Nicolas Ruiz wrote: > Pepo wrote: >> In some paper Ive read that IPv6 have better performance in routing than IPv4, >> but I dont know why. > >> Please, can you tell me why is better/fast IPv6 for routing than IPv4? > > Routing with IPv6 and IPv4 are done esentially in the same way. The > "better performance" part of IPv6 routing comes from the way the IPv6 > header is built: it has a fixed size and (with few exceptions) an > intermediate router does not need to look at the packet options. It does have a fixed size, but so does IPv4. IPv6 has the concept of 'next header', and routers do have to check these as there might be Hop-By-Hop option headers in there. As such this is exactly the same as IPv4, except written down in a different way. The *real* speed increase is gained from the mere fact that IPv6 headers don't have any checksum. Routers decrement the IPv4 TTL/IPv6 HopCount. In IPv4 this means the checksum has to be recalculated, as there is no such checksum in IPv6, the router simply decrements and forwards the packet. This saves a few cycles of processing. Next to that core routers can be optimized to route on /48 boundaries, delegating longer prefixes to a secondary lookups. This all makes it much more efficient to forward a packet. Greets, Jeroen
Attachment:
signature.asc
Description: OpenPGP digital signature