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Cisco IOS IP Command Reference, Volume 2 of 4: Routing Protocols, Release 12.3
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Introduction
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IP Routing Protocol Commands: A through B
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IP Routing Protocols Commands: C through H
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IP Routing Protocols Commands: I
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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 local policy
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IP Routing Protocols Commands: show ip ospf through version
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Table Of Contents
clear bgp nsap flap-statistics
default-information originate (RIP)
default-information originate (BGP)
default-information originate (IS-IS)
default-information originate (OSPF)
capability lls
To enable the use of the Link-Local Signalling (LLS) data block in originated OSPF packets and reenable OSPF nonstop forwarding (NSF) awareness, use the capability lls command in router configuration mode. To disable LLS and OSPF NSF awareness, use the no form of this command.
capability lls
no capability lls
Syntax Description
This command has no arguments or keywords.
Defaults
LLS is enabled.
Command Modes
Router configuration
Command History
Usage Guidelines
You might want to disable NSF awareness by disabling the use of the LLS data block in originated OSPF packets. You might want to disable NSF awareness if the router has no applications using LLS.
If NSF is configured and you try to disable LLS, you will receive the error message, "OSPF Non-Stop Forwarding (NSF) must be disabled first."
If LLS is disabled and you try to configure NSF, you will receive the error message, "OSPF Link-Local Signaling (LLS) capability must be enabled first."
Examples
The following example disables LLS support and OSPF NSF awareness:
router ospf 2no capability llscapability vrf-lite
To suppress the Provider Edge (PE) specific checks on a router when the OSPF process is associated with the VRF, use the capability vrf-lite command in router configuration mode. To restore the checks, use the no form of this command.
capability vrf-lite
no capability vrf-lite
Syntax Description
This command has no arguments or keywords.
Defaults
Disabled. PE specific checks are performed if the process is associated with VRF command modes.
Command Modes
Router configuration
Command History
Usage Guidelines
This command works only if the OSPF process is associated with the VRF.
When the OSPF process is associated with the VRF, several checks are performed when link-state advertisements (LSAs) are received. PE checks are needed to prevent loops when the PE is performing a mutual redistribution between OSPF and BGP interfaces.
In some situations, performing PE checks might not be desirable. The concept of VRFs can be used on a router that is not a PE router (that is, a router that is not running BGP). With the capability vrf-lite command, the checks can be turned off to allow correct population of the VRF routing table with routes to IP prefixes.
Examples
This example shows a router configured with multi-VRF.
router ospf 100 vrf grccapability vrf-liteclear bgp nsap
To clear and then reset Connectionless Network Service (CLNS) network service access point (NSAP) Border Gateway Protocol (BGP) sessions, use the clear bgp nsap command in privileged EXEC mode.
clear bgp nsap {* | as-number | ip-address} [soft] [in | out]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The clear bgp nsap command is similar to the clear ip bgp command, except that it is NSAP address family-specific.
Use of the clear bgp nsap command allows a reset of the neighbor sessions with varying degrees of severity, depending on the specified keywords and arguments.
Use the * keyword to reset all neighbor sessions. The software will clear and then reset the neighbor connections. Use this form of the command in the following situations:
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BGP timer specification change
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Use the soft out keywords to clear and reset only the outbound neighbor connections. Inbound neighbor sessions will not be reset. Use this form of the command in the following situations:
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Use the in keyword to clear only the inbound neighbor connections. Outbound neighbor sessions will not be reset. Use this form of the command in the following situations:
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Examples
The following example clears the inbound session with the neighbor 172.20.16.6 without the outbound session being reset:
Router# clear bgp nsap 172.20.16.6 inThe following example clears the outbound session with the neighbors in autonomous system 65000 without the inbound session being reset:
Router# clear bgp nsap 65000 soft outRelated Commands
show bgp nsap
Displays entries in the BGP routing table for the NSAP address family.
clear bgp nsap dampening
To clear Border Gateway Protocol (BGP) route dampening information for the network service access point (NSAP) address family and unsuppress the suppressed routes, use the clear bgp nsap dampening command in privileged EXEC mode.
clear bgp nsap dampening [nsap-prefix]
Syntax Description
nsap-prefix
(Optional) NSAP prefix about which to clear dampening information. This argument can be up to 20 octets long.
Defaults
When the nsap-prefix argument is not specified, the clear bgp nsap dampening command clears route dampening information for the entire BGP routing table for the NSAP address family.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The clear bgp nsap dampening command is similar to the clear ip bgp dampening command, except that it is specific to the NSAP address family.
Examples
The following example clears route dampening information about the route to NSAP prefix 49.6001 and unsuppresses its suppressed routes:
Router# clear bgp nsap dampening 49.6001Related Commands
bgp dampening
Enables BGP route dampening or changes various BGP route dampening factors.
show bgp nsap dampened-paths
Displays BGP dampened routes for the NSAP address family.
clear bgp nsap external
To clear all external Border Gateway Protocol (BGP) peers for the network service access point (NSAP) address family, use the clear bgp nsap external command in privileged EXEC mode.
clear bgp nsap external [soft] [in | out]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The clear bgp nsap external command is similar to the clear ip bgp external command, except that it is specific to the NSAP address family.
Examples
The following example clears the inbound session with external BGP peers without the outbound session being reset:
Router# clear bgp nsap external soft inRelated Commands
clear bgp nsap flap-statistics
To clear Border Gateway Protocol (BGP) flap statistics for the network service access point (NSAP) address family, use the clear bgp nsap flap-statistics command in privileged EXEC mode.
clear bgp nsap flap-statistics [nsap-prefix] [regexp regexp | filter-list access-list-number]
Syntax Description
Defaults
No statistics are cleared.
If no arguments or keywords are specified, the software clears flap statistics for all routes.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The clear bgp nsap flap-statistics command is similar to the clear ip bgp flap-statistics command, except that it is specific to the NSAP address family.
The flap statistics for a route are also cleared when an NSAP BGP peer is reset. Although the reset withdraws the route, no penalty is applied in this instance even though route flap dampening is enabled.
Examples
The following example clears all of the flap statistics for paths that pass access list 3:
Router# clear bgp nsap flap-statistics filter-list 3Related Commands
bgp dampening
Enables BGP route dampening or changes various BGP route dampening factors.
show bgp nsap flap-statistics
Displays BGP flap statistics for the NSAP address family.
clear bgp nsap peer-group
To clear the Border Gateway Protocol (BGP) TCP connections to all members of a BGP peer group for the network service access point (NSAP) address family, use the clear bgp nsap peer-group command in privileged EXEC mode.
clear bgp nsap peer-group peer-group-name
Syntax Description
Defaults
No BGP TCP connections are cleared.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The clear bgp nsap peer-group command is similar to the clear ip bgp peer-group command, except that it is specific to the NSAP address family.
Examples
The following example shows the BGP TCP connections being cleared for all members of the NSAP BGP peer group named internal:
Router# clear bgp nsap peer-group internalRelated Commands
neighbor peer-group (assigning members)
Configures a BGP neighbor to be a member of a peer group.
clear ip bgp
To reset a BGP connection using BGP soft reconfiguration, use the clear ip bgp command in privileged EXEC mode at the system prompt.
clear ip bgp {* | neighbor-address | peer-group-name} [soft [in | out]]
Syntax Description
Defaults
No reset is initiated.
Command Modes
Privileged EXEC
Command History
10.0
This command was introduced.
12.0(6)T
The dynamic inbound soft reset capability was added.
12.0(2)S
The dynamic inbound soft reset capability was added.
Usage Guidelines
You can reset inbound routing table updates dynamically or by generating new updates using stored update information. Using stored update information required additional memory for storing the updates.
