command to provide certain users a different default route. If the Cisco IOS software has no explicit route for the destination, then it routes the packet to this interface. The first interface specified with the set default interface command that is up is used. The optionally specified interfaces are tried in turn.
Use the ip policy route-map interface configuration command, the route-map global configuration command, and the match and set route-map configuration commands to define the conditions for policy routing packets. The ip policy route-map command identifies a route map by name. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which policy routing occurs. The set commands specify the set actions—the particular routing actions to perform if the criteria enforced by the match commands are met.
In PBR for IPv6, use the ipv6 policy route-map or ipv6 local policy route-map command with match and set route map configuration commands to define conditions for policy routing packets.
The set clauses can be used in conjunction with one another. They are evaluated in the following order:
1.
set ip next-hop
2.
3.
4.
Examples
In the following example, packets that have a Level 3 length of 3 to 50 bytes and for which the software has no explicit route to the destination are output to Ethernet interface 0:
interface serial 0ip policy route-map brighton!route-map brightonmatch length 3 50set default interface ethernet 0Related Commands
set extcommunity
To set Border Gateway Protocol (BGP) extended community attributes, use the set extcommunity command in route-map configuration mode. To delete the entry, use the no form of this command.
set extcommunity {rt extended-community-value [additive] | soo extended-community-value}
no set extcommunity {rt extended-community-value [additive] | soo extended-community-value}
Syntax Description
Defaults
Specifying new route targets with the rt keyword replaces existing route targets by default, unless the additive keyword is used. The use of the additive keyword adds the new route target to the existing route target list but does not replace any existing route targets.
Command Modes
Route-map configuration
Command History
Usage Guidelines
Extended community attributes are used to configure, filter, and identify routes for virtual routing and forwarding instances (VRFs) and Multiprotocol Label Switching (MPLS) Virtual Private Networks (VPNs).
The set extcommunity command is used to configure set clauses that use extended community attributes in route maps. All of the standard rules of match and set clauses apply to the configuration of extended community attributes.
The route target (RT) extended community attribute is configured with the rt keyword. This attribute is used to identify a set of sites and VRFs that may receive routes that are tagged with the configured route target. Configuring the route target extended attribute with a route allows that route to be placed in the per-site forwarding tables that are used for routing traffic that is received from corresponding sites.
The site of origin (SOO) extended community attribute is configured with the soo keyword. This attribute uniquely identifies the site from which the Provider Edge (PE) router learned the route. All routes learned from a particular site must be assigned the same SOO extended community attribute, whether a site is connected to a single PE router or multiple PE routers. Configuring this attribute prevents routing loops from occurring when a site is multihomed. The SOO extended community attribute is configured on the interface and is propagated into BGP through redistribution. The SOO can be applied to routes that are learned from VRFs. The SOO should not be configured for stub sites or sites that are not multihomed.
Examples
The following example sets the route target to extended community attribute 100:2 for routes that are permitted by the route map:
Router(config)# access-list 2 permit 192.168.78.0 255.255.255.0Router(config)# route-map MAP_NAME permit 10Router(config-route-map)# match ip-address 2Router(config-route-map)# set extcommunity rt 100:2The following example sets the route target to extended community attribute 100:3 for routes that are permitted by the route map. The use of the additive keyword adds route target 100:3 to the existing route target list but does not replace any existing route targets.
Router(config)# access-list 3 permit 192.168.79.0 255.255.255.0Router(config)# route-map MAP_NAME permit 10Router(config-route-map)# match ip-address 3Router(config-route-map)# set extcommunity rt 100:3 additive
Note
The following example sets the site of origin to extended community attribute 100:4 for routes that are permitted by the route map:
Router(config)# access-list 4 permit 192.168.80.0 255.255.255.0Router(config)# route-map MAP_NAME permit 10Router(config-route-map)# match ip-address 4Router(config-route-map)# set extcommunity soo 100:4Related Commands
set extcommunity cost
To create a set clause to apply the cost community attribute to routes that pass through a route map, use the set extcommunity cost command in route-map configuration mode. To delete the cost community set clause, use the no form of this command.
set extcommunity cost [igp] community-id cost-value
no set extcommunity cost [igp] community-id cost-value
Syntax Description
Defaults
•
•
Command Modes
Route-map configuration
Command History
Usage Guidelines
The cost community attribute is applied to internal routes by configuring the set extcommunity cost command in a route map. The cost community set clause is configured with a cost community ID number (0-255) and a cost community number value (0-4294967295). The path with the lowest cost community number is preferred. In the case where two paths have been configured with the same cost community value, the path selection process will then prefer the path with the lower community ID.
