Ucp With Stp; Ucp With Epsr/Rstp - Allied Telesis SwitchBlade x3100 Series Manual

UCP with STP

Introduction
4.8.2.4 UCP Redundancy (Same Node)
If the active and standby interfaces are on the same node, all messages are still flooded over the UCP-enabled
network ports. However, since both active and standby are on the same node, the failover and message can be
solely determined by port state.
4.8.3 UCP with STP
Many of the concepts about the interaction of UCP with EPSR also apply to UCP with STP; the STP protocol
ensures there are no loops in the converged (reconverged) topology, while UCP ensures that the UFO VLAN
interfaces are set correctly for that topology. Since STP is a port based topology (as opposed to EPSR which is a
VLAN based topology), the STP will perform blocking on the port and therefore block all the VLANs on that
port. The user should therefore ensure that no VLANs are isolated when STP changes the topology for the rele-
vant nodes. (Refer to 4.5.3.20 for details and an example.)

4.8.4 UCP with EPSR/RSTP

Although UCP can act as a standalone protocol when the topology control is further up in the network, it can
interact with the STP and EPSR features; for example, in a ring network, the EPSR feature ensures there is no
loop created over the protected domain, while the UPC is used in the non-upstream nodes to determine the
upstream interface for the (protected) UFO VLANs.
Figure 4-23 shows the resulting topology. Switch A is the upstream node for the UFO VLAN (V_80) in the
domain, and so sends out the Upstream Port Notification message (see 4.8.2.1) for each of the UFO VLANs
over its two ring ports. This message is received by nodes B and C on one side of the ring and node D on the
other. Note that switch C does not receive this message from Node D because the messaging is over the pro-
tected VLAN and this is blocked by EPSR.
The message when received at each node is intercepted by the classifier and sent to the CPU. If all ingress
checks pass (see 4.8.2.1), each node stores the VLAN ID (80) along with the MAC address of the upstream
node (Node A). The message is then forwarded over the other ring port towards the next node in the ring net-
work. Finally, the message is discarded at node C because the UFO VLAN is logically blocked.
4-177
Software Reference for SwitchBlade x3100 Series Switches (Layer Two Switching)