H3C S6850 Series Configuration Guide

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Figure 20 Dispute guard triggering scenario (on a root port)
However, dispute guard might disrupt the network connectivity. You can disable dispute guard to
avoid connectivity loss in VLAN networks. As shown in Figure 21, the sp
anning tree feature is
disabled on Device B and enabled on Device A and device C. Device B transparently transmits
BPDUs.
Device C cannot receive superior BPDUs of VLAN 1 from Device A because Port B1 of Device B is
configured to deny packets of VLAN 1. Device C determines itself as the root bridge after a certain
period of time. Then, Port C1 sends an inferior BPDU of VLAN 100 to Device A.
When Device A receives the inferior BPDU, dispute guard blocks Port A1, which causes traffic
interruption. To ensure service continuity, you can disable dispute guard on Device A to prevent the
link from being blocked.
Figure 21 Disabling dispute guard application scenario
Restrictions and guidelines
You can disable dispute guard if the network does not have unidirectional link failures.
Procedure
1. Enter system view.
system-view
2. Disable dispute guard.
undo stp dispute-protection
By default, dispute guard is enabled.
Root port
Designated port
Normal link
Blocked link
Blocked port BPDUs
Device A Device B
Device C
Hub
Root
Port A1 Port B1
Port C1
Device A Device B
Device C
Hub
Root
Port A1 Port B1
Port C1
Root
Device A Device B
Device C
Hub
Root
Port A1 Port B1
Port C1
Root

H3C S6850 Series Specifications

General

Brand	H3C
Model	S6850 Series
Category	Switch
Language	English