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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
key
To identify an authentication key on a key chain, use the key command in key-chain configuration mode. To remove the key from the key chain, use the no form of this command.
key key-id
no key key-id
Syntax Description
key-id
Identification number of an authentication key on a key chain. The range of keys is from 0 to 2147483647. The key identification numbers need not be consecutive.
Defaults
No key exists on the key chain.
Command Modes
key-chain configuration
Command History
Usage Guidelines
Only DRP Agent, Enhanced Interior Gateway Routing Protocol (EIGRP), and Routing Information Protocol (RIP) Version 2 use key chains.
It is useful to have multiple keys on a key chain so that the software can sequence through the keys as they become invalid after time, based on the accept-lifetime and send-lifetime key chain key command settings.
Each key has its own key identifier, which is stored locally. The combination of the key identifier and the interface associated with the message uniquely identifies the authentication algorithm and Message Digest 5 (MD5) authentication key in use. Only one authentication packet is sent, regardless of the number of valid keys. The software starts looking at the lowest key identifier number and uses the first valid key.
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.
To remove all keys, remove the key chain by using the no key chain command.
Examples
The following example configures a key chain named 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 a discrepancy 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
key chain
To enable authentication for routing protocols, identify a group of authentication keys by using the key chain command in global configuration mode. To remove the key chain, use the no form of this command.
key chain name-of-chain
no key chain name-of-chain
Syntax Description
name-of-chain
Name of a key chain. A key chain must have at least one key and can have up to 2147483647 keys.
Defaults
No key chain exists.
Command Modes
Global configuration
Command History
Usage Guidelines
Only DRP Agent, Enhanced Interior Gateway Routing Protocol (EIGRP), and Routing Information Protocol (RIP) Version 2 use key chains.
You must configure a key chain with keys to enable authentication.
Although you can identify multiple key chains, we recommend using one key chain per interface per routing protocol. Upon specifying the key chain command, you enter key-chain configuration mode.
Examples
The following example configures a key chain named 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 a discrepancy 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
key-string (authentication)
To specify the authentication string for a key, use the key-string command in key chain key configuration mode. To remove the authentication string, use the no form of this command.
key-string text
no key-string [text]
Syntax Description
Defaults
No key exists.
Command Modes
Key chain key configuration
Command History
Usage Guidelines
Only DRP Agent, Enhanced Interior Gateway Routing Protocol (EIGRP), and Routing Information Protocol (RIP) Version 2 use key chains. Each key can have only one key string.
If password encryption is configured (with the service password-encryption command), the software saves the key string as encrypted text. When you write to the terminal with the more system:running-config command, the software displays key-string 7 encrypted text.
Examples
The following example configures a key chain named 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 a discrepancy 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
limit retransmissions
To change or remove the limit in the number of retransmissions of database exchange and update packets for both demand and non-demand circuits, use the limit retransmissions command in router configuration mode. To reset the maximum number of retransmissions back to the default value of 24, use the no form of this command.
limit retransmissions {[dc {max-number | disable}] [non-dc {max-number | disable}]}
no limit transmissions [dc | non-dc]
Syntax Description
Defaults
Maximum number of retransmissions is 24.
Command Modes
Router configuration
Command History
Usage Guidelines
Cisco IOS Release 12.2(4)T added a limit to the number of retransmissions of database exchange and update packets for both demand and nondemand circuits. The retransmission of these packets stops once this retry limit is reached, thus preventing unnecessary use of the link in continual retransmission of the packets if, for some reason, a neighbor is not responding during adjacency forming.
The limit for both demand circuit and nondemand circuit retransmissions is 24.
The limit-retransmissions command allows you to either remove (disable) the limit or change the maximum number of retransmissions to be a number from 1 to 255. The configuration of this command provides for backward compatibility for previous or other releases of Cisco IOS Software or other routers that do not have this feature.
Note
The limit to the number of retransmissions does not apply for update packets on nonbroadcast multiaccess (NBMA) point-to-multipoint direct circuits. In this situation, the dead timer is used to end communication with nonresponding neighbors and thus stop the retransmissions.
Examples
The following example shows how to set the maximum number of demand circuit retransmissions to 10:
limit retransmissions dc 10The following example shows how to remove the limit for the number of demand circuit retransmissions:
limit retransmissions dc disableThe following example shows how to set the maximum number of demand circuit retransmissions to 10 and to set the maximum number of nondemand circuit retransmissions to 20:
limit retransmissions dc 10 non-dc 20The following example shows how to set the maximum number of demand circuit retransmissions to 10, and to remove the limit for the number of nondemand circuit retransmissions:
limit retransmissions dc 10 non-dc disableThe following example shows how to reset both the demand circuit and nondemand circuit maximum number of retransmissions back to the default of 24:
no limit retransmissionsRelated Commands
log-adjacency-changes
To configure the router to send a syslog message when an OSPF neighbor goes up or down, use the log-adjacency-changes command in router configuration mode. To turn off this function, use the no form of this command.
log-adjacency-changes [detail]
no log-adjacency-changes [detail]
Syntax Description
detail
(Optional) Sends a syslog message for each state change, not just when a neighbor goes up or down.
Defaults
Enabled
Command Modes
Router configuration
Command History
11.2
This command was introduced as "ospf log-adjacency-changes".
12.1
The ospf keyword was omitted and the detail keyword was added.
Usage Guidelines
This command allows you to know about OSPF neighbors going up or down without turning on the debug ip ospf adjacency command. The log-adjacency-changes command provides a higher level view of those changes of the peer relationship with less output. This command is on by default but only up/down (full/down) events are reported, unless the detail keyword is also configured.
Examples
The following example configures the router to send a syslog message when an OSPF neighbor state changes:
log-adjacency-changes detaillsp-full suppress
To control which routes are suppressed when the link-state PDU becomes full, use the lsp-full suppress command in router configuration mode. To stop suppression of redistributed routes, specify none or use the no form of this command.
lsp-full suppress {[external] [interlevel] | none}
no lsp-full suppress
Syntax Description
Defaults
If this command is not specified, or if this command is specified with no keyword, the default value used is external.
Command Modes
Router configuration
Command History
Usage Guidelines
In networks where there is no limit placed on the number of redistributed routes into IS-IS (that is, the redistribute maximum-prefix command was not configured), it is possible that the link-state PDU (LSP) could become full and routes will be dropped. Use the lsp-full suppress command to define in advance which routes are suppressed in the event that the LSP becomes full.