The BGP Cost Community feature can be configured only within the same autonomous-system or confederation. The cost community is a non-transitive extended community. The cost community is passed to internal BGP (iBGP) and confederation peers only and is not passed to external BGP (eBGP) peers. The cost community allows you to customize the local preference and best path selection process for specific paths. The cost extended community attribute is propagated to iBGP peers when extended community exchange is enabled with the neighbor send-community command.
The following commands can be used to apply the route map with the cost community set clause:
•
•
•
•
•
Multiple cost community set clauses may be configured with the set extcommunity cost command in a single route map block or sequence. However, each set clause must be configured with a different ID value for each point of insertion (POI).
Aggregate routes and multipaths are supported by the BGP Cost Community feature. The cost community attribute can be applied to either type of route. The cost community attribute is passed to the aggregate or multipath route from component routes that carry the cost community attribute. Only unique IDs are passed, and only the highest cost of any individual component route will be applied to the aggregate on a per-ID basis. If multiple component routes contain the same ID, the highest configured cost is applied to the route. If one or more component routes does not carry the cost community attribute or if the component routes are configured with different IDs, then the default value (2147483647) will be advertised for the aggregate or multipath route.
Note
Support for EIGRP MPLS VPN Back Door Links
The "pre-bestpath" point of insertion (POI) has been introduced in the BGP Cost Community feature to support mixed EIGRP VPN network topologies that contain VPN and backdoor links. This POI is applied automatically to EIGRP routes that are redistributed into BGP. The "pre-best path" POI carries the EIGRP route type and metric. This POI influences the best path calculation process by influencing BGP to consider this POI before any other comparison step. No configuration is required. This feature is enabled automatically for EIGRP VPN sites when a supporting is installed to a PE, CE, or back door router.
Examples
The following example configuration shows the configuration of the set extcommunity cost command. The following example applies the cost community ID of 1 and cost community value of 100 to routes that are permitted by the route map. This configuration will cause the best path selection process to prefer this route over other equal cost paths that were not permitted by this route map sequence.
Router(config)# router bgp 50000Router(config-router)# neighbor 10.0.0.1 remote-as 50000Router(config-router)# neighbor 10.0.0.1 update-source Loopback 0Router(config-router)# address-family ipv4Router(config-router-af)# neighbor 10.0.0.1 activateRouter(config-router-af)# neighbor 10.0.0.1 route-map COST1 inRouter(config-router-af)# neighbor 10.0.0.1 send-community bothRouter(config-router-af)# exitRouter(config)# route-map COST1 permit 10Router(config-route-map)# match ip-address 1Router(config-route-map)# set extcommunity cost 1 100Related Commands
set interface
To indicate where to output packets that pass a match clause of a route map for policy routing, use the set interface command in route-map configuration mode. To delete an entry, use the no form of this command.
set interface type number [...type number]
no set interface type number [...type number]
Syntax Description
type
Interface type, used with the interface number, to which packets are output.
number
Interface number, used with the interface type, to which packets are output.
Defaults
This command is disabled by default.
Command Modes
Route-map configuration
Command History
11.0
This command was introduced.
12.3(7)T
This command was updated for use in configuring IPv6 policy-based routing (PBR).
Usage Guidelines
An ellipsis (...) in the command syntax indicates that your command input can include multiple values for the type and number arguments.
Use the ip policy route-map interface configuration command, the route-map global configuration command, and the match and set route-map configuration commands to define the conditions for policy routing packets. The ip policy route-map command identifies a route map by name. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which policy routing occurs. The set commands specify the set actions—the particular routing actions to perform if the criteria enforced by the match commands are met.
In PBR for IPv6, use the ipv6 policy route-map or ipv6 local policy route-map command with match and set route map configuration commands to define conditions for policy routing packets.
If the first interface specified with the set interface command is down, the optionally specified interfaces are tried in turn.
The set clauses can be used in conjunction with one another. They are evaluated in the following order:
1.
2.
3.
4.
