negotiate duplex, both the 9H423-28 and the attached device must be configured for auto-negotiation. If only the 9H423-28 is configured for auto-negotiation, the module will set the connection to half duplex at either the 10 Mbps or 100 Mbps rate. This technology is similar to how modems negotiate transmission speed, finding the highest transmission rate possible. Similarly, auto-negotiation determines the highest common speed between two devices and communicates at that speed. If no common speed is detected, the device will be partitioned.
All RJ45 connections are capable of auto-negotiation, and can operate at 10 Mbps or 100 Mbps, full or half duplex. Fiber connections can only operate at the 100 Mbps rate, full or half duplex.
Standard Ethernet/Full Duplex Operation
The 9H423-28 module supports both 100BASE and 10BASE technology. This allows each port on the module to be configured, through local and or remote management (SNMP), to operate in standard Ethernet mode (simplex) or full duplex mode. Operating in standard Ethernet mode limits bandwidth to 10 Mbps/100Mbps per port, while operating in duplex mode doubles bandwidth from 10 Mbps/100Mbps to 20 Mbps/200 Mbps per port.
Management Information Base (MIB) Support
The 9H423-28 module provides MIB support including:
•RMON (RFC-1271)
•IETF MIB II (RFC-1213)
•IETF Bridge MIB (RFC-1493)
and a host of other Cabletron Enterprise MIBs.
For a complete list of supported MIBs, refer to the release notes provided with the 9H423-28.
INB
The 9H423-28 module attaches to INB-B of the SmartSwitch 9000 Backplane. The INB Backplane is designed to transport fixed length data blocks between modules in the SmartSwitch 9000 using an INB Time Division Multiplexing (ITDM) design. The SmartSwitch 9000 INB bus delivers 2.5 Gbps of true data bandwidth with all control and management communication being serviced on the 8-bit out-of-band bus. The time slices of the INB manager operates in all three modes at once, without user intervention.
