This may seem like a trivial question, but the last time I tried it, it didn't work.
I only have a small window to test, so wanted to see if I am doing everything correctly.
I have two routers, each with a separate /22 IP range on them being advertised out.
One router will be shutdown in the next few weeks, so I am going to move that /22. They way I am moving it is to move each /24 by itself over to the new router.
Global routing will go to the new router since the /24 advertisement over there is more specific.
So all I have to do is add the /24 advertisement on the new router.
I tried this last night, but it didn't seem to take.
Basically, I went into my "router bgp XYZ" config, and added the line:
network A.B.C.D mask 255.255.255.0
Then I did:
clear ip bgp X.X.X.X soft (where X.X.X.X is my upstream neighbor)
After doing that, I couldn't verify that the /24 was being advertised:
sh ip bgp neighbors X.X.X.X advertised-routes
And it only showed my existing /22, not the new /24 I just added.
I called the carrier and confirmed that they will allow the /24 advertisement.
Any ideas?