Migrating an EIGRP AS topology to Named mode

[millerjw]

I have a very large network that I need to migrate from classic EIGRP AS mode to Named mode. The network consists of hundreds of edge routers and L3 switches configured in the same AS. I can't seem to find any information regarding migration of AS mode to Named as it relates to supporting both modes at the same time. Will a router migrated to named mode peer directly with a legacy AS mode device? 

Thanks!

[Julio E. Moisa]

Hi

Unfortunately you cannot have Classic mode and Named mode using the same AS on the same router, for example:

R2(config)#router eigrp 1
R2(config-router)#net 0.0.0.0 255.255.255.255
R2(config-router)#no auto-summary
R2(config-router)#exit

R2(config)#router eigrp TEST
R2(config-router)#address-family ipv4 unicast autonomous-system 1
%ERROR: AS(1) in use by classic router

But you can use the command: eigrp upgrade-cli under the classic mode and it will convert to named mode

Use the eigrp upgrade-cli command to upgrade from classic mode to named mode. You must use the eigrp
upgrade-cli command for all classic router configurations to ensure that these configurations are upgraded
to the named mode. Therefore, if multiple classic configurations exist, you must use this command per
autonomous system number. You must use this command separately for IPv4 and IPv6 configurations

R2(config)#router eigrp 1
R2(config-router)#eigrp upgrade-cli NEW-TEST
Configuration will be converted from router eigrp 1 to router eigrp NEW-TEST.
Are you sure you want to proceed? ? [yes/no]: Y
R2(config)#

R2#show run

router eigrp NEW-TEST
!
address-family ipv4 unicast autonomous-system 1
!
topology base
exit-af-topology
exit-address-family

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:-)

[millerjw]

Thanks for the reply Julio. My question is though, will a router running named mode in as1 peer with a EIGRP classic mode router also in as1?

[Julio E. Moisa]

Yes they will create the EIGRP adjacency without problems. 

:-)