said by HELLFIRE:
Rule of thumb... 6x00-series linecard, the higher X is, the higher the bandwidth?
meh. close. its not always 100% foolproof, as the series of linecard may vary in the mode of operation (6700, 6800 series especially).
from the whitepaper:
Cisco Catalyst 6500 Line Cards
The lineup of Cisco Catalyst 6500 line cards provides a full complement of media and speed options to meet the needs of deployment in the access, distribution and core layers of the network. Each line-card slot provides a connection into the 32-Gbps shared bus and the crossbar switch fabric (if either a Supervisor Engine 720 or switch fabric module is present). Cisco Catalyst 6500 line cards fall into one of four general families of line cards:
â¢ Classic: In this mode the line card has a single connection into the 32-Gbps shared bus.
â¢ CEF256: The line card in this mode supports a connection into the 32-Gbps shared bus and the switch fabric-these line cards will use the switch fabric for data switching when the Supervisor Engine 720 is present-if a Supervisor Engine 32 is present it will revert back to using the 32-Gbps shared bus.
â¢ CEF256 and CEF720: The line card in this mode supports a connection into the 32-Gbps shared bus and the switch fabric: these line cards will use the switch fabric on the Supervisor Engine720 for data switching.
â¢ dCEF256: These line cards require the presence of the switch fabric to operate-these line cards do not connect into the shared bus.
â¢ dCEF720: Like the dCEF256 linecards, they only require the switch fabric to be present to switch packets. They connect into the switch fabric channels at 20Gbps as opposed to the 8Gbps that the dCEF256 linecards connect.
keep these modes of operation in the back of your head. also keep in mind the difference between bus or fabric interconnects.
as you look at each card -- and their mode of operation/interconnect -- you start seeing patterns about different series of cards and how they interact with each other (yes -- what operationally exists is just as important as what you're buying).
this is why the c6k needs to go away. while the limitations of the chassis are documented -- its such a finicky platform and has limitations that are consistent with the growth of the technology at each interval of production. its a swiss army knife -- it'll whittle a stick, pick your teeth, and saw some small limbs -- but don't expect to skin a deer with it.
I'm also trying to get familar with the bandwidth limitations of the SUPs themselves -- 720 is 40Gbps per slot, and 2T is 80Gbps
per slot. To say nothing of the whole headache of keeping in mind Nexus and "Fabric Modules." Well, that's why types like us
draw a paycheck...
the sup throughput limitations are just a byproduct of the way the sup interfaces with the backplane fabric. nothing magical there. the magic of the sup is in the pfc and what version (if you're looking at s720/s2t) you're running. each pfc has slightly different features/improvements (pfc3a, pfc3b, pfc3c) over the previous generation. s2t runs pfc4 -- which is consistent with the nexus -- so there is a tighter parity of support between the two (within reason). the pfc is what does all of the "magic" (qos, acl, etc) -- and these limitations are just as important as the linecards -- because the c6k will shit the bed quite spectacularly if you exceed the hardware support within the pfc and its forced to punt excessive amounts of traffic.
this is to say nothing about the limitations of copp, etc -- which can also have undue effects if done incorrectly -- affecting even required traffic for production (i.e. glean traffic for arp queries, etc).
the c6k is a terribly idiosyncratic box that if you know it well -- can perform like a rockstar. if you don't -- its going to be a long trip with them.
"...if I in my north room dance naked, grotesquely before my mirror waving my shirt round my head and singing softly to myself..."