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New Member

With the MLS default settings on a 6500 with MSFC2 are there any benefits?

We have a pair of 6500's with sup2/msfc2's in our core. At this time we are not running SRM. We do not have MLS configured between the switch and the MSFC's. I see on the switch that by default MLS is enabled. I understand that on the msfc's this alos holds true for the vlan interfaces yet I do not see any line commands stating that. What benefit if any do I realize with the standard MLS default setup provided by Cisco? Does the router still take only the first packet and leave the remaining packets for the switch to route? If not why in default mode are MLS entrys listed?

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Accepted Solutions
New Member

Re: With the MLS default settings on a 6500 with MSFC2 are there

Sup2/MSFC2 uses CEF-based MLS. You cannot disable it. Unlike traditional MLS seen on Cat5k and earlier Sup1A, the first packet is not seen on the MSFC. The FIB (routing) and Adj (ARP) tables are programmed in HW before any packets are switched.

6 REPLIES
New Member

Re: With the MLS default settings on a 6500 with MSFC2 are there

Hi,

With SUP2, all packets are switched in hardware using CEF so the MSFC does not have to process the first packet.

The following link provides more details:

Catalyst 6000 and 6500 Series Architecture:

http://www.cisco.com/en/US/customer/products/hw/switches/ps708/products_white_paper09186a0080092389.shtml

New Member

Re: With the MLS default settings on a 6500 with MSFC2 are there

If I understand the information from the URL correctly in a sup2/msfc2 scenario layer 3 routing is on automatically and I don't need to use any of the global MLS commands on the MSFC2. What about in a sup1a/msfc2 scenario is there any benefit there? Since this is traffic-based switching do I then need the global definitions and the VTP parms on the vlans to utilize mls? Or is this again on by default?

New Member

Re: With the MLS default settings on a 6500 with MSFC2 are there

Sup2/MSFC2 uses CEF-based MLS. You cannot disable it. Unlike traditional MLS seen on Cat5k and earlier Sup1A, the first packet is not seen on the MSFC. The FIB (routing) and Adj (ARP) tables are programmed in HW before any packets are switched.

New Member

Re: With the MLS default settings on a 6500 with MSFC2 are there

Then when using sup2/msfc2 - you no longer need to have the global commands MLS RP IP or the vtp commands on the logical interfaces?

New Member

Re: With the MLS default settings on a 6500 with MSFC2 are there

Nope. Unless the MSFC also acts as an external MLS RP for another switch such as a Cat5500 with NFFC.

New Member

Re: With the MLS default settings on a 6500 with MSFC2 are there

Thanks

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