Route-map and prefix-list

[jeffersoncbriones]

Hi Gurus,

Will

route-map

and

prefix-list

command work together on bgp ? i tried using filter-list and

route-map

they work properly. This is on outgoing.

tia.

[royalblues]

yes it will work

eg..

ip prefix-list default seq 10 permit 0.0.0.0/0




route-map ISP1 permit 10

match ip address prefix-list default

set local-preference 200




router bgp 1

neighbor x.x.x.x remote-as 2

neighbor x.x.x.x route-map ISP1 in

Narayan

[jeffersoncbriones]

Hi Naraya,

what i mean is in the same line.

neighbor x.x.x.x route-map ISP1 out

neighbor x.x.x.x prefix-list SAMPLE out

how bout this?

tnx.

[royalblues]

yes can be done

Narayan

[Harold Ritter]

Jefferson,

Yes, a

route-map

and

prefix-list

can be used in conjunction. Here what the order of operation will be for both

inbound and outbound

Inbound:

route-map

filter-list

prefix-list

distribute-list







Outbound:

distribute-list

prefix-list

filter-list

route-map

Regards

[Giuseppe Larosa · Accepted solution]

Hello Jefferson,

Harold has provided the order in which the different filters are combined.

For outgoing the first filter used in your case is the

prefix-list

the output of this filter becomes the input of the

route-map filter

The output of the second filter are the prefixes actually advertised to the neighbor.

Hope to help

Giuseppe

[marikakis]

Hello Harold,

What you mentioned is also mentioned in the BGP FAQ (Q. What is the order of preference of attributes when some or all are applied to one neighbor in BGP?):

http://www.ciscosystems.com/en/US/tech/tk365/technologies_q_and_a_item09186a00800949e8.shtml#one

It also says there that a

prefix-list

and a

distribute-list

are mutually exclusive.

I just wanted to take the opportunity to report that in another part of the same BGP FAQ (Q. How can I filter all IP routes advertised to a BGP neighbor except the default route 0.0.0.0/0?):

http://www.ciscosystems.com/en/US/tech/tk365/technologies_q_and_a_item09186a00800949e8.shtml#fil

a different order is specified for inbound.

I think that the order of precedence of filters has changed at some point and not all relevant documentation has been updated.

Kind Regards,

M.

[jeffersoncbriones]

Guys,

Thanks a lot, i've tested it and works well.

Here's my testing.

Outgoing:

prefix-list and route-map

filter-list and route-map

tnx again.