Sehi Overview; Sehi Features - Cabletron Systems SEHI-22 User Manual

1.3

SEHI OVERVIEW

The 10BASE-T SEHI-22 and SEHI-24 are intelligent repeater hubs. The
SEHI-22 has 12 RJ45 ports and one Ethernet Port Interface Module
(EPIM) port on the front panel for network connections while the
SEHI-24 has 24 RJ45 ports and two EPIM ports on the front panel for
network connections. Both models have one rear panel HubSTACK
Interconnect Bus port for stackable connections. The SEHI is designed to
manage the Cabletron SEH series of non-intelligent stackable hubs.
1.4

SEHI FEATURES

Repeater Functionality
The SEHI fully conforms to the IEEE 802.3 Repeater, AUI, and
10BASE-T specifications, and provides the flexibility to connect
networks using IEEE 802.3, Ethernet Version 1 or Version 2 equipment.
The SEHI transmits retimed data packets, regenerates the preamble,
extends fragments, and arbitrates collisions.
The SEHI automatically partitions problem segments, and reconnects
repaired segments to the network. This feature minimizes the impact on
network operation resulting from a problem on one segment by isolating
the problem segment. Only devices on the problem segment are affected.
When the problem is solved, the SEHI automatically reconnects the
isolated segment to the network.
Polarity Detection and Correction
Each twisted pair port on the SEHI incorporates a Polarity Detection and
Correction feature that allows the SEHI to pass data regardless of the
polarity of the twisted pair segment's receive link. Cabletron does not
recommend operating in this condition. When this condition is detected,
remove the segment from the network and wire it correctly to reduce the
potential for problems if equipment changes are made.
Flash EEPROMs
The SEHI uses Flash EEPROMs that allow the downloading of new and
updated firmware in conjunction with Cabletron's Remote LANVIEW/
Windows, version 2.3 or later or any device utilizing BOOTP or TFTP
protocols.
SEHI USER'S GUIDE
SEHI OVERVIEW
1-3