bus vs. crossbar fabric

[revlon2004]

what is bus enabled module and crossbar fabric

what these thing means?

32-Gbps bus—Allowing access to a central shared bus

•256-Gbps switch fabric—Located on the switch fabric module (SFM)

•720 Gbps switch fabric—Located on Cisco Catalyst 6500 Series Supervisor Engine 720

which one is better? how they differ?

[befthimi]

bus vs crossbar, basically refers to the two different methods employed by the catalyst 6500 to switch packets between interfaces/switchports.

With the introduction of the supervisor2 w/MSFC2, you had the option of purchasing a Switch fabric Module (SFM/SFM2). The SFM introduces the crossbar fabric. Without the SFM, the switch will use normal bus mode with a maximum backplane switching capacity of 32Gbps. Using the sup2 & SFM, you have a max of 256Gbps backplane switching capacity.

The sup720 has the SFM integrated into the supervisor itself. So no seperate SFM is required. The sup720 also increaded the maximum backplane switching capacity to 720Gbps.

For further details I encourage you to read the following architecture white paper:

http://www.cisco.com/en/US/partner/products/hw/switches/ps708/products_white_paper09186a0080092389.shtml

I hope this helps.

Bill.