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Cisco IOS IP Routing Protocols Command Reference
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Introduction
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BGP Commands: A through B
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BGP Commands: C through I
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BGP Commands: M through neighbor soo
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BGP Commands: neighbor timers through show bgp nsap summary
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BGP Commands: show ip bgp through T
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EIGRP Commands: A through I
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EIGRP Commands: M through V
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Integrated IS-IS Commands: A through I
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Integrated IS-IS Commands: L through V
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On-Demand Routing Commands
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OSPF Commands: A through ip ospf demand-circuit
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OSPF Commands: ip ospf flood-reduction through R
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OSPF Commands: show ip ospf through T
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IP Routing Protocol-Independent Commands: A through R
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IP Routing Protocol-Independent Commands: S through T
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RIP Commands
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Table Of Contents
neighbor maximum-prefix (EIGRP)
redistribute maximum-prefix (EIGRP)
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
Command Default
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
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.
Command Default
The holddown state is 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 EIGRP 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 10.0.0.0 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 tune 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.
Command Default
tos: 0
k1: 1
k2: 0
k3: 1
k4: 0
k5: 0Command 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 66 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
neighbor (EIGRP)
To define a neighboring router with which to exchange routing information on a router that is running Enhanced Interior Gateway Routing Protocol (EIGRP), use the neighbor command in router configuration mode. To remove an entry, use the no form of this command.
neighbor {ip-address | ipv6-address} interface-type interface-number
no neighbor {ip-address | ipv6-address} interface-type interface-number
Syntax Description
Command Default
No neighboring routers are defined.
Command Modes
Router configuration
Command History
Usage Guidelines
Multiple neighbor statements can be used to establish peering sessions with specific EIGRP neighbors. The interface through which EIGRP will exchange routing updates must be specified in the neighbor statement. The interfaces through which two EIGRP neighbors exchange routing updates must be configured with IP addresses from the same network.
Note
Configuring the passive-interface command suppresses all incoming and outgoing routing updates and hello messages. EIGRP neighbor adjacencies cannot be established or maintained over an interface that is configured as passive.
Examples
The following example configures EIGRP peering sessions with the 192.168.1.1 and 192.168.2.2 neighbors:
router eigrp 1network 192.168.0.0neighbor 192.168.1.1 Ethernet 0/0neighbor 192.168.2.2 Ethernet 1/1Related Commands
ipv6 router eigrp
Configures the EIGRP for IPv6 routing process.
passive-interface
Disables sending routing updates on an interface.
neighbor maximum-prefix (EIGRP)
To limit the number of prefixes that are accepted from an Enhanced Interior Gateway Protocol (EIGRP) neighbor or all EIGRP neighbors, use the neighbor maximum-prefix command in address-family IPv4 VPN Routing and Forwarding (VRF) configuration mode. To disable this function, use the no form of this command.
Single Neighbor Configuration CLI
neighbor ip-address maximum-prefix maximum [threshold] [warning-only]
no neighbor ip-address maximum-prefix
All Neighbor Configuration CLI
neighbor maximum-prefix maximum [threshold] [[dampened] [reset-time minutes] [restart minutes] [restart-count number] | [warning-only]]
no neighbor maximum-prefix
Syntax Description
Command Default
The number of prefixes that can be configured is limited only by the available system resources on the router.
Command 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 neighbor maximum-prefix command can be configured to protect an individual peering session or protect all peering sessions. When this feature is enabled and the maximum-prefix limit has been exceeded, the router will tear down the peering session, clear all routes that were learned from the peer, and then place the peer in a penalty state for the default or user-defined time period. After the penalty time period expires, normal peering will be reestablished.
Note
When configuring the neighbor maximum-prefix command to protect a single peering session, only the maximum-prefix limit, the percentage threshold, the warning-only configuration options can be configured. Session dampening, restart, and reset timers are configured on a global basis
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
Configuring the Maximum Prefix Limit for a Single Peer
The following example, starting in global configuration mode, configures the maximum prefix limit for a single peer. The maximum limit is set to 1000 prefixes, and the warning threshold is set to 80 percent. When the maximum prefix limit is exceeded for the configured neighbor, adjacency with this neighbor will be brought down and all routes learned from it will be cleared. The neighbor will be placed in a penalty state for 4 minutes (user-defined penalty value). This function will not affect the relationship with any other neighbor.
