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 >