The external and interlevel keywords can be specified together or separately.
Use the clear isis lsp-full command to clear the LSPFULL state.
Examples
This example specifies that if the LSP becomes full, both redistributed routes and routes from another level will be suppressed from the LSP:
router isislsp-full suppress external interlevelRelated Commands
lsp-gen-interval (IS-IS)
To customize IS-IS throttling of LSP generation, use the lsp-gen-interval command in router configuration mode. To restore default values, use the no form of this command.
lsp-gen-interval [level-1 | level-2] lsp-max-wait [lsp-initial-wait lsp-second-wait]
no lsp-gen-interval
Syntax Description
Defaults
lsp-max-wait: 5 seconds
lsp-initial-wait: 50 milliseconds
lsp-second-wait: 5000 millisecondsCommand Modes
Router configuration
Command History
Usage Guidelines
The following description will help you determine whether to change the default values of this command:
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Notice that the lsp-gen-interval command controls the delay between LSPs being generated, as opposed to the following related commands:
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These commands can be used in combination to control the rate of LSP packets being generated, transmitted, and retransmitted.
Examples
The following example configures intervals for SPF calculations, PRC, and LSP generation:
router isisspf-interval 5 10 20prc-interval 5 10 20lsp-gen-interval 2 50 100Related Commands
lsp-refresh-interval (IS-IS)
To set the link-state packet (LSP) refresh interval, use the lsp-refresh-interval command in router configuration mode. To restore the default refresh interval, use the no form of this command.
lsp-refresh-interval seconds
no lsp-refresh-interval
Syntax Description
seconds
Interval (in seconds) at which LSPs are refreshed.The range is 1 to 65535 seconds. The default value is 900 seconds (15 minutes).
Defaults
900 seconds (15 minutes)
Command Modes
Router configuration
Command History
Usage Guidelines
The refresh interval determines the rate at which Cisco IOS software periodically transmits in LSPs the route topology information that it originates. This is done to keep the database information from becoming too old.
LSPs must be periodically refreshed before their lifetimes expire. The value set for the lsp-refresh-interval command should be less than the value set for the max-lsp-lifetime command; otherwise, LSPs will time out before they are refreshed. If you misconfigure the LSP lifetime to be too low compared to the LSP refresh interval, the software will reduce the LSP refresh interval to prevent the LSPs from timing out.
Reducing the refresh interval reduces the amount of time that undetected link state database corruption can persist at the cost of increased link utilization. (This is an extremely unlikely event, however, because there are other safeguards against corruption.) Increasing the interval reduces the link utilization caused by the flooding of refreshed packets (although this utilization is very small).
Examples
The following example configures the IS-IS LSP refresh interval to be 1080 seconds (18 minutes):
router isislsp-refresh-interval 1080Related Commands
max-lsp-lifetime (IS-IS)
Sets the maximum time that link-state packets (LSPs) can remain in a router's database without being refreshed.
match as-path
To match a BGP autonomous system path access list, use the match as-path command in route-map configuration mode. To remove a path list entry, use the no form of this command.
match as-path path-list-number
no match as-path path-list-number
Syntax Description
Defaults
No path lists are defined.
Command Modes
Route-map configuration
Command History
Usage Guidelines
The values set by the match as-path and set weight commands override global values. For example, the weights assigned with the match as-path and set weight route-map configuration commands override the weight assigned using the neighbor weight command.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want to modify only some data, you must configure a second route-map section with an explicit match specified.
Examples
The following example sets the autonomous system path to match BGP autonomous system path access list 20:
route-map IGP2BGPmatch as-path 20Related Commands
match community
To match a Border Gateway Protocol (BGP) community, use the match community command in route-map configuration mode. To remove the match community command from the configuration file and restore the system to its default condition where the software removes the BGP community list entry, use the no form of this command.
match community {standard-list-number | expanded-list-number | community-list-name [exact]}
no match community {standard-list-number | expanded-list-number | community-list-name [exact]}
Syntax Description
Defaults
No community list is matched by the route map.
Command Modes
Route-map configuration
Command History
Usage Guidelines
A route map can have several parts. Any route that does not match at least one match command relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want to modify only some data, you must configure a second route-map section with an explicit match specified.
Matching based on community list number is one of the types of match commands applicable to BGP.
Examples
The following example shows that the routes matching community list 1 will have the weight set to 100. Any route that has community 109 will have the weight set to 100.
Router(config)# ip community-list 1 permit 109Router(config)# !Router(config)# route-map set_weightRouter(config-route-map)# match community 1Router(config-route-map)# set weight 100The following example shows that the routes matching community list 1 will have the weight set to 200. Any route that has community 109 alone will have the weight set to 200.
Router(config)# ip community-list 1 permit 109Router(config)# !Router(config)# route-map set_weightRouter(config-route-map)# match community 1 exactRouter(config-route-map)# set weight 200In the following example, the routes that match community list LIST_NAME will have the weight set to 100. Any route that has community 101 alone will have the weight set to 100.
Router(config)# ip community-list 1 permit 101Router(config)# !Router(config)# route-map set_weightRouter(config-route-map)# match community LIST_NAMERouter(config-route-map)# set weight 100The following example shows that the routes that match expanded community list 500. Any route that has extended community 1 will have the weight set to 150.
Router(config)# ip community-list 500 permit [0-9]*Router(config)# !Router(config)# route-map MAP_NAME permit 10Router(config-route-map)# match extcommunity 500Router(config-route-map)# set weight 150Related Commands
match extcommunity
To match Border Gateway Protocol (BGP) extended community list attributes, use the match extcommunity command in route-map configuration mode. To remove the match extcommunity command from the configuration file and remove the BGP extended community list attribute entry, use the no form of this command.
match extcommunity standard-list-number expanded-list-number
no match extcommunity standard-list-number expanded-list-number
Syntax Description
Defaults
This command is disabled by default.
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 match extcommunity command is used to configure match clauses that use extended community attributes in route maps. The range of numbers that can be configured with the match extcommunity command is from 1 to500. All of the standard rules of match and set clauses apply to the configuration of extended community attributes.
Examples
The following example shows that the routes that match extended community list 500 will have the weight set to 100. Any route that has extended community 1 will have the weight set to 100.
