Re: [Devmon] New template for collision detection on Cisco 3550

[Buchan M. <bg...@st...>]

On Friday 04 April 2008 16:03:33 W.J.M. Nelis wrote:
> Hello,
>
> we've been using Hobbit / Devmon for a few months now. One problem we found
> is that often high collision (red) rates were reported on back-up trunks.
> It was found that this is caused by using the variable ifOutPktsSec, the
> average number of packets per second. However, if the number of packets per
> 5-minute interval is less than 300, this variable will have the value zero.
> This causes the value of the collision rate to become 1.0. On a back-up
> trunk, the packet-rate often is less than 1.0 packet per second.
>
> We've modified the templates of cisco_3550/if_col in the following way:
>
> [hobbit if_col]$ cat oids.old
> ifName          : .1.3.6.1.2.1.31.1.1.1.1       : branch
> ifAlias         : .1.3.6.1.2.1.31.1.1.1.18      : branch
> ifBps           : .1.3.6.1.2.1.2.2.1.5          : branch
> ifOutCollisions : .1.3.6.1.4.1.9.2.2.1.1.25     : branch
> ifOutPktsSec    : .1.3.6.1.4.1.9.2.2.1.1.9      : branch
> [hobbit if_col]$ cat oids
> ifName                  : .1.3.6.1.2.1.31.1.1.1.1       : branch
> ifHCOutUcastPkts        : .1.3.6.1.2.1.31.1.1.1.11      : branch
> ifHCOutMcastPkts        : .1.3.6.1.2.1.31.1.1.1.12      : branch
> ifHCOutBcastPkts        : .1.3.6.1.2.1.31.1.1.1.13      : branch
> ifAlias                 : .1.3.6.1.2.1.31.1.1.1.18      : branch
> ifOutCollisions         : .1.3.6.1.4.1.9.2.2.1.1.25     : branch
>
> [hobbit if_col]$ cat transforms.old
> # Convert our total ifc octets(bytes) into bits
> ifOutCps        : DELTA         : {ifOutCollisions}
>
> # Create our REAL packets per second
> ifOutPps        : MATH          : {ifOutCps} + {ifOutPktsSec}
>
> # Determine percentage of packets that are collisions
> ifOutColPct     : MATH          : ({ifOutCps} / {ifOutPps}) x 100
>
> # Create an alias in a bracketed box, or nothing if alias is blank
> ifAliasBox      : REGSUB        : {ifAlias} /(\S+.*)/ [$1]/
>
> [hobbit if_col]$ cat transforms
> # Fetch output packet rates and the collision rate
> ifOutUP         : DELTA         : {ifHCOutUcastPkts}
> ifOutMP         : DELTA         : {ifHCOutMcastPkts}
> ifOutBP         : DELTA         : {ifHCOutBcastPkts}
> ifOutC          : DELTA         : {ifOutCollisions}
>
> # Compute the total output packet rate, such that the collision ratio
> # is at most 1.00
> ifOutPkts       : MATH          : {ifOutUP} + {ifOutMP} + {ifOutBP} +
> {ifOutC}
>
> # Determine number of collisions per 100 packets
> ifOutColPct     : MATH          : ({ifOutC} / {ifOutPkts}) x 100
>
> # Create an alias in a bracketed box, or nothing if alias is blank
> ifAliasBox      : REGSUB        : {ifAlias} /(\S+.*)/ [$1]/
>
>
> Since this modification, we haven't had a single false red on
> collision-rate.

From an initial look, it looks correct, but I won't have time to 

Just to assist in seeing the differences, and applying them, can you post 
diffs instead, e.g. the output of:

diff -u transforms.old transforms


Regards,
Buchan