Cat6509 question

Answered Question
Feb 29th, 2008

Hello...

My question is, does supervisor engine with CatOS support L3 switching?

I was compare images CatOS and IOS and saw that common feature in both of them have IP Multilayer switching (IP MLS).

What that mean?

Thanks

I have this problem too.
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Correct Answer by Jon Marshall about 8 years 9 months ago

Hi

On the supervisor engine there is a PFC (Policy Feature Card) and an MSFC (Multilayer Switch Feature Card).

Among other things the PFC is repsonsible for the L2 and L3 forwarding of data.

The MSFC is repsonsible for establishing routing tables, creating the CEF table (CEF having replaced MLS as such) and pushing this down to the PFC. The MSFC is generally not responsible for forwarding data but without it there would be no layer 3 forwarding information for the PFC to use.

You can run a 6500 in two modes

1) Native mode - where IOS is used to configure both the l2 and L3 features.

2) Hybrid mode - where CatOS is used on the supervisor engine for forwarding data, QOS etc. and IOS is used on the MSFC for the establishement of forwarding tables etc.

So in summary a supervisor with CatOS cannot do L3 switching. Please see the attached link on the architecture of the 6500 for more details:-

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

HTH

Jon

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Correct Answer
Jon Marshall Fri, 02/29/2008 - 01:50

Hi

On the supervisor engine there is a PFC (Policy Feature Card) and an MSFC (Multilayer Switch Feature Card).

Among other things the PFC is repsonsible for the L2 and L3 forwarding of data.

The MSFC is repsonsible for establishing routing tables, creating the CEF table (CEF having replaced MLS as such) and pushing this down to the PFC. The MSFC is generally not responsible for forwarding data but without it there would be no layer 3 forwarding information for the PFC to use.

You can run a 6500 in two modes

1) Native mode - where IOS is used to configure both the l2 and L3 features.

2) Hybrid mode - where CatOS is used on the supervisor engine for forwarding data, QOS etc. and IOS is used on the MSFC for the establishement of forwarding tables etc.

So in summary a supervisor with CatOS cannot do L3 switching. Please see the attached link on the architecture of the 6500 for more details:-

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

HTH

Jon

aadilovic Fri, 02/29/2008 - 02:14

Thank you..

Some things are more clearer to me now...

I am thinking about conversion CatOS to IOS. Is that smart idea or not?

Have you some links about how to do that?

Thanks

Regards

Jon Marshall Fri, 02/29/2008 - 03:04

Hi

This is a rather large question so you need to have a read of the docs at the bottom of this response.

At a high level Cisco has made it clear that it sees the future as IOS on the 6500 switch. So any new features will be developed for IOS. It also depends on

1) What you are comfortable with. With the majority of Catalyst switches now running IOS anyway you may find it easier to have just IOS on your 6500's.

2) What features you absolutely must have. There are very few features that CatOS has that IOS doesn't, VTPv3 is the only one that springs to mind at the moment but you do need to make sure that all features you require are present in IOS. To be honest you would have to be fairly unlucky if they weren't.

3) There is also the "if it isn't broke, don't fix it" thing. Depending on how critical your 6500's are and how much downtime you can get to upgrade.

Below are 2 docs, one comparing running Native against Hybrid and the second covering how to upgrade to Native.

1) 6500 CatOS / IOS comparison

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps708/prod_white_paper09186a00800c8441.html

2) Upgrade CatOS to IOS

http://www.cisco.com/en/US/products/hw/switches/ps708/products_tech_note09186a008015bfa6.shtml

HTH

Jon

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