[nsp] Architecture question

[Burns, Keith]

Please note that all this is to the best of my recollection:

Essentially the CxBus, CyBus and CzBus are from the 7500.

CyBus was a clocking improvement on the CxBus. Both had separate 32bit buses
for "address/instruction" and "data"

CzBus took the 32bit "address" portion of the Cx/CyBus and the 32-bit "data"
portion of the bus and interleaved address and data words over the combined
buses making it 64-bit and hence 64-bit words.

I forget exactly which RSPs introduced which buses but from memory I believe
the RSP4 onwards was CzBus, but it MIGHT be a gen higher than RSP4,
definitely not lower.

Hope this helps.

Keith Burns
Principal Network Architect
ICG Telecommunications
IP Ph: 303-414-5385
Cell:   303-912-3777 

"The dogs may bark, but the caravan rolls on...."


> -----Original Message-----
> From: sthaug at nethelp.no [mailto:sthaug at nethelp.no]
> Sent: Friday, December 19, 2003 10:23 AM
> To: ringwyrm27 at comcast.net
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [nsp] Architecture question
> 
> 
> 
> > I see references littered throughout the internet to the CzBus
> > architecture.  Are there any good documents on this?
> 
> None that I know of. However, I don't see the Czbus as all 
> that relevant
> today.
> 
> > Is the 3600, 3700, 7600, & 2600 series routers architectures
> > documented anywhere?  In detail like the IOS book?  Are they CyBus,
> > CzBus?
> 
> 2600, 3600 and 3700 are traditional "one processor does all the work"
> routers. Yes, they are modular - but the NM / WIC / VIC cards are all
> passive in the sense that they don't make any forwarding descisions.
> 
> 7600 is really a 6500 in disguise. This is a rather complex box,
> with one of the most important characteristics being that almost all
> packet handling is done in hardware. This includes normal IP routing/
> forwarding, policy routing, and also for instance access lists. The
> 7600 *can* be distributed (line cards with independent forwarding
> using a DFCx, e.g. the 6816 16-port GigE card), and it can also be
> centralized (forwarding decisions done by the PFCx).
> 
> Steinar Haug, Nethelp consulting, sthaug at nethelp.no
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