Router(config)# ip extcommunity-list 500 rt 100:2Router(config)# !Router(config)# route-map MAP_NAME permit 10Router(config-route-map)# match extcommunity 1Router(config-route-map)# set weight 100Related Commands
match interface (IP)
To distribute any routes that have their next hop out one of the interfaces specified, use the match interface command in route-map configuration mode. To remove the match interface entry, use the no form of this command.
match interface interface-type interface-number [... interface-type interface-number]
no match interface interface-type interface-number [... interface-type interface-number]
Syntax Description
Defaults
No match interfaces are defined.
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 interface-type interface-number arguments.
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 match route-map configuration command has multiple formats. The match commands may be given in any order, and all match commands must "pass" to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want to modify only some data, you must configure a second route map section with an explicit match specified.
Examples
In the following example, routes that have their next hop out Ethernet interface 0 will be distributed:
route-map namematch interface ethernet 0Related Commands
match ip address
To distribute any routes that have a destination network number address that is permitted by a standard access list, an extended access list, or a prefix list, or to perform policy routing on packets, use the match ip address command in route-map configuration mode. To remove the match ip address entry, use the no form of this command.
match ip address {access-list-number [access-list-number... | access-list-name...] | access-list-name [access-list-number...| access-list-name] | prefix-list prefix-list-name [prefix-list-name...]}
no match ip address {access-list-number [access-list-number... | access-list-name...] | access-list-name [access-list-number...| access-list-name] | prefix-list prefix-list-name [prefix-list-name...]}
Syntax Description
Defaults
No access list numbers or prefix lists are specified.
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 access-list-number, access-list-name, or prefix-list-name arguments.
Like matches in the same route map subblock are filtered with "or" semantics. If any one match clause is matched in the entire route map subblock, this match is treated as a successful match. Dissimilar match clauses are filtered with "and" semantics. So dissimilar matches are filtered logically. If the first set of conditions is not met, the second match clause is filtered. This process continues until a match occurs or there are no more match clauses.
Use route maps to redistribute routes or to subject packets to policy routing. Both purposes are described in this section.
Redistribution
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 match route-map configuration command has multiple formats. The match commands can be given in any order, and all match commands must "pass" to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
When you are passing routes through a route map, a route map can have several sections that contain specific match clauses. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want to modify only some data, you must configure a second route map section with an explicit match specified.
Policy Routing
Another purpose of route maps is to enable policy routing. The match ip address command allows you to policy route packets based on criteria that can be matched with an extended access list; for example, a protocol, protocol service, and source or destination IP address. To define the conditions for policy routing packets, use the ip policy route-map interface configuration command, in addition to the route-map global configuration command, and the match and set route-map configuration commands. 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. You might want to policy route packets based on their source, for example, using an access list.
Examples
In the following example, routes that have addresses specified by access list numbers 5 or 80 will be matched:
route-map namematch ip address 5 80Route maps that use prefix lists can be used for route filtering, default origination, and redistribution in other routing protocols. In the following example, a default route 0.0.0.0/0 is conditionally originated when there exists a prefix 10.1.1.0/24 in the routing table:
ip prefix-list cond permit 10.1.1.0/24!route-map default-condition permit 10match ip address prefix-list cond!router ripdefault-information originate route-map default-condition!In the following policy routing example, packets that have addresses specified by access list numbers 6 or 25 will be routed to Ethernet interface 0:
interface serial 0ip policy route-map chicago!route-map chicagomatch ip address 6 25set interface ethernet 0Related Commands
match ip next-hop
To redistribute any routes that have a next hop router address passed by one of the access lists specified, use the match ip next-hop command in route-map configuration mode. To remove the next hop entry, use the no form of this command.
match ip next-hop {access-list-number | access-list-name}[...access-list-number | ...access-list-name]
no match ip next-hop {access-list-number | access-list-name}[...access-list-number | ...access-list-name]
Syntax Description
access-list-number | access-list-name
Number or name of a standard or extended access list. It can be an integer from 1 to 199.
Defaults
Routes are distributed freely, without being required to match a next hop address.
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 access-list-number or access-list-name argument.
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 match route-map configuration command has multiple formats. The match commands can be given in any order, and all match commands must "pass" to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
When you are passing routes through a route map, a route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want to modify only some data, you must configure a second route map section with an explicit match specified.
Examples
The following example distributes routes that have a next hop router address passed by access list 5 or 80 will be distributed:
route-map namematch ip next-hop 5 80Related Commands
match ip route-source
To redistribute routes that have been advertised by routers and access servers at the address specified by the access lists, use the match ip route-source command in route-map configuration mode. To remove the route-source entry, use the no form of this command.
match ip route-source {access-list-number | access-list-name}[...access-list-number | ...access-list-name]
no match ip route-source {access-list-number | access-list-name}[...access-list-number | ...access-list-name]
Syntax Description
access-list-number | access-list-name
Number or name of a standard or extended access list. It can be an integer from 1 to 199.
Defaults
No filtering on route source.
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 access-list-number or access-list-name argument.
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 match route-map configuration command has multiple formats. The match commands can be given in any order, and all match commands must "pass" to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want to modify only some data, you must configure second route map section with an explicit match specified.
There are situations in which the next hop and source router address of the route are not the same.
Examples
The following example distributes routes that have been advertised by routers and access servers at the addresses specified by access lists 5 and 80:
route-map namematch ip route-source 5 80Related Commands
match length
To base policy routing on the Level 3 length of a packet, use the match length command in route-map configuration mode. To remove the entry, use the no form of this command.
match length minimum-length maximum-length
no match length minimum-length maximum-length
Syntax Description
Defaults
No policy routing occurs on the length of a packet.
Command Modes
Route-map configuration
Command History
10.0
This command was introduced.
12.3(7)T
This command was updated for use in configuring IPv6 policy-based routing (PBR).
Usage Guidelines
In IPv4, 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 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 to define conditions for policy routing packets.
In IPv4, the match route-map configuration command has multiple formats. The match commands can be given in any order, and all match commands must "pass" to cause the packet to be routed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
In IPv4, you might want to base your policy routing on the length of packets so that your interactive traffic and bulk traffic are directed to different routers.
