[j-nsp] Netflow equivalent for MX5 11.4

[Phil Mayers]

On 06/08/2012 02:36 AM, Chris Kawchuk wrote:
> JunOS Routing for all intents and purposes is stateless.
>
> It doesn't cache information concerning the IP lookup (CEF-Style),

IOS hasn't worked like this for years. CEF is per-packet LPM, same as 
JunOS, on both CPU- and ASIC-based platforms. If you enable netflow, the 
box still creates/updates flows - but they're not (usually - see below) 
used for forwarding.

One minor caveat: if I remember correctly, there are some platform and 
feature combinations where the netflow cache is used to override 
CEF-based forwarding because some non-CEF action needs to be taken - for 
example, the NAT functionality on the 6500/sup720 is, IIRC, implemented 
by punting the first packet to CPU, and building a flow entry that 
contains the NAT rewrite for 2nd and subsequent packets. However, these 
are very much the exception.

Cheers,
Phil