fwiw - we tried to explain the decision process in RFC 1752 Scott > On Nov 1, 2021, at 4:06 PM, Stewart Bryant <stewart.bryant@xxxxxxxxx> wrote: > > > > Sent from my iPad > >> On 1 Nov 2021, at 19:49, Brian E Carpenter <brian.e.carpenter@xxxxxxxxx> wrote: >> >> Somebody whose email never reaches my inbox alledgedly said: >> >>>> IPv6 with unnecessarily lengthy 16B addresses without valid >>>> technical reasoning only to make network operations prohibitively >>>> painful is a garbage protocol. >> >> Apart from its incivility, this sentence is factually untrue. The address >> length was 8 bytes in the early design of what became IPv6, which was of >> course essential to overcome the main limitation of IPv4. > > There were other techniques of course such as IPv4 in IPv4 which would allowed existing network kit to largely be used unchanged, and would probably have given fewer migration issues. > > However you cannot refute a criticism of IPv6 having 128bit addresses by arguing that it started with 64bits because it does actually have 128 bit addresses. > >> It was expanded >> to 16 bytes when the value of an interface identifier in addition to >> a routeable prefix was considered.That idea was based on existing >> practice in several non-IP network technologies, and on the IPng >> requirements process. In other words, on technical reasoning and on >> running code. > > Of course variable length and multi-address family approaches existed at the time, and were rejected. One of the reasons for this was politics, in particular a desire not to use an ISO protocol. There was also a counter argument based on forwarder performance, but there were ISO routers that were of comparable speed. > >> >> Professionalism includes factual accuracy. > > It also includes reviewing if the right decisions were taken so we learn from history. > > Stewart > >> >> Brian >> >
