Re: MRTG for 6513 MSFC interface

chwing · ‎02-05-2003

Hi, I have created certain VLANs on MSFC. I FAIL to capture those VLANs traffic (after generating, it shows very very little network traffic, e.g. 3k-4k, that's impossible) from MRTG. But it worked for my older 5500 with RSM VLANs while using similar MRTG generation procedures. What's wrong with my 6513 MSFC? Attached is the 6513 MSFC IOS version for your reference.

Cisco Internetwork Operating System Software

IOS (tm) MSFC2 Software (C6MSFC2-DSV-M), Version 12.1(11b)E3, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)

TAC Support: http://www.cisco.com/tac

Compiled Thu 09-May-02 03:38 by hqluong

Image text-base: 0x40008980, data-base: 0x41772000

ROM: System Bootstrap, Version 12.1(4r)E, RELEASE SOFTWARE (fc1)

BOOTLDR: MSFC2 Software (C6MSFC2-BOOT-M), Version 12.1(8a)EX, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)

ecao · ‎02-12-2003

The reason is that Cat6K uses MLS. Cat6000 MLS documentation does state and explain how packets are switched through hardware (PFC) which means only the first packet in the flow will hit the MSFC (by default) so subsequent packets for the same flow will not hit the MSFC, in turn causing the counters on the VLAN interface to be inaccurate for the amount of traffic actually passing through the switch from say one VLAN to another.

The best way to solve this is to get a NAM (Network Analysis Module) for your Cat6K or an RMON probe. Then you can get your VLAN stats via RMON.

Hope this helps.

--Eugene