DFC memory on 6500

[Antonio_1_2]

Hello,

does anybody knows what is used DDR memory on DFC on linecards for Cisco 7600 or Catalyst6500?

I thought that DFC has copy of TCAMs from PFC. That PFC only has TCAMs, and it doesn't have DRAM on itself?

I've been said that if I have full BGP table in memory on supervisor on 6500 (that should be DRAM on RP on MSFC) that I also need 1GB additional memory on DFC on linecards? Is this true? But that should implied that DFC also has copy from MSFC not only from PFC, is this correct?

thanks in advance,

A

[nkarpysh]

Hi Antonio,

Basically DFC has only copy of PFC tables - actually FIB and LFIB and some other TCAM tables. But as you have big Routing table on MSFC - that in turn would cause FIB table to become big too, so TCAM tables also getting begger on PFC and DFC.

However DRAM on DFC is capable to handle only particular routes in FIB TCAM - thus as that number grows - your old DRAM is not able to support it and so it should be also upgraded.

Nik

[Antonio_1_2]

Hi,

thank you very much for your answer Nik but I'm still confused regarding the purpose of a DRAM on DFC cards.

Can you please clarify me with answering which of these statements are true:

1) DFC has only TCAMs on the board. PFC TCAMs content is copied directly to DFC TCAMs. DRAM is not needed at all.

2) MSFC copies FIB and Adj tables from RP DRAM to DFC DRAM, and than DFC creates TCAM on its own. (this should be because you cannot copy directly the content from one TCAM to another one)?

3) DFC TCAMs don't contain full FIB and Adj tables. They correlate somehow with DRAM(caching?), so it is mandatory to have DRAM as well.

Thanks,

A

[Antonio_1_2]

Hi,

If anyone can help me with prevous post please.

Does anybody know maybe which one of the statemenets are true?

Regards,

A

[nkarpysh · Accepted solution]

Hi,

Basically copy from PFC TCAM is not done directly to DFC TCAM - it is passing through Line card software first - which is indeed handled by DRAM where LC has it's image.

So to handle all thos routes in PFC TCAM we need to copy those first to DRAM on LC and then store in HW.

Thus DRAM also need to be of particular size.

Hope this helps.

Nik

[Antonio_1_2]

Thank you very much Nikolay

regrds,

A