conflicting route-map prefix list

[Amafsha1]

Hello, I'm really confused about a couple commands for BGP

router bgp 555555

neighbor test peer-group
neighbor test remote-as 444444
neighbor test send-community
neighbor test prefix-list default-route in
neighbor test route-map internet_in in
neighbor test route-map internet_out out

!

!

route-map internet_in permit 10
match ip address prefix-list default-route 
set local-preference 200

!

!

ip prefix-list default-route seq 10 permit 0.0.0.0/0

!

!

I have highlighted what I believe to be redundant commands.   First we specify "prefix-list default-route in" which consists of 0.0.0.0/0 network, then we have "route-map internet_in in" which just references the same prefix-list of 0.0.0.0/0.  Am I correct?  Is that just a waste of space?

Thank you

[Seb Rupik · Accepted solution]

Hi there,
At first glance they look similar but they actually achieve different objectives.
The prefix-list ensures that the BGP process only receives a default route 0.0.0.0/0, all other prefixes will be dropped. It is a route filter.

The route-map compliments the prefix-list. It will match the received 0.0.0.0/0 route and set the local-preference to 200. A higher preference is preferred (the default being 100). The local preference value is advertised to other routers within the same AS, therefore all traffic destined for the default route will arrive at this BGP router.
Of course, if you are not running iBGP within your AS, then the route-map and local preference are redundant and will achieve nothing.

https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/26634-bgp-toc.html#localpref

cheers,
Seb.