Specifications
IPmux-1/1E Installation and Operation Manual Chapter 4 Troubleshooting and Diagnostics
Performance Monitoring and Troubleshooting Statistics 4-13
Table 4-4. LAN Statistics Parameters (Cont.)
Parameter Description
Frames Transmitted
Correct
Frames
The number of frames successfully transmitted. When a valid connection is established
the number should increase steadily.
Correct
Octets
The number of octets successfully transmitted. When a valid connection is established
the number should increase steadily.
Single
Collision
Collisions occur only in Half-duplex mode (RFC 1643). Counts the successfully
transmitted frames for which transmission is inhibited by exactly one collision (see
Collision above).
Recommendations:
Use a Full-duplex mode if possible.
Multi
Collision
Multi Collisions occur only in Half Duplex mode (RFC 1643). Counts the successfully
transmitted frames for which transmission is inhibited by more than
one collision (multi-collision).
Recommendations:
Use a Full-duplex mode if possible.
Deferred
Transmission
Occur only in half-duplex mode (RFC 1643). Counts the number of frames for which
the first transmission attempt (carrier sense) is delayed because the medium is busy.
This is normal behavior when trying to transmit high traffic rate in a half-duplex
environment. The higher the traffic rate is, the higher the chances of collisions and
deferred transmissions.
Recommendations:
Use a Full-duplex mode if possible.
Late
Collision
Occur only in Half-duplex mode (RFC 1643). In order to allow collision detection to
work properly, the period in which collisions are detected is restricted (512 bit-times).
For 10BaseT Ethernet (10 Mbps), it is 51.2us (microseconds), and for Fast Ethernet
(100Mbps), 5.12us. For Ethernet stations, collisions can be detected up to 51.2
microseconds after the beginning of the transmission, or in other words: up to the
512th bit of the frame. When a station detects a collision after it has sent the 512th bit
of its frame, this is counted as a late collision.
Recommendations:
Possible causes are usually incorrect cabling or a non-compliant number of hubs in the
network. Bad Network Interface Cards (NICs) can also cause late collisions.
Carrier
Sense
The counter increments when a packet collides because carrier sense is disabled.
Recommendations:
Check connection between the interface and its Ethernet transceiver.