User's Manual

2. System Description 2-14

Figure 2-11. Consecutive Point Network

2.6 Spanning Tree Protocol (STP)

Spanning Tree Protocol (STP) keeps Ethernet loops from forming in a ring architecture.

Without STP, loops would flood a network with packets. STP prevents loops by creating

an artificial network break. In the event of a network outage, STP automatically removes

the artificial break, restoring connectivity.

2.7 1+1 Protection

EVENT 5800 supports 1+1 protection as an option for a critical link. In this configuration,

EVENT 5800 contains two power supplies and two modems. The power supply, radio

transceiver, IF/telemetry and modem are protected. The digital framing and LIUs are not.

One modem is referred to as the west modem and the other as the east modem. 1+1

protection can be run in two modes: Protected Non-Diversity and Protected Diversity.

2.7.1 Protected Non-Diversity (Hot Standby)

The following illustration shows operation in Protected Non-Diversity mode, also called

Hot Standby. In this mode, one EVENT 5800 at each location transmits to two EVENT

5800 units at the other location. This mode does not require the extra bandwidth or

interference protection. It provides hitless receive switching and hot standby. EVENT

5800 automatically switches between the two units when an appropriate alarm or

interface error occurs, minimizing transmit outage time.