A useful next hop implies an interface. As soon as a next hop and an interface are found, the packet is routed.
Specifying the set interface null 0 command is a way to write a policy that the packet be dropped and an "unreachable" message be generated.
Examples
In the following example, packets with a Level 3 length of 3 to 50 bytes are output to Ethernet interface 0:
interface serial 0ip policy route-map testing!route-map testingmatch length 3 50set interface ethernet 0In the following example for IPv6, packets with a Level 3 length of 3 to 50 bytes are output to Ethernet interface 0:
interface serial 0ipv6 policy route-map testing!route-map testingmatch length 3 50set interface ethernet 0Related Commands
set ip default next-hop
To indicate where to output packets that pass a match clause of a route map for policy routing and for which the Cisco IOS software has no explicit route to a destination, use the set ip default next-hop command in route-map configuration mode. To delete an entry, use the no form of this command.
set ip default next-hop ip-address [...ip-address]
no set ip default next-hop ip-address [...ip-address]
Syntax Description
ip-address
IP address of the next hop to which packets are output.The next hop must be an adjacent router.
Defaults
This command is disabled by default.
Command Modes
Route-map configuration
Command History
Usage Guidelines
An ellipsis (...) in the command syntax indicates that your command input can include multiple values for the ip-address argument.
Use this command to provide certain users a different default route. If the software has no explicit route for the destination in the packet, then it routes the packet to this next hop. The first next hop specified with the set ip default next-hop command needs to be adjacent to the router. The optional specified IP addresses are tried in turn.
Use the ip policy route-map interface configuration command, the route-map global configuration command, and the match and set route-map configuration commands to define the conditions for policy routing packets. The ip policy route-map command identifies a route map by name. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which policy routing occurs. The set commands specify the set actions—the particular routing actions to perform if the criteria enforced by the match commands are met.
The set clauses can be used in conjunction with one another. They are evaluated in the following order:
1.
2.
3.
4.
Note
Examples
The following example provides two sources with equal access to two different service providers. Packets arriving on asynchronous interface 1 from the source 10.1.1.1 are sent to the router at 172.16.6.6 if the software has no explicit route for the destination of the packet. Packets arriving from the source 10.2.2.2 are sent to the router at 172.17.7.7 if the software has no explicit route for the destination of the packet. All other packets for which the software has no explicit route to the destination are discarded.
access-list 1 permit ip 10.1.1.1 0.0.0.0access-list 2 permit ip 10.2.2.2 0.0.0.0!interface async 1ip policy route-map equal-access!route-map equal-access permit 10match ip address 1set ip default next-hop 172.16.6.6route-map equal-access permit 20match ip address 2set ip default next-hop 172.17.7.7route-map equal-access permit 30set default interface null0Related Commands
set ip next-hop
To indicate where to output packets that pass a match clause of a route map for policy routing, use the set ip next-hop command in route-map configuration mode. To delete an entry, use the no form of this command.
set ip next-hop {ip-address [...ip-address] | recursive ip-address}
no set ip next-hop ip-address [...ip-address]
Syntax Description
Defaults
This command is disabled by default.
Command Modes
Route-map configuration
Command History
11.0
This command was introduced.
12.0(28)S
The recursive keyword was added.
12.3(14)T
This command was integrated into Cisco IOS Release 12.3(14)T.
Usage Guidelines
An ellipsis (...) in the command syntax indicates that your command input can include multiple values for the ip-address argument.
Use the ip policy route-map interface configuration command, the route-map global configuration command, and the match and set route-map configuration commands to define the conditions for policy routing packets. The ip policy route-map command identifies a route map by name. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which policy routing occurs. The set commands specify the set actions—the particular routing actions to perform if the criteria enforced by the match commands are met.
If the interface associated with the first next hop specified with the set ip next-hop command is down, the optionally specified IP addresses are tried in turn.
The set clauses can be used in conjunction with one another. They are evaluated in the following order:
1.
2.
3.
4.