To reset inbound routing table updates dynamically, all BGP routers must support the route refresh capability. To determine whether a BGP router supports this capability, use the show ip bgp neighbors command. If a router supports the route refresh capability, the following message is displayed:
Received route refresh capability from peer.If all BGP routers support the route refresh capability, use the clear ip bgp {* | address | peer-group-name} in command. You need not use the soft keyword, because soft reset is automatically assumed when the route refresh capability is supported.
To generate new inbound updates from stored update information (rather than dynamically) without resetting the BGP session, you must preconfigure the local BGP router using the neighbor soft-reconfiguration inbound command. This preconfiguration causes the software to store all received updates without modification regardless of whether an update is accepted by the inbound policy. Storing updates is memory intensive and should be avoided if possible.
Outbound BGP soft configuration has no memory overhead and does not require any preconfiguration. You can trigger an outbound reconfiguration on the other side of the BGP session to make the new inbound policy take effect.
Use this command whenever any of the following changes occur:
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Examples
The following example clears the inbound session with the neighbor 10.108.1.1 without resetting the session:
Router# clear ip bgp 10.108.1.1 soft inThe following example clears the outbound session with the peer group named corp without resetting the session:
Router# clear ip bgp corp soft outRelated Commands
neighbor soft-reconfiguration
Configures the Cisco IOS software to start storing updates.
show ip bgp
Displays entries in the BGP routing table.
clear ip bgp dampening
To clear BGP route dampening information and unsuppress the suppressed routes, use the clear ip bgp dampening command in privileged EXEC mode.
clear ip bgp dampening [ip-address network-mask]
Syntax Description
ip-address
(Optional) IP address of the network about which to clear dampening information.
network-mask
(Optional) Network mask applied to the ip-address argument.
Command Modes
Privileged EXEC
Command History
Examples
The following example clears route dampening information about the route to network 192.168.0.0 and unsuppresses its suppressed routes. When the address and mask arguments are not specified, the clear ip bgp dampening command clears route dampening information for the entire BGP routing table.
Router# clear ip bgp dampening 192.168.0.0 255.255.0.0Related Commands
bgp dampening
Enables BGP route dampening or changes various BGP route dampening factors.
show ip bgp dampened-paths
Displays BGP dampened routes.
clear ip bgp external
To clear external Border Gateway Protocol (eBGP) peers, use the clear ip bgp external command in privileged EXEC mode.
clear ip bgp external [in | out]
clear ip bgp external [soft [in | out]]
clear ip bgp external {ipv4 | ipv6 {multicast | unicast [in | out | soft]}}
clear ip bgp external [vpn4 unicast {in | out | soft}}
Syntax Description
Defaults
A reset is not initiated.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Using the clear ip bgp external command without the soft keyword will reset the session.
Examples
The following examples clear an inbound session with the eBGP peers:
Router# clear ip bgp external inor
clear ip bgp external soft inThe following example clears an outbound address family IPv4 multicast session with the eBGP peers:
Router# clear ip bgp external ipv4 multicast outRelated Commands
clear ip bgp flap-statistics
To clear BGP flap statistics, use the clear ip bgp flap-statistics command in privileged EXEC mode.
clear ip bgp flap-statistics [{regexp regexp} | {filter-list list-name} | {ip-address network-mask}]
clear ip bgp [ip-address] flap-statistics
Syntax Description
Defaults
No statistics are cleared.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
If no arguments or keywords are specified, the router will clear BGP flap statistics for all routes.
The flap statistics for a route are also cleared when a BGP peer is reset. Although the reset withdraws the route, no penalty is applied in this instance even though route flap dampening is enabled.
Examples
The following example clears all of the flap statistics for paths that pass filter list 3:
Router# clear ip bgp flap-statistics filter-list 3Related Commands
bgp dampening
Enables BGP route dampening or changes various BGP route dampening factors.
clear ip bgp peer-group
To clear all the members of a BGP peer group, use the clear ip bgp peer-group command in privileged EXEC mode.
clear ip bgp peer-group tag
Syntax Description
Defaults
No BGP peer group members are cleared.
Command Modes
Privileged EXEC
Command History
Examples
The following example clears all members from the BGP peer group named internal:
Router# clear ip bgp peer-group internalRelated Commands
neighbor peer-group (assigning members)
Configures a BGP neighbor to be a member of a peer group.
clear ip eigrp neighbors
To delete entries from the neighbor table, use the clear ip eigrp neighbors command in EXEC mode.
clear ip eigrp neighbors [ip-address | interface-type interface-number]
Syntax Description
Command Modes
EXEC
Command History
Examples
The following example removes the neighbor whose address is 172.16.8.3:
Router# clear ip eigrp neighbors 172.16.8.3Related Commands
show ip eigrp interfaces
Displays information about interfaces configured for EIGRP.
clear ip eigrp vrf neighbor
To clear neighbor entries of the specified Enhanced Interior Gateway Routing Protocol (EIGRP) virtual routing and forwarding instance (VRF) from the Routing Information Base (RIB), use the clear ip eigrp vrf command in privileged EXEC mode.
clear ip eigrp vrf {vrf-name as-number} neighbor [interface-number]
Syntax Description
Command Modes
Privileged EXEC
Command History
12.0(22)S
This command was introduced.
12.2(15)T
This command was integrated into 12.2(15)T.
Examples
The following example clears EIGRP neighbors reached through the VRF named VRF-RED in autonomous system 101:
clear ip eigrp vrf VRF-RED 101 neighborThe following example clears EIGRP neighbors reached through the VRF named VRF-GREEN in autonomous-system 101 learned through Ethernet interface 0/0:
clear ip eigrp vrf VRF-RED 101 neighbor ethernet 0/0Related Commands
clear ip ospf
To clear redistribution based on the OSPF routing process ID, use the clear ip ospf command in privileged EXEC mode.
clear ip ospf [pid] {process | redistribution | counters [neighbor [neighbor-interface] [neighbor-id]]}
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Use the pid argument to clear only one OSPF process. If the pid argument is not specified, all OSPF processes are cleared.
Examples
The following example clears all OSPF processes:
clear ip ospf processclear ip prefix-list
To reset the hit count of the prefix list entries, use the clear ip prefix-list command in privileged EXEC mode.
clear ip prefix-list [prefix-list-name] [network/length]
Syntax Description
Defaults
Does not clear the hit count.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The hit count is a value indicating the number of matches to a specific prefix list entry.
Examples
The following example clears the hit count from the prefix list entries for the prefix list named first_list that match the network mask 10.0.0.0/8:
Router# clear ip prefix-list first_list 10.0.0.0/8Related Commands
compatible rfc1583
To restore the method used to calculate summary route costs per RFC 1583, use the compatible rfc1583 command in router configuration mode. To disable RFC 1583 compatibility, use the no form of this command.
compatible rfc1583
no compatible rfc1583
Syntax Description
This command has no arguments or keywords.
Defaults
Compatible with RFC 1583.
Command Modes
Router configuration
Command History
Usage Guidelines
This command is backward compatible with Cisco IOS Release 12.0.
To minimize the chance of routing loops, all OSPF routers in an OSPF routing domain should have RFC compatibility set identically.
Because of the introduction of RFC 2328, OSPF Version 2, the method used to calculate summary route costs has changed. Use the no compatible rfc1583 command to enable the calculation method used per RFC 2328.
Examples
The following example specifies that the router process is compatible with RFC 1583:
router ospf 1 compatible rfc1583!dampening
To configure a router to automatically dampen a flapping interface, use the dampening command in interface configuration mode. To disable automatic route dampening, use the no form of this command.
dampening[half-life-period reuse-threshold] [suppress-threshold max-suppress-time [restart-penalty]]
no dampening
Syntax Description
Defaults
This command is disabled by default. To manually configure the timer for the restart-penalty argument, the value for all arguments must be manually entered.
