IPmux-1/1E Installation and Operation Manual Chapter 4 Troubleshooting and Diagnostics
Performance Monitoring and Troubleshooting Statistics 4-15
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.