Note
Examples
In the following example, packets with a Level 3 length of 3 to 50 bytes are output to the router at IP address 10.14.2.2:
interface serial 0ip policy route-map thataway!route-map thatawaymatch length 3 50set ip next-hop 10.14.2.2In the following example, the IP address of 10.3.3.3 is set as the recursive next-hop address:
route-map map_recurseset ip next-hop recursive 10.3.3.3Related Commands
set ip next-hop (BGP)
To indicate where to output packets that pass a match clause of a route map for policy routing, use the set ip next-hop command in route-map configuration mode. To delete an entry, use the no form of this command.
set ip next-hop ip-address [... ip-address] [peer-address]
no set ip next-hop ip-address [... ip-address] [peer-address]
Syntax Description
ip-address
IP address of the next hop to which packets are output. It need not be an adjacent router.
peer-address
(Optional) Sets the next hop to be the BGP peering address.
Defaults
This command is disabled by default.
Command Modes
Route-map configuration
Command History
Usage Guidelines
An ellipsis (...) in the command syntax indicates that your command input can include multiple values for the ip-address argument.
Use the ip policy route-map interface configuration command, the route-map global configuration command, and the match and set route-map configuration commands to define the conditions for policy routing packets. The ip policy route-map command identifies a route map by name. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which policy routing occurs. The set commands specify the set actions—the particular routing actions to perform if the criteria enforced by the match commands are met.
If the first next hop specified with the set ip next-hop command is down, the optionally specified IP addresses are tried in turn.
When the set ip next-hop command is used with the peer-address keyword in an inbound route map of a BGP peer, the next hop of the received matching routes will be set to be the neighbor peering address, overriding any third-party next hops. So the same route map can be applied to multiple BGP peers to override third-party next hops.
When the set ip next-hop command is used with the peer-address keyword in an outbound route map of a BGP peer, the next hop of the advertised matching routes will be set to be the peering address of the local router, thus disabling the next hop calculation. The set ip next-hop command has finer granularity than the (per-neighbor) neighbor next-hop-self command, because you can set the next hop for some routes, but not others. The neighbor next-hop-self command sets the next hop for all routes sent to that neighbor.
The set clauses can be used in conjunction with one another. They are evaluated in the following order:
1.
2.
3.
4.
Examples
In the following example, three routers are on the same FDDI LAN (with IP addresses 10.1.1.1, 10.1.1.2, and 10.1.1.3). Each is in a different autonomous system. The set ip next-hop peer-address command specifies that traffic from the router (10.1.1.3) in remote autonomous system 300 for the router (10.1.1.1) in remote autonomous system 100 that matches the route map is passed through the router bgp 200, rather than sent directly to the router (10.1.1.1) in autonomous system 100 over their mutual connection to the LAN.
router bgp 200neighbor 10.1.1.3 remote-as 300neighbor 10.1.1.3 route-map set-peer-address outneighbor 10.1.1.1 remote-as 100route-map set-peer-address permit 10set ip next-hop peer-addressRelated Commands
set ip next-hop verify-availability
To configure policy routing to verify the reachability of the next hop of a route map before the router performs policy routing to that next hop, use the set ip next-hop verify-availability command in route-map configuration mode. To disable this function, use the no form of this command.
set ip next-hop verify-availability [next-hop-address sequence track object]
no set ip next-hop verify-availability [next-hop-address sequence track object]
Syntax Description
Defaults
This command is disabled.
Command Modes
Route-map configuration
Command History
12.0(3)T
This command was introduced.
12.3(4)T
The optional track keyword and next-hop-address, sequence, and object arguments were added.
Usage Guidelines
The set ip next-hop verify-availability command can be used in the following two ways:
•
•
Using CDP
This command is used to verify that the next hop is reachable before the router tries to policy route to it.
This command has the following characteristics:
•
•
•
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If the router is policy routing packets to the next hop and the next hop is down, the router will try unsuccessfully to use Address Resolution Protocol (ARP) for the next hop (which is down). This behavior will continue indefinitely.
To prevent this situation from occurring, use the set ip next-hop verify-availability command to configure the router to verify that the next hop of the route map is a CDP neighbor before routing to that next hop.
This command is optional because some media or encapsulations do not support CDP, or it may not be a Cisco device that is sending traffic to the router.
If this command is set and the next hop is not a CDP neighbor, then the router looks to the subsequent next hop, if there is one. If there is no next hop, the packets are not policy routed.
If this command is not set, the packets are either successfully policy routed or remain forever unrouted.
If you want to selectively verify availability of only some next hops, you can configure different route map entries (under the same route map name) with different criteria (using access list matching or packet size matching), and then use the set ip next-hop verify-availability command selectively.