Command Modes
Interface configuration
Command History
12.0(22)S
This command was introduced.
12.2(13)T
This command was integrated into Cisco IOS Release 12.2(13)T.
Usage Guidelines
he IP Event Dampening feature will function on a subinterface but cannot be configured on only the subinterface. Only the primary interface can be configured with this feature, and all the subinterfaces are subject to the same dampening configuration.
When an interface is dampened, the interface is dampened to both IP and Connectionless Network Services (CLNS) routing equally. The interface is dampened to both IP and CLNS because integrated routing protocols like Intermediate System-to-Intermediate System (IS-IS), IP, and CLNS routing protocols are closely interconnected, so it is impossible to apply dampening separately.
This occurs because for integrated protocols like Intermediate System-to-Intermediate System (IS-IS), IP, and CLNS routing are closely interconnected, so it is impossible to apply dampening separately.
Copying a dampening configuration from virtual templates to virtual access interfaces is not supported because dampening has limited usefulness to existing applications using virtual templates. Virtual access interfaces are released when an interface flaps, and new connections and virtual access interfaces are acquired when the interface comes up and is made available to the network. Because dampening states are attached to the interface, the dampening states would not survive an interface flap.
If this command is applied to an interface that already has dampening configured, all dampening states are reset and the accumulated penalty will be set to 0. If the interface has been dampened, the accumulated penalty will fall into the reuse threshold range, and the dampened interface will be made available to the network. The flap counts, however, are retained.
Examples
The following example sets the half life to 30 seconds, the reuse threshold to 1500, the suppress threshold to 10000, and the maximum suppress time to 120 seconds:
interface Ethernet 0/0dampening 30 1500 10000 120The following example configures the router to apply a penalty of 500 on Ethernet interface 0/0 when the interface comes up for the first time after the router is reloaded:
interface Ethernet 0/0dampening 5 500 1000 20 500Related Commands
default-information
To control the candidate default routing information or Enhanced Interior Gateway Routing Protocol (EIGRP) processes, use the default-information command in router configuration mode. To suppress EIGRP candidate information in incoming or outbound updates, use the no default-information in command.
default-information {allowed {in | out} | in | out} [acl-number | acl-name]
no default-information {allowed {in | out} | in | out}
Syntax Description
Defaults
Normally, exterior routes are always accepted and default information is passed between EIGRP processes when redistribution occurs.
Command Modes
Router configuration
Command History
10.0
This command was introduced.
11.2
The access-list-number and access-list-name arguments were added.
Usage Guidelines
The default network of 0.0.0.0 used by Routing Information Protocol (RIP) can be redistributed by EIGRP.
Examples
The following example allows exterior or default routes to be received by an EIGRP peer in autonomous system 23:
router eigrp 23default-information indefault-information originate (RIP)
To generate a default route into Routing Information Protocol (RIP), use the default-information originate command in router configuration mode. To disable this feature, use the no form of this command.
default-information originate [route-map map-name]
no default-information originate
Syntax Description
route-map map-name
(Optional) Routing process will generate the default route if the route map is satisfied.
Defaults
This command is disabled by default.
Command Modes
Router configuration
Command History
Usage Guidelines
The route map referenced in the default-information originate command cannot use an extended access list; it can use a standard access list.
Examples
The following example originates a default route (0.0.0.0/0) over a certain interface when 172.68.0.0/16 is present. Applying a condition (in this case a route map) to determine when the default route is originated is called "conditional default origination."
router ripversion 2network 172.68.16.0default-information originate route-map condition!route-map condition permit 10match ip address 10set interface s1/0!access-list 10 permit 172.68.16.0 0.0.0.255!default-information originate (BGP)
To control the redistribution of a protocol or network into the BGP, use the default-information originate command in address family or router configuration mode. To disable this function, use the no form of this command.
default-information originate
no default-information originate
Syntax Description
This command has no arguments or keywords.
Defaults
This command is disabled by default.
Command Modes
Address family configuration
Router configuration
Command History
10.0
This command was introduced.
12.0(7)T
Address family configuration mode was added.
Usage Guidelines
The default-information originate command should be used if the network operator needs to control the redistribution of default routes. Using the default-information originate command in BGP is similar to using the network command. However, to achieve the same result as configuring the network command with the route 0.0.0.0, the default-information originate command requires an explicit redistribution of the route 0.0.0.0. The network command requires only that route 0.0.0.0 is specified in the Interior Gateway Protocol (IGP) routing table. For this reason, the network command is preferred for redistributing default routes and protocols into BGP.
Examples
The following address family configuration mode example configures BGP to redistribute OSPF into BGP:
router bgp 164address-family ipv4 unicastdefault-information originateredistribute ospf 109The following router configuration mode example configures BGP to redistribute OSPF into BGP:
router bgp 164default-information originateredistribute ospf 109Related Commands
default-information originate (IS-IS)
To generate a default route into an IS-IS routing domain, use the default-information originate command in router configuration mode. To disable this feature, use the no form of this command.
default-information originate [route-map map-name]
no default-information originate [route-map map-name]
Syntax Description
route-map map-name
(Optional) Routing process will generate the default route if the route map is satisfied.
Defaults
This command is disabled by default.
Command Modes
Router configuration
Command History
Usage Guidelines
If a router configured with this command has a route to 0.0.0.0 in the routing table, IS-IS will originate an advertisement for 0.0.0.0 in its link-state packets (LSPs).
Without a route map, the default is advertised only in Level 2 LSPs. For Level 1 routing, there is another mechanism to find the default route, which is to look for the closest Level 1 or Level 2 router. The closest Level 1 or Level 2 router can be found by looking at the attached-bit (ATT) in Level 1 LSPs.
A route map can be used for two purposes:
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With a match ip address standard-access-list command, you can specify one or more IP routes that must exist before the router will advertise 0/0.
Examples
The following example forces the software to generate a default external route into an IS-IS domain:
router isis! BGP routes will be distributed into IS-ISredistribute bgp 120! access list 2 is applied to outgoing routing updatesdistribute-list 2 outdefault-information originate! access list 2 defined as giving access to network 10.105.0.0access-list 2 permit 10.105.0.0 0.0.255.255Related Commands
redistribute (IP)
Redistributes routes from one routing domain into another routing domain.
show isis database
Displays the IS-IS link-state database.
default-information originate (OSPF)
To generate a default external route into an OSPF routing domain, use the default-information originate command in router configuration mode. To disable this feature, use the no form of this command.
default-information originate [always] [metric metric-value] [metric-type type-value] [route-map map-name]
no default-information originate [always] [metric metric-value] [metric-type type-value] [route-map map-name]
Syntax Description
Defaults
This command is disabled by default.
Command Modes
Router configuration
Command History
Usage Guidelines
Whenever you use the redistribute or the default-information router configuration command to redistribute routes into an OSPF routing domain, the Cisco IOS software automatically becomes an Autonomous System Boundary Router (ASBR). However, an ASBR does not, by default, generate a default route into the OSPF routing domain. The software still must have a default route for itself before it generates one, except when you have specified the always keyword.
When you use this command for the OSPF process, the default network must reside in the routing table, and you must satisfy the route-map map-name keyword and argument. Use the default-information originate always route-map map-name form of the command when you do not want the dependency on the default network in the routing table.
Examples
The following example specifies a metric of 100 for the default route redistributed into the OSPF routing domain and an external metric type of Type 1:
router ospf 109redistribute eigrp 108 metric 100 subnetsdefault-information originate metric 100 metric-type 1Related Commands
redistribute (IP)
Redistributes routes from one routing domain into another routing domain.
default-metric (BGP)
To set a default metric for routes redistributed into Border Gateway Protocol (BGP), use the default-metric command in address family or router configuration mode. To remove the configured value and return BGP to default operation, use the no form of this command.
default-metric number
no default-metric number
Syntax Description
number
Default metric value applied to the redistributed route. The range of values for this argument is from 1 to 4294967295.
