E3Switch DS3 Operating Information Manual - page 17
Chapter 8: LAN Connections and Performance
by the industry at the inception of 100BaseTX, resulting in some older LAN equipment not understanding
the gateway's autonegotiation advertisement of strictly full-duplex capability.
It is highly desirable to leave autonegotiation enabled so that changing attached LAN equipment does not
result in the new equipment defaulting to half-duplex if set to autonegotiate. Autonegotiation must always
be enabled for 1000Mbit/s links.
LAN Cabling
It is important to use the correct cabling for proper operation. Use UTP Category 5 network cable with RJ-
45 connectors for the LAN ports, and do not exceed 100 meters (328 feet) in length. Either a straight-
through or crossover cable may be used.
LAN Buffering, Loading and Flow Control
This gateway contains approximately 500kBytes of total packet buffer. Queue utilization can be monitored
at the gateway's statistics HTTP page, and buffer overflow will appear as “Rx oflow” errors at the same
HTTP page.
Chapter 9: TDM LAN Packet Format
General
A variety of different headers may be configured on the LAN packets that transport TDM data. The header
format must be manually specified. The gateways do not currently negotiate with each other to determine
packet format. The header format must be identical for each pair of connected gateways. Either
SAToP or CESoTDM protocols may be selected depending upon whether full-rate or fractional TDM is
desired.
Transport Layer
Depending upon the model purchased, LAN packets may be configured with simple MAC Layer 2
addressing or more sophisticated IP/UDP or MPLS headers.
Chapter 10: Troubleshooting
General
A great deal of diagnostic information is available by accessing the HTTP management interface of the
gateway. Refer to the management section of this document for additional information.
The gateway's front panel lights can provide useful information but are often under-utilized. They are
simple to read and can indicate where a data connection is being lost. It can be very helpful to learn their
meaning and monitor flashes as a packet is received at each port.
Incoming Circuit ID is shown at the top of the gateway's HTTP management page for C-Bit DS3 links,
facilitating confirmation of the remote data transmitter when presented with a pair of unlabeled BNC cables.
The Ethernet networks to which the gateway connects are complex and may contain thousands of devices,
each of which requires proper configuration and performance. As such, network configuration and
topology issues dominate when problems arise. When troubleshooting, solutions can be reached more
rapidly by remembering that the most frequent cause of problems arises from improper network
configurations.
The next most frequent source of problems generally arises from faulty cabling or connectors or incorrect
cable type. Cabling must be UTP5 or better for LAN and 75-Ohm rather than 50-Ohm for TDM. If long
TDM cable runs or an electrically noisy environment exists, high-quality coaxial cable will be required.
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