Cisco 6500 Module Compatibility and Design Suggestions

[caplinktech]

Hi,

We are looking for some suggestions on how to best design a new network deployment that will give the best bang for the buck while still allowing us to grow capacity with as few hardware changes as possible.

The big dilemma that we are having is our need for IP transit redundancy despite initially low throughput requirements (<300Mbps).  Despite our initial, low throughput requirements, we would like a solution that we can scale to 10-20Gbps of throughput with minimal infrastructure changes.

Our initial thought was going the Catalyst 6500 route, however, the latest supervisor engines would put us a bit over the budget that we would really like to stay within for the initial deployment and the Sup720-3B which would keep up within budget does not support the full routing tables.  Budget wise we would really like to stay under $16,000 for initial hardware costs.  Because of this, the second thought that came to mind was deploying with 7200 series routers with NPE-G1s and use 3750G switches as an aggregation switch.  This second option would allow us to take the full routes while still being able to handle the initial throughput we require.

The problem is that the 7200 route has extremely limited scability and would require a migration to the 6500 platform at some point.

With all that in mind, I have several questions regarding the compatibility of various modules of the 6500 platform and how we may limit our initial costs while still being able to grow as needed.

1.  If we take partial routes from 3 different transit providers and use a default route, the Sup720-3B should be able to handle this correct?

2.  If we use the Sup720-3B, can we immediately upgrade to WS-F6700-DFC3BXL on WS-X6748-GE-TX line cards and maintain compatibility with the Sup720-3B while providing a seemless upgrade path to the Sup720-3BXL/RSP720-3CXL without the need to change daughter cards on the line cards?

3.  Same question as 2 in regards to the WS-F6K-DFC3BXL on the WS-X6548-RJ-45 Line card.

4.  A more general question with the same requirements as question 2 for the WS-X6816-GBIC...What is the appropriate daughter card for DFC for this module, all documenation I read references DFC3A card, I assume there is a newer daughter card for this module as well.

5.  If a WS-X6548-RJ-45 is used in the same chassis as the WS-X6748-GE-TX (both with the appropriate DFC3 daughter cards), will the X6548 cause the performance of the X6748 to be scaled back?  Same question in regards to the X6816 (could not find a newer card supporting fiber ports).

I know there is a lot of questions being asked and numerous variables, however, I would appreciate whatever feedback that you are able to offer.

[caplinktech]

Any info or suggestions?

Should this be posted in a different forum?

[Edison Ortiz · Accepted solution]

1.  If we take partial routes from 3 different transit providers and  use a default route, the Sup720-3B should be able to handle this  correct?

3B's limit is 256k routes - if the aggregate of those routes is less than 256k, you should be fine.

2.  If we use the Sup720-3B, can we immediately upgrade to WS-F6700-DFC3BXL on WS-X6748-GE-TX line cards and maintain compatibility with the Sup720-3B while providing a seamless upgrade path to the Sup720-3BXL/RSP720-3CXL without the need to change daughter cards on the line cards?

The switch will run on its lowest denominator which is 3B, even if you have 3BXL on the DFCs.

3.  Same question as 2 in regards to the WS-F6K-DFC3BXL on the WS-X6548-RJ-45 Line card.

Same answer

4.  A more general question with the same requirements as question 2 for the WS-X6816-GBIC...What is the appropriate daughter card for DFC for this module, all documentation I read references DFC3A card, I assume there is a newer daughter card for this module as well.

The Release notes indicates the module supports 3BXL as well

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/release/notes/hardware.html#wp3752951

5.  If a  WS-X6548-RJ-45 is used in the same chassis as the WS-X6748-GE-TX (both  with the appropriate DFC3 daughter cards), will the X6548 cause the  performance of the X6748 to be scaled back?  Same question in regards to  the X6816 (could not find a newer card supporting fiber ports).

6548 are dCEF256 while 6748 are dCEF720. They both connect to the fabric instead of the bus but dCEF256 only provides 8Gbps while dCEF720 provides 20Gbps

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps708/prod_white_paper0900aecd80673385.html

• dCEF256: These line cards require the presence of the switch fabric to operate-these line cards do not connect into the shared bus.

• dCEF720:  Like the dCEF256 linecards, they only require the switch fabric to be  present to switch packets. They connect into the switch fabric channels  at 20Gbps as opposed to the 8Gbps that the dCEF256 linecards connect.

[caplinktech]

Hi Edison,

I appreciate your reply.  Most seemed to have been answered however, I have a few clarifying/followup questions:

1.  That is what I expected, perfect.

2/3.  So I can use the 3BXL DFCs and they will function without a problem, except I would get the performance level of a 3B, I expected nothing more, perfect.  Would I be correct to assume them if I upgraded the Supervisor to a RSP720-3CXL, I would be limited to the performance of a 3BXL until the DFC were upgraded or would this configuration not function?  Can I simply start with a DFC-3CXL for the cards that support it from the outset and still have compatibility with the Sup720-3B?

4.  Thanks, I was looking in the release notes for 6816 card and found nothing, didn't think of checking the IOS release notes.

5.  I was aware of the differences in the channel fabric connection speeds, however, what I was unsure of was if the cards were mixed in the chassis, if the switch would downgrade to the lowest speed card.  The whitepaper you linked to seems to confirm that 8 Gbps would operate at 8Gbps and dual channel 20 Gbps would operate at full speed in a mixed chassis confirming each slot is independent.  What doesn't seem to be clear is what happens in one card is using a DFC and another is not.  Will the lines cards with a DFC use the full 20Gbps fabric or would they be limited unless all cards use a DFC.

Do you think that this is the better way to go as opposed to the 720X and 3750s?  I personally think it is a no brainer, but I would appreciate your/others input.

[Edison Ortiz]

Would I be correct to assume them if I upgraded  the Supervisor to a RSP720-3CXL, I would be limited to the performance  of a 3BXL until the DFC were upgraded or would this configuration not  function?  Can I simply start with a DFC-3CXL for the cards that support  it from the outset and still have compatibility with the Sup720-3B?

Yes.

What doesn't seem to be clear is what happens in one card is using a DFC  and another is not.  Will the lines cards with a DFC use the full  20Gbps fabric or would they be limited unless all cards use a DFC.

the DFC module will communicate to the non-DFC module via the PFC. IOW, DFC speed to the PFC will be 20Gbps (40 Gbps for dual fabric modules). From the PFC to the non-DFC module, it will use the bus.

Do you think that this is the better way to go as opposed to the 720X  and 3750s?  I personally think it is a no brainer, but I would  appreciate your/others input.

Hard to say without a formal evaluation. It is your call.