Specifications

Emergency Services
133
Other considerations
• The Spanning Tree Protocol allows multiple ethernet connections to be made between a
device and the network without introducing a network loop. In the event that the active
network connection fails, the Spanning Tree Protocol will enable a standby connection so
that network connectivity is maintained.
• RSTP (Rapid Reconfiguration of Spanning Tree Protocol) is available on some network
devices. STP is more widely deployed but may not be available on all network devices.
RSTP is backward-compatible with STP and is the preferred setting.
• In older installations STP might be the most widely available network setting but it has the
disadvantage of disconnecting ports for, potentially, up to 50 seconds. Network changes
could have a significant effect on IP devices, especially if resiliency is also a requirement.
Figure 15: Non-compatible Network Configuration - L2 Switch with both CDP and STP Disabled
Figure 16: Non-compatible Network Configuration - Devices Connected to L2 via Hub