Using Object Tracking
With optional arguments to support object tracking, this command allows PBR to make decisions based on the following criteria:
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Object tracking functions in the following manner. PBR will inform the tracking process that it is interested in tracking a certain object. The tracking process will in turn notify PBR when the state of the object changes. This notification is done via registries and is event driven.
The tracking subsystem is responsible for tracking the state of an object. The object can be an IP address that is periodically being pinged by the tracking process. The state of the object (up or down) is stored in a track report data structure. The tracking process will create the tracking object report. Then the exec process that is configuring the route map can query the tracking process to determine if a given object exists. If the object exists, the tracking subsystem can start tracking it and read the initial state of the object. If the object changes state, the tracking process will notify all the clients that are tracking this process that the state of the object has changed. So, the route map structure that PBR is using can be updated to reflect the current state of the object in the track report. This interprocess communication is done by means of registries and the shared track report.
Note
Examples
Using CDP
The following example configures CEF-based Policy Routing. In this example Policy routing is configured to verify that next hop 50.0.0.8 of route map named test is a CDP neighbor before the router tries to policy route to it. Note that CDP must be enabled on all devices referenced by the set ip next-hop verify-availability command.
If the first packet is being policy routed via route map named test sequence 10, the subsequent packets of the same flow always take the same route map named test sequence 10, not route map named test sequence 20, because they all match or pass access list 1 check.
ip cefinterface ethernet0/0/1ip route-cache flowip policy route-map testroute-map test permit 10match ip address 1set ip precedence priorityset ip next-hop 50.0.0.8set ip next-hop verify-availabilityroute-map test permit 20Using Object Tracking
The following example shows the configuration to use to track an object:
! Configure the objects to be tracked.! Object 123 will be up if the router can ping 10.1.1.1.! Object 124 will be up if the router can ping 10.2.2.2.rtr 1type echo protocol ipicmpecho 10.1.1.1rtr schedule 1 start-time now life forever!rtr 2type echo protocol ipicmpecho 10.2.2.2rtr schedule 2 start-time now life forever!track 123 rtr 1 reachabilitytrack 124 rtr 2 reachability!! Enable policy routing using route-map alpha on Ethernet 0.interface ethernet 0ip address 10.4.4.254 255.255.255.0ip policy route-map alpha!! 10.1.1.1 is via this interfaceinterface ethernet 1ip address 10.1.1.254 255.255.255.0! 10.2.2.2 is via this interfaceinterface ethernet 2ip address 10.2.2.254 255.255.255.0!! Configure a route-map to set the next-hop to 10.1.1.1 if object 123 is up. If object 123! is down, the next hop will be set to 10.2.2.2 if object 124 is up. If object 124 is also! down, then policy routing fails and unicast routing will route the packet.route-map alphaset ip next-hop verify-availability 10.1.1.1 10 track 123set ip next-hop verify-availability 10.2.2.2 20 track 124Related Commands
set ip precedence
To set the precedence value in the IP header, use the set ip precedence command in route-map configuration mode. To instruct the router to leave the precedence value alone, use the no form of this command.
set ip precedence number | name
no set ip precedence
Syntax Description
Defaults
This command has no default behavior.
Command Modes
Route-map configuration
Command History
Usage Guidelines
You can set the precedence using either a number or the corresponding name.
Note
The way the network gives priority (or some type of expedited handling) to the marked traffic is through the application of WFQ or weighted random early detection (WRED) at points downstream in the network. Typically, you would set IP precedence at the edge of the network (or administrative domain) and have queueing act on it thereafter. WFQ can speed up handling for high precedence traffic at congestion points. WRED ensures that high precedence traffic has lower loss rates than other traffic during times of congestion.
The mapping from keywords such as routine and priority to a precedence value is useful only in some instances. That is, the use of the precedence bit is evolving. The customer can define the meaning of a precedence value by enabling other features that use the value. In the case of Cisco high-end Internet quality of service (QoS), IP precedences can be used to establish classes of service that do not necessarily correspond numerically to better or worse handling in the network. For example, IP Precedence 2 can be given 90 percent of the bandwidth on output links in the network, and IP Precedence 6 can be given 5 percent using the distributed weight fair queueing (DWFQ) implementation on the Versatile Interface Processors (VIPs).