Defaults
The following is default behavior if this command is not configured or if the no form of this command is entered:
•
•
When this command is enabled, the metric for redistributed connected routes is set to 0.
Command Modes
Address family configuration
Router configurationCommand History
10.0
This command was introduced.
12.0(7)T
Address family configuration mode support was added.
Usage Guidelines
The default-metric command is used to set the metric value for routes redistributed into BGP with the redistribute command. A default metric can be configured to solve the problem of redistributing routes with incompatible metrics. Assigning the default metric will allow redistribution to occur.
This value is the Multi Exit Discriminator (MED) that is evaluated by BGP during the best path selection process. The MED is a non-transitive value that is processed only within the local autonomous system and adjacent autonomous systems. The default metric is not set if the received route has a MED value.
Note
Examples
In the following example, a metric of 1024 is set for routes redistributed into BGP from OSPF:
Router(config)# router bgp 50000Router(config-router)# address-family ipv4 unicastRouter(config-router-af)# default-metric 1024Router(config-router-af)# redistribute ospf 10Router(config-router-af)# endRelated Commands
redistribute (IP)
Redistributes routes from one routing domain into another routing domain.
default-metric (EIGRP)
To set metrics for the Enhanced Interior Gateway Routing Protocol (EIGRP), use the default-metric command in router configuration mode. To remove the metric value and restore the default state, use the no form of this command.
default-metric bandwidth delay reliability loading mtu
no default-metric bandwidth delay reliability loading mtu
Syntax Description
Defaults
Only connected routes can be redistributed without a default metric. The metric of redistributed connected routes is set to 0.
Command Modes
Address family configuration
Router configurationCommand History
Usage Guidelines
A default metric is required to redistribute a protocol into EIGRP, unless you use the redistribute command. You do not need default metrics to redistributed EIGRP into itself.
Note
Metric defaults have been carefully set to work for a wide variety of networks. Take great care when changing these values. Keeping the same metrics is supported only when redistributing from EIGRP, or static routes.
When enabled, the default-metric command applies a metric value of 0 to redistributed connected routes. The default-metric command does not override metric values that are applied with the redistribute command.
Examples
The following example takes redistributed Routing Information Protocol (RIP) metrics and translates them into EIGRP metrics with values as follows: bandwidth = 1000, delay = 100, reliability = 250, loading = 100, and MTU = 1500.
router eigrp 109network 172.16.0.0redistribute ripdefault-metric 1000 100 250 100 1500Related Commands
redistribute (IP)
Redistributes routes from one routing domain into another routing domain.
default-metric (OSPF)
To set default metric values for the OSPF routing protocol, use the default-metric command in router configuration mode. To return to the default state, use the no form of this command.
default-metric metric-value
no default-metric metric-value
Syntax Description
Defaults
Built-in, automatic metric translations, as appropriate for each routing protocol. The metric of redistributed connected and static routes is set to 0.
Command Modes
Router configuration
Command History
Usage Guidelines
The default-metric command is used in conjunction with the redistribute router configuration command to cause the current routing protocol to use the same metric value for all redistributed routes. A default metric helps solve the problem of redistributing routes with incompatible metrics. Whenever metrics do not convert, using a default metric provides a reasonable substitute and enables the redistribution to proceed.
Note
Examples
The following example shows a router in autonomous system 109 using both the Routing Information Protocol (RIP) and the OSPF routing protocols. The example advertises OSPF-derived routes using RIP and assigns the Internal Gateway Protocol (IGP)-derived routes a RIP metric of 10.
router ripdefault-metric 10redistribute ospf 109Related Commands
redistribute (IP)
Redistributes routes from one routing domain into another routing domain.
default-metric (RIP)
To set default metric values for Routing Information Protocol (RIP), use the default-metric command in router configuration mode. To return to the default state, use the no form of this command.
default-metric number-value
no default-metric [number-value]
Syntax Description
Defaults
Built-in, automatic metric translations, as appropriate for each routing protocol. The metric of redistributed connected and static routes is set to 0.
Command Modes
Router configuration
Command History
Usage Guidelines
The default-metric command is used in conjunction with the redistribute router configuration command to cause the current routing protocol to use the same metric value for all redistributed routes. A default metric helps solve the problem of redistributing routes with incompatible metrics. Whenever metrics do not convert, using a default metric provides a reasonable substitute and enables the redistribution to proceed.
Note
Examples
The following example shows a router in autonomous system 109 using both the RIP and the Open Shortest Path First (OSPF) routing protocols. The example advertises OSPF-derived routes using RIP and assigns the OSPF-derived routes a RIP metric of 10.
router ripdefault-metric 10redistribute ospf 109Related Commands
redistribute (IP)
Redistributes routes from one routing domain into another routing domain.
discard-route
To reinstall either an external or internal discard route that was previously removed, use the discard-route command in router configuration mode. To remove either an external or internal discard route, use the no form of this command.
discard-route [external | internal]
no discard-route [external | internal]
Syntax Description
Defaults
External and internal discard route entries are installed.
Command Modes
Router configuration
Command History
Usage Guidelines
External and internal discard route entries are installed in routing tables by default. During route summarization, routing loops may occur when data is sent to a nonexisting network that appears to be a part of the summary, and the router performing the summarization has a less specific route (pointing back to the sending router) for this network in its routing table. To prevent the routing loop, a discard route entry is installed in the routing table of the ABR or ASBR.
If for any reason you do not want to use the external or internal discard route, remove the discard route by entering the no discard-route command with either the external or internal keyword.
Examples
The following display shows the discard route functionality installed by default. When external or internal routes are summarized, a summary route to Null0 will appear in the router output from the show ip route command. See the router output lines that appear in bold font:
Router# show ip routeCodes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGPi - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static routeGateway of last resort is not set172.16.0.0/24 is variably subnetted, 3 subnets, 2 masksC 172.16.0.128/25 is directly connected, Loopback1O 172.16.0.0/24 is a summary, 00:00:14, Null0C 172.16.0.0/25 is directly connected, Loopback0172.31.0.0/24 is variably subnetted, 3 subnets, 2 masksC 172.31.0.128/25 is directly connected, Loopback3O 172.31.0.0/24 is a summary, 00:00:02, Null0C 172.31.0.0/25 is directly connected, Loopback2C 192.168.0.0/24 is directly connected, Ethernet0/0RouterB# show ip route ospf172.16.0.0/24 is variably subnetted, 3 subnets, 2 masksO 172.16.0.0/24 is a summary, 00:00:29, Null0172.16.0.0/24 is variably subnetted, 3 subnets, 2 masksO 201.0.0.0/24 is a summary, 00:00:17, Null0When the no discard-route command with the internal keyword is entered, notice the following route change, indicated by the router output lines that appear in bold font:
RouterB# configure terminalEnter configuration commands, one per line. End with CNTL/Z.RouterB(config)# router ospf 1RouterB(config-router)# no discard-route internalRouterB(config-router)#endRouterB# show ip route ospf172.31.0.0/24 is variably subnetted, 3 subnets, 2 masksO 172.16.0.0/24 is a summary, 00:04:14, Null0Next, the no discard-route command with the external keyword is entered to remove the external discard route entry:
RouterB# configure terminalEnter configuration commands, one per line. End with CNTL/Z.RouterB(config)# router ospf 1RouterB(config-router)# no discard-route externalRouterB(config-router)# endThe following router output from the show running-config command confirms that both the external and internal discard routes have been removed from the routing table of RouterB. See the router output lines that appear in bold font:
RouterB# show running-configBuilding configuration...Current configuration : 1114 bytes!version 12.2service timestamps debug uptimeservice timestamps log uptimeno service password-encryption!hostname RouterB...router ospf 1log-adjacency-changesno discard-route externalno discard-route internalarea 1 range 172.16.0.0 255.255.255.0summary-address 172.31.0.0 255.255.255.0redistribute rip subnetsnetwork 192.168.0.0 0.0.0.255 area 0network 172.16.0.0 0.0.0.255 area 1!Related Commands
distance (IP)
To define an administrative distance, use the distance command in router configuration mode. To remove a distance definition, use the no form of this command.
distance {ip-address {wildcard-mask}} [ip-standard-list] [ip-extended-list]
no distance {ip-address {wildcard-mask}} [ip-standard-list] [ip-extended-list]
Syntax Description
Defaults
For more information on default administrative distance, see "Usage Guidelines."