Examples
In the following example, packets 3 to 200 bytes long, inclusive, will be routed to FDDI interface 0:
interface serial 0ip policy route-map interactive!route-map interactivematch length 3 200set interface fddi 0In the following example for IPv6, packets 3 to 200 bytes long, inclusive, will be routed to FDDI interface 0:
interface Ethernet0/0ipv6 policy-route-map interactive!route-map interactivematch length 3 200set interface fddi 0Related Commands
match local-preference
To configure a route map to match routes based on the Border Gateway Protocol (BGP) local-preference attribute, use the match local-preference command in route-map configuration mode. To remove the match clause entry from the route map, use the no form of this command.
match local-preference {value}
no match local-preference {value}
Syntax Description
Command Default
Cisco IOS software uses a default value of 100 for the local-preference attribute. However, a local-preference value must be entered when configuring a match clause with this command.
Command Modes
Route-map configuration
Command History
12.3(14)T
This command was introduced.
12.2(30)S
This command was integrated into Cisco IOS Release 12.2(30)S.
Usage Guidelines
The match local-preference command is used to filter routes based on the value of the local preference attribute. The local-preference attribute is a well-known discretionary attribute that is used to set the preference for an exit point within an autonomous system. The route with the highest local-preference value is preferred by the BGP best path selection process.
Redistributing OER Injected Routes
Optimized Edge Routing (OER) uses a local-preference value of 5000 (default) to move traffic to the preferred exit point in a BGP network (This value can be configured on the OER master controller). The match local-preference command can be used to redistribute OER injected routes within an autonomous system that is monitored and controlled by OER.
Examples
The following example configures the route-map name RED to match OER injected routes:
Router(config)# route-map RED permit 10Router(config-route-map)# match local-preference 5000Router(config-route-map)#Related Commands
match metric (IP)
To redistribute routes with the metric specified, use the match metric command in route-map configuration mode. To remove the entry, use the no form of this command.
match metric metric-value | [external [+/- deviation-number]
no match metric metric-value | [external [+/- deviation-number]
Syntax Description
Defaults
No filtering on a metric value.
Command Modes
Route-map configuration
Command History
11.2
This command was introduced.
12.3(8)T
The external and plus/minus keywords were added.
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 match route-map configuration command has multiple formats. The match commands can be given in any order, and all match commands must "pass" to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want to modify only some data, you must configure second route map section with an explicit match specified.
Note
Examples
In the following example, routes with the metric 5 will be redistributed:
route-map namematch metric 5In the following example, any metric that falls inclusively in the range from 400 to 600 is matched:
route-map namematch metric 500 +/- 100Related Commands
match policy-list
To configure a route map to evaluate and process a Border Gateway Protocol (BGP) policy list in a route map, use the match policy-list command in route-map configuration mode. To remove a path list entry, use the no form of this command.
match policy-list policy-list-name
no match policy-list policy-list-name
Syntax Description
Defaults
This command is not enabled by default.
Command Modes
Route-map configuration
Command History
12.0(22)S
This command was introduced.
12.2(15)T
This command was integrated into 12.2(15)T.
Usage Guidelines
When a policy list is referenced within a route map, all the match statements within the policy list are evaluated and processed.
Two or more policy lists can be configured with a route map. Policy lists can be configured within a route map to be evaluated with AND semantics or OR semantics.
Policy lists can also coexist with any other preexisting match and set statements that are configured within the same route map but outside of the policy lists.
When multiple policy lists perform matching within a route map entry, all policy lists match on the incoming attribute only.
Examples
The following configuration example creates a route map that references policy lists and separate match and set clauses in the same configuration:
Router(config)# route-map MAP-NAME-1 10Router(config-route-map)# match ip-address 1Router(config-route-map)# match policy-list POLICY-LIST-NAME-1Router(config-route-map)# set community 10:1Router(config-route-map)# set local-preference 140Router(config-route-map)# endThe following configuration example creates a route map that references policy lists and separate match and set clauses in the same configuration. This example processes the policy lists named POLICY-LIST-NAME-2 and POLICY-LIST-NAME-3 with OR semantics. A match is required from only one of the policy lists.
Router(config)# route-map MAP-NAME-2 10Router(config-route-map)# match policy-list POLICY-LIST-NAME-2 POLICY-LIST-NAME-3Router(config-route-map)# set community 10:1Router(config-route-map)# set local-preference 140Router(config-route-map)# endRelated Commands
match route-type (IP)
To redistribute routes of the specified type, use the match route-type command in route-map configuration mode. To remove the route type entry, use the no form of this command.
match route-type {local | internal | external [type-1 | type-2] | level-1 | level-2}
no match route-type {local | internal | external [type-1 | type-2] | level-1 | level-2}
Syntax Description
Defaults
This command is disabled by default.
Command Modes
Route-map configuration
Command History
10.0
This command was introduced.
11.2
The local and external [type-1 | type-2] keywords were added.
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 match route-map configuration command has multiple formats. The match commands can be given in any order, and all match commands must "pass" to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want to modify only some data, you must configure second route map section with an explicit match specified.
Examples
The following example redistributes internal routes:
route-map namematch route-type internalRelated Commands
match source-protocol
To enable matching EIGRP external routes based on a source protocol and autonomous system number, use the match source-protocol command in route-map configuration mode. To remove the protocol to be matched, use the no form of this command.
match source-protocol {source-protocol [as-number]}
no match source-protocol {source-protocol [as-number]}
Syntax Description
Defaults
No matching of a source protocol.
Command Modes
Route-map configuration
Command History
Usage Guidelines
This command may not be useful with a redistribution operation that employs route maps since redistribution usually requires the configuration of a source protocol and an AS value in order to redistribute. It is more useful in many cases to configure the route map that includes matching the route type based on the source protocol and AS using the distribute-list command for EIGRP.
Examples
In the following example, the source protocol is specified as BGP and the AS number is 2 which permits external EIGRP routes of BGP:
match source-protocol bgp 2Related Commands
match tag
To redistribute routes in the routing table that match the specified tags, use the match tag command in route-map configuration mode. To remove the tag entry, use the no form of this command.
match tag tag-value [...tag-value]
no match tag tag-value [...tag-value]
Syntax Description
Defaults
No match tag values are defined.
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 tag-value argument.
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 match route-map configuration command has multiple formats. The match commands can be given in any order, and all match commands must "pass" to cause the route to be redistributed according to the set actions given with the set commands. The no forms of the match commands remove the specified match criteria.
A route map can have several parts. Any route that does not match at least one match clause relating to a route-map command will be ignored; that is, the route will not be advertised for outbound route maps and will not be accepted for inbound route maps. If you want to modify only some data, you must configure second route map section with an explicit match specified.
