On 11/08/2021 14:09, Jon Lewis wrote: > What sort of hands-on experience is this opinion based on?
Having an upstream provider that did it, in a very aggressive fashion. > I've done this manually in the past (quite some time ago), and done > properly, it works fine. > > At least one major network hardware vendor has implemented it as a > feature. Turn it on, and the "deaggregates" with same next-hop as an > aggregate are not programmed into the FIB. The savings will vary > depending on the device's connectivity, but I've seen >40%. Limiting the pruning to cases with the same next-hop does indeed sound like it would be safer than what I've seen done in the past. Doing this with per-peer prefix-lists would not (certainly not in classic IOS) provide you with the ability to compare the next-hop before rejecting those more-specific prefixes, and likely why the attempts to do this caused the problems that I'm referring to. I'm glad to hear a vendor has implemented a useful knob. Which vendor? -- Tom
