Figure 7 Bpdu Protection Of Edge Port; Bpdu Protection - Zte ZXR10 5900 Series User Manual

ZXR10 5900/5200 Series User Manual (Ethernet Switching Volume)

BPDU Protection

Switches calculating spanning tree according to the content of
BPDU Overview
BPDU packet. Network topology once changes spanning tree will
be calculated again. If the network is large, the calculation will be
very frequent. This influence switches to transmit packet. At the
same time, the change of Root Bridge also brings some problem.
BPDU protection overcomes these problems.
If a port is set as an edge port, BPDU protection function will shut
BPDU Protection
of Edge Port
down this port when the edge port receives a BPDU packet. It
outputs alarm information to monitor terminal.
BPDU protection of edge port maintains the stable of network
topology. Device which connects to edge port can not influence
the spanning-tree. It can implement by setting port DOWN and
outputing alarm information at terminal when receiving BPDU
packet at the edge port. The example is shown as Figure 7.
F 7 BPDU P E P
IGURE ROTECTION OF DGE ORT
See the first status in the figure, priority of switch A is 8192.
Switch A is a root switch. Priority of switch B is 16384. Link be-
tween Switch A and Switch B is 1000M and other link is 100M.
Switch A and Switch B are both core switches. Switch C is a edge
switch. Port of switch C connects to switch D edge port. spanning
tree is enabled in switches except switch D. After switches calcu-
late spanning tree the port of switch C which connects to switch B
is blocked. Switch D doesn't take part in calculating spanning-tree.
Direction of arrow represents the direction of BPDU.
See the second status in the figure, spanning tree is enabled in
switch D. Its priority is smaller than switch A which is root switch.
Switch D will become a root switch. After switches calculate span-
ning tree, port of switch B which connects to switch A will be
blocked. Its priority is smaller than switch A which is root switch.
Switch D will become a root switch. After switches calculate span-
ning tree, port of switch B which connects to switch A will be
blocked.
If configuration of BPDU protection in edge port of switch C takes
place. Switch D sends BPDU packet, switch C will receive this
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