C
HAPTER
16
| STP Commands
– 401 –
■
STP Mode – If the switch receives an 802.1D BPDU (i.e., STP BPDU)
after a port’s migration delay timer expires, the switch assumes it is
connected to an 802.1D bridge and starts using only 802.1D
BPDUs.
■
RSTP Mode – If RSTP is using 802.1D BPDUs on a port and receives
an RSTP BPDU after the migration delay expires, RSTP restarts the
migration delay timer and begins using RSTP BPDUs on that port.
◆ MSTP generates a unique spanning tree for each instance. This provides
multiple pathways across the network, thereby balancing the traffic
load, preventing wide-scale disruption when a bridge node in a single
instance fails, and allowing for faster convergence of a new topology for
the failed instance.
■
To allow multiple spanning trees to operate over the network, you
must configure a related set of bridges with the same MSTP
configuration, allowing them to participate in a specific set of
spanning tree instances.
■
A spanning tree instance can exist only on bridges that have
compatible VLAN instance assignments.
■
Be careful when switching between spanning tree modes. Changing
modes stops all spanning-tree instances for the previous mode and
restarts the system in the new mode, temporarily disrupting user
traffic.
EXAMPLE
STP>version rstp
STP>
stp txhold This command displays or sets STP bridge Transmit Hold Count.
SYNTAX
stp txhold [transmit-hold]
transmit-hold - The number of BPDUs a bridge port can send per
second. When exceeded, transmission of the next BPDU will be
delayed. (Range: 1-10)
DEFAULT SETTING
6
EXAMPLE
STP>txhold 10
STP>
To Next Page
