In traditional way we were configuring EIGRP like this,
We go to configuration mode and defining EIGRP with process number
R1#conf t
R1(config)#router eigrp 1
R1(config-router)#
R1(config)#router eigrp 1
R1(config-router)#
After that if we have to run EIGRP on the interfaces then we have to specify each network with wildcard mask for every interface:
R1(config-router)#network 10.1.1.0 0.0.0.3
R1(config-router)#network 1.1.1.1 0.0.0.0
R1(config-router)#network 1.1.1.1 0.0.0.0
And for some the command like EIGRP authentication, defining Bandwidth to control EIGRP packets or to define EIGRP next-hop you have exit Router config mode and switch to interface mode as shown below:
R1(config-router)#exit
R1(config)#int fa0/0
R1(config-if)#ip authentication mode eigrp 1 md5
R1(config-if)#ip authentication key-chain eigrp 1 cisco
R1(config-if)#ip bandwidth-percent eigrp 1 75
R1(config)#int fa0/0
R1(config-if)#ip authentication mode eigrp 1 md5
R1(config-if)#ip authentication key-chain eigrp 1 cisco
R1(config-if)#ip bandwidth-percent eigrp 1 75
This was what we discussed for IPv4 Eigrp. Now to run EIGRP for IPv6 we have to configure in different way define the IPv6 router process and run Eigrp under interface mode.
ipv6 router eigrp 1
eigrp router-id 10.1.1.1
no shut
!
Interface f0/0
ipv6 enabe
ipv6 eigrp 1
!
eigrp router-id 10.1.1.1
no shut
!
Interface f0/0
ipv6 enabe
ipv6 eigrp 1
!
So In traditional way for every address family (IPv4/VRF/IPv6) you have to configure EIGRP separately .You have to switch config mode to interface mode, also another interesting point is that there was no way to configure VRF in traditional IPv6 EIGRP implementation but in “EIGRP Name Mode configuration” you can config all in one place, plus you have the option to run IPv6 Eigrp for VRF
Let’s discussed EIGRP name mode configuration in detail.
EIGRP named configuration is available in following IOS release and onwards:
15.0(1)M
12.2(33)SRE
12.2(33)XNE
Cisco IOS XE Release 2.5
If you are running any of the above IOS versions then you will see 2 options after you do question mark as shown.
R2(config)#router eigrp ?
<1-65535> Autonomous System
WORD EIGRP Virtual-Instance Name
<1-65535> Autonomous System
WORD EIGRP Virtual-Instance Name
To define Name mode configuration define word option as show below:
R2(config)#router eigrp CISCO
Unlike traditional way, EIGRP instance not create or it doesn't start running the moment following is configured on the router. The instance will be created when address-family and autonomous system number is configured for e.g.:
For IPv4:
R2(config-router)#address-family ipv4 unicast autonomous-system 1
For IPv4 VRF:
R2(config-router)#address-family ipv4 unicast vrf Customer_A autonomous-system 1
For IPv6:
R2(config-router)#address-family ipv6 unicast autonomous-system 1
For IPv6 VRF
R2(config-router)#address-family ipv6 unicast vrf site_A autonomous-system 1
With this Named mode, we can create a single Instance of EIGRP, which can be used for all address family type as shown above.
Another simplicity is if want to turn off the entire AS, you can use “shutdown” command under address-family to turn off the entire instance.
Named EIGRP has 3 configuration modes. These are:
1) address-family configuration mode - (config-router-af)#
2) address-family interface configuration mode - (config-router-af-interface)#
3) address-family topology configuration mode - (config-router-af-topology)#
A) Address-family configuration mode:
In this mode, you can configure networks, EIGRP neighbor, EIGRP Router-id, metric etc. From this mode you can access the other two configuration modes used in EIGRP named configuration.
R2(config-router)#address-family ipv4 unicast autonomous-system 1
R2(config-router-af)#?