Command Modes
Router configuration
Command History
Usage Guidelines
Table 2 lists default administrative distances.
Numerically, an administrative distance is an integer from 0 to 255. In general, the higher the value, the lower the trust rating. An administrative distance of 255 means that the routing information source cannot be trusted at all and should be ignored.
When the optional access list number is used with this command, it is applied when a network is being inserted into the routing table. This behavior allows filtering of networks according to the IP address of the router supplying the routing information. This option could be used, as an example, to filter out possibly incorrect routing information from routers not under your administrative control.
The order in which you enter distance commands can affect the assigned administrative distances in unexpected ways (see the "Examples" section for further clarification).
For BGP, the distance command sets the administrative distance of the External BGP (EBGP) route.
The show ip protocols EXEC command displays the default administrative distance for a specified routing process.
Always set the administrative distance from the least to the most specific network.
Note
Examples
In the following example, the router eigrp global configuration command sets up EIGRP routing in autonomous system number 109. The network router configuration commands specify EIGRP routing on networks 192.168.7.0 and 172.16.0.0. The first distance router configuration command sets the default administrative distance to 255, which instructs the Cisco IOS software to ignore all routing updates from routers for which an explicit distance has not been set. The second distance command sets the administrative distance for all routers on the Class C network 192.168.7.0 to 90. The third distance command sets the administrative distance for the router with the address 172.16.1.3 to 120.
router eigrp 109network 192.168.7.0network 172.16.0.0distance 255distance 90 192.168.7.0 0.0.0.255distance 120 172.16.1.3 0.0.0.0In the following example, the set distance is from the least to the most specific network:
router eigrp 100network 10.0.0.0distance 22 10.0.0.0distance 33 10.11.0.0 0.0.255.255distance 44 10.11.12.0 0.0.0.255
Note
Related Commands
distance bgp
Allows the use of external, internal, and local administrative distances that could be a better route to a node.
distance bgp
To allow the use of external, internal, and local administrative distances that could be a better route than other external, internal, or local routes to a node, use the distance bgp command in address family or router configuration mode. To return to the default values, use the no form of this command.
distance bgp external-distance internal-distance local-distance
no distance bgp
Syntax Description
Defaults
external-distance: 20
internal-distance: 200
local-distance: 200
Command Modes
Address family configuration
Router configuration
Command History
10.0
This command was introduced.
12.0(7)T
Address family configuration mode was added.
Usage Guidelines
An administrative distance is a rating of the trustworthiness of a routing information source, such as an individual router or a group of routers. Numerically, an administrative distance is a positive integer from 1 to 255. In general, the higher the value, the lower the trust rating. An administrative distance of 255 means the routing information source cannot be trusted at all and should be ignored.
Use this command if another protocol is known to be able to provide a better route to a node than was actually learned via external BGP (eBGP), or if some internal routes should be preferred by BGP.
Caution
The distance bgp command replaces the distance mbgp command.
Examples
In the following router configuration mode example, internal routes are known to be preferable to those learned through the Interior Gateway Protocol (IGP), so the administrative distance values are set accordingly:
router bgp 109network 10.108.0.0neighbor 192.168.6.6 remote-as 123neighbor 172.16.1.1 remote-as 47distance bgp 20 20 200In the following address family configuration mode example, internal routes are known to be preferable to those learned through IGP, so the administrative distance values are set accordingly:
router bgp 109neighbor 192.168.6.6 remote-as 123neighbor 172.16.1.1 remote-as 47address family ipv4 multicastnetwork 10.108.0.0distance bgp 20 20 200neighbor 192.168.6.6 activateneighbor 172.16.1.1 activateRelated Commands
distance eigrp
To allow the use of two administrative distances—internal and external—that could be a better route to a node, use the distance eigrp command in router configuration mode. To reset these values to their defaults, use the no form of this command.
distance eigrp internal-distance external-distance
no distance eigrp
Syntax Description
Defaults
internal-distance: 90
external-distance: 170
Command Modes
Router configuration
Command History
Usage Guidelines
An administrative distance is a rating of the trustworthiness of a routing information source, such as an individual router or a group of routers. Numerically, an administrative distance is an integer from 0 to 255. In general, the higher the value, the lower the trust rating. An administrative distance of 255 means the routing information source cannot be trusted at all and should be ignored.
Use the distance eigrp command if another protocol is known to be able to provide a better route to a node than was actually learned via external EIGRP, or if some internal routes should really be preferred by EIGRP.
Table 3 lists the default administrative distances.
To display the default administrative distance for a specified routing process, use the show ip protocols EXEC command.
Examples
In the following example, the router eigrp global configuration command sets up EIGRP routing in autonomous system number 109. The network router configuration commands specify EIGRP routing on networks 192.168.7.0 and 172.16.0.0. The distance eigrp command sets the administrative distance of all EIGRP internal routes to 80 and all EIGRP external routes to 130.
Router(config)# router eigrp 109Router(config-router)# network 192.168.7.0Router(config-router)# network 172.16.0.0Router(config-router)# distance eigrp 80 130Related Commands
show ip protocols
Displays the parameters and current state of the active routing protocol process.
distance ospf
To define OSPF route administrative distances based on route type, use the distance ospf command in router configuration mode. To restore the default value, use the no form of this command.
distance ospf {[intra-area dist1] [inter-area dist2] [external dist3]}
no distance ospf
Syntax Description
Defaults
dist1: 110
dist2: 110
dist3: 110
Command Modes
Router configuration
Command History
Usage Guidelines
You must specify at least one of the keyword-argument pairs.
This command performs the same function as the distance command used with an access list. However, the distance ospf command allows you to set a distance for an entire group of routes, rather than a specific route that passes an access list.
A common reason to use the distance ospf command is when you have multiple OSPF processes with mutual redistribution, and you want to prefer internal routes from one over external routes from the other.
Examples
The following example changes the external distance to 200, making the route less reliable:
Router A Configuration
router ospf 1redistribute ospf 2 subnetdistance ospf external 200!router ospf 2redistribute ospf 1 subnetdistance ospf external 200Router B Configuration
router ospf 1 redistribute ospf 2 subnetdistance ospf external 200 ! router ospf 2redistribute ospf 1 subnetdistance ospf external 200Related Commands
distribute-list in (BGP)
To filter routes or networks received in incoming Border Gateway Protocol (BGP) updates, use the distribute-list in command in router configuration mode. To delete the distribute list and remove it from the running configuration file, use the no form of this command.
distribute-list {acl-number | prefix list-name} in
no distribute-list {acl-number | prefix list-name} in
Syntax Description
Note
Defaults
If this command is configured without a predefined access list, the distribute list will default to permitting all traffic.
Command Modes
Router configuration
Note
Command History
10.0
This command was introduced.
11.2
The acl-number arguments was added.
12.0
The prefix list-name argument was added.
