nanog mailing list archives
Re: any dangers of filtering every /24 on full internet table to preserve FIB space ?
From: Nick Suan via NANOG <nanog () nanog org>
Date: Mon, 10 Oct 2022 10:25:59 -0500
There's 69,055 pure /24's allocated or assigned directly from an RIRs. At least c,d,e, and g root servers only have /24s allocated to them. Major services like Cloudflare only advertise the /24 without advertising an aggregate. Unless you're also getting a default from upstream, it sounds like you're going to end up wasting the money you saved on chasing down subtle brokenness. On Mon, Oct 10, 2022, at 9:58 AM, Edvinas Kairys wrote:
Hello, We're considering to buy some Cisco boxes - NCS-55A1-24H. That box has 24x100G, but only 2.2mln route (FIB) memory entries. In a near future it will be not enough - so we're thinking to deny all /24s to save the memory. What do you think about that approach - I know it could provide some misbehavior. But theoretically every filtered /24 could be routed via smaller prefix /23 /22 /21 or etc. But of course it could be a situation when denied /24 will not be covered by any smaller prefix. What do you think about this approach ? Also maybe you know - some advices for edge routers that have at least 8x100G interfaces and "good" memory for prefix count ? Thanks
Current thread:
- Re: any dangers of filtering every /24 on full internet table to preserve FIB space ?, (continued)
- Re: any dangers of filtering every /24 on full internet table to preserve FIB space ? Randy Bush (Oct 10)
- Re: any dangers of filtering every /24 on full internet table to preserve FIB space ? John Gilmore (Oct 10)
- RE: any dangers of filtering every /24 on full internet table to preserve FIB space ? Tobias Fiebig (Oct 10)
- Re: any dangers of filtering every /24 on full internet table to preserve FIB space ? Geoff Huston (Oct 10)
- Re: any dangers of filtering every /24 on full internet table to preserve FIB space ? richey goldberg (Oct 10)
- Re: any dangers of filtering every /24 on full internet table to preserve FIB space ? David Bass (Oct 10)
- Re: any dangers of filtering every /24 on full internet table to preserve FIB space ? Brandon Martin (Oct 21)
- RE: any dangers of filtering every /24 on full internet table to preserve FIB space ? Adam Thompson (Oct 24)
- Re: any dangers of filtering every /24 on full internet table to preserve FIB space ? Jon Sands (Oct 27)
- Re: any dangers of filtering every /24 on full internet table to preserve FIB space ? Jim Troutman (Oct 10)
- Re: any dangers of filtering every /24 on full internet table to preserve FIB space ? Elmar K. Bins (Oct 10)
- Re: any dangers of filtering every /24 on full internet table to preserve FIB space ? Mike Hammett (Oct 10)
- Re: any dangers of filtering every /24 on full internet table to preserve FIB space ? William Herrin (Oct 10)
- Re: any dangers of filtering every /24 on full internet table to preserve FIB space ? Jeff Tantsura (Oct 10)
- Re: any dangers of filtering every /24 on full internet table to preserve FIB space ? William Herrin (Oct 10)