Stp Fast-Uplink; Loop Protection - Fujitsu PSWITCH 2048T User Manual

User's Guide
 VLAN 1 STP BPDUs are sent to the IEEE STP MAC address (0180.c200.0000),
untagged.
 VLAN 1 STP BPDUs are also sent to the SSTP MAC address, untagged.
 Non-VLAN 1 STP BPDUs are sent to the SSTP MAC address (also called the Shared
Spanning Tree Protocol [SSTP] MAC address, 0100.0ccc.cccd), tagged with a
corresponding IEEE 802.1Q VLAN tag.
If the native VLAN on an IEEE 802.1Q trunk is not VLAN 1:
 VLAN 1 STP BPDUs are sent to the SSTP MAC address, tagged with a
corresponding IEEE 802.1Q VLAN tag.
 VLAN 1 STP BPDUs are also sent to the IEEE STP MAC address on the Native VLAN
of the IEEE 802.1Q trunk, untagged.
 Non-VLAN 1 STP BPDUs are sent to the SSTP MAC address, tagged with a
corresponding IEEE 802.1Q VLAN tag
If the switch that is running a standard IEEE spanning tree protocol (STP, RSTP, or
MSTP), and it receives the SSTP format BPDUs, the switch does not treat them as
standard BPDUs. Hence, the received SSTP-formatted BPDUs are flooded on all the
ports of the corresponding VLAN. The SSTP BPDUs are multicast over the region.
The interoperation between a switch that runs a standard IEEE spanning tree
protocol and a switch that runs PVSTP/PVRSTP is achieved using CIST. In other words,
to communicate with each other, a switch running the standard IEEE spanning tree
protocol uses its CIST, and a switch running PVSTP/PVRSTP uses an access VLAN or
native VLAN instance.

3.1.2.8.13. STP Fast-Uplink

The PVSTP/PVRSTP FastUplink feature is used for quick selection of a port with the
lowest cost when the root port fails. In other words, the FastUplink feature is used
to reduce convergence time when a link fails. This feature is similar to Cisco's
UplinkFast feature. When the primary link fails, FastUplink creates an alternate
path immediately. Since the ports that apply FastUplink do not have to wait for
normal convergence time, this will speed up the transition from the failed primary
link to the backup link (the port in a blocking state).

3.1.2.9. Loop Protection

Loop protection is used in LAN to detect any loop and then protect against it. The
loop is detected by sending out Loop Detect Frame (LDF) at each port and to see
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