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This chapter describes how to configure the Enhanced Interior Gateway Routing Protocol (EIGRP) on the Cisco NX-OS device.
This chapter includes the following sections:
•Licensing Requirements for EIGRP
•Configuration Guidelines and Limitations
•Configuring Virtualization for EIGRP
•Verifying EIGRP Configuration
EIGRP combines the benefits of distance vector protocols with the features of link-state protocols. EIGRP sends out periodic Hello messages for neighbor discovery. Once EIGRP learns a new neighbor, it sends a one-time update of all the local EIGRP routes and route metrics. The receiving EIGRP router calculates the route distance based on the received metrics and the locally assigned cost of the link to that neighbor. After this initial full route table update, EIGRP sends incremental updates to only those neighbors affected by the route change. This process speeds convergence and minimizes the bandwidth used by EIGRP.
This section includes the following topics:
EIGRP has the following basic components:
•Neighbor Discovery and Recovery
The Reliable Transport Protocol guarantees ordered delivery of EIGRP packets to all neighbors. (See the "Neighbor Discovery and Recovery" section.) The Reliable Transport Protocol supports an intermixed transmission of multicast and unicast packets. The reliable transport can send multicast packets quickly when unacknowledged packets are pending. This provision helps to ensure that the convergence time remains low for various speed links. See the "Configuring Advanced EIGRP" section for details about modifying the default timers that control the multicast and unicast packet transmissions.
The Reliable Transport Protocol includes the following message types:
•Hello—Used for neighbor discovery and recovery. By default, EIGRP sends a periodic multicast Hello message on the local network at the configured hello interval. By default, the hello interval is 5 seconds.
•Acknowledgement—Verify reliable reception of Updates, Queries, and Replies.
•Updates—Send to affected neighbors when routing information changes. Updates include the route destination, address mask, and route metrics such as delay and bandwidth. The update information is stored in the EIGRP topology table.
•Queries and Replies—Sent as necessary as part of the Diffusing Update Algorithm used by EIGRP.
EIGRP uses the Hello messages from the Reliable Transport Protocol to discover neighboring EIGRP routers on directly attached networks. EIGRP adds neighbors to the neighbor table. The information in the neighbor table includes the neighbor address, the interface it was learned on, and the hold time, which indicates how long EIGRP should wait before declaring a neighbor unreachable. By default, the hold time is three times the hello interval or 15 seconds.
EIGRP sends a series of Update messages to new neighbors to share the local EIGRP routing information. This route information is stored in the EIGRP topology table. After this initial transmission of the full EIGRP route information, EIGRP sends Update messages only when a routing change occurs. These Update messages contain only the new or changed information and are sent only to the neighbors affected by the change. See the "EIGRP Route Updates" section.
EIGRP also uses the Hello messages as a keepalive to its neighbors. As long as Hello messages are received, Cisco NX-OS can determine that a neighbor is alive and functioning.
The Diffusing Update Algorithm (DUAL) calculates the routing information based on the destination networks in the topology table. The topology table includes the following information:
•IPv4 or IPv6 address/mask—The network address and network mask for this destination.
•Successors—The IP address and local interface connection for all feasible successors or neighbors that advertise a shorter distance to the destination than the current feasible distance.
•Feasibility distance (FD)—The lowest calculated distance to the destination. The feasibility distance is the sum of the advertised distance from a neighbor plus the cost of the link to that neighbor.
DUAL uses the distance metric to select efficient, loop-free paths. DUAL selects routes to insert into the unicast Routing Information Base (RIB) based on feasible successors. When a topology change occurs, DUAL looks for feasible successors in the topology table. If there are feasible successors, DUAL selects the feasible successor with the lowest feasible distance and inserts that into the unicast RIB, avoiding unnecessary recomputation.
When there are no feasible successors but there are neighbors advertising the destination, DUAL transitions from the passive state to the active state and triggers a recomputation to determine a new successor or next-hop router to the destination. The amount of time required to recompute the route affects the convergence time. EIGRP sends Query messages to all neighbors, searching for feasible successors. Neighbors that have a feasible successor send a Reply message with that information. Neighbors that do not have feasible successors trigger a DUAL recomputation.