Usage Guidelines
The distribute-list in command is used to filter incoming BGP updates. An access list must be defined prior to configuration of this command. In addition to access lists, prefix list can be used to filter based upon the prefix length, making it possible to filter either on the prefix list, the gateway, or both for incoming updates. The session must be reset with the clear ip bgp command before the distribute list will take effect. To suppress networks from being advertised in updates, use the distribute-list out command.
Note
Note
Examples
In the following example, a prefix list and distribute list are defined to configure the BGP routing process to accept traffic from only network 192.168.1.0 and network 10.108.0.0. An inbound route refresh is initiated to activate the distribute-list.
Router(config)# ip prefix-list RED deny 0.0.0.0/0 le 32Router(config)# ip prefix-1ist RED permit 10.108.0.0/16Router(config)# ip prefix-list RED permit 192.168.1.0/24Router(config)# !Router(config)# router bgp 50000Router(config-router)# network 10.108.0.0Router(config-router)# distribute-list prefix RED inRouter(config-router)# endRouter# clear ip bgp inIn the following example, an access list and a distribute list are defined to configure the BGP routing process to accept traffic from only network 192.168.1.0 and network 10.108.0.0. An inbound route refresh is initiated to activate the distribute-list.
Router(config)# access-list 1 permit 192.168.1.0Router(config)# access-list 1 permit 10.108.0.0Router(config)# access-list 1 deny 0.0.0.0 255.255.255.255Router(config)# !Router(config)# router bgp 50000Router(config-router)# network 10.108.0.0Router(config-router)# distribute-list 1 inRouter(config-router)# endRouter# clear ip bgp inRelated Commands
distribute-list in (IP)
To filter networks received in updates, use the distribute-list in command in router configuration mode. To change or cancel the filter, use the no form of this command.
distribute-list [access-list-number | name] | [route-map map-tag] in [interface-type | interface-number]
no distribute-list [access-list-number | name] | [route-map map-tag] in [interface-type | interface-number]
Syntax Description
Defaults
This command is disabled by default.
Command Modes
Address family configuration
Router configurationCommand History
Usage Guidelines
This command must specify either an access list or a map-tag name of a route map. The route map is supported for OSPF filtering only.
The interface-type and interface-number arguments cannot be used in address family configuration mode.
OSPF routes cannot be filtered from entering the OSPF database. If you use this command for OSPF, it only filters routes from the routing table; it does not prevent link-state packets from being propagated.
If a route map is specified, the route map can be based on the following match options:
•
•
•
•
•
•
•
Configure the route map before specifying it in the distribute-list in command.
Examples
In the following example, the EIGRP routing process accepts only two networks—network 0.0.0.0 and network 10.108.0.0:
access-list 1 permit 0.0.0.0access-list 1 permit 10.108.0.0access-list 1 deny 0.0.0.0 255.255.255.255router eigrpnetwork 10.108.0.0distribute-list 1 inIn the following example, OSPF external LSAs have a tag. The value of the tag is examined before the prefix is installed in the routing table. All OSPF external prefixes that have the tag value of 777 are filtered (prevented from being installed in the routing table). The permit statement with sequence number 20 has no match conditions, and there are no other route-map statements after sequence number 20, so all other conditions are permitted.
route-map tag-filter deny 10match tag 777route-map tag-filter permit 20!router ospf 1router-id 10.0.0.2log-adjacency-changesnetwork 172.16.2.1 0.0.0.255 area 0distribute-list route-map tag-filter inRelated Commands
distribute-list out (BGP)
To suppress networks from being advertised in outbound Border Gateway Protocol (BGP) updates, use the distribute-list out command in router configuration mode. To delete the distribute list and remove it from the running configuration file, use the no form of this command.
distribute-list acl-number | prefix list-name out [protocol process-number | connected | static]
no distribute-list acl-number | prefix list-name out [protocol process-number | connected | static]
Syntax Description
Note
Defaults
If this command is configured without a predefined access list, the distribute list will default to permitting all traffic.
Command Modes
Router configuration
Command History
10.0
This command was introduced.
11.2
The acl-number argument was added.
12.0
The prefix list-name argument was added.
Usage Guidelines
The distribute-list out command is used to filter outbound BGP updates. An access list must be defined prior to configuration of this command. In addition to access lists, prefix list can be used to filter based upon the prefix length, making it possible to filter either on the prefix list, the gateway, or both for incoming updates. The session must be reset with the clear ip bgp command before the distribute list will take effect. To filter routes that are received in inbound updates, use the distribute-list in command.
Entering a protocol and/or process-number arguments causes the distribute list to be applied to only routes derived from the specified routing process. Addresses not specified in the distribute-list command will not be advertised in outgoing routing updates after a distribute list is configured.
Note
Note
Examples
In the following example, an access list and a distribute list are defined to configure the BGP routing process to advertise only network 192.168.0.0. An outbound route refresh is initiated to activate the distribute-list.
Router(config)# access-list 1 permit 192.168.0.0 0.0.255.255Router(config)# access-list 1 deny 0.0.0.0 255.255.255.255Router(config)# !Router(config)# router bgp 50000Router(config-router)# distribute-list 1 outRouter(config-router)# endRouter# clear ip bgp outRelated Commands
distribute-list out (IP)
To suppress networks from being advertised in updates, use the distribute-list out command in router configuration mode. To cancel this function, use the no form of this command.
distribute-list {access-list-number | access-list-name} out [interface-name | routing-process | as-number]
no distribute-list {access-list-number | access-list-name} out [interface-name | routing-process | as-number]
Syntax Description
Defaults
This command is disabled by default.
Command Modes
Address family configuration
Router configurationCommand History
10.0
This command was introduced.
11.2
The access-list-name argument was added.
12.0(7)T
Address family configuration mode was added.
Usage Guidelines
When networks are redistributed, a routing process name can be specified as an optional trailing argument to the distribute-list command. Specifying this option causes the access list to be applied to only those routes derived from the specified routing process. After the process-specific access list is applied, any access list specified by a distribute-list command without a process name argument will be applied. Addresses not specified in the distribute-list command will not be advertised in outgoing routing updates.
The interface-name argument cannot be used in address family configuration mode.
Note
Examples
The following example would cause only one network to be advertised by a RIP routing process, network 10.108.0.0:
access-list 1 permit 10.108.0.0access-list 1 deny 0.0.0.0 255.255.255.255router ripnetwork 10.108.0.0distribute-list 1 outThe following example applies access list 1 to outgoing routing updates and enables Enhanced Interior Gateway Routing Protocol (EIGRP) on Ethernet interface 0. Only network 10.10.101.0 will be advertised in outgoing EIGRP routing updates.
router isisredistribute ospf 109distribute-list 1 outinterface Ethernet 0ip router eigrp 100access-list 1 permit 10.10.101.0 0.0.0.255Related Commands
domain-password
To configure the IS-IS routing domain authentication password, use the domain-password command in router configuration mode. To disable a password, use the no form of this command.
domain-password password [authenticate snp {validate | send-only}]
no domain-password [password]
Syntax Description
Defaults
No domain password is specified and no authentication is enabled for exchange of Level 2 routing information.
Command Modes
Router configuration
Command History
10.0
This command was introduced.
12.0(21)ST
The authenticate snp, validate, and send-only keywords were added.
Usage Guidelines
This password is exchanged as plain text and thus this feature provides only limited security.
This password is inserted in Level 2 (area router level) PDU link-state packets (LSPs), complete sequence number PDUs (CSNPs), and partial sequence number PDUs (PSNPs).
If you do not specify the authenticate snp keyword along with either the validate or send-only keyword, then the IS-IS routing protocol does not insert the password into SNPs.
