Cabletron Systems 2200 manual Standard/Full Duplex Auto-Negotiation, Runtime IP Address Discovery

Overview

1.1.3Standard/Full Duplex Auto-Negotiation

Ports 1 through 48 on the 2E253-49R have the ability to auto-negotiate the port mode of operation (standard [half duplex] or full duplex) between two devices according to the 802.3x standard. Full duplex mode is the default mode of operation for each port. During Auto-Negotiation, two devices automatically exchange information “telling” each other their current operating mode. The Auto-Negotiation feature targets the maximum capability that can be reached between the two devices. For example, the 2E253-49R can adjust to full duplex operation when the device on the other end of the connection can also adjust from standard to full duplex. If the device on the other end of the connection can only operate in standard mode, then the 2E253-49R simply adjusts to operate to the standard mode.

1.1.4Runtime IP Address Discovery

This feature enables the 2E253-49R device to automatically accept an IP address from a Boot Strap Protocol (BootP) server on the network into NVRAM without requiring a user to enter an IP address through Local Management.

When the device is connected to the network and powered up, Runtime IP Address Discovery (RAD) checks the device for an IP address. If one has not yet been assigned (device IP address set to 0.0.0.0), RAD checks to see if any of the device interfaces have a link. If so, RAD sends out Reverse Address Resolution Protocol (RARP) and BootP requests to obtain an IP address from a BootP server on the network.

The RAD requests start at an interval of 1 per second. The interval then doubles after every transmission until an interval of 300 seconds is reached. At this point, the interval remains at 300 seconds. The RAD requests continue until an IP address is received from an RARP or BootP server, or an IP address is entered using Local Management.

NOTE

The 2E253-49R will reboot after RAD is successful.

1.1.5SmartTrunk

Traditional 802.1D Spanning Tree Bridges only allow one active data path between any two switches; all other parallel data paths are in Standby or Blocking mode. If one interface or path should fail, then the other interface automatically comes out of Blocking mode and forwards all of the traffic. This is fine for redundancy purposes. However, it is not the most efficient use of resources.

Introduction 1-3