What does it mean "fabric-enabled"

Discussion in 'Cisco' started by hktco, Oct 17, 2004.

  1. hktco

    hktco Guest

    Hi,

    What does it mean "fabric-enabled" in 6500 switches and how much
    difference is it between a normal module and a fabric-enabled module
    in terms of performance?

    hktco
     
    hktco, Oct 17, 2004
    #1
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  2. That the card supporting this connection will have more throughput
    available.
    If You have Sup2 and Switch Fabric Module and hardware-ready cards,
    read here:

    http://www.cisco.com/en/US/products/hw/modules/ps2797/ps742/index.html

    Alternatively, You can have Sup720, which integrates SFM and gives
    additional bandwidth to distributed forwarding ready cards.

    There was also session on Brisbane Networkers detailing all the
    architectural details and gotchas of 6500 family. I don't remember
    specific session number, but You can browse them here:

    https://www.conveneit.com/secure/cisco_networkers/client/default.asp?pg=4
     
    =?ISO-8859-2?Q?=A3ukasz_Bromirski?=, Oct 17, 2004
    #2
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  3. hktco

    stephen Guest

    performance depend son the set of modules you have fitted, and the traffic
    type and patterns.

    cat 6500s have a bus between the modules, and a "star wired" backplane as
    well.

    fabric enabled modules connect to both the bus and the star (with 1
    exception which is "star" only).

    The bus is always there, but you have to meet various conditions to use the
    star - a single box can be running in a mix of modes between different
    module pairs at the same time.

    if you have comms between 2 modules, and they are both fabric enabled, and
    you have a fabric (SFM or Sup 720), and everything is compatible, then layer
    2 traffic will go via the fabric and not the bus.

    if it is IPv4 routing and you want the traffic to avoid the bus, then you
    need MSFC / sup 720, and a DFC daughtercard on the module where the packet
    enters the switch. AFAIK any other protocol cant be routed via the star.
    Even with IP, some processing forces traffic either onto the bus, or to the
    CPU.

    then, your module may have 1 or 2 fabric taps, and the chassis may have some
    slots with only 1 fabric connection(6513), or all with 2.

    different modules operate at different speeds across the star wiring - SFM
    and 65xx modules do 8 Gbps per fabric tap, 67xx and Sup 720 do 20G, but the
    720 is backward compatible with 65xx......

    Finally, different DFCs are needed for different modules to do star layer 3
    forwarding (and some modules cant support DFC at all yet), and the DFC, MSFC
    / Sup combo has to be compatible with the s/w you run.

    the online config tool is the only easy way to get close to a working config
    if you have several card types in your mix - but it doesnt understand any
    obsolete module types and the rules that apply to them. at that point you
    start scanning the Rel notes.
     
    stephen, Oct 17, 2004
    #3
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