Kingston Technology KNE16TP manual Design Features, Repeater Functions, Jabber Lock-up Protection

4 Design Features

Design Features

The EtheRx hub complies with the full set of repeater basic functions as defined by IEEE 802.3, Section 9. These functions include all Repeater Functions, Signal Regeneration, Jabber Lockup Protection, Fragment Extension, Collision Handling, Auto Partitioning/Reconnection, and Link Test. These functions are usually transparent to all network activities and are summarized below.

Repeater Functions

If any single port senses the start of a valid packet on its receiving line, the EtheRx hub will re-transmit the received data to all other ports on the network. The re-transmission of packets complies with the IEEE 802.3 specification in terms of preamble structure, voltage amplitude, and timing characteristics. These timing regenerations prevent cumulative signal loss, jitter, and distortion caused by the network cabling, and allow the EtheRx hubs to be cascaded to other Ethernet hubs.

Jabber Lock-up Protection

The EtheRx hub implements a built-in MAU jabber lockup protection (MJLP) scheme to ensure that the network is not disabled due to transmission of excessively long data packets. This protection scheme will automatically interrupt excessively long transmissions to prevent jabber lock-up.

Fragment Extension

If the total packet length received by the EtheRx hub is less than 96 bits, including preamble, then the hub will automatically extend the repeated packet length to 96 bits by appending a jam sequence to the original fragment. The extension of a fragmented packet allows the reliable detection of a collision by all stations attached to the network.

Collision Handling

The EtheRx hub will detect and respond to collision conditions as outlined in the IEEE 802.3 specifications.

Kingston Technology Company EtheRx User’s Guide - Rev. B00