[nsp] Catalyst 5000(5500) over 4000(4500)???

[David Sinn]

The 5000 has a single 1.2 Gig switching bus.  The 5500 series has three
1.2 Gig switching buses, and depending on platform the line cards touch
one of those buses based on slot (exception being some line cards that
can touch all three if they are in certain slots).  Sup2's bridge all
three of the buses into one 1.2 Gig bus, while the Sup3 runs each
independently and does some special work to move packets between the
buses.  There is shared intelligent between the line cards and the
supervisor, with each taking part in the overall flow of packets.  CatOS
is you only option in the 5000 series.


The 4000 series is an entirely different beast, but also varies
depending on the Supervisor you choose.  In a nutshell the line cards
are little more then media converters.  There is not a bus per-say, but
rather the equivalent of 6 Gig ports per line card slot.  How those 6
ports are leveraged is based on the line card that you use:  6 ports of
non-blocking Gig, 14/18 ports Gig with some being oversubscribed,
48-ports of 10/100 muxed into 6 Gig streams, etc.

Depending on the Supervisor you choose will get you different levels of
performance:

The SupII effectively segments the box in to three groups of 10 Gig
ports (2 per slot for each of the five slots).  These group of 10 ports
are then switched by an independent ASIC.  The three ASIC's are then
linked together by either 1 or 2 Gig's, depending on whether you enable
the two Gig ports on the Supervisor.  You can only run CatOS on the
SupII.

The SupIII & SupIV is a 32Gig switch, where all of the ports (30 for the
line cards & two on the front of the Sup) land on one ASIC who centrally
switches them.  You also gain L3 routing abilities with these
Supervisors, and must run IOS on them.


Your overall bandwidth requirements & projections should probably
dictate what platform you choose.  Either can work well as long as you
understand their respective performance envelopes, and plan accordingly.

David

-----Original Message-----
From: mac at telvia.it [mailto:mac at telvia.it] 
Sent: Wednesday, April 16, 2003 7:06 AM
To: cisco-nsp at puck.nether.net

Hi all,

i have to upgrade our network core. I have to choose between a new 4005 
or a used 5000 (supervisor 2). Someone can explain the main difference 
between the two series (apart the 5000 is EOL).

Regards

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