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1136 Views 6 Replies Latest reply: Sep 6, 2012 4:21 AM by aaceituno RSS

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EIGRP and OSPF mixed distribution control

Sep 6, 2012 12:05 AM

Ismail 12 posts since
Jul 8, 2012

Dear All,

can someone helps for any Reference/Expample for EIGRP and OSPF mixed distribution control.

 

Regards,

Ismail

  • aaceituno 242 posts since
    Feb 18, 2009
    Currently Being Moderated
    1. Sep 6, 2012 12:23 AM (in response to Ismail)
    Re: EIGRP and OSPF mixed distribution control

       If you means mutual redistribution, into eigrp you need to set the eigrp metric when redistributing from other protocols. Into ospf, you dont need to apply any metric unless you need to set metrics, type or tags.

     

       If you have a redistribution loop, then would need to configure some route-maps, that set a tag to the redistributed routes into the other routing protocol. This way, on the other redistribution point, you could match on this tag and deny the redistribution. This way will avoid redistribution loops from eigrp to ospf and from ospf to eigrp.

     

      Also, take in account the administrative distances. The redistributed route should have always higher AD than the source routing protocol if there is several redistribution points. If not, will be preferred the redistributed route before the "natural" route in that redistribution points.

  • Currently Being Moderated
    3. Sep 6, 2012 12:51 AM (in response to Ismail)
    Re: EIGRP and OSPF mixed distribution control

    The most basic redistribution commands is:

     

    For routes into EIGRP:

     

    R1(config)#router eigrp 1

    R1(config-router)#redistribute ospf 23

    R1(config-router)#default-metric 100000 10 255 1 1500

     

    For routes into OSPF:

     

    R1(config)#router ospf 23

    R1(config-router)#redistribute eigrp 1 subnets

     

    As Alejandro also writes, take care of redistribution loop and suboptimal routing.

  • Mayowa 42 posts since
    Aug 3, 2012
    Currently Being Moderated
    5. Sep 6, 2012 2:00 AM (in response to Ismail)
    Re: EIGRP and OSPF mixed distribution control

    Hi Ismail,

     

    If you're experiencing routing loops, i suggest you set different 'tags' to routes from each protocol. For example you set a tag of 10 for eigrp routes and 20 for ospf routes.

     

    You can then deny any routes with a tag of 10 from entering the eigrp process domain and do the same for routes with a tag of 20 for the ospf domain.

     

    This would ensure you dont have routing loops in your network.

     

    Cheers,

     

    Mayowa

  • aaceituno 242 posts since
    Feb 18, 2009
    Currently Being Moderated
    6. Sep 6, 2012 4:21 AM (in response to Ismail)
    Re: EIGRP and OSPF mixed distribution control

    The way to use route-maps, access-lists and set a tag is the following :

     

     

    !

    router ospf 1

    log-adjacency-changes

    redistribute eigrp 100 subnets route-map EIGRP-to-OSPF

     

     

     

    ip access-list standard ODD

    permit 0.0.1.0 255.255.254.255

     

     

    ! this entry will deny redistribution for routes with tag 3333. This tag wil be set in the other redistribution point, from OSPF to EIGRP.

    !

    route-map EIGRP-to-OSPF deny 5

      match tag 3333

     

    ! will match some specific routes, will tag this and sets metric-type.

    route-map EIGRP-to-OSPF permit 10

    match ip address ODD

    set metric-type type-2

    set tag 1111

     

    ! will match everything else, and set tag and metric-type.

    route-map EIGRP-to-OSPF permit 20

    set metric-type type-1

    set tag 2222

     

     

     

      On the other redistribution point, route map redistributing from OSPF to EIGRP will have to match first on tags 1111 and 2222 and deny redistribution. Will match everything else and set tag to 3333 from OSPF to EIGRP.

     

     

      Under the redistribute command, have to add the route-map option, and the appropiate route-map, with the right match and set commands. Anything that will be denied for redistribution will match a route-map deny, anything will be redistribute will match a route-map permit and will have the set tag.

     

      So what you tag on outgoing direction, will have to be denied in the opposite direction.

     

    br

    Alex.

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