When a topology change occurs, EIGRP sends an Update message with only the changed routing information to affected neighbors. This Update message includes the distance information to the new or updated network destination.
The distance information in EIGRP is represented as a composite of available route metrics, including bandwidth, delay, load utilization, and link reliability. Each metric has an associated weight that determines if the metric is included in the distance calculation. You can configure these metric weights. You can fine-tune link characteristics to achieve optimal paths, but we recommend that you use the default settings for most configurable metrics.
This section includes the following topics:
Internal routes are routes that occur between neighbors within the same EIGRP autonomous system. These routes have the following metrics:
•Next hop—The IP address of the next-hop router.
•Delay—The sum of the delays configured on the interfaces that make up the route to the destination network. Configured in tens of microseconds.
•Bandwidth—The calculation from the lowest configured bandwidth on an interface that is part of the route to the destination.
Note We recommend that you use the default bandwidth value. This bandwidth parameter is also used by EIGRP.
•MTU—The smallest maximum transmission unit value along the route to the destination.
•Hop count—The number of hops or routers that the route passes through to the destination. This metric is not directly used in the DUAL computation.
•Reliability—An indication of the reliability of the links to the destination.
•Load—An indication of how much traffic is on the links to the destination.
By default, EIGRP uses the bandwidth and delay metrics to calculate the distance to the destination. You can modify the metric weights to include the other metrics in the calculation.
External routes are routes that occur between neighbors in different EIGRP autonomous systems. These routes have the following metrics:
•Next hop—The IP address of the next-hop router.
•Router ID—The router ID of the router that redistributed this route into EIGRP.
•AS Number—The autonomous system number of the destination.
•Protocol ID—A code that represents the routing protocol that learned the destination route.
•Tag—An arbitrary tag that can be used for route maps.
•Metric—The route metric for this route from the external routing protocol.
EIGRP adds all learned routes to the EIGRP topology table and the unicast RIB. When a topology change occurs, EIGRP uses these routes to search for a feasible successor. EIGRP also listens for notifications from the unicast RIB for changes in any routes redistributed to EIGRP from another routing protocol.
You can use the advanced features of EIGRP to optimize your EIGRP configuration.
This section includes the following topics:
•Graceful Restart and High Availability
EIGRP supports both IPv4 and IPv6 address families. For backward compatibility, you can configure EIGRPv4 in route configuration mode or in IPV4 address family mode. You must configure EIGRP for IPv6 in address family mode.
Address family configuration mode includes the following EIGRP features:
•Authentication
•AS number
•Default route
•Metrics
•Distance
•Graceful restart
•Logging
•Load balancing
•Redistribution
•Router ID
•Stub router
•Timers
You cannot configure the same feature in more than one configuration mode. For example, if you configure the default metric in router configuration mode, you cannot configure the default metric in address family mode.
You can configure authentication on EIGRP messages to prevent unauthorized or invalid routing updates in your network. EIGRP authentication supports MD5 authentication digest.
You can configure the EIGRP authentication per virtual routing and forwarding (VRF) instance or interface using key-chain management for the authentication keys. Key-chain management allows you to control changes to the authentication keys used by MD5 authentication digest. See the Cisco Nexus 7000 Series NX-OS Security Configuration Guide, Release 4.x, for more details about creating key-chains.
For MD5 authentication, you configure a password that is shared at the local router and all remote EIGRP neighbors. When an EIGRP message is created, Cisco NX-OS creates an MD5 one-way message digest based on the message itself and the encrypted password and sends this digest along with the EIGRP message. The receiving EIGRP neighbor validates the digest using the same encrypted password. If the message has not changed, the calculation is identical and the EIGRP message is considered valid.
MD5 authentication also includes a sequence number with each EIGRP message that is used to ensure that no message is replayed in the network.
You can use the EIGRP stub routing feature to improve network stability, reduce resource usage, and simplify stub router configuration. Stub routers connect to the EIGRP network through a remote router. See the "Stub Routing" section on page 1-7.
When using EIGRP stub routing, you need to configure the distribution and remote routers to use EIGRP and configure only the remote router as a stub. EIGRP stub routing does not automatically enable summarization on the distribution router. In most cases, you need to configure summarization on the distribution routers.
