[c-nsp] Sup32 Memory upgrade

[Tim Stevenson]

Right, NAT is a so-called "Netflow feature", it does not use the 
FIB/ADJ model for forwarding but rather a NF/ADJ model (it also 
leverages the ACL TCAM for the initial session redirection to the CPU).

In general packets are fwded by a FIB lookup pointing to a h/w 
adjacency, but that's not the only way - we can also point to an adj 
via the NF table or via an ACL lookup (eg, for PBR). All three 
lookups (FIB, NF, ACL) occur in parallel and the appropriate one 
overrides based on your configuration/features applied.

For example, for NAT, NF overrides ACL overrides FIB. If there is no 
existing NF entry for a session, the ACL lookup overrides the FIB & 
the packet is punted to the RP to set up the xlation and/or session. 
The s/w installs a NF entry in the h/w - the next packet in the flow 
matches the NF entry & that overrides the ACL & FIB results.

Tim

At 03:33 AM 5/2/2006, Yuri Selivanov quipped:
>      Hi.
>
>[snip]
>
> > >H/w NAT entries in PFC3 are bound by the size of the netflow table.
> > >Each NAT entry requires 2 NF entries, hence, you can get at most
> > >64K/128K (PFC3AB/BXL) NAT entries in h/w. For overload (PAT) case,
> > >each NAT entry requires 4 NF entries, so 32K/64K.
> >
> > Hi Tim,
> >
> >  Are you sure with regard to the sup720BXL ?
> > Or am I misunderstanding you ?
> >
> > gp1#sh mls cef maximum-routes
> > FIB TCAM maximum routes :
> > =======================
> > Current :-
> > -------
> >  IPv4 + MPLS         - 512k (default)
> >  IPv6 + IP Multicast - 256k (default)
>
>     As far as I understand that's not NF-entries info but IPv4.
>For NF-entries take a look-see at:
>
> 
>http://www.cisco.com/univercd/cc/td/doc/product/core/cis7600/software/122sx/swcg/nde.htm#wp1106378
>
>      .. or at official Sup720 data sheet.
>
> > gp1#sh module 7
> > Mod Ports Card Type                              Model              Serial
> > No.
> > --- ----- -------------------------------------- ------------------
> > -----------
> >   7    2  Supervisor Engine 720 (Active)         WS-SUP720-3BXL
> >   SAD090502PG
> >
> > [snipped]
> >
> > --
> > Thanks
> >    Rafi
>
>--
>Best Regards,
>Yuri Selivanov [URI2-RIPE]
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Tim Stevenson, tstevens at cisco.com
Routing & Switching CCIE #5561
Technical Marketing Engineer, Catalyst 6500
Cisco Systems, http://www.cisco.com
IP Phone: 408-526-6759
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