Command Usage; Configuring The Spanning Tree Algorithm; Stp - AMX NXA-ENET8-2POE Operation/Reference Manual

Loop Protection Configuration parameters (Cont.)
Port Configuration
• Port
• Enable
• Action
• Tx Mode

Command Usage



1.
Click Configuration, Loop Protection.
2.
Enable loop protection globally, set the transmission interval for LPPDUs, and set the shutdown time for
ports with a detected loop.
3.
Enable loop protection on the ports where required, set the response to a detected loop, and specify
whether the port actively sends LPPDUs or just monitors for looped LPPDUs.
4.
Click Save.

Configuring The Spanning Tree Algorithm

The Spanning Tree Algorithm (STA) can be used to detect and disable network loops, and to provide backup
links between switches, bridges or routers. This allows the switch to interact with other bridging devices (that
is, an STA-compliant switch, bridge or router) in your network to ensure that only one route exists between
any two stations on the network, and provide backup links which automatically take over when a primary link
goes down.
The spanning tree algorithms supported by this switch include these versions:




STP

STP uses a distributed algorithm to select a bridging device (STP-compliant switch, bridge or router) that
serves as the root of the spanning tree network. It selects a root port on each bridging device (except for the
root device) which incurs the lowest path cost when forwarding a packet from that device to the root device.
Then it selects a designated bridging device from each LAN which incurs the lowest path cost when
forwarding a packet from that LAN to the root device. All ports connected to designated bridging devices are
assigned as designated ports. After determining the lowest cost spanning tree, it enables all root ports and
designated ports, and disables all other ports. Network packets are therefore only forwarded between root ports
and designated ports, eliminating any possible network loops (FIG. 66).
FIG. 66
STP Root Ports and Designated Ports
Once a stable network topology has been established, all bridges listen for Hello BPDUs (Bridge Protocol
Data Units) transmitted from the Root Bridge.
NXA-ENET8-2POE Gigabit Ethernet Layer 2 PoE Switch
Port Identifier.
Enables/disables loop protection for a port.
Sets the response to take when a loop is detected. (Options: Shutdown Port,
Shutdown Port and Log, Log Only; Default: Shutdown Port and Log)
Controls whether a port is actively generating loop protection PDUs, or just pas-
sively looking for looped PDUs. (Default: Enable)
When loop protection is globally disabled, any LPPDUs received from the same switch are
dropped, while any LPPDUs received from other devices are flooded onto the same VLAN.
When loop protection is globally enabled and enabled on a port, any LPPDUs received from the
same port are processed according the configuration settings, while any LPPDUs received from
other ports are flooded onto the same VLAN.
STP - Spanning Tree Protocol (IEEE 802.1D)
RSTP - Rapid Spanning Tree Protocol (IEEE 802.1w)
MSTP - Multiple Spanning Tree Protocol (IEEE 802.1s)
Configuring the NXA-ENET8-2POE
89