Use the route-map global configuration command with match and set route-map configuration commands to define the conditions for redistributing routes from one routing protocol into another, or for policy routing. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution or policy routing is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution or policy routing actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all the match criteria of a route map are met. When all match criteria are met, all set actions are performed.
Examples
The following example sets the IP Precedence value to 5 (critical) for packets that pass the route map match:
interface serial 0ip policy route-map texas!route-map texasmatch length 68 128set ip precedence 5Related Commands
set level (IP)
To indicate where to import routes, use the set level command in route-map configuration mode. To delete an entry, use the no form of this command.
set level {level-1 | level-2 | level-1-2 | stub-area | backbone}
no set level {level-1 | level-2 | level-1-2 | stub-area | backbone}
Syntax Description
Defaults
This command is disabled by default.
For Intermediate System-to-Intermediate System (IS-IS) destinations, the default value is level-2. For OSPF destinations, the default value is backbone.
Command Modes
Route-map configuration
Command History
Usage Guidelines
Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all the match criteria of a route map are met. When all match criteria are met, all set actions are performed.
Examples
In the following example, routes will be imported into the Level 1 area:
route-map nameset level level-lRelated Commands
set local-preference
To specify a preference value for the autonomous system path, use the set local-preference command in route-map configuration mode. To delete an entry, use the no form of this command.
set local-preference number-value
no set local-preference number-value
Syntax Description
Defaults
Preference value of 100
Command Modes
Route-map configuration
Command History
Usage Guidelines
The preference is sent only to all routers in the local autonomous system.
You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.
Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all the match criteria of a route map are met. When all match criteria are met, all set actions are performed.
You can change the default preference value with the bgp default local-preference command.
Examples
The following example sets the local preference to 100 for all routes that are included in access list 1:
route-map map-preferencematch as-path 1set local-preference 100Related Commands
set metric (BGP, OSPF, RIP)
To set the metric value for a routing protocol, use the set metric command in route-map configuration mode. To return to the default metric value, use the no form of this command.
set metric metric-value
no set metric metric-value
Syntax Description
metric-value
Metric value; an integer from -294967295 to 294967295. This argument applies to all routing protocols except Enhanced Interior Gateway Routing Protocol (EIGRP).
Defaults
The dynamically learned metric value.
Command Modes
Route-map configuration
Command History
Usage Guidelines
We recommend that you consult your Cisco technical support representative before changing the default value.
Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all the match criteria of a route map are met. When all match criteria are met, all set actions are performed.
Examples
The following example sets the metric value for the routing protocol to 100:
route-map set-metricset metric 100Related Commands
set metric (EIGRP)
To set the metric value for Enhanced Interior Gateway Routing Protocol (EIGRP) in a route map, use the set metric route-map configuration command. To return to the default metric value, use the no form of this command.
set metric bandwidth delay reliability loading mtu
no set metric bandwidth delay reliability loading mtu
Syntax Description
Defaults
No metric will be set in the route map.
Command Modes
Route-map configuration
Command History
Usage Guidelines
We recommend you consult your Cisco technical support representative before changing the default value.
Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all of the match criteria for a router are met. When all match criteria are met, all set actions are performed.
Examples
The following example sets the bandwidth to 10,000, the delay to 10, the reliability to 255, the loading to 1, and the MTU to 1500:
set metric 10000 10 255 1 1500set metric-type
To set the metric type for the destination routing protocol, use the set metric-type command in route-map configuration mode. To return to the default, use the no form of this command.
set metric-type {internal | external | type-1 | type-2}
no set metric-type {internal | external | type-1 | type-2}
Syntax Description
Defaults
This command is disabled by default.
Command Modes
Route-map configuration
Command History
Usage Guidelines
Use the route-map global configuration command with match and set route-map configuration commands to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all the match criteria of a route map are met. When all match criteria are met, all set actions are performed.
Note
Examples
The following example sets the metric type of the destination protocol to OSPF external Type 1:
route-map map-typeset metric-type type-1Related Commands
set metric-type internal
To set the Multi Exit Discriminator (MED) value on prefixes advertised to external BGP (eBGP) neighbors to match the Interior Gateway Protocol (IGP) metric of the next hop, use the set metric-type internal command in route-map configuration mode. To return to the default, use the no form of this command.
set metric-type internal
no set metric-type internal
Syntax Description
This command has no arguments or keywords.