Without EIGRP stub routing, even after the routes that are sent from the distribution router to the remote router have been filtered or summarized, a problem might occur. For example, if a route is lost somewhere in the corporate network, EIGRP could send a query to the distribution router. The distribution router could then send a query to the remote router even if routes are summarized. If a problem communicating over the WAN link between the distribution router and the remote router occurs, EIGRP could get stuck in active condition and cause instability elsewhere in the network. EIGRP stub routing allows you to prevent queries to the remote router.
You can configure a summary aggregate address for a specified interface. Route summarization simplifies route tables by replacing a number of more-specific addresses with an address that represents all the specific addresses. For example, you can replace 10.1.1.0/24, 10.1.2.0/24, and 10.1.3.0/24 with one summary address, 10.1.0.0/16.
If more specific routes are in the routing table, EIGRP advertises the summary address from the interface with a metric equal to the minimum metric of the more specific routes.
Note EIGRP does not support automatic route summarization.
You can use EIGRP to redistribute direct routes, static routes, routes learned by other EIGRP autonomous systems, or routes from other protocols. You must configure a route map with the redistribution to control which routes are passed into EIGRP. A route map allows you to filter routes based on attributes such as the destination, origination protocol, route type, route tag, and so on. See Chapter 16, "Configuring Route Policy Manager."
You also configure the default metric that is used for all imported routes into EIGRP.
You use distribute lists to filter routes from routing updates. These filtered routes are applied to each interface with the ip distribute-list eigrp command.
You can use load balancing to allow a router to distribute traffic over all the router network ports that are the same distance from the destination address. Load balancing increases the utilization of network segments which increases effective network bandwidth.
Cisco NX-OS supports the Equal Cost Multiple Paths (ECMP) feature with up to 16 equal-cost paths in the EIGRP route table and the unicast RIB. You can configure EIGRP to load balance traffic across some or all of those paths.
Note EIGRP in Cisco NX-OS does not support unequal cost load balancing.
You can use split horizon to ensure that EIGRP never advertises a route out of the interface where it was learned.
Split horizon is a method that controls the sending of EIGRP update and query packets. When you enable split horizon on an interface, Cisco NX-OS does not send update and query packets for destinations that were learned from this interface. Controlling update and query packets in this manner reduces the possibility of routing loops.
Split horizon with poison reverse configures EIGRP to advertise a learned route as unreachable back through that the interface that EIGRP learned the route from.
EIGRP uses split horizon or split horizon with poison reverse in the following scenarios:
•Exchanging topology tables for the first time between two routers in startup mode.
•Advertising a topology table change.
•Sending a Query message.
By default, the split horizon feature is enabled on all interfaces.
Cisco NX-OS supports multiple instances of the EIGRP protocol that runs on the same system. EIGRP supports Virtual Routing and Forwarding instances (VRFs). VRFs exist within virtual device contexts (VDCs). By default, Cisco NX-OS places you in the default VDC and default VRF unless you specifically configure another VDC and VRF. See the Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide, Release 4.x and Chapter 14, "Configuring Layer 3 Virtualization."
By default, every instance uses the same system router ID. You can optionally configure a unique router ID for each instance.
Cisco NX-OS supports nonstop forwarding and graceful restart for EIGRP.
You can use nonstop forwarding for EIGRP to forward data packets along known routes in the FIB while the EIGRP routing protocol information is being restored following a failover. With NSF, peer networking devices do not experience routing flaps. During failover, data traffic is forwarded through intelligent modules while the standby supervisor becomes active.
If a Cisco NX-OS system experiences a cold reboot, network does not forward traffic to the system and removes the system from the network topology. In this scenario, EIGRP experiences a stateless restart, and all neighbors are removed. Cisco NX-OS applies the startup configuration, and EIGRP rediscovers the neighbors and shares the full EIGRP routing information again.
A dual supervisor platform that runs Cisco NX-OS can experience a stateful supervisor switchover. Before the switchover occurs, EIGRP uses a graceful restart to announce that EIGRP will be unavailable for some time. During a switchover, EIGRP uses nonstop forwarding to continue forwarding traffic based on the information in the FIB, and the system is not taken out of the network topology.
