Chapter 5: Operating Modes and Configuration
●
GbE, GigE 1000Base-T for the RJ-45 LAN Port 2
●
SFP LAN Port 1 which can accept optical or copper (100/1000) SFP transceivers.
●
If SFP port has been enabled, either LAN port can be configured as a dedicated out-of-band
management port if desired.
●
jumbo frames (9600 bytes)
See the “Interoperability” section of this manual for information on packet lengths and detailed port
connection/autonegotiation discussion.
The autonegotiation mode of the Monitor must match the autonegotiation mode of attached LAN
equipment.
If autonegotiation is enabled on the Monitor it must be enabled on the attached equipment. If
disabled on the Monitor, it must be disabled on the attached equipment. This requirement is necessary to
fulfill 802.3 standards which mandate a fallback to half-duplex operation if an autonegotiation mismatch
exists. The Monitors require full duplex LAN connections to operate.
LAN Port Speed
1000Mbit/s LAN speeds are only available via the SFP port or if GbE LAN has been purchased.
100Mbit/s is generally preferred over 1000Mbit/s, which generates significantly more power-requirements,
heat, and radiated noise even in the absence of packet flow.
1000Mbit/s LAN port speed may be desireable when one LAN port is configured to monitor the other LAN
port in addition to receiving incoming DS3/E3 data. In such a case, the data rate that the LAN port is
expected to transmit (the sum of all ports that could be a data source for the LAN port) may be greater than
100Mbit/s. The HTTP management statistics screen will show overflow errors if a port's data rates are
exceeded.
Setting more than one LAN port to 1000Mbit/s is not recommended and may result in
underflow/overflow errors in certain high packet load, memory-intensive cases.
Autonegotiation Problems
There are rare cases with older LAN equipment in which it may be necessary to disable autonegotiation. If
CRC-errors or short packet errors are seen in the management statistics of the LAN port, the attached LAN
equipment has probably configured itself to half-duplex mode and colliding packets are being lost. In such
a case, autonegotiation should be disabled on both the Monitor and the attached LAN equipment, with both
forced to 100BaseTX full-duplex. Autonegotiation interoperability and standards were not well understood
by the industry at the inception of 100BaseTX, resulting in some older LAN equipment not understanding
the Monitor's autonegotiation advertisement of strictly full-duplex capability.
SFP Second LAN Port
The SFP LAN Port 1 hardware exists on all Monitors shipped and may be enabled as purchased or enabled
by purchasing an upgrade password. This upgrade allows an SFP transceiver to enable out-of-band
management or data transfer through either LAN port, or enable fiber-optic LAN connections of 10km or
more. Refer to interoperability section of this document for compatible SFP transceivers.
Dedicated Management/Data LAN Ports
If the SFP Second LAN Port is in use, then either LAN port may be configured to pass TDM data packets
or, selectively, to pass only management or only TDM data packets when such can be determined.
If a LAN port is configured for TDM data-only packets, the unit will drop incoming management packets
on that LAN port. On a “data-only” LAN port, these management unicast packets and management
broadcast/multicast packets may not be forwarded to the second LAN even if LAN-to-LAN traffic flow is
configured.
13