Examples
The following example redistributes routes stored in the routing table with tag 5:
route-map namematch tag 5Related Commands
maximum-paths
To configure the maximum number of parallel routes that an IP routing protocol will install into the routing table, use the maximum-paths command in router configuration or address family configuration mode. To restore the default value, use the no form of this command.
maximum-paths number [import number]| import number
no maximum-paths number | import number
Syntax Description
Defaults
Border Gateway Protocol (BGP) by default will install only one best path in the routing table. The default for all other IP routing protocols is four paths.
Command Modes
Router configuration
Address family configurationCommand History
Usage Guidelines
The maximum-paths command is used to set the number of parallel (equal-cost) routes that BGP will install in the routing table to configure multipath loadsharing. The number of paths that can be configured is determined by the version of Cisco IOS software. The following list shows current limits:
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•
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The maximum-paths command cannot be configured with the maximum-paths eibgp command for the same BGP routing process.
Configuring VRF Import Paths
A VRF will import only one path (best path) per prefix from the source VRF table, unless the prefix is exported with a different route-target. If the best path goes down, the destination will not be reachable until the next import event occurs, and then a new best path will be imported into the VRF table. The import event runs every 15 seconds by default.
The import keyword allows you to configure the VRF table to accept multiple redundant paths in addition to the best path. An import path is a redundant path, and it can have a next hop that matches an installed multipath.This feature should be used when there are multiple paths with identical next hops available to ensure optimal convergence times. A typical application of this feature is to configure redundant paths in a network that has multiple route reflectors for redundancy.
Note
Examples
In the following example, the router is configured to install 2 parallel routes in the BGP routing table:
Router(config)# router bgp 40000Router(config-router)# maximum-paths 2In the following example, the router is configured to install 6 equal-cost routes and 2 import routes (backup) in the VRF routing table:
Router(config)# router bgp 40000Router(config-router)# address-family ipv4 vrf REDRouter(config-router-af)# maximum-paths 6 import 2In the following example, the router is configured to install 2 import routes in the VRF routing table:
Router(config)# router bgp 100Router(config-router)# address-family ipv4 vrf BLUERouter(config-router-af)# maximum-paths import 2maximum-paths eibgp
To configure multipath load sharing for external BGP (eBGP) and internal (iBGP) routes, use the maximum-paths eibgp command in address family configuration mode. To disable multipath load sharing for eBGP and iBGP routes, use the no form of this command.
maximum-paths eibgp number [import number]
no maximum-paths eibgp number [import number]
Syntax Description
Defaults
Border Gateway Protocol (BGP) by default will install only one best path in the routing table.
Command Modes
Address family configuration
Command History
Usage Guidelines
The maximum-paths eibgp command used to configure Border Gateway Protocol (BGP) multipath load sharing in an Multiprotocol Label Switching (MPLS) virtual private network (VPN) using eBGP and iBGP routes. This feature is configured under a virtual routing and forwarding instance (VRF) in address family configuration mode. The number of multipaths is configured separately for each VRF. The number of paths that can be configured is determined by the version of Cisco IOS software. The following list shows current limits:
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•
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The maximum-paths eibgp command cannot be configured with the maximum-paths or maximum-paths ibgp command because the maximum-paths eibgp command is a superset of these commands.
Note
Configuring VRF Import Paths
A VRF will import only one path (best path) per prefix from the source VRF table, unless the prefix is exported with a different route-target. If the best path goes down, the destination will not be reachable until the next import event occurs, and then a new best path will be imported into the VRF table. The import event runs every 15 seconds by default.
The import keyword allows you to configure the VRF table to accept multiple redundant paths in addition to the best path. An import path is a redundant path, and it can have a next hop that matches an installed multipath.This feature should be used when there are multiple paths with identical next hops available to ensure optimal convergence times. A typical application of this feature is to configure redundant paths in a network that has multiple route reflectors for redundancy.
Note
Examples
In the following example, the router is configured to install 6 eBGP or iBGP routes into the VRF routing table:
Router(config)# router bgp 40000Router(config-router)# address-family ipv4 vrf YELLOWRouter(config-router-af)# maximum-paths eibgp 6In the following example, the router is configured to install 4 equal-cost routes and 2 import routes (backup) in the VRF routing table:
Router(config)# router bgp 45000Router(config-router)# address-family ipv4 vrf GREENRouter(config-router-af)# maximum-paths eibgp 4 import 2In the following example, the router is configured to install 2 import routes in the VRF routing table:
Router(config)# router bgp 50000Router(config-router)# address-family ipv4 vrf ORANGERouter(config-router-af)# maximum-paths eibgp import 2Related Commands
maximum-paths ibgp
To configure the number of number of equal-cost or unequal-cost routes that internal BGP (iBGP) will install in the routing table, use the maximum-paths ibgp command in router configuration mode. To restore the default value, use the no form of this command.
maximum-paths ibgp number [import number] | unequal-cost number [import number]
no maximum-paths ibgp number [import number] | unequal-cost number [import number]
Syntax Description
Defaults
Border Gateway Protocol (BGP) by default will install only one best path in the routing table.
Command Modes
Address family configuration
Router configurationCommand History
Usage Guidelines
The maximum-paths ibgp command is used to configure equal-cost or unequal-cost multipath load sharing for iBGP peering sessions. In order for a route to be installed as a multipath in the BGP routing table, the route cannot have a next hop that is the same as another route that is already installed. The BGP routing process will still advertise a best path to iBGP peers when iBGP multipath load sharing is configured. For equal-cost routes, the path from the neighbor with the lowest router ID is advertised ad the best path.
To configure equal-cost multipath load sharing, all path attributes must be the same. The path attributes include weight, local preference, autonomous system path (entire attribute and not just the length), origin code, Multi Exit Discriminator (MED), and Interior Gateway Protocol (IGP) distance.
Configuring VRF Import Paths
A VRF will import only one path (best path) per prefix from the source VRF table, unless the prefix is exported with a different route-target. If the best path goes down, the destination will not be reachable until the next import event occurs, and then a new best path will be imported into the VRF table. An import path is a redundant path, and it can have a next hop that matches an installed multipath. The import event runs every 15 seconds by default.
The import keyword allows the network operator to configure the VRF table to accept multiple redundant paths in addition to the best path. This feature should be used when there are multiple paths with identical next hops available to ensure optimal convergence times. A typical application of this feature is to configure redundant paths in a network that has multiple route reflectors for redundancy.