The graceful restart-capable router uses Hello messages to notify its neighbors that an graceful restart operation has started. When an graceful restart-aware router receives a notification from a graceful restart-capable neighbor that a graceful restart operation is in progress, both routers immediately exchange their topology tables. The graceful restart-aware router then performs the following actions to assist the restarting router:
•The router expires the EIGRP Hello hold timer to reduce the time interval set for Hello messages. This allows the graceful restart-aware router to reply to the restarting router more quickly and reduces the amount of time required for the restarting router to rediscover neighbors and rebuild the topology table.
•The router starts the route-hold timer. This timer sets the period of time that the graceful restart-aware router will hold known routes for the restarting neighbor. The default time period is 240 seconds.
•The router notes in the peer list that the neighbor is restarting, maintains adjacency, and holds known routes for the restarting neighbor until the neighbor signals that it is ready for the graceful restart-aware router to send its topology table or the route-hold timer expires. If the route-hold timer expires on the graceful restart-aware router, the graceful restart-aware router discards held routes and treats the restarting router as a new router joining the network and reestablishing adjacency.
After the switchover, Cisco NX-OS applies the running configuration, and EIGRP informs the neighbors that it is operational again.
Note You must enable graceful restart to support in-service software upgrades (ISSU) for EIGRP. If you disable graceful restart, Cisco NX-OS issues a warning that ISSU cannot be supported with this configuration.
The following table shows the licensing requirements for this feature:
EIGRP has the following prerequisites:
•You must enable the EIGRP feature (see the "Enabling the EIGRP Feature" section).
•If you configure VDCs, install the Advanced Services license and enter the desired VDC (see the Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide, Release 4.x).
EIGRP has the following configuration guidelines and limitations:
•A metric configuration (either through the default-metric configuration option or through a route map) is required for redistribution from any other protocol, connected routes, or static routes (see Chapter 16, "Configuring Route Policy Manager").
•For graceful restart, an NSF-aware router must be up and completely converged with the network before it can assist an NSF-capable router in a graceful restart operation.
•For graceful restart, neighboring devices participating in the graceful restart must be NSF-aware or NSF-capable.
•Cisco NX-OS EIGRP is compatible with EIGRP in the Cisco IOS software.
•Do not change the metric weights without a good reason. If you change the metric weights, you must apply the change to all EIGRP routers in the same autonomous system.
•Consider using stubs for larger networks.
•Avoid redistribution between different EIGRP autonomous systems because the EIGRP vector metric will not be preserved.
•The no {ip | ipv6} next-hop-self command does not guarantee reachability of the next hop.
•The {ip | ipv6} passive-interface eigrp command suppresses neighbors from forming.
•Cisco NX-OS does not support IGRP or connecting IGRP and EIGRP clouds.
•Autosummarization is not enabled by default.
•Cisco NX-OS supports only IP.
Note If you are familiar with the Cisco IOS CLI, be aware that the Cisco NX-OS commands for this feature might differ from the Cisco IOS commands that you would use.
This section includes the following topics:
•Shutting Down an EIGRP Instance
•Shutting Down EIGRP on an Interface
You must enable the EIGRP feature before you can configure EIGRP.
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. feature eigrp
3. show feature
4. copy running-config startup-config
Use the no feature eigrp command to disable the EIGRP feature and remove all associated configuration.
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no feature eigrp Example: switch(config)# no feature eigrp |
Disables the EIGRP feature and removes all associated configuration. |
You can create an EIGRP instance and associate an interface with that instance. You assign a unique autonomous system number for this EIGRP process (see the "Autonomous Systems" section on page 1-5). Routes are not advertised or accepted from other autonomous systems unless you enable route redistribution.
Ensure that you have enabled the EIGRP feature (see the "Enabling the EIGRP Feature" section).
EIGRP must be able to obtain a router ID (for example, a configured loopback address) or you must configure the router ID option.
If you configure an instance tag that does not qualify as an AS number, you must configure the AS number explicitly or this EIGRP instance will remain in the shutdown state.