Router(config)# router eigrp 100Router(config-router)# address-family ipv4 vrf REDRouter(config-router-af)# neighbor 10.0.0.1 maximum-prefix 1000 80Router(config-router-af)# endConfiguring the Maximum Prefix Limit for all Peers
The following example, starting in global configuration mode, configures the maximum prefix limit for all peers. The maximum limit is set to 10000 prefixes, the warning threshold is set to 90 percent, the restart timer is set to 4 minutes, a decay penalty is configured for the restart timer with the dampened keyword, and all timers are configured to be reset to 0 every 60 minutes. When the maximum prefix limit is exceeded for any neighbor, adjacency with this neighbor will be brought down and all routes learned from it will be cleared. This function will not affect the relationship with any other neighbor. The offending peer will be placed in a penalty state for 4 minutes (user-defined penalty value). A dampening exponential decay penalty will also be applied.
Router(config)# router eigrp 100Router(config-router)# address-family ipv4 vrf REDRouter(config-router-af)# neighbor maximum-prefix 10000 90 dampened reset-time 60 restart4Router(config-router-af)# endRelated Commands
network (EIGRP)
To specify the network for an Enhanced Interior Gateway Routing Protocol (EIGRP) routing process, use the network command in router configuration mode. To remove an entry, use the no form of this command.
network ip-address [wildcard-mask]
no network ip-address [wildcard-mask]
Syntax Description
Command Default
No networks are specified.
Command Modes
Address family configuration
Router configurationCommand History
Usage Guidelines
When the network command is configured for an EIGRP routing process, the router matches one or more local interfaces. The network command matches only local interfaces that are configured with addresses that are within the same subnet as the address that has been configured with the network command. The router then establishes neighbors through the matched interfaces. There is no limit to the number of network statements (network commands) that can be configured on a router.
Examples
The following example configures EIGRP autonomous system 1 and establishes neighbors through network 172.16.0.0 and 192.168.0.0:
router eigrp 1network 172.16.0.0network 192.168.0.0offset-list (EIGRP)
To add an offset to incoming and outgoing metrics to routes learned via Enhanced Interior Gateway Routing Protocol (EIGRP), use the offset-list command in router configuration mode. To remove an offset list, use the no form of this command.
offset-list {access-list-number | access-list-name} {in | out} offset [interface-type interface-number]
no offset-list {access-list-number | access-list-name} {in | out} offset [interface-type interface-number]
Syntax Description
Command Default
No offset values are added to incoming or outgoing metrics to routes learned via EIGRP.
Command Modes
Router configuration
Command History
Usage Guidelines
The offset value is added to the routing metric. An offset list with an interface type and interface number is considered extended and takes precedence over an offset list that is not extended. Therefore, if an entry passes the extended offset list and the normal offset list, the offset of the extended offset list is added to the metric.
Examples
In the following example, the router applies an offset of 10 to the delay component of the router only to access list 21:
offset-list 21 out 10In the following example, the router applies an offset of 10 to routes learned from Ethernet interface 0:
offset-list 21 in 10 ethernet 0redistribute maximum-prefix (EIGRP)
To limit the number of prefixes redistributed into an Enhanced Interior Gateway Routing Protocol (EIGRP) process, use the redistribute maximum-prefix command in address-family configuration mode. To disable this function, use the no form of this command.
redistribute maximum-prefix maximum [threshold] [[dampened] [reset-time minutes] [restart minutes] [restart-count number] | [warning-only]]
no redistribute 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 redistribute maximum-prefix command is used to configure limit prefixes learned through redistribution. When the maximum-prefix limit is exceeded, all routes learned from the Routing Information Base (RIB) will be discarded and redistribution will be suspended for the default or user-defined time period. The maximum-prefix limit that can be configured for redistributed prefixes is limited only by the available system resources on the router.
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 routes learned through redistribution. The maximum limit is set to 5000 prefixes and the warning threshold is set to 95percent. When the number of prefixes learned through redistribution reaches 4750 (95 percent of 5000), warning messages will be displayed in the console. Because the warning-only keyword was configure, the topology and routing tables will not be cleared and route redistribution will not be placed in a penalty state.
Router(config)# router eigrp 100Router(config-router)# address-family ipv4 vrf REDRouter(config-router-af)# redistribute maximum-prefix 5000 95 warning-onlyRouter(config-router-af)# endRelated Commands
router eigrp
To configure the Enhanced Interior Gateway Routing Protocol (EIGRP) process, use the router eigrp command in global configuration mode. To shut down an EIGRP routing process, use the no form of this command.
router eigrp autonomous-system-number
no router eigrp autonomous-system-number
Syntax Description
autonomous-system-number
Autonomous system number that identifies the routes to the other EIGRP routers. It is also used to tag the routing information.
Command Default
No EIGRP processes are configured.