Note
Examples
In the following example, the router is configured to install 6 equal-cost iBGP paths in the routing table. This router is not configured in to use MPLS.
Router(config)# router bgp 40000Router(config-router)# address-family ipv4Router(config-router-af)# maximum-paths ibgp 6In the following example, the router is configured to install 3 equal-cost iBGP paths in the VRF routing table. This router is part of a MPL-VPN topology.
Router(config)# router bgp 45000Router(config-router)# address-family ipv4 unicast vrf REDRouter(config-router-af)# maximum-paths ibgp 3In the following example, the router is configured to install 2 unequal-cost routes and 2 import routes (backup) in theVRF routing table:
Router(config)# router bgp 50000Router(config-router)# address-family ipv4 vrf YELLOWRouter(config-router-af)# maximum-paths ibgp unequal-cost 2 import 2Related Commands
maximum-prefix
To limit the number of prefixes that are accepted under an address- family by an Enhanced Interior Gateway Routing Protocol (EIGRP) process, use the maximum-prefix command in address-family configuration mode. To disable this function, use the no form of this command.
maximum-prefix maximum [threshold] [[dampened] [reset-time minutes] [restart minutes] [restart-count number] | [warning-only]]
no maximum-prefix
Syntax Description
Defaults
threshold: 75 percent
reset-time: 15 minutes
restart: 5 minutes
restart-count: 3Command Modes
Address-family (IPv4 VRF)
Command History
12.0(29)S
This command was introduced.
12.3(14)T
This command was integrated into Cisco IOS Release 12.3(14)T.
Usage Guidelines
The maximum-prefix is used to configure an EIGRP process to limit the number prefixes that are accepted from all sources. When the maximum-prefix limit is exceeded, sessions with remote peers are torn down, all routes learned from remote peers and through redistribution are removed from the topology and routing tables, and redistribution and peering is suspended for the default or user-defined time period.
Inherited Timer Values
Default or user-defined restart, restart-count, and reset-time values for the process-level configuration of this feature, configured with the maximum-prefix command, are inherited by the redistribute maximum-prefix and neighbor maximum-prefix command configurations by default. If a single peer is configured with the neighbor maximum-prefix command, a process-level configuration or a configuration that is applied to all neighbors will be inherited.
Examples
The following example, starting in global configuration mode, configures the maximum prefix limit for an EIGRP process, which includes routes learned through redistribution and routes learned through EIGRP peering sessions. The maximum limit is set to 50000 prefixes. When the number of prefixes learned through redistribution reaches 37500 (75 percent of 50000), warning messages will be displayed in the console. When the maximum prefix limit is exceeded, all peering sessions will be reset, the topology and routing tables will be cleared and redistributed routes and all peering sessions will be placed in a penalty state.
Router(config)# router eigrp 100Router(config-router)# address-family ipv4 vrf REDRouter(config-router-af)# maximum-prefix 50000Router(config-router-af)# endRelated Commands
Deletes neighbor entries from the routing table.
Deletes neighbor entries from the VRF table.
clear ip route
Deletes routes from the IP routing table.
max-area-addresses
To configure additional manual addresses for an IS-IS area, use the max-area-addresses command in router configuration mode. To disable the manual addresses, use the no form of this command.
max-area-addresses number
no max-area-addresses number
Syntax Description
Command Default
No manual addresses are configured for an IS-IS area.
Command Modes
Router configuration
Command History
Usage Guidelines
The max-area-addresses command allows you to maximize the size of an IS-IS area by configuring additional manual addresses. You specify the number of manual addresses that you want to add by entering the max-area-addresses command, and you assign a NET address to create each manual address by entering the net command.
Examples
The following example configures three manual addresses as follows:
router isismax-area-addresses 3net 50.3131.3131.3131.00net 51.3131.3131.3131.00net 52.3131.3131.3131.00In the following example, an error message appears because the user has exceeded the maximum number of manual addresses that were configured with the max-area-addresses command:
router isismax-area-addresses 2net 50.3131.3131.3131.00net 51.3131.3131.3131.00net 52.3131.3131.3131.00%The maximum allowed addresses already configuredRelated Commands
max-lsa
To limit the number of nonself-generated link-state advertisements (LSAs) that an Open Shortest Path First (OSPF) routing process can keep in the OSPF link-state database (LSDB), use the max-lsa command in router configuration mode. To remove the limit of non self-generated LSAs that an OSPF routing process can keep in the OSPF LSDB, use the no form of this command.
max-lsa maximum-number [threshold-percentage] [warning-only] [ignore-time minutes] [ignore-count count-number] [reset-time minutes]
no max-lsa maximum-number [threshold-percentage] [warning-only] [ignore-time minutes] [ignore-count count-number] [reset-time minutes]
Syntax Description
Defaults
The number of nonself-generated LSAs that an OSPF routing process can keep in the OSPF LSDB is not limited.
threshold-percentage: 75 percent
warning-only warning message: disabled
ignore-time minutes: 5 minutes
ignore-count count-number: 5 times
reset-time minutes: 10 minutesCommand Modes
Router configuration
Command History
12.0(27)S
This command was introduced.
12.3(7)T
This command was integrated into Cisco IOS Release 12.3(7)T.
Usage Guidelines
To prevent the OSPF process from endlessly changing from the normal state of operation to the ignore state as a result of the LSA count exceeding the maximum configured number immediately after it returns from the ignore state to the normal state of operation, the OSPF process keeps a counter on how many times the process went into the ignore state. This counter is called the ignore count. If the ignore count exceeds the maximum number of LSAs that is specified by the ignore-count keyword and counter-number argument, the OSPF process remains in the ignore state permanently. To return the OSPF process to the state of normal operation, enter the clear ip ospf command.
If the router is placed into a permanent ignore state, we recommend that you identify and correct the cause of the problem involving the router that is generating the LSAs, or, if possible, increase the limit that has been configured by the max-lsa command before you try to bring the router back into normal operation.
If the router that has generated large numbers of LSAs is not reachable, these LSAs cannot be removed from the OSPF area and domain. As a result, any other router leaving the ignore state and returning to normal operation may reach the ignore state again. We recommend that you take one of the following actions in order to bring the router back into the network:
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When the warning-only keyword is used, the OSPF process never enters the ignore state. When the LSA count exceeds the maximum limit that is specified by the maximum-number argument, only an error message is logged and the OSPF process continues in its normal operation.