Defaults
This command is disabled by default.
Command Modes
Route-map configuration
Command History
Usage Guidelines
This command will cause BGP to advertise a MED value that corresponds to the IGP metric associated with the next hop of the route. This command applies to generated, internal BGP (iBGP)-, and eBGP-derived routes.
If this command is used, multiple BGP speakers in a common autonomous system can advertise different MED values for a particular prefix. Also, note that if the IGP metric changes, BGP will readvertise the route every 10 minutes.
Use the route-map global configuration command and the match and set route-map configuration commands to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all of the match criteria of the route map are met. When all match criteria are met, all set actions are performed.
Note
Examples
In the following example, the MED value for all the advertised routes to neighbor 172.16.2.3 is set to the corresponding IGP metric of the next hop:
router bgp 109network 172.16.0.0neighbor 172.16.2.3 remote-as 200neighbor 172.16.2.3 route-map setMED out!route-map setMED permit 10match as-path 1set metric-type internal!ip as-path access-list 1 permit .*Related Commands
route-map (IP)
Defines the conditions for redistributing routes from one routing protocol into another, or enables policy routing.
set next-hop
To specify the address of the next hop, use the set next-hop command in route-map configuration mode. To delete an entry, use the no form of this command.
set next-hop next-hop
no set next-hop next-hop
Syntax Description
Defaults
Default next hop address.
Command Modes
Route-map configuration
Command History
Usage Guidelines
You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.
Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all the match criteria of the router are met. When all match criteria are met, all set actions are performed.
Examples
In the following example, routes that pass the access list have the next hop set to 172.160.70.24:
route-map map_hopmatch address 5set next-hop 172.160.70.24Related Commands
set origin (BGP)
To set the BGP origin code, use the set origin command in route-map configuration mode. To delete an entry, use the no form of this command.
set origin {igp | egp as-number | incomplete}
no set origin {igp | egp as-number | incomplete}
Syntax Description
Defaults
Default origin, based on route in main IP routing table
Command Modes
Route-map configuration
Command History
Usage Guidelines
You must have a match clause (even if it points to a "permit everything" list) if you want to set tags.
Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all of the match criteria of a route map are met. When all match criteria are met, all set actions are performed.
Examples
The following example sets the origin of routes that pass the route map to IGP:
route-map set_originmatch as-path 10set origin igpRelated Commands
set tag (IP)
To set a tag value of the destination routing protocol, use the set tag command in route-map configuration mode. To delete the entry, use the no form of this command.
set tag tag-value
no set tag tag-value
Syntax Description
Defaults
If not specified, the default action is to forward the tag in the source routing protocol onto the new destination protocol.
Command Modes
Route-map configuration
Command History
Usage Guidelines
Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all the match criteria of a route map are met. When all match criteria are met, all set actions are performed.
Examples
The following example sets the tag value of the destination routing protocol to 5:
route-map tagset tag 5Related Commands
set traffic-index
To indicate how to classify packets that pass a match clause of a route map for Border Gateway Protocol (BGP) policy accounting, use the set traffic-index command in route-map configuration mode. To delete an entry, use the no form of this command.
set traffic-index bucket-number
no set traffic-index bucket-number
Syntax Description
bucket-number
Number that represents a bucket into which packet and byte statistics are collected for a specific traffic classification. The range is from 1 to 64.
Defaults
Routing traffic is not classified.
Command Modes
Route-map configuration
Command History
Usage Guidelines
Use the set traffic-index route-map configuration command, the route-map global configuration command, and the match route-map configuration command to define the conditions for BGP policy accounting. The match commands specify the match criteria—the conditions under which policy routing occurs. The set traffic-index command specifies the set actions—the particular routing actions to perform if the criteria specified by the match commands are met.
Examples
In the following example, an index for BGP policy accounting is set according to autonomous system path criteria:
route-map buckets permit 10match as-path 1set traffic-index 1Related Commands
set weight
To specify the BGP weight for the routing table, use the set weight command in route-map configuration mode. To delete an entry, use the no form of this command.
set weight number
no set weight number
Syntax Description
Defaults
The weight is not changed by the specified route map.
Command Modes
Route-map configuration
Command History
Usage Guidelines
The implemented weight is based on the first matched autonomous system path. Weights indicated when an autonomous system path is matched override the weights assigned by global neighbor commands. In other words, the weights assigned with the set weight route-map configuration command override the weights assigned using the neighbor weight command.