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. router eigrp instance-tag
3. autonomous-system as-number
4. interface interface-type slot/port
5. {ip | ipv6} router eigrp instance-tag
6. show {ip | ipv6} eigrp interfaces
7. copy running-config startup-config
Use the no router eigrp command to remove the EIGRP process and the associated configuration.
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no router eigrp instance-tag Example: switch(config)# no router eigrp Test1 |
Deletes the EIGRP process and all associated configuration. |
Note You should also remove any EIGRP commands configured in interface mode if you remove the EIGRP process.
The following example shows how to create an EIGRP process and configure an interface for EIGRP:
switch# config t
switch(config)# router eigrp Test1
switch(config)# interface ethernet 1/2
switch(config-if)# ip router eigrp Test1
switch(config-if)# no shutdown
switch(config-if)# copy running-config startup-config
For more information about other EIGRP parameters, see the "Configuring Advanced EIGRP" section.
You can restart an EIGRP instance. This clears all neighbors for the instance.
To restart an EIGRP instance and remove all associated neighbors, use the following commands:
You can gracefully shut down an EIGRP instance. This action emoves all routes and adjacencies but preserves the EIGRP configuration.
To disable an EIGRP instance, use the following command in router configuration mode:
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switch(config-router)# shutdown Example: switch(config-router)# shutdown |
Disables this instance of EIGRP. The EIGRP router configuration remains. |
You can configure a passive interface for EIGRP. A passive interface does not participate in EIGRP adjacency but the network address for the interfacee remains in the EIGRP topology table.
To configure a passive interface for EIGRP, use the following command in interface configuration mode:
You can gracefully shut down EIGRP on an interface. This action removes all adjacencies and stops EIGRP traffic on this interface but preserves the EIGRP configuration.
To disable EIGRP on an interface, use the following command in interface configuration mode:
This section includes the following topics:
•Configuring Authentication in EIGRP
•Configuring EIGRP Stub Routing
•Configuring a Summary Address for EIGRP
•Redistributing Routes into EIGRP
•Limiting the Number of Redistributed Routes
•Configuring Load Balancing in EIGRP
•Configuring Graceful Restart for EIGRP
•Adjusting the Interval Between Hello Packets and the Hold Time
You can configure authentication between neighbors for EIGRP. See the "Authentication" section.
You can configure EIGRP authentication for the EIGRP process or for individual interfaces. Interface EIGRP authentication configuration overrides the EIGRP process-level authentication configuration.
Ensure that you have enabled the EIGRP feature (see the "Enabling the EIGRP Feature" section).
Ensure that all neighbors for an EIGRP process share the same authentication configuration, including the shared authentication key.
Create the key-chain for this authentication configuration. See the Cisco NX-OS Security Configuration Guide.
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. router eigrp instance-tag
3. address-family {ipv4 | ipv6} unicast
4. authentication key-chain key-chain
5. authentication mode md5
6. interface interface-type slot/port
7. {ip | ipv6} router eigrp instance-tag
8. {ip | ipv6} authentication key-chain eigrp instance-tag key-chain
9. {ip | ipv6} authentication mode eigrp instance-tag md5
10. copy running-config startup-config
The following example shows how to configure MD5 message digest authentication for EIGRP over Ethernet interface 1/2:
switch# config t
switch(config)# router eigrp Test1
switch(config-router)# exit
switch(config)# interface ethernet 1/2
switch(config-if)# ip router eigrp Test1
switch(config-if)# ip authentication key-chain eigrp Test1 routeKeys
switch(config-if)# ip authentication mode eigrp Test1 md5
switch(config-if)# copy running-config startup-config
To configure a router for EIGRP stub routing, use the following command in address-family configuration mode:
The following example shows how to configure a stub router to advertise directly connected and redistributed routes:
switch# config t
switch(config)# router eigrp Test1
switch(config-router)# address-family ipv6 unicast
switch(config-router-af)# stub direct redistributed
switch(config-router-af)# copy running-config startup-config
Use the show ip eigrp neighbor detail command to verify that a router has been configured as a stub router. The last line of the output shows the stub status of the remote or spoke router. The following example shows that output from the show ip eigrp neighbor detail command:
Router# show ip eigrp neighbor detail
IP-EIGRP neighbors for process 201
H Address Interface Hold Uptime SRTT RTO Q Seq Type
(sec) (ms) Cnt Num
0 10.1.1.2 Se3/1 11 00:00:59 1 4500 0 7
Version 12.1/1.2, Retrans: 2, Retries: 0
Stub Peer Advertising ( CONNECTED SUMMARY ) Routes
You can configure a summary aggregate address for a specified interface. If any more specific routes are in the routing table, EIGRP will advertise the summary address out the interface with a metric equal to the minimum of all more specific routes. See the "Route Summarization" section.