When the max-lsa command is entered for the first time or when any of the parameters of the command are changed, the OSPF process undergoes a soft-reset procedure.
Examples
The following example sets a limit of 12,000 LSAs that can be received before the OSPF process enters the ignore state:
Router(config)# router ospf 100Router(config-router)# router-id 209.165.201.0Router(config-router)# log-adjacency-changesRouter(config-router)# max-lsa 12000Router(config-router)# network 209.165.201.1 255.255.255.255In the following example, an OSPF process has remained in the ignore state permanently. When the clear ip ospf command is entered the OSPF process returns to the state of normal operation and clears redistribution based on the OSPF routing process ID.
Router(config-router)# clear ip ospf 100 processRelated Commands
max-metric router-lsa
To configure a router that is running the Open Shortest Path First (OSPF) protocol to advertise a maximum metric so that other routers do not prefer the router as an intermediate hop in their shortest path first (SPF) calculations, use the max-metric router-lsa command in router configuration mode. To disable the advertisement of a maximum metric, use the no form of this command.
max-metric router-lsa [on-startup {announce-time | wait-for-bgp}]
no max-metric router-lsa [on-startup {announce-time | wait-for-bgp}]
Syntax Description
Defaults
Router link-state advertisements (LSAs) are originated with normal link metrics.
Command Modes
Router configuration
Command History
Usage Guidelines
Enabling the max-metric router-lsa command will cause a router to originate LSAs with a maximum metric (LSInfinity: 0xFFFF) through all nonstub links, which allows BGP routing tables to converge without attracting transit traffic (if there are not alternate lower cost paths around the router). The router will advertise accurate (normal) metrics after the configured or default timers expire or after BGP sends a notification that routing tables have converged.
Note
The max-metric router-lsa command is useful in the following situations:
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Note
Note
Examples
The following example configures a router that is running OSPF to advertise a maximum metric for 100 seconds:
Router(config)# router ospf 100Router(config-router)# max-metric router-lsa on-startup 100The following example configures a router to advertise a maximum metric until BGP routing tables converge or until the default timer expires (600 seconds):
Router(config)# router ospf 100Router(config-router)# max-metric router-lsa on-startup wait-for-bgpThe following example configures a router that is running OSPF to advertise a maximum metric until the router shuts down:
Router(config)# router ospf 100Router(config-router)# max-metric router-lsaRouter(config-router)# exitRouter(config)# exitRouter# show ip ospfRelated Commands
show ip ospf
Displays general information about OSPF routing processes.
show ip ospf database
Displays lists of information related to the OSPF database for a specific router.
metric
To globally change the metric value for all Intermediate System-to-Intermediate System (IS-IS) interfaces, use the metric command in interface configuration or address family configuration mode. To disable the metric value and reinstate the default metric value of 10, use the no form of this command.
metric default-value [level-1 | level-2]
no metric default-value [level-1 | level-2]
Syntax Description
Defaults
The default value for active IS-IS interfaces is 10; the default value for inactive IS-IS interfaces is zero.
If the level-1 or level-2 keyword is not entered, the metric will be applied to both Level 1 and Level 2 IS-IS interfaces.Command Modes
Interface configuration
Address family configurationCommand History
Usage Guidelines
When you need to change the default metric value for all IS-IS interfaces, it is recommended to use the metric command in order to configure all interfaces globally. Globally configuring the metric values prevents user errors, such as unintentionally removing a set metric from an interface without configuring a new value and unintentionally allowing the interface to revert to the default metric 10 and thereby become a highly preferred interface in the network.
For networks running IPv4, enter the metric command in interface configuration mode. For networks running IPv6, enter the metric command in address family configuration mode.
Once you enter the metric command to change the default IS-IS interface metric value, an enabled interface will use the new value instead of the default value 10. Passive interfaces will continue to use the metric value 0.
Note
Examples
The following example configures the IS-IS interfaces with a global default value 111 for an IS-IS IPv4 network:
interface Ethernet3/1ip address 10.10.10.2 255.255.0.0ip router isis area1no ip route-cacheduplex half!interface Ethernet3/2ip address 10.10.10.130 255.255.255.0ip router isis area1no ip route-cacheduplex half!router isis area1net 01.0000.0309.1234.00metric-style widemetric 111Entering the show clns interface command returns the following information:
Router# show clns interfaceEthernet3/1 is up, line protocol is upChecksums enabled, MTU 1497, Encapsulation SAPERPDUs enabled, min. interval 10 msec.CLNS fast switching enabledCLNS SSE switching disabledDEC compatibility mode OFF for this interfaceNext ESH/ISH in 39 secondsRouting Protocol: IS-ISCircuit Type: level-1-2Interface number 0x0, local circuit ID 0x1Level-1 Metric: 111, Priority: 64, Circuit ID: mekong.01Level-1 IPv6 Metric: 10Number of active level-1 adjacencies: 0Level-2 Metric: 111, Priority: 64, Circuit ID: mekong.01Level-2 IPv6 Metric: 10Number of active level-2 adjacencies: 0Next IS-IS LAN Level-1 Hello in 922 millisecondsNext IS-IS LAN Level-2 Hello in 1 secondsEthernet3/2 is up, line protocol is upChecksums enabled, MTU 1497, Encapsulation SAPERPDUs enabled, min. interval 10 msec.CLNS fast switching enabledCLNS SSE switching disabledDEC compatibility mode OFF for this interfaceNext ESH/ISH in 20 secondsRouting Protocol: IS-ISCircuit Type: level-1-2Interface number 0x1, local circuit ID 0x2Level-1 Metric: 111, Priority: 64, Circuit ID: mekong.02Level-1 IPv6 Metric: 10Number of active level-1 adjacencies: 1Level-2 Metric: 111, Priority: 64, Circuit ID: mekong.02Level-2 IPv6 Metric: 10Number of active level-2 adjacencies: 1Next IS-IS LAN Level-1 Hello in 2 secondsNext IS-IS LAN Level-2 Hello in 1 secondsThe following example configures IPv6 for IS-IS and a global default value of 222 IPv6 metric for the IS-IS interfaces. The metric of 10 that was entered using the isis metric command will take precedence.
