Re: Notes about identifier - locator separator

[Frank Kastenholz <fkastenholz@juniper.net>]

At 11:59 AM 11/8/2002 -0500, J. Noel Chiappa wrote:
>   > That doesn't work e.g. for the passive side of a TCP conenction where
>    > the transport protocol, and often not even the application, do a DNS
>    > lookup. Unless you carry a source identifier plus a list of source
>    > locators in e.g. the TCP SYN packet.
>
>Yes, exactly. If you implement it as an IP option (I first thought of a TCP
>option, but then every transport would have to define the same functionality,
>and some e.g. UDP can't), then it has the added benefit that hosts which
>don't understand it can ignore it, at some loss in functionality/robustness.

The presence of IPv4 options in a packet header cause the IPv4
packet to be kicked out of the silicon-path of many of today's
high speed routers. Given that history, I could easily forsee
a silicon-forwarder for IPv6 that kicks packets to the slow
path if the next-header field is _not_ one of several known
values (on the theory that if the next header is not X, Y, or Z
then there _might_ be something in there that the router needs
to look at...). This has undesired effects on throughput.


Frank Kastenholz