Cabletron Systems SEH-22

SEH FEATURES

SEH USER’S GUIDE

1-3

Stack up to ﬁve SEH hubs using Cabletron Systems external HubSTACK

Interconnect cables. Manage the stack by using the Cabletron Systems

MicroMMAC or SEHI (Stackable Ethernet Hub with Intelligence). Up to

four SEH hubs can be stacked with one intelligent hub. Stackable

conﬁgurations make it possible to maintain only one IEEE repeater hop

while providing up to 130 Ethernet ports.

1.4 SEH FEATURES

Repeater Functionality

The SEH 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 SEH transmits re-timed data packets, regenerates the preamble,

extends fragments, and arbitrates collisions.

The SEH automatically partitions problem segments, and reconnects

repaired segments to the network. This feature minimizes the impact on

network operation by isolating the problem segment. Only devices on the

problem segment are affected. When the problem is solved, the SEH

automatically reconnects the isolated segment to the network.

Polarity Detection and Correction

Each twisted pair port on the SEH incorporates a Polarity Detection and

Correction feature that allows the SEH 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

discovered, remove the segment from the network and wire it correctly to

reduce the potential for problems if equipment changes are made.

LANVIEW LEDs

Cabletron Systems LANVIEW Status Monitoring and Diagnostics

System is a troubleshooting tool that helps in diagnosing power failures,

collisions, cable faults, and link problems. The LANVIEW LEDs are

located on the front panel.

SEH Book Page 3 Tuesday, March 19, 1996 4:12 PM