alt for @[email protected]Sep 21, 2018

Monday marks a quarter century of classless routing, or CIDR.

25 years since Class A, B, and C addresses were the standard.

On #CIDRDay, saying "class C address" outside a historic/ironic context is a request for enthusiastic wedgies.

Otherwise: cider!

How will you celebrate? #sysadmin #netadmin

Show threadthe Hearth Sep 21, 2018
@mwlucas Is there any simple way to explain to a non-networking electrical engineer what exactly this means? I'm curious!
Show threadalt for @[email protected]Sep 21, 2018

@Felthry As you're an electrical engineer, so I'll assume you know binary math.

An IPv4 address is a 32-bit number. Under classful routing, you can only divide networks by size on 8 bit boundaries: 8-bit, 16-bit, 24-bit. Most networks are 256 addresses, even if they only need 3 hosts.

With CIDR, you can divide networks on any bit you like.

Show threadthe Hearth Sep 21, 2018
@mwlucas That makes sense. Well, it doesn't make sense why they would design it that way but I guess they probably had a reason.
Show threadalt for @[email protected]
@Felthry The reason's easy. "The Internet's never going to go anywhere. We'll never have more than, say, three hundred hosts on it."
Sep 21, 2018 at 5:21pmWeb