Examples
The following example assigns an authentication password to the routing domain and specifies that the password be inserted in SNPs and checked in SNPs that the system receives:
router isisdomain-password users2j45 authenticate snp validateRelated Commands
area-password
Configures the IS-IS area authentication password.
isis password
Configures the authentication password for an interface.
domain-tag
To set the Open Shortest Path First (OSPF) domain tag value for Type-5 or Type-7 link-state advertisements (LSAs) when OSPF is used as a protocol between a provider edge (PE) router and customer edge (CE) router, use the domain-tag command in router configuration mode. To reinstate the default tag value, use the no form of this command.
domain-tag tag-value
no domain-tag tag-value
Syntax Description
Defaults
The default value is calculated based on the BGP autonomous system number of the MPLS VPN backbone. The four highest bits are set to 1101 according to RFC 1745. The lowest 16 bits map the BGP autonomous system number of the MPLS VPN backbone.
Command Modes
Router configuration
Command History
Usage Guidelines
When OSPF is used between a PE router and a CE router, BGP routes that come from the MPLS backbone are redistributed to OSPF. These redistributed routes can be announced in Type-3, Type-5, or Type-7 LSAs. If the redistribution of the BGP routes results in Type-5 or Type-7 LSAs, the External Route Tag will be set to the value of the tag. If another PE router receives a Type-5 or Type-7 LSA with an External Route Tag equal to the set tag value, it will ignore the LSA, therefore preventing the redistributed routes that originated from the MPLS backbone from returning via some other location on the MPLS backbone.
Examples
The following example configures the tag value 777:
Router(config)# router ospf 10 vrf grcRouter(config-router)# domain-tag 777The show ip ospf database command is entered to verify that the tag value 777 has been applied to the External Route Tag:
Router# show ospf database external 192.168.50.1OSPF Router with ID (192.168.239.66) (Process ID 10)Type-5 AS External Link StatesLS age: 18Options: (No TOS-capability, DC)S Type: AS External LinkLink State ID: 192.168.238.1 (External Network Number )Advertising Router: 192.168.239.66LS Seq Number: 80000002Checksum: 0xDAB0Length: 36Network Mask: /32Metric Type: 2 (Larger than any link state path)TOS: 0Metric: 1Forward Address: 0.0.0.0External Route Tag: 777...OSPF Router with ID (198.168.237.56) (Process ID 1)Related Commands
show ospf database
Displays lists of information related to the OSPF database for a specific router.
eigrp log-neighbor-changes
To enable the logging of changes in Enhanced Interior Gateway Routing Protocol (EIGRP) neighbor adjacencies, use the eigrp log-neighbor-changes command in router configuration mode. To disable the logging of changes in EIGRP neighbor adjacencies, use the no form of this command.
eigrp log-neighbor-changes
no eigrp log-neighbor-changes
Syntax Description
This command has no arguments or keywords.
Defaults
Adjacency changes are logged.
Command Modes
Router configuration
Command History
Usage Guidelines
This command enables the logging of neighbor adjacency changes to monitor the stability of the routing system and to help detect problems. Logging is enabled by default. To disable the logging of neighbor adjacency changes, use the no form of this command.
Examples
The following configuration disables logging of neighbor changes for EIGRP process 209:
router eigrp 209no eigrp log-neighbor-changesThe following configuration enables logging of neighbor changes for EIGRP process 209:
router eigrp 209eigrp log-neighbor-changeseigrp log-neighbor-warnings
To enable the logging of Enhanced Interior Gateway Routing Protocol (EIGRP)) neighbor warning messages, use the eigrp log-neighbor-warnings command in router configuration mode. To disable the logging of EIGRP neighbor warning messages, use the no form of this command.
eigrp log-neighbor-warnings [seconds]
no eigrp log-neighbor-warnings
Syntax Description
seconds
(Optional) The time interval (in seconds) between repeated neighbor warning messages. The range of seconds is from 1 to 65535.
Defaults
Neighbor warning messages are logged.
Command Modes
Router configuration
Command History
Usage Guidelines
When neighbor warning messages occur, they are logged by default. With this command, you can disable and enable neighbor warning messages, and configure the interval between repeated neighbor warning messages.
Examples
The following command will log neighbor warning messages for EIGRP process 209 and repeat the warning messages in 5-minute (300 seconds) intervals:
router eigrp 209eigrp log-neighbor-warnings 300eigrp router-id
To set the router ID used by Enhanced Interior Gateway Routing Protocol (EIGRP) when communicating with its neighbors, use the eigrp router-id command in router configuration mode. To remove the configured router ID, use the no form of this command.
eigrp router-id ip-address
no eigrp router-id ip-address
Syntax Description
Defaults
EIGRP automatically selects an IP address to use as the router ID when an EIGRP process is started. The highest local IP address is selected and loopback interfaces are preferred. The router ID is not changed unless the EIGRP process is removed with the no router eigrp command or if the router ID is manually configured with the eigrp router-id command.
Command Modes
Address family configuration
Router configurationCommand History
Usage Guidelines
The router ID is used to identify the originating router for external routes. If an external route is received with the local router ID, the route is discarded. The router ID can be configured with any IP address with two exceptions; 0.0.0.0 and 255.255.255.255 are not legal values and cannot be entered. A unique value should be configured for each router.
Examples
The following command will set a fixed router ID:
router eigrp 209eigrp router-id 172.16.1.3eigrp stub
To configure a router as a stub using Enhanced Interior Gateway Routing Protocol (EIGRP), use the eigrp stub command in router configuration mode. To disable the EIGRP stub routing feature, use the no form of this command.
eigrp stub [receive-only | connected | static | summary | redestributed]
no eigrp stub [receive-only | connected | static | summary | redistributed]
Syntax Description
Defaults
Stub routing is not enabled by default.
Command Modes
Router configuration
Command History
12.0(7)T
This command was introduced.
12.0(15)S
This command was integrated into Cisco IOS Release 12.0(15)S.
12.2
Keyword redistributed was added.
Usage Guidelines
Use the eigrp stub command to configure a router as a stub where the router directs all IP traffic to a distribution router.
The eigrp stub command can be modified with several options, and these options can be used in any combination except for the receive-only keyword. The receive-only keyword will restrict the router from sharing any of its routes with any other router in that EIGRP autonomous system, and the receive-only keyword will not permit any other option to be specified because it prevents any type of route from being sent. The four other optional keywords (connected, static, summary, and redistributed) can be used in any combination but cannot be used with the receive-only keyword.
If any of these four keywords is used with the eigrp stub command, only the route types specified by the particular keyword(s) will be sent. Route types specified by the non-used keyword(s) will not be sent.
The connected keyword permits the EIGRP Stub Routing feature to send connected routes. If the connected routes are not covered by a network statement, it may be necessary to redistribute connected routes with the redistribute connected command under the EIGRP process. This option is enabled by default.
The static keyword permits the EIGRP Stub Routing feature to send static routes. Without the configuration of this option, EIGRP will not send any static routes, including internal static routes that normally would be automatically redistributed. It will still be necessary to redistribute static routes with the redistribute static command.
The summary keyword permits the EIGRP Stub Routing feature to send summary routes. Summary routes can be created manually with the summary address command or automatically at a major network border router with the auto-summary command enabled. This option is enabled by default.
The redistributed keyword permits the EIGRP Stub Routing feature to send other routing protocols and autonomous systems. Without the configuration of this option, EIGRP will not advertise redistributed routes.
Note
Examples
In the following example, the eigrp stub command is used to configure the router as a stub that advertises connected and summary routes:
router eigrp 1network 10.0.0.0eigrp stubIn the following example, the eigrp stub command is issued with the connected and static keywords to configure the router as a stub that advertises connected and static routes (sending summary routes will not be permitted):
router eigrp 1network 10.0.0.0eigrp stub connected staticIn the following example, the eigrp stub command is issued with the receive-only keyword to configure the router as a receive-only neighbor (connected, summary, and static routes will not be sent):
router eigrp 1network 10.0.0.0 eigrpeigrp stub receive-onlyIn the following example, the eigrp stub command is issued with the redistributed keyword to configure the router to advertize other protocols and autonomous systems:
router eigrp 1network 10.0.0.0 eigrpeigrp stub redistributedexit-address-family
To exit from address family configuration mode, use the exit-address-family command in address family configuration mode.
exit-address-family
Syntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values
Command Modes
Address family configuration
Command History
12.0(5)T
This command was introduced.
