BGP Redistribution

[colmgrier]

What is the best way to redistribute BGP routes into Eigrp (please see network diagram)

I wish to have switch 1 as the primary route and switch 2 as backup only.

Please advise.

Kind Regards,

Colm

[Giuseppe Larosa · Accepted solution]

Hello Colm,

in EIGRP you need to specify a seed metric using 5 values in order to make one ASBR device the preferred exit point is enough to use better values on it

R1:

router eigrp 100

red bgp 64600

default-metric 10000 100 255 1 1500

R2:

router eigrp 100

red bgp 64600

default-metric 5000 500 255 1 1500

! bw delay relaibility load mtu are the five values

Note:

using route filters is recommended if you are going to redistribute also EIGRP into BGP on R1,R2.

as an alternate method you can consider using network command under router bgp process to match EIGRP routes (BGP allows this)

Hope to help

Giuseppe

[Chetan Kumar Ress · Accepted solution]

Hi

If you want Switch 1 should Primary for incomming & outgoing then you can use metric while redistributing from BGP to Eigrp.

For Example : The router connected to primary switch you can use lower metric & The router commected to Backup Switch you can use higher metric.

Regards

Chetan Kumar

[colmgrier]

Thanks Lads. Solution now working.

[colmgrier]

Guys,

Will the below work on router 1 using route-maps for redistribution? How will I configure router 2 with higher metric?

### Router 1 ###

router eigrp 90
redistribute bgp 64600 route-map bgp->eigrp

no auto-summary

router bgp 64600
no synchronization
bgp router-id 198.18.255.1
bgp log-neighbor-changes
redistribute connected
redistribute eigrp 90 route-map eigrp->bgp
neighbor 198.18.3.1 remote-as 43984
neighbor 198.18.3.1 send-community
neighbor 198.18.3.1 soft-reconfiguration inbound
no auto-summary

ip prefix-list 1 seq 5 permit 10.1.0.0/16 le 32
ip prefix-list 2 seq 5 permit 10.2.0.0/16 le 32

route-map bgp->eigrp permit 10
match ip address prefix-list 2
set metric 1 2 3 4 5

route-map eigrp->bgp permit 10
match ip address prefix-list 1

Thanks,

Colm

[Giuseppe Larosa]

Hello Colm,

you can use set metric <5 values> also on the backup router in a route-map

follow my first post with set metric instead of default-metric this can be done

I suggest to use meaningful values, for an example an MTU of 5 bytes has no real counterpart

Hope to help

Giuseppe

[Chetan Kumar Ress]

Hi Colm,

Redistribution between routing protocol should be meaningful.

As Giulsar told  "I suggest to use meaningful value" . I Really respect those words.

In network whenever you redistribute you should keep trak of those number that you had used and make sure that you should not tewak the EIGRP metric if you are not aware of those vlaue.

In your post "set metric 1 2 3 4 5" is not meaning ful .

And EIGRP use only Bandwidth & Delay  then why you are using other vlaues. If you want to use you should keep track of thos vlaue for future purpose.

For Example

Redistribution : Primary Link : Metric : 5000 500 255 1 1500

Redistribution : Backup Link : Metric : 8000 500 255 1 1500

Like this you should keep record of metric & Whenever you get new locaiton with same senario you should follow the same metric.

This make you network perfect & stable . In future if you face any issue then you can trouble shoot easily because you have clear picture of you network.

Regards

Chetan Kumar

[joealbergo]

Gentlemen,

I have not gone over redistribution in a while. I was curious to know when redistributing from one routing protocol to the next, is this now simultaneously using BPG/EIGRP or does it only convert where needed?

Joe

[Giuseppe Larosa]

Hello Joseph,

redistribution is a unidirectional process with a source protocol and a target protocol (the one that receives routes from source protocol)

the conditions for redistribution are:

- the routes have to be present in the source protocol database

- the routes have to be installed in IP routing table of local node (unless they are present in the IP routing table as connected)

- an appropriate seed metric is configured to allow the routes to enter the database of target protocol (protocol specific)

- an explicit redistribute command is present in target protocol routing process configuration.

if redistribution is performed in both directions p1 -> p2 and p2 -> p1 we speak of mutual = biridirectional redistribution

Most of the times we don't need to perfom mutual redistribution because the use of a default route may be appropriate on the edge protocol to reach the core without providing details of core protocol routes.

When mutual redistivbution is needed in multiple nodes special care is needed for avoiding unwanted routing feedback between routing domains.

the use of route-maps and eventually the use of route tags allow for controlled redistribution in mutual redistribution scenarios with multiple redistribution points.

Hope to help

Giuseppe

[joealbergo]

Giuseppe

Your knowledge & information is wonderful!

Thank you so much!

Joe