Examples
The following example sets the BGP weight for the routes matching the autonomous system path access list to 200:
route-map set-weightmatch as-path 10set weight 200Related Commands
set-attached-bit
To specify constraints for when a Level 1 - Level 2 (L1L2) router should set its attached-bit, use the set-attached-bit route-map command in router configuration mode. To disable this function, use the no form of this command.
set-attached-bit route-map map-tag
no set-attached-bit route-map map-tag
Syntax Description
route-map map-tag
(Required) Identifier of a configured route map. If the specified route map is matched, the router continues to set its attached-bit.
Defaults
This command is disabled by default.
Command Modes
Router configuration
Command History
12.2
This command was introduced.
12.2(4)B
This command was integrated into Cisco IOS Release 12.2(4)B.
12.2(14)S
This command was integrated into Cisco IOS Release 12.2(14)S.
Usage Guidelines
In the current IS-IS implementation, as specified in ISO 10589, L1L2 routers set their Level 1 (L1) link-state packet (LSP) attached-bit when they see other areas in their own domain, or see other domains. However, in some network topologies, adjacent L1L2 routers in different areas may lose connectivity to the Level 2 (L2) backbone. Level 1 (L1) routers may then send traffic destined outside of the area or domain to L1L2 routers that may not have such connectivity.
To allow more control over the attached-bit setting for L1L2 routers, enter the set-attached-bit command in router configuration mode. The route map can specify one or more CLNS routes. If at least one of the match address route-map clauses matches a route in the L2 CLNS routing table, and if all other requirements for setting the attached-bit are met, the L1L2 router will continue to set the attached-bit in its L1 LSP. If the requirements are not met or no match address route-map clauses match a route in the L2 CLNS routing table, the attached-bit will not be set.
Note
Examples
In the following example, the attached-bit will stay set when the router matches 49.00aa in the L2 CLNS routing table.
clns filter-set L2_backbone_connectivity permit 49.00aaroute-map check-for-L2_backbone_connectivitymatch clns address L2_backbone_connectivityrouter isisset-attached-bit route-map check-for-L2_backbone_connectivityendshow clns route 49.00aaKnown via "isis", distance 110, metric 30, Dynamic EntryRouting Descriptor Blocks:via tr2, Serial0isis, route metric is 30, route version is 58Related Commands
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 command in router configuration mode. To remove the designation, use the no form of this command.
set-overload-bit [on-startup {seconds | wait-for-bgp}] [suppress {[interlevel] [external]}]
no set-overload-bit
Syntax Description
Defaults
The overload bit is not set.
Command Modes
Router configuration
Command History
Usage Guidelines
This command forces the router to set the overload bit (also known as the hippity bit) in its nonpseudonode link-state packets (LSPs). Normally, the setting of the overload bit is allowed only when a router runs into problems. For example, when a router is experiencing a memory shortage, it might be that the link-state database is not complete, resulting in an incomplete or inaccurate routing table. By setting the overload bit in its LSPs, other routers can ignore the unreliable router in their SPF calculations until the router has recovered from its problems.
The result will be that no paths through this router are seen by other routers in the IS-IS area. However, IP and Connectionless Network Service (CLNS) prefixes directly connected to this router will still be reachable.
This command can be useful when you want to connect a router to an IS-IS network but do not want real traffic flowing through it under any circumstances. Examples situations are as follows:
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Unless you specify the on-startup keyword, this command sets the overload bit immediately.
In addition to setting the overload bit, you might want to suppress certain types of IP prefix advertisements from LSPs. For example, allowing IP prefix propagation between Level 1 and Level 2 effectively makes a node a transit node for IP traffic, which might be undesirable. The suppress keyword used with the interlevel or external keyword (or both) accomplishes that suppression while the overload bit is set.
Examples
The following example sets the overload bit upon startup and until BGP has converged, and suppresses redistribution between IS-IS levels and suppresses redistribution from external routing protocols while the overload bit is set:
interface Ethernet0ip address 10.1.1.1 255.255.255.0ip router isisrouter isisnet 49.0001.0000.0000.0001.00set-overload-bit on-startup wait-for-bgp suppress interlevel externalrouter bgp 100
