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Community Member

STM-1 interfaces and 3CXL operation

Hi!

In our environment we have a 7609 router with RSP720-3CXL and several 76-ES+XT-2TG3CXL, all components are operating at 3CXL mode ( XL - is requirement because equipment holds full internet table). Now we have a need to add STM-1 interfaces to that box. As far as understood there is two ways to deploy STM-1 interfaces there:

1. SIP with SPAs

2. Enhanced FlexWan module with port adapters.

My main concern is 3CXL operation of a system. As far as I know whole system will work in the mode of lowest installed DFC type. So if I install SIP-600 (which is 3BXL) all my modules with DFCs will work in 3BXL mode. Sounds bad. Another problem is that I cannot find any information on what it will change. Couldn't find any information on differences between 3BXL and 3CXL. Somewhere I found that 3BXL has lower TCAM table 64k, 3xcl has 96k, but this is not a big concern to me.

As for FlexWan I couldn't even find in which mode this module works, somewhere I found that it is CEF256 module. But on other side It has its own memory and processors, so it's somehow taking part in distributed forwarding.

So my questions are:

1. What impact besides TCAM size it will have if I move from 3CXL to 3BXL?

2. Will Enhanced FlexWan module somehow affect operation of 76-ES+XT-2TG3CXL modules?

Does anyone have any idea on it?

Thanks in advance!

Best Regards

Kamil

1 ACCEPTED SOLUTION

Accepted Solutions
Hall of Fame Super Silver

Re: STM-1 interfaces and 3CXL operation

Hello Kamil,

>> I understand that Enhanced Flexwan doesn't have DFC onboard, but it has its own processor and memory, may be this could also affect DFC operation mode.

I don't think so because the flexwan does not have a link to the fabric, so it cannot be the cause of a downgrade

for this reason in your case the use of the flexwan might be a better choice even if a SIP linecard is more powerful

I would consider a SIP-400 instead of a SIP-600 for the same reason

I have a system similar (aligned with DFC 3BXL) with a SIP-400 installed this does not create problems to linecards with DFC

sh platform hard pfc mode

PFC operating mode : PFC3BXL

sh platform hard capacity

System Resources

  PFC operating mode: PFC3BXL

  Supervisor redundancy mode: administratively sso, operationally sso

  Switching resources: Module   Part number               Series      CEF mode

                       1        WS-X6724-SFP              CEF720          dCEF

                       2        WS-X6748-GE-TX            CEF720          dCEF

                       3        7600-SIP-400              CEF256           CEF

                       4        WS-X6708-10GE             CEF720          dCEF

                       6        WS-SUP720-3BXL        supervisor           CEF

Power Resources

in this case PFC mode is 3BXL, WS-6708 has a DFC 3 CXL on it but it works in DFC 3BXL mode. the SIP-400 does not create any problem to the other linecards

see C6500 architecture

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

enhanced flexwan performance data

http://www.cisco.com/en/US/products/hw/routers/ps368/products_white_paper09186a00801df1d8.shtml

I would point to SIP-400 for your needs, as SIP-600 may cause a little downgrade to 3BXL mode

Hope to help

Giuseppe

4 REPLIES
Hall of Fame Super Silver

Re: STM-1 interfaces and 3CXL operation

Hello Kamil,

flexwan has only access to 32 Gbps shared bus

sh platform hard capacity

System Resources

  PFC operating mode: PFC3B

  Supervisor redundancy mode: administratively rpr-plus, operationally rpr-plus

  Switching resources: Module   Part number               Series      CEF mode

                       1        WS-X6516A-GBIC            CEF256           CEF

                    >>>>>   2        WS-X6182-2PA             classic           CEF

                       3        WS-X6748-GE-TX            CEF720           CEF

                       4        WS-X6408A-GBIC           classic           CEF

                       5        WS-SUP720-BASE        supervisor           CEF

                       6        WS-X6724-SFP              CEF720          dCEF

                       7        WS-X6708-10GE             CEF720          dCEF

                       8        WS-SVC-FWM-1              CEF256           CEF

                       9        WS-X6708-10GE             CEF720          dCEF

C6500 architecture should allow to use the best mode between each linecard pair
as you see above there are dCEF 720, centralized CEF 720, CEF256 and classic modules in same chassis
Hope to help
Giuseppe

Community Member

Re: STM-1 interfaces and 3CXL operation

Hello Giuseppe.


Thank you for you information, but unfortunately it doesn't help in my situation.  WS-X6182-2PA module that is installed on your 65xx isn't supported on 76xx with RSP720 supervisors. The only option is Enhanced Flexwan module WS-X6582-2PA which as far as I know is fabric enabled. I understand that installation of this card won't affect switch fabric connections, I'm concerned on DFC operation mode.


Thanks anyway!

I found this in  ES line card hw installation guide:

The Distributed Forwarding Card (DFC) on a 7600 ES+ line card functions at the level of the lowest common denominator DFC in the system. If the only DFC in a system is a DFC 3CXL, then the system would operate at the 3CXL level. If a DFC 3CXL is configured in a system with a DFC3BXL present, then the system will function at the DFC 3BXL level. Additionally, a DFC 3CXL provides for more TCAM entries than does a DFC 3C.

Link: http://www1.cisco.com/en/US/docs/routers/7600/Hardware/Module_and_Line_Card_Installation_Guides/ES40_Line_Card_Installation_Guide/es40_chap1.html

I understand that Enhanced Flexwan doesn't have DFC onboard, but it has its own processor and memory, may be this could also affect DFC operation mode. 

Regards,

Kamil

Hall of Fame Super Silver

Re: STM-1 interfaces and 3CXL operation

Hello Kamil,

>> I understand that Enhanced Flexwan doesn't have DFC onboard, but it has its own processor and memory, may be this could also affect DFC operation mode.

I don't think so because the flexwan does not have a link to the fabric, so it cannot be the cause of a downgrade

for this reason in your case the use of the flexwan might be a better choice even if a SIP linecard is more powerful

I would consider a SIP-400 instead of a SIP-600 for the same reason

I have a system similar (aligned with DFC 3BXL) with a SIP-400 installed this does not create problems to linecards with DFC

sh platform hard pfc mode

PFC operating mode : PFC3BXL

sh platform hard capacity

System Resources

  PFC operating mode: PFC3BXL

  Supervisor redundancy mode: administratively sso, operationally sso

  Switching resources: Module   Part number               Series      CEF mode

                       1        WS-X6724-SFP              CEF720          dCEF

                       2        WS-X6748-GE-TX            CEF720          dCEF

                       3        7600-SIP-400              CEF256           CEF

                       4        WS-X6708-10GE             CEF720          dCEF

                       6        WS-SUP720-3BXL        supervisor           CEF

Power Resources

in this case PFC mode is 3BXL, WS-6708 has a DFC 3 CXL on it but it works in DFC 3BXL mode. the SIP-400 does not create any problem to the other linecards

see C6500 architecture

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

enhanced flexwan performance data

http://www.cisco.com/en/US/products/hw/routers/ps368/products_white_paper09186a00801df1d8.shtml

I would point to SIP-400 for your needs, as SIP-600 may cause a little downgrade to 3BXL mode

Hope to help

Giuseppe

Community Member

Re: STM-1 interfaces and 3CXL operation

Hello Giuseppe.

Thank you for your help. After your suggestion and some reading i finally made decision to go with SIP-400.  

Regards,

Kamil

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