When troubleshooting a slow network connection I wanted to get an idea of the link load. Usually I power up my linux-based Virtual Machine which polls the SNMP interface counters and draws nice graphs. But I was working remotely over an RDP connection, so SNMP was not possible.

So I had to use the build-in tools of the ProCurve switch. The “show interface” output looks like this:

Status and Counters - Port Counters for port 24

  Name  :
  Link Status     : Up
  Totals (Since boot or last clear) :
   Bytes Rx        : 819,265,344        Bytes Tx        : 1,217,179,587
   Unicast Rx      : 4,052,391          Unicast Tx      : 5,062,876
   Bcast/Mcast Rx  : 1,142,020          Bcast/Mcast Tx  : 7,390,717
  Errors (Since boot or last clear) :
   FCS Rx          : 0                  Drops Rx        : 0
   Alignment Rx    : 0                  Collisions Tx   : 0
   Runts Rx        : 0                  Late Colln Tx   : 0
   Giants Rx       : 0                  Excessive Colln : 0
   Total Rx Errors : 0                  Deferred Tx     : 0
  Rates (5 minute weighted average) :
   Total Rx  (bps) : 501944             Total Tx  (bps) : 504256
   Unicast Rx (Pkts/sec) : 0            Unicast Tx (Pkts/sec) : 0
   B/Mcast Rx (Pkts/sec) : 0            B/Mcast Tx (Pkts/sec) : 4
   Utilization Rx  : 00.04 %            Utilization Tx  : 00.04 %

Note the values on the bottom indicating the “Rates”? They’re not what they claim to be! This particular interface has approximately 1kbps input (Rx) and 3kbps output (Tx); not exactly the 500kbps the output claims. Also, try to explain how to receive 502kbps of data with less than 1 packet per second…

This particular switch is a 2610-24PWR with firmware R.11.16; but it’s probably a more general problem.

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