[F10-nsp] code to determine IfIndex

[Jo Rhett]

If you build your own internal management tools, you may have found the 
following page lacking in useful details:
   https://www.force10networks.com/CSPortal20/KnowledgeBase/SNMPFAQ.aspx

Well, using that information and snmpwalk output, I found the following 
code to determine the IfIndex.

The only gotcha is that you really need to know the card type to get the 
interface index, which I think blows chunks.  So to use this script you 
may need to modify the cardtype value to match your environment.  The 
script as published below assumings slot 0-1 contains 24-port SFP cards, 
and all other slots contain 48-port copper cards.

#!/usr/local/bin/perl
my $slot = $ARGV[0];
my $port = $ARGV[1];

my $cardtype = 49209;  # bits 1-18
if( $slot < 2 ) {
         $cardtype = 49208;  # sfp cards in slot 0-1
}
my $portmultiply = 262144; # bits 19-25
my $slotmultiply = 33554432; # bits 26-30

my $ifindex = ( ($slot + 1) * $slotmultiply) + ( ($port + 1) * 
$portmultiply) + $cardtype;

print "Ifindex for gi${slot}/${port} = $ifindex\n";

exit 0;

-- 
Jo Rhett
senior geek
Silicon Valley Colocation