Meridian 2300M Series, Manual

Page: 11 / 46

11/11/2006 6 Rev 2.0
2.1 Self-healing ring
Self-healing ring with One Master
Figure 2-2 above illustrates how the SHR ring provides signal protection. A fiber break is shown on the
primary ring (‘A’) between Slave #1 & Slave #2. The master detects the broken fiber ring and ‘listens’ to
the network on the secondary ring. This secondary ring (‘B’) transmits data in the counter-clockwise
direction from the master to all of the slaves and then back to the master – providing uninterrupted
communications around the ring.
2.2 Self-healing ring with Dual Master
Self-healing ring with Redundant Masters
In a standard SHR with one master modem, this single master modem can represent a single-point
failure. Unlike the redundant fiber ring, the failure of this single master will cause the entire network to
fail. Figure 2-3 illustrates a similar SHR network that incorporates dual master modems (either surface or
rack mount types. This dual master configuration eliminates the single-point failure associated with an
individual master modem and provides an additional level of network protection and redundancy.
Figure 2-3
Typical Self-Healing Ring (SHR)
Configuration w/Dual Master