To configure a summary aggregate address, use the following command in interface configuration mode:
The following example causes EIGRP to summarize network 192.0.2.0 out Ethernet 1/2 only:
switch(config)# interface ethernet 1/2
switch(config-if)# ip summary-address eigrp Test1 192.0.2.0 255.255.255.0
You can redistribute routes in EIGRP from other routing protocols.
Ensure that you have enabled the EIGRP feature (see the "Enabling the EIGRP Feature" section).
You must configure the metric (either through the default-metric configuration option or through a route map) for routes redistributed from any other protocol.
You must create a route map to control the types of routes that are redistributed into EIGRP. See Chapter 16, "Configuring Route Policy Manager."
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. router eigrp instance-tag
3. address-family {ipv4 | ipv6} unicast
4. redistribute {bgp as | {eigrp | isis | ospf | ospfv3 | rip} instance-tag | direct | static} route-map name
5. default-metric bandwidth delay reliability loading mtu
6. show {ip | ipv6} eigrp route-map statistics redistribute
7. copy running-config startup-config
The following example shows how to redistribute BGP into EIGRP for IPv4:
switch# config t
switch(config)# router eigrp Test1
switch(config-router)# redistribute bgp 100 route-map BGPFilter
switch(config-router)# default-metric 500000 30 200 1 1500
switch(config-router)# copy running-config startup-config
Route redistribution can add many routes to the EIGRP route table. You can configure a maximum limit to the number of routes accepted from external protocols. EIGRP provides the following options to configure redistributed route limits:
•Fixed limit—Logs a message when EIGRP reaches the configured maximum. EIGRP does not accept any more redistributed routes. You can optionally configure a threshold percentage of the maximum where EIGRP will log a warning when that threshold is passed.
•Warning only—Logs a warning only when EIGRP reaches the maximum. EIGRP continues to accept redistributed routes.
•Withdraw—Start the timeout period when EIGRP reaches the maximum. After the timeout period, EIGRP requests all redistributed routes if the current number of redistributed routes is less than the maximum limit. If the current number of redistributed routes is at the maximum limit, EIGRP withdraws all redistributed routes. You must clear this condition before EIGRP accepts more redistributed routes.
You can optionally configure the timeout period.
Ensure that you have enabled the EIGRP feature (see the "Enabling the EIGRP Feature" section).
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. router eigrp instance-tag
3. redistribute {bgp id | direct | eigrp id | isis id | ospf id | rip id | static} route-map map-name
4. redistribute maximum-prefix max [threshold] [warning-only | withdraw [num-retries timeout]]
5. show running-config eigrp
6. copy running-config startup-config
The following example shows how to limit the number of redistributed routes into EIGRP:
switch# config t
switch(config)# router eigrp Test1
switch(config-router)# redistribute bgp route-map FilterExternalBGP
switch(config-router)# redistribute maximum-prefix 1000 75
You can configure load balancing in EIGRP. You can configure the number of Equal Cost Multiple Path (ECMP) routes using the maximum paths option. See the "Configuring Load Balancing in EIGRP" section.
Ensure that you have enabled the EIGRP feature (see the "Enabling the EIGRP Feature" section).
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. router eigrp instance-tag
3. address-family {ipv4 | ipv6} unicast
4. maximum-paths num-paths
5. copy running-config startup-config
The following example shows how to configure equal cost load balancing for EIGRP over IPv4 with a maximum of six equal cost paths:
switch# config t
switch(config)# router eigrp Test1
switch(config-router)# maximum-paths 6
switch(config-router)# copy running-config startup-config
You can configure graceful restart or nonstop forwarding for EIGRP. See the "Graceful Restart and High Availability" section.
