CEF 6509

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Feb 25th, 2009
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Hi.

One of our sites currently runs on a 6509 conhtaining a supervisor WS-X6K-SUP1A-2GE with PFC and MSFC2. I have learned that CEF requires supervisor 2 at least. On the switch CEF is enabled and populated. How is this possible? Is MLS using the CEF fib, or is it really CEF running? Im a bit confused...

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Giuseppe Larosa Wed, 02/25/2009 - 07:15
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Hello Andreas,


in any case the difference is between a flow based traffic based multilayer switching (sup1 msfc1)

and CEF based topology driven multilayer switching (sup2/MSFC2 and above for sure)


You have a sup1A and MSFC2


Cisco Catalyst 6000 series switches with Supervisor Engine I support MLS with a Multilayer Switch Feature Card (MSFC1 or MSFC2) and a Policy Feature Card (PFC). The MSFC2 with PFC2 perform Layer 3 (L3) switching using CEF. The Supervisor Engine 720, PFC3, and MSFC3 perform L3 switching with CEF for the PFC3. Refer to the document Configuring CEF for PFC2 and PFC3 for more information.


see


http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a0080133fc5.shtml#cat6500


Have you got a Native System ?

or it is in hybrid and you are looking at CEF entries on MSFC2 ?


This could explain what you see


a PFC2 is needed according the document linked above for CEF multilayer switching.


An MSFC2 can create its own CEF entries but they are not used to switch real traffic.


Hope to help

Giuseppe


martensa Wed, 02/25/2009 - 07:22
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Hi Giuseppe.


Well, the system is native, but i noticed that the config doesn't show 'ip cef'. The followin information is displayed with 'show ip cef summary';


IP Distributed CEF with switching (Table Version 188410), flags=0x0

2399 routes, 0 reresolve, 0 unresolved (0 old, 0 new), peak 0

2399 leaves, 253 nodes, 590616 bytes, 171662 inserts, 169263 invalidations

14 load sharing elements, 4704 bytes, 14 references

universal per-destination load sharing algorithm, id 1F5A110A

3(0) CEF resets, 16503 revisions of existing leaves

Resolution Timer: Exponential (currently 1s, peak 1s)

16761 in-place/0 aborted modifications

refcounts: 69582 leaf, 65024 node


Table epoch: 0 (2399 entries at this epoch)


Adjacency Table has 1330 adjacencies



So it sure looks like the CEF is running...

Giuseppe Larosa Wed, 02/25/2009 - 07:28
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Hello Andreas,

being native it is very likely it is working you can check with


sh mls


Probably you are in the "grey zone" and Sup1A has to be different from sup1 in some way.


is the PFC a PFC1 (PFC) or a PFC2 ?


Hope to help

Giuseppe


martensa Thu, 02/26/2009 - 00:43
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Good Morning..


It is a PFC1 (PFC). The 'sh mls ip' shows that mls is running. I didn't think mls was enable when the switch was running CEF. I thought it was either MLS or CEF.


So the switch is running both mls and cef, doesn't this seems odd?


/Andreas

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