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View Full Version : H2+ avoid Loop between R9,R10,R53,R54



olivereng20
08-20-2019, 01:03 PM
i want to share how i made loop avoidance in H2+

create a route-map to distribute tag 172.172.172.172 in eigrp:

route-map TAG permit 10
ste tag 172.172.172.172
exit

router eigrp AS65006
add-famil ipv4 as 10
topology base
distribute-list route-map TAG out
end

on R9 and R10
do:
route-map DENY-TAG deny 10
match tag 172.172.172.172
exit
route-map DENY-TAG permit 20
set metric 10000 100 1 255 1500
exit
route-map DENY-TAG permit 30
exit


router eigrp AS65006
add-famil ipv4 as 10
topology base
redistribute ospf 1 route-map DENY-TAG
exit

router ospf 1
redistribute eigrp 10 subnets


It works fine for me
Try it...

firas81
08-21-2019, 02:14 AM
Hi,

it works, but i think this is not a perfect solution to do it, but why do you have three entry in your map??? and why do you use it from ospf into eigrp????

the idea here to block the exteranl eigrp prefixes in ospf domain, because the transition from higher AD to lower AD makes the routers border ospf R9/10 choose it, and then we get the loop.


I think the solution by using your map with a littel bitte updating will be on R9/10 as the next:

route-map DENY-TAG deny 10
match tag 172.172.172.172
route-map DENY-TAG permit 20

router ospf 1
distribute-list route-map DENY-TAG in

Only this, it is simple and perfect.

and with using the Ad in H2+ will be:

router os 1
distance ospf external 175 ------> a little bit higher than external eigrp 170

All the best.

olivereng20
08-21-2019, 10:28 PM
Hi,

it works, but i think this is not a perfect solution to do it, but why do you have three entry in your map??? and why do you use it from ospf into eigrp????

the idea here to block the exteranl eigrp prefixes in ospf domain, because the transition from higher AD to lower AD makes the routers border ospf R9/10 choose it, and then we get the loop.


I think the solution by using your map with a littel bitte updating will be on R9/10 as the next:

route-map DENY-TAG deny 10
match tag 172.172.172.172
route-map DENY-TAG permit 20

router ospf 1
distribute-list route-map DENY-TAG in

Only this, it is simple and perfect.

and with using the Ad in H2+ will be:

router os 1
distance ospf external 175 ------> a little bit higher than external eigrp 170

All the best.

Hi Thank you for your explanation. Your Solution works fine for me too! Many thanks for share

Hyosub Seo
11-17-2019, 01:19 PM
Thank you for your sharing!!