interface Ethernet3/1ip address 10.10.10.2 255.255.0.0ip router isis area1no ip route-cacheduplex halfisis metric 10!interface Ethernet3/2ip address 10.10.10.10 255.255.255.0ip router isis area1no ip route-cacheduplex halfrouter isis area1net 01.0000.0309.1234.00metric-style widemetric 111!address-family ipv6metric 222exit-address-familyEnter the show clns interface command to verify that the global default metric for IS-IS IPv6 interfaces for IPv6 network is 222:
Router# show clns interfaceEthernet3/1 is up, line protocol is upChecksums enabled, MTU 1497, Encapsulation SAPERPDUs enabled, min. interval 10 msec.CLNS fast switching enabledCLNS SSE switching disabledDEC compatibility mode OFF for this interfaceNext ESH/ISH in 51 secondsRouting Protocol: IS-ISCircuit Type: level-1-2Interface number 0x0, local circuit ID 0x1Level-1 Metric: 10, Priority: 64, Circuit ID: mekong.01Level-1 IPv6 Metric: 222Number of active level-1 adjacencies: 0Level-2 Metric: 10, Priority: 64, Circuit ID: mekong.01Level-2 IPv6 Metric: 222Number of active level-2 adjacencies: 0Next IS-IS LAN Level-1 Hello in 2 secondsNext IS-IS LAN Level-2 Hello in 2 secondsEthernet3/2 is up, line protocol is upChecksums enabled, MTU 1497, Encapsulation SAPERPDUs enabled, min. interval 10 msec.CLNS fast switching enabledCLNS SSE switching disabledDEC compatibility mode OFF for this interfaceNext ESH/ISH in 17 secondsRouting Protocol: IS-ISCircuit Type: level-1-2Interface number 0x1, local circuit ID 0x2Level-1 Metric: 111, Priority: 64, Circuit ID: mekong.02Level-1 IPv6 Metric: 222Number of active level-1 adjacencies: 1Level-2 Metric: 111, Priority: 64, Circuit ID: mekong.02Level-2 IPv6 Metric: 222Number of active level-2 adjacencies: 1Next IS-IS LAN Level-1 Hello in 1 secondsNext IS-IS LAN Level-2 Hello in 89 millisecondsRelated Commands
isis ipv6 metric
Configures the value of an IS-IS IPv6.
isis metric
Configures the metric for an interface.
metric holddown
To keep new Enhanced Interior Gateway Routing Protocol (EIGRP) routing information from being used for a certain period of time, use the metric holddown command in router configuration mode. To disable this feature, use the no form of this command.
metric holddown
no metric holddown
Syntax Description
This command has no arguments or keywords.
Defaults
Disabled
Command Modes
Router configuration
Command History
Usage Guidelines
The holddown state keeps new routing information from being used for a certain period of time. This function can prevent routing loops caused by slow convergence. It is sometimes advantageous to disable the holddown state to increase the ability of the network to quickly respond to topology changes; this command provides this function.
Use the metric holddown command if other routers or access servers within the autonomous system are not configured with the no metric holddown command. If all routers are not configured the same way, you increase the possibility of routing loops.
Examples
The following example disables metric holddown:
router eigrp 15network 172.16.0.0network 192.168.7.0no metric holddownRelated Commands
metric maximum-hops
To have the IP routing software advertise as unreachable those routes with a hop count higher than is specified by the command (Enhanced Interior Gateway Routing Protocol [EIGRP] only), use the metric maximum-hops command in router configuration mode. To reset the value to the default, use the no form of this command.
metric maximum-hops {hops-number}
no metric maximum-hops {hops-number}
Syntax Description
hops-number
Maximum hop count (in decimal). The default value is 100 hops; the maximum number of hops that can be specified is 255.
Defaults
100 hops
Command Modes
Router configuration
Command History
Usage Guidelines
This command provides a safety mechanism that breaks any potential count-to-infinity problems. It causes the IP routing software to advertise as unreachable routes with a hop count greater than the value assigned to the hops-number argument.
Examples
In the following example, a router in autonomous system 71 attached to network 15.0.0.0 wants a maximum hop count of 200, doubling the default. The network administrators configured the router hop count to 200 because they have a complex WAN that can generate a large hop count under normal (nonlooping) operations.
router eigrp 71network 172.16.0.0metric maximum-hops 200Related Commands
metric holddown
Keeps new EIGRP routing information from being used for a certain period of time.
metric weights (EIGRP)
Allows the tuning of the EIGRP metric calculations.
metric weights (EIGRP)
To allow the tuning of Enhanced Interior Gateway Routing Protocol (EIGRP) metric calculations, use the metric weights command in router configuration mode. To reset the values to their defaults, use the no form of this command.
metric weights tos k1 k2 k3 k4 k5
no metric weights
Syntax Description
tos
Type of service must always be zero.
k1k2 k3 k4 k5
Constants that convert an EIGRP metric vector into a scalar quantity.
Defaults
tos: 0
k1: 1
k2: 0
k3: 1
k4: 0
k5: 0
Command Modes
Router configuration
Command History
Usage Guidelines
Use this command to alter the default behavior of EIGRP routing and metric computation and allow the tuning of the EIGRP metric calculation for a particular type of service (ToS).
If k5 equals 0, the composite EIGRP metric is computed according to the following formula:
metric = [k1 * bandwidth + (k2 * bandwidth)/(256 - load) + k3 * delay]
If k5 does not equal zero, an additional operation is performed:
metric = metric * [k5/(reliability + k4)]
Bandwidth is inverse minimum bandwidth of the path in BPS scaled by a factor of 2.56 * 1012. The range is from a 1200-bps line to 10 terabits per second.
Delay is in units of 10 microseconds. The range of delay is from 10 microseconds to 168 seconds. A delay of all ones indicates that the network is unreachable.
The delay parameter is stored in a 32-bit field, in increments of 39.1 nanoseconds. The range of delay is from 1 (39.1 nanoseconds) to hexadecimal FFFFFFFF (decimal 4,294,967,040 nanoseconds). A delay of all ones (that is, a delay of hexadecimal FFFFFFFF) indicates that the network is unreachable.
Table 4 lists the default values used for several common media.
Reliability is given as a fraction of 255. That is, 255 is 100 percent reliability or a perfectly stable link.
Load is given as a fraction of 255. A load of 255 indicates a completely saturated link.
Examples
The following example sets the metric weights to slightly different values than the defaults:
router eigrp 109network 192.168.0.0metric weights 0 2 0 2 0 0Related Commands
