nanog mailing list archives
Re: Class D addresses? was: Redploying most of 127/8 as unicast public
From: William Herrin <bill () herrin us>
Date: Sat, 20 Nov 2021 11:51:24 -0800
On Sat, Nov 20, 2021 at 11:02 AM Michael Thomas <mike () mtcc com> wrote:
Even if it has some niche uses, I seriously doubt that it needs 400M addresses. If you wanted to reclaim ipv4 addresses it seems that class D and class E would be a much better target than loopback.
Hi Mike, If you follow the links there are multiple proposals split by the address space they apply to. There's one for 240/4 and another for 224/4 in addition to the one we've been discussing for 127/8. Obviously the one for 240/4 is the lowest hanging fruit of the bunch.
There is just as big a block of addresses with class D addresses for broadcast. Is broadcast really even a thing these days?
Multicast is not the same as broadcast and yes, it's a thing. Mainly it's a thing confined to the local broadcast domain but in that scope it's quite widely used. A lot of routing protocols (including OSPF) use multicast, for example. However, while it's widely used there aren't very many -different- things using it so only a tiny fraction of the 224/4 space has been assigned to anything in common use. If I had to guess, changing 224/4 is probably the biggest lift. The other proposals mainly involve altering configuration, removing some possibly hardcoded filters and in a few cases waiting for silicon to age out of the system. Changing 224/4 means following a different code path which does something fundamentally different with the packets -- unicast instead of multicast. Regards, Bill Herrin -- William Herrin bill () herrin us https://bill.herrin.us/
Current thread:
- Re: Redploying most of 127/8 as unicast public, (continued)
- Re: Redploying most of 127/8 as unicast public Matthew Walster (Nov 20)
- Re: Redploying most of 127/8 as unicast public Owen DeLong via NANOG (Nov 20)
- Re: Redploying most of 127/8 as unicast public Francis Booth via NANOG (Nov 23)
- Re: fun with TLDs and captive portals was, Redploying most of 127/8 as unicast public John Levine (Nov 23)
- Re: Redploying most of 127/8 as unicast public Masataka Ohta (Nov 20)
- Re: Redploying most of 127/8 as unicast public Måns Nilsson (Nov 20)
- Re: Redploying most of 127/8 as unicast public Masataka Ohta (Nov 20)
- Re: Redploying most of 127/8 as unicast public Chris Adams (Nov 20)
- Class D addresses? was: Redploying most of 127/8 as unicast public Michael Thomas (Nov 20)
- Re: Class D addresses? was: Redploying most of 127/8 as unicast public Jim (Nov 20)
- Re: Class D addresses? was: Redploying most of 127/8 as unicast public William Herrin (Nov 20)
- Re: Class D addresses? was: Redploying most of 127/8 as unicast public Michael Thomas (Nov 20)
- Re: Class D addresses? was: Redploying most of 127/8 as unicast public William Herrin (Nov 20)
- Re: Class D addresses? was: Redploying most of 127/8 as unicast public Michael Thomas (Nov 20)
- Re: Class D addresses? was: Redploying most of 127/8 as unicast public james.cutler () consultant com (Nov 20)
- RE: Class D addresses? was: Redploying most of 127/8 as unicast public Richard Irving (Nov 21)
- Re: Class D addresses? was: Redploying most of 127/8 as unicast public Eliot Lear (Nov 21)
- Re: Class D addresses? was: Redploying most of 127/8 as unicast public William Herrin (Nov 21)
- Re: Class D addresses? was: Redploying most of 127/8 as unicast public Greg Skinner via NANOG (Nov 22)
- Re: Class D addresses? was: Redploying most of 127/8 as unicast public Eliot Lear (Nov 23)
- Re: Class D addresses? was: Redploying most of 127/8 as unicast public William Herrin (Nov 23)