Address Family configuration commands:
af-interface Enter Address Family interface configuration
default Set a command to its defaults
eigrp EIGRP Address Family specific commands
exit-address-family Exit Address Family configuration mode
help Description of the interactive help system
maximum-prefix Maximum number of prefixes acceptable in aggregate
metric Modify metrics and parameters for address advertisement
neighbor Specify an IPv4 neighbor router
network Enable routing on an IP network
no Negate a command or set its defaults
shutdown Shutdown address family
timers Adjust peering based timers
topology Topology configuration mode
R2(config-router-af)#
B) Address-family interface configuration mode:
This mode takes all the interface specific commands that were previously configured on an actual interface (logical or physical) and moves them into the EIGRP configuration. EIGRP authentication, Bandwidth-percentage, split-horizon, and summary-address configuration are some of the options that are now configured here instead of in interface configuration mode.
R2(config-router-af)#af-interface fa0/0
R2(config-router-af-interface)#?
Address Family Interfaces configuration commands:
authentication authentication subcommands
bandwidth-percent Set percentage of bandwidth percentage limit
bfd Enable Bidirectional Forwarding Detection
dampening-change Percent interface metric must change to cause update
dampening-interval Time in seconds to check interface metrics
default Set a command to its defaults
exit-af-interface Exit from Address Family Interface configuration mode
hello-interval Configures hello interval
hold-time Configures hold time
next-hop-self Configures EIGRP next-hop-self
no Negate a command or set its defaults
passive-interface Suppress address updates on an interface
shutdown Disable Address-Family on interface
split-horizon Perform split horizon
summary-address Perform address summarization
R2(config-router-af-interface)#
In traditional way if we want run EIGRP on all interface we use "network 0.0.0.0 0.0.0.0" command. Here you can use “af-interface default” to function same.
R2(config-router-af)#af-interface default
R2(config-router-af-interface)#
R2(config-router-af-interface)#
C) Address-family topology configuration mode:
This mode provide several options which operates on EIGRP topology table .here you can define content like redistribution, distance, offset list, variance etc. To enter this mode, we need to go back to address-family configuration mode:
R2(config-router-af-interface)#exit
R2(config-router-af)#topology base
R2(config-router-af-topology)#?
Address Family Topology configuration commands:
auto-summary Enable automatic network number summarization
default Set a command to its defaults
default-information Control distribution of default information
default-metric Set metric of redistributed routes
distance Define an administrative distance
distribute-list Filter entries in eigrp updates
eigrp EIGRP specific commands
exit-af-topology Exit from Address Family Topology configuration mode
fast-reroute Configure Fast-Reroute
maximum-paths Forward packets over multiple paths
metric Modify metrics and parameters for advertisement
no Negate a command or set its defaults
offset-list Add or subtract offset from EIGRP metrics
redistribute Redistribute IPv4 routes from another routing protocol
snmp Modify snmp parameters
summary-metric Specify summary to apply metric/filtering
timers Adjust topology specific timers
traffic-share How to compute traffic share over alternate paths
variance Control load balancing variance
R2(config-router-af-topology)#
Comparison chart between Eigrp “traditional Configuration” and “Name mode Configuration”:
| EIGRP Tradition way of Configuration | EIGRP Name Mode Configuration |
|---|---|
| int fa0/0 ip add 10.1.1.1 255.255.255.252 ip authentication mode eigrp 1 md5 ip authentication key-chain eigrp 1 cisco ip bandwidth-percent eigrp 1 75 ip hello eigrp 1 10 IPv6 enable IPv6 eigrp 1 router eigrp 1 network 10.1.1.0 0.0.0.3 redistribute connected ipv6 router eigrp 1 eigrp router-id 10.1.1.1 no shut router eigrp 2 address-family ipv4 vrf CUST_A network 0.0.0.0 0.0.0.0 "No IPv6 EIGRP support for VRF" | int fa0/0 ip add 10.1.1.1 255.255.255.252 IPv6 enable router eigrp CISCO ! address-family ipv6 unicast autonomous-system 1 ! topology base exit-af-topology eigrp router-id 1.1.1.1 exit-address-family ! address-family ipv4 unicast autonomous-system 1 ! af-interface FastEthernet0/0 authentication mode md5 authentication key-chain cisco bandwidth-percent 75 hello-interval 10 exit-af-interface ! topology base redistribute connected exit-af-topology exit-address-family ! address-family ipv6 unicast vrf CUST_B autonomous-system 2 ! topology base exit-af-topology exit-address-family ! address-family ipv4 unicast vrf CUST_A autonomous-system 2 ! af-interface default ! topology base exit-af-topology exit-address-family |
