Hello
Today let’s have a brief look at what we can use the continue keyword for in BGP route-maps.
Let’s say we have four customers: three customers in AS100 and one customer in AS200. We need to send routes from the customers in AS100 to other ISPs, but not the routes from the customer in AS200.
On our edge, we gave each customer a community:
Customer A: 100:10 (Acomm)
Customer B: 200:20 (Bcomm)
Customer C: 300:30 (Ccomm)
Now we want to advertise these routes to some other ISPs such that all ISPs get these routes with MED equal 100, but AS path prepending will be different. It’s a silly requirement but i only want to demonstrate how the continue phrase can simplify an otherwise complex route-map.
A route-map with continue:
Route-map X permit 10
match as-path 100
continue
set metric 100
Route-map X permit 20
match community Acomm
set as-path prepend 100 100 100
Route-map X permit 30
match community Bcomm
set as-path prepend 100 100 100 100
Route-map X permit 40
match community Ccomm
set as-path prepend 100 100 100 100 100
———————–Route-map without continue—
Route-map X permit 20
match as-path 100
match community Acomm
set as-path prepend 100 100 100
set metric 100
Route-map X permit 30
match as-path 100
match community Bcomm
set as-path prepend 100 100 100 100
set metric 100
Route-map X permit 40
match as-path 100
match community Ccomm
set as-path prepend 100 100 100 100 100
set metric 100