12.0(22)S
EIGRP support was added.
12.2(15)T
EIGRP support was added.
Usage Guidelines
This command can be abbreviated to exit.
Examples
The following example shows how to exit address family configuration mode:
(config-router-af)# exit-address-familyRelated Commands
export map
To configure an export route map for a VRF, use the export map command in VRF configuration mode.
export map route-map
Syntax Description
Defaults
This command has no default behavior.
Command Modes
VRF configuration mode
Command History
Usage Guidelines
Use an export route map when an application requires finer control over the routes that are exported out of a VRF than the control that is provided by import and export extended communities configured for the importing and exporting VRFs.
The export map command associates a route map with the specified VRF. You can use a route map to filter routes that are eligible for export out of a VRF, based on the route target extended community attributes of the route.
Only one export route map per VRF is supported.
Examples
The following example shows how to configure an export route map for a VRF:
Router(config)# ip vrf vrf_redRouter(config-vrf)# export map blue_export_mapRelated Commands
flash-update-threshold
To suppress regularly scheduled flash updates, use the flash-update-threshold command in router configuration mode. To return to the default state, use the no form of this command.
flash-update-threshold seconds
no flash-update-threshold
Syntax Description
seconds
The time interval in seconds for which the suppression of flash updates can be configured. The range is from 1 to 30 seconds.
Defaults
This command is disabled by default.
Command Modes
Router configuration
Command History
Usage Guidelines
This command suppresses flash updates when the arrival of a regularly scheduled update matches the number of seconds that is configured with the seconds argument. The range of seconds that can be configure is from 0 to 30 seconds. If the number of seconds matches the number of seconds or is less than the number seconds that is configured with the seconds argument, the flash update is suppressed. If the numbers seconds until the flash update arrives exceeds the number of seconds that is configured with the seconds argument, the flash update is not suppressed. The regular scheduled interval for flash updates and the configuration of the suppression of flash updates can be verified with the show ip protocol command.
Examples
The following example configures a router to suppress a regularly scheduled flash update if the update is due in 10 seconds or less:
router ripflash-update-threshold 10Related Commands
show ip protocols
Displays the parameters and current state of the active routing protocol process.
hello padding
To reenable IS-IS hello padding at the router level, enter the hello padding command in router configuration mode. To disable IS-IS hello padding, use the no form of this command.
hello padding
no hello padding
Syntax Description
This command has no arguments or keywords.
Defaults
IS-IS hello padding is enabled.
Command Modes
Router configuration
Command History
12.0(5)T
This command was introduced.
12.0(5)S
This command was integrated into Cisco IOS Release 12.0(5)S.
Usage Guidelines
Intermediate System-to-Intermediate System (IS-IS) hellos are padded to the full maximum transmission unit (MTU) size. The benefit of padding IS-IS hellos to the full MTU is that it allows for early detection of errors that result from transmission problems with large frames or errors that result from mismatched MTUs on adjacent interfaces.
You can disable hello padding in order to avoid wasting network bandwidth in case the MTU of both interfaces is the same or, in case of translational bridging. While hello padding is disabled, Cisco routers still send the first five IS-IS hellos padded to the full MTU size, in order to maintain the benefits of discovering MTU mismatches.
To disable hello padding for all interfaces on a router for the IS-IS routing process, enter the no hello padding command in router configuration mode. To selectively disable hello padding for a specific interface, enter the no isis hello padding command in interface configuration mode.
Examples
In the following example the no hello padding command is used to turn off hello padding at the router level:
Router(config)# router isisRouter(config-router)# no hello paddingRouter(config-router)# endThe show clns interfaces command is entered to show that hello padding has been turned off at router level:
Router# show clns interface e0/0Ethernet0/0 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 4 secondsRouting Protocol: IS-ISCircuit Type: level-1-2Interface number 0x0, local circuit ID 0x1Level-1 Metric: 10, Priority: 64, Circuit ID: Router_B.01Level-1 IPv6 Metric: 10Number of active level-1 adjacencies: 1Level-2 Metric: 10, Priority: 64, Circuit ID: Router_B.01Level-2 IPv6 Metric: 10Number of active level-2 adjacencies: 1Next IS-IS LAN Level-1 Hello in 6 seconds! No hello paddingNext IS-IS LAN Level-2 Hello in 2 seconds! No hello paddingWhen the debug isis adj packets command is entered, the output will show the IS-IS hello protocol data unit (PDU) length when a hello packet has been sent to or received from an IS-IS adjacency. In the following example the IS-IS hello PDU length is 1497:
Router# debug isis adj packets e0/0IS-IS Adjacency related packets debugging is onRouter_A#*Oct 11 18:04:17.455: ISIS-Adj: Sending L1 LAN IIH on Ethernet0/0, length 55*Oct 11 18:04:19.075: ISIS-Adj: Rec L2 IIH from aabb.cc00.6600 (Ethernet0/0), cir type L1L2, cir id 0000.0000.000B.01, length 1497Related Commands
hostname dynamic
To enable IS-IS dynamic hostname capability on the router, use the hostname dynamic command in router configuration mode. To disable the dynamic hostname feature, use the no form of this command.
hostname dynamic
no hostname dynamic
Syntax Description
This command has no arguments or keywords.
Command Default
The dynamic hostname feature is enabled by default.
Command Modes
Router configuration
Command History
12.0
This command was introduced.
12.0S
This command was integrated into Cisco IOS Release 12.0(S).
Usage Guidelines
In the IS-IS routing domain, the system ID is used to represent each router. The system ID is part of the network entity title (NET) that is configured for each IS-IS router. For example, a router with a configured NET of 49.0001.0023.0003.000a.00 has a system ID of 0023.0003.000a. Router-name-to-system-ID mapping is difficult for network administrators to remember during maintenance and troubleshooting on the routers. Entering the show isis hostname command displays the entries in the system-ID-to-router-name mapping table.
The dynamic hostname mechanism uses link-state protocol (LSP) flooding to distribute the router-name-to-system-ID mapping information across the entire network. Every router on the network will try to install the system ID-to-router name mapping information in its routing table.
If a router that has been advertising the dynamic name type, length, value (TLV) on the network suddenly stops the advertisement, the mapping information last received will remain in the dynamic host mapping table for up to one hour, allowing the network administrator to display the entries in the mapping entry during a time when the network experiences problems. Entering the show isis hostname command displays the entries in the mapping table.
Note
Examples
The following example changes the hostname from Router to RouterA and assigns the NET 49.0001.0000.0000.000b.00 to RouterA. The dynamic hostname feature is disabled by entering the no dynamic hostname command. The dynamic hostname feature is then reeanabled by entering the dynamic hostname command.
Router> enableRouter# configure terminalRouter(config)# hostname RouterARouterA(config)# router isis CompanyARouterA(config-router)# net 49.0001.0000.0000.000b.00RouterA(config-router)# hostname dynamicRouterA(config-router)# endEntering the show isis hostname command displays the dynamic host mapping table. The * symbol signifies that this is the hostname for the local router. The dynamic host mapping table confirms that system ID 0000.0000.000B belongs to a router with the dynamic hostname RouterA. This router is running the IS-IS process named CompanyA.
Router# show isis hostnameLevel System ID Dynamic Hostname (CompanyA)* 0000.0000.000B RouterARelated Commands