Note Graceful restart is enabled by default.
Ensure that you have enabled the EIGRP feature (see the "Enabling the EIGRP Feature" section).
An NSF-aware router must be up and completely converged with the network before it can assist an NSF-capable router in a graceful restart operation.
Neighboring devices participating in the graceful restart must be NSF-aware or NSF-capable.
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. router eigrp instance-tag
3. address-family {ipv4 | ipv6} unicast
4. graceful-restart
5. timers nsf converge seconds
6. timers nsf route-hold seconds
7. timers nsf signal seconds
8. copy running-config startup-config
The following example shows how to configure graceful restart for EIGRP over IPv6 using the default timer values:
switch# config t
switch(config)# router eigrp Test1
switch(config-router)# address-family ipv6 unicast
switch(config-router-af)# graceful-restart
switch(config-router-af)# copy running-config startup-config
You can adjust the interval between Hello messages and the hold time.
By default, Hello messages are sent every 5 seconds. The hold time is advertised in Hello messages and indicates to neighbors the length of time that they should consider the sender valid. The default hold time is three times the hello interval, or 15 seconds.
To change the interval between hello packets, use the following command in interface configuration mode:
On very congested and large networks, the default hold time might not be sufficient time for all routers to receive hello packets from their neighbors. In this case, you might want to increase the hold time.
To change the hold time, use the following command in interface configuration mode:
Use the show ip eigrp interface detail command to verify timer configuration.
You can use split horizon to block route information from being advertised by a router out of any interface from which that information originated. Split horizon usually optimizes communications among multiple routing devices, particularly when links are broken.
By default, split horizon is enabled on all interfaces.
To disable split horizon, use the following command in interface configuration mode:
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switch(config-if)# no {ip | ipv6} split-horizon eigrp instance-tag Example: switch(config-if)# no ip split-horizon eigrp Test1 |
Disables split horizon. |
You can configure optional parameters to tune EIGRP for your network.
You can configure the following optional parameters in address-family configuration mode:
You can configure the following optional parameters in interface configuration mode:
You can configure multiple EIGRP processes in each VDC. You can also create multiple VRFs within each VDC and use the same or multiple EIGRP processes in each VRF. You assign an interface to a VRF
Note Configure all other parameters for an interface after you configure the VRF for an interface. Configuring a VRF for an interface deletes all other configuration for that interface.
Ensure that you have enabled the EIGRP feature (see the "Enabling the EIGRP Feature" section).
Create the VDCs and VRFs.
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. vrf context vrf-name
3. router eigrp instance-tag
4. interface ethernet slot/port
5. vrf member vrf-name
6. {ip | ipv6} router eigrp instance-tag
7. copy running-config startup-config
The following example shows how to create a VRF and add an interface to the VRF:
switch# config t
switch(config)# vrf context NewVRF
switch(config-vrf)# router eigrp Test1
switch(config-router)# interface ethernet 1/2
switch(config-if)# ip router eigrp Test1
switch(config-if)# vrf member NewVRF
switch(config-if)# copy running-config startup-config
To verify the EIGRP configuration, use the following commands:
To display EIGRP statistics, use the following commands:
The following example shows how to configure EIGRP:
feature eigrp
interface ethernet 1/2
ip address 192.0.2.55/24
ip router eigrp Test1
no shutdown
router eigrp Test1
router-id 192.0.2.1
See Chapter 16, "Configuring Route Policy Manager" for more information on route maps.
Table 8-1 lists the default settings for EIGRP parameters.
For additional information related to implementing EIGRP, see the following sections:
|
|
---|---|
EIGRP CLI commands |
Cisco Nexus 7000 Series NX-OS Unicast Routing Command Reference |
VDCs and VRFs |
Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide, Release 4.x |
Introduction to EIGRP Tech Note |
|
http://www.cisco.com/en/US/tech/tk365/technologies_q_and_a_item09186a008012dac4.shtml |
EIGRP Frequently Asked Questions |
|
|
---|---|
CISCO-EIGRP-MIB |
To locate and download MIBs, go to the following URL: http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml |
Table 8-2 lists the release history for this feature.