Network Performance Counters

The network performance counters are not typically installed. The Network Segment object that is referred to here is installed when the Network Monitor Agent is installed. The network interface is installed when the SNMP service is installed. Many of the counters have to do with TCP/IP components, such as the SNMP service which relies on TCP/IP.

• Network Interface : Bytes Sent/sec. This is how many bytes of data are sent to the NIC. This is a raw measure of throughput for the network interface. We are really measuring the information sent to the interface which is the lowest point we can measure. If you have multiple NIC, you will see multiple instances of this particular counter.
• Network Interface: Bytes Received/sec. This, of course, is how many bytes you get from the NIC. This is a measure of the inbound traffic In measuring the bytes, NT isn't too particular at this level. So, no matter what the byte is, it is counted. This will include the framing bytes as opposed to just the data.
• Network Interface : Bytes Total/sec. This is simply a combination of the other two counters. This will tell you overall how much information is going in and out of the interface. Typically, you can use this to get a general feel, but will want to look at the Bytes Sent/sec and the Bytes Received/sec for a more exact detail of the type of traffic.
• Processor : % DPC Time. Interrupts can be handled later. These are called Deferred Procedure Calls. You will want to keep track of these as well. The combination of this time with the % Interrupt Time will give you a strong idea of how much of the precious processor time is going to servicing the network.
• Processor : DPCs queued/sec. This will give you the rate at which DPC are being sent to the process queue. Unlike the Processor Queue Length and the Disk Queue Length, this value only shows you the rate at which the DPCs are being added to the queue, no how many are in the queue. Still, observing this value can give you an indication of a growing problem.
• Network Segment : %Broadcasts. This value will let you know how much of the network bandwidth is dedicated to broadcast traffic. Broadcasts are network packets that have been designated as intended for all machines on the segment. Often, it is this type of traffic that has a detrimental affect on the network.
• Network Segment : %Multicasts. This is a measure of the % of the network bandwidth that multicast traffic is taking. Multicast traffic is similar to the broadcast, however, there is a limited number of intended recipients. The idea was that if you can identify multiple recipients you can reduce the repetitive transmission of data. This type of transfer is used most commonly with video conferencing.
• TCP : Segments Sent/sec. This is the rate at which TCP segments are sent. This is how much information that is being sent out for TCP/IP transmissions.
• TCP : Segments Received/sec. Of course, the rate at which segments are received for the protocol.
• TCP : Segments/sec. This is just the total of the previous two counters. This is the information being sent and received. This is a general indication of how busy the TCP/IP traffic is. The segment size is variable and thus, this does not translate easily to bytes.
• TCP : Segments Retransmitted/sec. This is the rate at which retransmissions occur. Retransmissions are measured based on bytes in the data that are recognized as being transmitted before. On a Ethernet/TCP/IP network retransmissions are a fact of life. However, excessive retransmissions indicate a distinct reduction in bandwidth.
• TCP : Connection Failures. This is the raw number of TCP connections that have failed since the server was started. A failure usually indicates a loss of data somewhere in the process. Data lose can occur at many locations. This could be an indication of another device being down, or problems with the client-side configuration of the software.
• TCP : Connections Reset. This is typically a result of a timeout as opposed to an erroneous set of information. The reset results from the a lack of any information over a period of time.
• TCP : Connections Established. This counter represents them number of connections. Unlike the other two this is more and instantaneous counter of how many TCP connections are currently on the system as opposed to a count of the number of successful connections.