nanog mailing list archives
Re: BGP prefix filter list
From: Blake Hudson <blake () ispn net>
Date: Mon, 20 May 2019 09:14:58 -0500
Baldur Norddahl wrote on 5/18/2019 3:57 AM:
...One router knows about 2 paths, the other about 4 paths. Why? Because BGP only advertises the route that is in use. Everyone here of course knows this, I am just pointing it out because culling information before allowing it to be redistributed within your network is what BGP is already doing anyway. It is possible to remove some of that information from the local FIB too without losing anything at all.Using a default also gives you a dramatically shorter convergence time if one of the transits goes down. Having 800k routes can be harmful to your network even with equipment that can handle it. Yes I am aware that I am not doing what I am preaching here, but I am considering it :-).
Thanks for the clarification. Yes, you are correct that each router will have its own unique view. By full view I meant that a router has at least one route for every prefix advertised into the DFZ. One should also expect that each transit provider will provide a slight variation in the routes provided via its "full BGP feed" because each transit provider has its own unique view and may include routes in its feeds that are not advertised into the DFZ.
Appreciate the discourse my friend, --B
Current thread:
- Re: BGP prefix filter list, (continued)
- Re: BGP prefix filter list Blake Hudson (May 17)
- Re: BGP prefix filter list / BGP hijacks, different type Denys Fedoryshchenko (May 17)
- Re: BGP prefix filter list / BGP hijacks, different type Christopher Morrow (May 17)
- Re: BGP prefix filter list Radu-Adrian Feurdean (May 17)
- Re: BGP prefix filter list Blake Hudson (May 17)
- Re: BGP prefix filter list Baldur Norddahl (May 17)
- Re: BGP prefix filter list Blake Hudson (May 17)
- Re: BGP prefix filter list Baldur Norddahl (May 17)
- Re: BGP prefix filter list Blake Hudson (May 17)
- Re: BGP prefix filter list Baldur Norddahl (May 18)
- Re: BGP prefix filter list Blake Hudson (May 20)
- Re: BGP prefix filter list William Herrin (May 20)
- Re: BGP prefix filter list i3D . net - Martijn Schmidt (May 20)
- Re: BGP prefix filter list Seth Mattinen (May 20)
- Re: BGP prefix filter list William Herrin (May 20)
- Message not available
- Re: BGP prefix filter list John Kristoff (May 20)
- Re: BGP prefix filter list Seth Mattinen (May 20)
- Re: BGP prefix filter list Ca By (May 20)
- Re: BGP prefix filter list Alejandro Acosta (May 21)
- Re: BGP prefix filter list Tom Beecher (May 22)
- Re: BGP prefix filter list Alejandro Acosta (May 22)