Total capacity does not correspond to any known standard

Network measurements indicate a Total Capacity corresponding to no known standard.

Recommended action

  1. If the measured Total Capacity is deemed to be acceptable, no action is required.
  2. If Total Capacity is below expectations, and one or more diagnostic messages has been generated, take the recommended course of action for each message. Start with the diagnostic message with the highest certainty value.

Detailed explanation

Total Capacity is the calculated maximum data rate that could be achieved across the network path. It is a one-way measurement based on the network's capability to transmit in two directions, i.e. receive and transmit, simultaneously. It is measured in megabits per second (Mbps).

Most common network standards (e.g. DS0, ISDN, T1, E1, DS3, 10M/100M/1Gbps Ethernet etc.) have fixed, identifiable capacities. Therefore, the Total Capacity measurement can be used to determine which network standard is being employed with a given path. In this case, the measured Total Capacity does not correspond to any of the commonly known standards.

There are a variety of reasons for a non-standard measurement. For example, a fractional T1 link provides only a portion of the full T1 capacity, often resulting in a non-standard Total Capacity measurement. However, in some cases a non-standard measurement may be an indication of a serious performance problem. For example, most well-functioning 100Mbps full- duplex paths achieve a Total Capacity of 90 to 98Mbps regardless of path length or traffic load, and if you achieve these results, this message will not be thrown.

Some network characteristics that can cause this message to be thrown are:

  • Slow routers/switches/NICs
  • Down-level drivers on NICs
  • Routing/configuration errors
  • Existence of hubs rather than switches
  • Half-duplex interface settings

Possible secondary messages

  • "May indicate a performance problem"

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