Command Modes
Global configuration
Command History
Examples
The following example configures EIGRP process 109:
router eigrp 109Related Commands
set metric (EIGRP)
To set the metric value for Enhanced Interior Gateway Routing Protocol (EIGRP) in a route map, use the set metric route-map configuration command. To return to the default metric value, use the no form of this command.
set metric bandwidth delay reliability loading mtu
no set metric bandwidth delay reliability loading mtu
Syntax Description
Defaults
No metric will be set in the route map.
Command Modes
Route-map configuration
Command History
Usage Guidelines
We recommend you consult your Cisco technical support representative before changing the default value.
Use the route-map global configuration command, and the match and set route-map configuration commands, to define the conditions for redistributing routes from one routing protocol into another. Each route-map command has a list of match and set commands associated with it. The match commands specify the match criteria—the conditions under which redistribution is allowed for the current route-map command. The set commands specify the set actions—the particular redistribution actions to perform if the criteria enforced by the match commands are met. The no route-map command deletes the route map.
The set route-map configuration commands specify the redistribution set actions to be performed when all of the match criteria for a router are met. When all match criteria are met, all set actions are performed.
Examples
The following example sets the bandwidth to 10,000, the delay to 10, the reliability to 255, the loading to 1, and the MTU to 1500:
set metric 10000 10 255 1 1500show ip eigrp accounting
To display prefix accounting information for Enhanced Interior Gateway Routing Protocol (EIGRP) processes, use the show ip eigrp accounting command in privileged EXEC mode.
show ip eigrp accounting [autonomous-system-number]
Syntax Description
Command Modes
Privileged EXEC
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.
Examples
The following is sample output from the show ip eigrp accounting command:
Router# show ip eigrp accountingIP-EIGRP accounting for AS(100)/ID(10.0.2.1) Routing Table: REDTotal Prefix Count: 4 States: A-Adjacency, P-Pending, D-DownState Address/Source Interface Prefix Restart Restart/Count Count Reset(s)P Redistributed ---- 0 3 211A 10.0.1.2 Et0/0 2 0 84P 10.0.2.4 Se2/0 0 2 114D 10.0.1.3 Et0/0 0 3 0
Note
Table 67 describes the significant fields shown in the display.
show ip eigrp interfaces
To display information about interfaces configured for Enhanced Interior Gateway Routing Protocol (EIGRP), use the show ip eigrp interfaces command in privileged EXEC mode.
show ip eigrp interfaces [type number] [as-number] [detail]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Use the show ip eigrp interfaces command to determine on which interfaces EIGRP is active and to learn information about EIGRP relating to those interfaces.
If an interface is specified, only information about that interface is displayed. Otherwise, information about all interfaces on which EIGRP is running is displayed.
If an autonomous system is specified, only the routing process for the specified autonomous system is displayed. Otherwise, all EIGRP processes are displayed.
Examples
The following is sample output from the show ip eigrp interfaces command:
Router# show ip eigrp interfacesIP EIGRP interfaces for process 109Xmit Queue Mean Pacing Time Multicast PendingInterface Peers Un/Reliable SRTT Un/Reliable Flow Timer RoutesDi0 0 0/0 0 11/434 0 0Et0 1 0/0 337 0/10 0 0SE0:1.16 1 0/0 10 1/63 103 0Tu0 1 0/0 330 0/16 0 0Cisco IOS Release 12.2(18)SXE
The following is sample output from the show ip eigrp interfaces command to verify that the BFD feature has been enabled on the EIGRP interfaces for process 123. The relevant command output is shown in bold in the output.
Router# show ip eigrp interfaces detailIP-EIGRP interfaces for process 123Xmit Queue Mean Pacing Time Multicast PendingInterface Peers Un/Reliable SRTT Un/Reliable Flow Timer RoutesIP-EIGRP interfaces for process 123Xmit Queue Mean Pacing Time Multicast PendingInterface Peers Un/Reliable SRTT Un/Reliable Flow Timer RoutesFa0/1 0 0/0 0 0/10 0 0Next xmit serial <none>Un/reliable mcasts: 0/0 Un/reliable ucasts: 0/0Mcast exceptions: 0 CR packets: 0 ACKs suppressed: 0Retransmissions sent: 0 Out-of-sequence rcvd: 0Authentication mode is not setBFD is enabledEt3/0 0 0/0 0 0/10 0 0Next xmit serial <none>Un/reliable mcasts: 0/0 Un/reliable ucasts: 0/0Mcast exceptions: 0 CR packets: 0 ACKs suppressed: 0Retransmissions sent: 0 Out-of-sequence rcvd: 0Authentication mode is not setBFD is enabled
