Dell Networking 7048, Reference Manual

Page: 754 / 1788

754
Spanning Tree Commands
port. In this way, the root guard enforces the position of the root bridge. In
MSTP scenario the port may be designated in one of the instances while
being alternate in the CIST, and so on. Root guard is a per port (not a per port
per instance command) configuration so all the MSTP instances this port
participates in should not be in root role.
STP BPDU Filtering - STP BPDU filtering applies to all operational edge
ports. Edge Port in an operational state is supposed to be connected to hosts
that typically drop BPDUs. If an operational edge port receives a BPDU, it
immediately loses its operational status. In that case, if BPDU filtering is
enabled on this port then it drops the BPDUs received on this port.
STP BPDU Flooding
- STP BPDU flooding feature applies to the STP
disabled switch. To enable BPDU flooding on a port, STP should be disabled
on the switch administratively. When this feature is enabled on the switch, it
floods all the ports which have the BPDU flood feature enabled.
BPDU Storm Protection - If STP BPDUs are received at a rate of 15 pps or
greater for 3 consecutive seconds on a port, the port will be diagnostically
disabled. A message of the following form is logged:
<188> MAY 04 09:45:23 10.10.10.10-1 DOT1S[276072720]:
dot1s_ih.c(1587) 15855515 %% Diagnostically disabling
interface 2/0/41
Use the no shut command to return the port to service.
Commands in this Chapter
This chapter explains the following commands:
clear spanning-tree
detected-protocols
spanning-tree auto-
portfast
spanning-tree max-
age
spanning-tree portfast
bpdufilter default
exit (mst) spanning-tree bpdu
flooding
spanning-tree max-
hops
spanning-tree portfast
default
instance (mst) spanning-tree
bpdu-protection
spanning-tree mode spanning-tree port-
priority
name (mst) spanning-tree cost spanning-tree mst
configuration
spanning-tree priority
2CSPC4.X7000-SWUM204.book Page 754 Friday, March 15, 2013 8:22 AM