[e2e] Question about fast path / slow path and IPv6

Cannara cannara at attglobal.net
Sat Aug 30 21:31:42 PDT 2003


Note also that routers aren't the only elements in a path that can be affected
by IP options -- load balancers, firewalls, security gateways, etc. all
process pkts in much the same way as routers with respect to Layer 2, but
since they're built by a variety of vendors, using a variety of processing
hardware and architectures, and programmed by a variety of people, they may
well do things that appear very good or very poor when pkts with options

To get an assessment of what kinds of behaviors to expect, it's probably
worthwhile contacting some of the 3rd-party software vendors, like Level7, to
see how their Layer 2 code works in various almost-end systems.


RJ Atkinson wrote:
> On Saturday, Aug 30, 2003, at 05:43 America/Montreal, Michael Welzl
> wrote:
> > This goes to the router people out there:
> >
> > Is IP fast path / slow path processing (for packets carrying
> > IP options) similar for IPv4 and IPv6 in most current routers?
> The answer depends *entirely* on which hardware one is talking about.
> Some products can handle IP packets (with or without options)
> at wire speed (usually because this is done in hardware).
> Other products cannot do so -- in which case only packets without
> options are "fast path" and packets with options are "slow path".
> This last case includes all (or nearly all) routers that use
> CPU-based packet forwarding.
> "Most" could mean the the largest-volume deployments of a single
> router model, in which case ask your nearest vendor C salesperson
> what they do.  I'm assuming "most" means "most vendors" in the
> quoted text above.
> Ran
> rja at extremenetworks.com

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