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Community Member

6516A Architecture

Hi All,

Is there any detailed documentation on the architecture of the WS-X6516A-GBIC Linecard. From previous threads I have gathered that this line card is 2:1 oversubscribed because it has a single 8 Gb connection to the fabric. However in my case there is no SFM and this is a supervisor 2 chassis .

1.Since this is a CEF 256 line card it also has a connection to the local bus. So would it be correct to say that the Fabric Asic connects into the 16Gb Local bus and all data traffic would flow across this connection. How would the oversubscription work in this case?

2. I believe there are 2 x port Asics on this card with 8xports per Port Asic. The port ASIC connects to the fFabric ASIC and the Fabric ASIC and that in turn connects to the Local 16Gb bus etc. What is the connection between the Port ASIC and the Fabric ASIC?


Hall of Fame Super Silver

Re: 6516A Architecture

Hello Vdadlaney,

if your chassis has sup2 and no SFM all you have is the connection to the shared bus 33 Gbps shared bus for all the chassis

Single 8 Gbps channel connection to switch fabric (on Supervisor Engine 720 or Supervisor Engine 2-MSFC2 with Switch Fabric Module {SFM]) and 32 Gbps shared bus connection

I agree on the possible internal architecture of the linecard

Hope to help


Community Member

Re: 6516A Architecture

There are 4 ASIC's with 4 ports per ASIC:

See the white paper that disusses this modules architecture...

Hall of Fame Super Blue

6516A Architecture

Re the oversubscription issue. Impossible to say really if it using the 32Gbps shared bus. It really depends on how many other modules are using the shared bus. Also all cards, fabric and non fabric use the shared bus for forwarding the header (+ part of the packet in truncated mode) to the supervisor for a forwarding decision if running in CFC (Centralised Forwarding) mode.


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