Stp Configuration With Ufo Vlan - Allied Telesis SwitchBlade x3100 Series Manual

Introduction

4.7.4 STP Configuration with UFO VLAN

Figure 4-20. shows an example ring configuration that uses (R)STP with UFO VLANs
If Device A is not the root, VLAN is set at STP at all
three interfaces
If Device A is the root, UFO VLAN is set at interfaces:
0.1 = DOWNSTREAM
0.2 = DOWNSTREAM
0.3 = PRIMARYUPSTREAM
For other devices, UFO VLAN on the interface
set to STP for dynamic state change
(Upstream to Downstream,
Downstream to Upstream)
0.2
Ring_Topology_STP_60
Once the topology stabilizes, in each system one of the ports will become the root port (the one closest to the
root bridge as determined by STP) and the other port(s) become the designated port. The port which is the
root port is considered to be the upstream port and the port which is not the root port (designated port) is
considered to be the downstream port.
The user can provision the ports in each shelf with
allowing the STP protocol to determine the exact upstream.
To prevent one of the systems from becoming the Spanning Tree root bridge, the network design must ensure
that the appropriate STP parameters are set such that the root bridge is always located above the ring configu-
ration made up of the systems.
4-168
Software Reference for SwitchBlade x3100 Series Switches (Layer Two Switching)
1
Upstream
V_60
0.1
Downstream
Upstream
2
Ring Topology Using STP and UFO VLAN
FIGURE 4-20
STP Configuration with UFO VLAN
To / From Network
0.3
A
V_60
A = Devices
D
1 4 = Links
Downstream
Downstream
V_60
C
indicating that the topology is a ring and
FORWARDING=STP
= Physical Link
= VLAN 60 (V_60)
= STP Blocking of Physical Link
4
Upstream
0.1
V_60
0.2
3