Zte ZXR10 2900E series Configuration Manual page 84

ZXR10 2900E Series Configuration Guide
Port Role
Alternate
Edged
Protection Feature Overview
BPDU Protection on a Port
A boundary port is not expected to receive any BPDUs. Receipt of any BPDUs indicates
a failure in the network. To avoid this situation, BPDU protection can be configured on a
boundary port.
After being configured with
shut down and a warning message will be displayed. The system waits for some seconds
of user configured and then tries to re-open the port. If it still receives BPDUs, the port will
be shut down again. By doing so, the network can be protected from being attacked by
abnormal BPDUs to maintain the stability of the topology.
Loopback Protection on a Port
When a non-designated ports other than port breaks down and cannot receive any BPDUs,
STP will transit the port to a designated port and its state to Forwarding state, which leads
to loops. To avoid this situation, port loopback protection can be configured on a blocked
port.
After being configured with port loopback protection, if a blocked port no longer receives
any BPDUs, it will enter Loop_Inconsistent state, under which no data will be forwarded
from this port. When it receives BPDUs again, the port will automatically recover to a
blocked port.
Root Protection on a Port
After the network has completed the spanning tree calculation, if a new switch is involved
and the numerical value for its bridge ID is lower than that for the root bridge, the new
switch will become the new root bridge to replace the old root bridge, which causes the
entire network to recalculate the spanning tree. To avoid this situation, port root protection
can be configured on the port where a new switch accesses the network.
The port root protection feature is used to protect the root bridge. After being configured
with root protection, if a port receives a BPDU in which the numerical value for the bridge
ID is lower, the port will enter RootGuard state to avoid spanning tree recalculation. In
this state, no data will be forwarded from this port. Once the port no longer receives any
BPDU in which the numerical value for the bridge ID is lower, it will go through the transitory
states, that is, Listening state and Learning state, and finally transit to Forwarding state.
The recovery is automatic, without any human intervention.
Configuring STP
In the default configuration, the MSTP only has the instance with ins_id being 0. This
instance always exists and users cannot manually delete it. This instance is mapped with
VLANs 1 to 4094.
SJ-20130731155059-002|2013-11-27 (R1.0)
Port State
Discard
Forward
BPDU protection, if a port receives a BPDU, the port will be
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