Greetings all. In practice, We've always advertised our space all the way down to /24's but also the aggregate block (the /20 or the /21). Just so there was still reachability to our network in the event that someone made the foolish mistake of filtering lets say prefixes smaller /23... Anyways, I've always thought that was standard practice. And its never been a problem. Until we brought up peering with level 3.. I noticed that while the /24's made it out to the world. The larger counterparts (2 /21's and a /20) did not. So, I start sniffing around. Find that I do indeed see the prefixes in Level 3's looking glass but they aren't handing it off to peers. So, Naturally, I land on this being some kind of prefix filtering issue and open a ticket with Level 3. They tell me this is standard practice. And If I want to see the /20 or /21's make it out to the rest of the world, I need to stop sending the /24's. Does this sound normal? Is what I'm doing (Advertising the aggregate prefix) a good rule of thumb? Any other thoughts? Nick Olsen Network Operations (855) FLSPEED x106