BGP route-map continue

Unanswered Question
Jan 23rd, 2008
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Hi,


On the following web page http://www.cisco.com/en/US/products/ps6566/products_feature_guide09186a00801a7f7a.html#wp1027188 there is something I can't understand concerning the BGP route-map continue command.


With this configuration:

route-map ROUTE-MAP-NAME permit 10


match ip address 1


match metric 10


set as-path prepend 10


continue 30


!


route-map ROUTE-MAP-NAME permit 20


match ip address 2


match metric 20


set as-path prepend 10 10


!


route-map ROUTE-MAP-NAME permit 30


set as-path prepend 10 10 10


continue


!


route-map ROUTE-MAP-NAME permit 40


match community 10:1


set local-preference 104


it is written the following:


"If a successful match does not occur in route-map entry 20, the route map will "fall through" to route-map entry 30. This sequence does not contain a match clause, so the set clause will be automatically executed and the continue clause will go to the next route-map entry because a sequence number is not specified.


If there are no successful matches, the route-map will "fall through" to route-map entry 30 and execute the set clause, and route-map entry 40 will not be evaluated."


What I don't understand is the last sentence. Howcome entry 40 will not be evaluated?


Can you please explain to me if this is correct?


Thank you in advance

Eduardo

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eduardonpinto Wed, 01/23/2008 - 03:44
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Hi Ivan,


thank you for your reply. I also think there is a mistake on that page. Things just don't add up:


"Match Operations with Continue Clauses


If a match clause does not exist in the route-map entry but a continue clause does, the continue clause will be automatically executed and go to the specified route-map entry."


, therefore after statement 30, it should 'continue' to statement 40.

nordick26 Wed, 01/23/2008 - 05:48
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Hi all,


I've just made a test on my lab and things are going strange.

Just a simple test:

R1--R2

I'm running BGP between them.

Route-map on R1 is configured in this way:


route-map TEST permit 10

continue

set as-path prepend 10

!

route-map TEST permit 20

match ip address 20

set metric 20

!

access-list 20 permit 10.3.3.0 0.0.0.255


Routers are connected throught serial interface.


10.3.3.0 is a LAN subnet on R1.


In R2 bgp table, i can see that AS number 10 was prepended correctly, but I'd like to see the metric 20 as well. But actually it seems route-map has stoped at sequence 10.


Do you have any ideas why?


Cheers

Ivan


eduardonpinto Wed, 01/23/2008 - 05:54
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Ivan,


have you tried using the continue command after the set action on statement 10?

nordick26 Wed, 01/23/2008 - 06:15
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Yes,


It just appears like this in the config.

CONTINUE was configured after SET.


R1#sh route-map TEST

route-map TEST, permit, sequence 10

Match clauses:

Continue: to next entry 20

Set clauses:

as-path prepend 10

Policy routing matches: 0 packets, 0 bytes

route-map TEST, permit, sequence 20

Match clauses:

ip address (access-lists): 20

Set clauses:

metric 20

Policy routing matches: 0 packets, 0 bytes



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