What happens when the remaining 104 unassigned protocol numbers are exhausted?

hylaride 18 hours ago | parent | next [-]

We're about half-way to exhausted, but a huge chunk of the ones assigned are long deprecated and/or proprietary technologies and could conceivably be reassigned. Assignment now is obviously a lot more conservative than it was in the 1980s.

There is sometimes drama with it, though. Awhile back, the OpenBSD guys created CARP as a fully open source router failover protocol, but couldn't get an official IP number and ended up using the same one as VRRP. There's also a lot of historical animosity that some companies got numbers for proprietary protocols (eg Cisco got one for its then-proprietary EIGRP).

https://en.wikipedia.org/wiki/List_of_IP_protocol_numbers

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Ekaros 15 hours ago | parent | prev | next [-]

Probably use of some type of options. Up to 320 bits, so I think there is reasonable amount of space there for good while. Ofc, this makes really messy processing, but with current hardware not impossible.

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marcosdumay 18 hours ago | parent | prev [-]

People will start overloading the numbers.

I do hope we'll have stopped using IPv4 by then... But well, a decade after address exhaustion we are still on it, so who knows?

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kbolino 17 hours ago | parent [-]

IPv6 uses the exact same 8-bit codes as IPv4.

It uses them a little differently -- in IPv4, there is one protocol per packet, while in IPv6, "protocols" can be chained in a mechanism called extension headers -- but this actually makes the problem of number exhaustion more acute.

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brewmarche 15 hours ago | parent [-]

What if extension headers made it better? We could come up with a protocol consisting solely of a larger Next Header field and chain this pseudo header with the actual payload whenever the protocol number is > 255. The same idea could also be used in IPv4.

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kbolino 14 hours ago | parent [-]

I didn't mean to imply otherwise. But, as you say, this is equally applicable to IPv4 and IPv6. There were a lot of issues solved by IPv6, but "have even more room for non-TCP/UDP transports" wasn't one of them (and didn't need to be, tbqh).

	▲	brewmarche 9 hours ago \| parent [-]
		I agree, although I am a bit surprised to see that we’ve used more than half of the protocol numbers already