Line card options

[sg_network]

We are trying to buy fews line card.. but there are many options per line card...

I am not sure... what is exactly and what is the affect ... pls help to guide.. if possible...

For example,      Line card WS-X6748-GE-TX                    Cat6500 48-port 10/100/1000 GE Mod: fabric enabled, RJ-45

Why do we need to buy 256 / 512 / 1G Mem?

( 1 )          MEM-XCEF720-256M          Catalyst 6500 256MB DDR, xCEF720 (67xx interface, DFC3A)

( 1 )          MEM-XCEF720-512M          Cat 6500 512MB DDR, xCEF720 (67xx interface, DFC3A/DFC3B)

( 1 )          MEM-XCEF720-1GB                    Catalyst 6500 1GB DDR, xCEF720 (67xx interface, DFC3BXL)

Also... There are fews Central Fwd vs Dist Fwd.. where should I get more info this..

( 1 )          WS-F6700-CFC         Catalyst 6500 Central Fwd Card for WS-X67xx modules

( 1 )          WS-F6700-DFC3B     Catalyst 6500 Dist Fwd Card, 256K Routes for WS-X67xx

( 1 )          WS-F6700-DFC3BXL                    Catalyst 6500 Dist Fwd Card- 3BXL, for WS-X67xx

( 1 )          WS-F6700-DFC3C     Catalyst 6500 Dist Fwd Card for WS-X67xx modules

( 1 )          WS-F6700-DFC3CXL          Catalyst 6500 Dist Fwd Card- 3CXL, for WS-X67xx

Thanks

John

[darren.g]

John SG wrote:
We are trying to buy fews line card.. but there are many options per line card...
I am not sure... what is exactly and what is the affect ... pls help to guide.. if possible... 
For example,      Line card WS-X6748-GE-TX                    Cat6500 48-port 10/100/1000 GE Mod: fabric enabled, RJ-45
 Why do we need to buy 256 / 512 / 1G Mem?
( 1 )          MEM-XCEF720-256M          Catalyst 6500 256MB DDR, xCEF720 (67xx interface, DFC3A)
( 1 )          MEM-XCEF720-512M          Cat 6500 512MB DDR, xCEF720 (67xx interface, DFC3A/DFC3B)
( 1 )          MEM-XCEF720-1GB                    Catalyst 6500 1GB DDR, xCEF720 (67xx interface, DFC3BXL)
Also... There are fews Central Fwd vs Dist Fwd.. where should I get more info this..
( 1 )          WS-F6700-CFC         Catalyst 6500 Central Fwd Card for WS-X67xx modules
( 1 )          WS-F6700-DFC3B     Catalyst 6500 Dist Fwd Card, 256K Routes for WS-X67xx
( 1 )          WS-F6700-DFC3BXL                    Catalyst 6500 Dist Fwd Card- 3BXL, for WS-X67xx
( 1 )          WS-F6700-DFC3C     Catalyst 6500 Dist Fwd Card for WS-X67xx modules
( 1 )          WS-F6700-DFC3CXL          Catalyst 6500 Dist Fwd Card- 3CXL, for WS-X67xx
Thanks
John

What do you want the cards to do?

The different models have different performance levels - the line cards with DFC modules, for example, have a much higher forwarding rate, but also need a supervisor engine which has the associated DFC module attached - which may not necessarily be there.

The memory you quoted is used to provide packet buffers - the more you have (up to a limit), the better you can perform in heavily loaded environments - in a CEF/DFC environment. If you don;t have the DFC module in your dupervisor, then you don't need it.

The Cisco specifications for the WS-X6748-GE-TX module you're looking at state it is ONLY supported on the Cat 6500 with a Sup720 (or better), so if you don't have at least one of those in your Cat6500, then don't bother buying this line card (or plan to upgrade your Sup at the same time). The DFC setups provide faster inter-card switching than a CFC setup does, and *may* improve intra-card switching as well.

You really should contact your Cisco sales rep for a more definitive response on what they have which will meet your needs - they'll know far, far more about what will fit your environment than anyone here possibly could.

Cheers.

[Joseph W. Doherty]

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Posting

Picking a line card for a 6500 can be complex.  There are often interdependencies between cards, and often many considerations for choosing a card and its options dependent on intended usage.

Darren, for example, mentioned the 6748 requires a Sup720 (or better), but it also can have slot dependencies within the 6513 chassis.

The 6748 (CFC) uses the main sup for forwarding traffic decisions.  A DFC adds local forwarding decision capability.  As a sup720B only has 15/30 Mpps for whole chassis, the DFC would be needed to handle high bandwidth usage.

XL Supervisor and DFC variants can handle 4x the number of routes as the non-XL variants, although many internal busines networks don't need this capacity.

As Darren also suggested, you probably should obtain consultation, and your Cisco sales rep would be a good place to start.  However, Cisco recommendations tend to be very conservative, so you might also want to obtain an independent recommendation too.