But in fact with local number portability, you cannot rely on the county code to tell you where to route a telephone call anymore. Which is many calls result in a data dip to provide you the routing information from a central repository. Shane On Tue, Sep 14, 2021 at 10:07 AM Masataka Ohta < mohta@necom830.hpcl.titech.ac.jp> wrote:
Eliot Lear wrote:
Operators and router manufacturers at the time pushed TUBA, which was considerably less compatible with the concepts used in v4 because of variable length addressing.
That address length is variable is not a problem at all. Byte-wise barrel shifters by hardware for CLNP are trivially easy and light weight to implement.
The real problem is on the number of prefix bits which must be looked up by backbone routers, which means IPv6 abandoning TLA is hopeless.
NSAP addresses, which essentially are telephone numbers, assume geographically aggregated addresses at country level (so called, country code), which is why they don't need large global routing tables.
8+8 has nothing to do with the problem and LISP came a lot later as a broken solution for the problem.
Masataka Ohta