Specifications

ALAXALA Ring Configuration Guide (Edition 1)
Copyright © 2008, ALAXALA Networks Corporation. All rights reserved.
68
4.2 Notes
When you use the Ring Protocol, you need to carefully read the notes provided in the following manuals and in
this section to design your network.
- Notes in the manuals
AX6700S/AX6300S 21.6 Notes on Ring Protocol usage
Configuration Guide Vol. 1 23.1.5 Notes on using of the Ring Protocol and spanning trees together
23.2.6 Notes on running the Ring Protocol and GSRP together
AX3600S, AX2400S 20.6 Notes on Ring Protocol usage
Configuration Guide Vol. 1 22.1.5 Notes on using of the Ring Protocol and spanning trees together
22.2.6 Notes on running the Ring Protocol and GSRP together
4.2.1 General notes on the Ring Protocol
(1) Switching a redundant MSU or BCU system in chassis-type switches
When an active chassis-type switch is switched to a standby system, the Ring Protocol restarts at the new
active system and runs from the initial state.
If the new active switch is the master node, the primary port is in FWD status and the secondary port is in BLK
status. Therefore, when the ring is operated normally, the Ring Protocol starts status monitoring immediately
after the system is switched. If a ring failure has occurred, the Ring Protocol detects the failure again after the
system is switched, which causes a transition to failure state.
If the active switch is a transit node, the switch first sets a data transfer VLAN in BLK status and then puts the
port in FWD status when the switch receives flush control frames from the master node or after
Forwarding-shift-time elapses.
In both cases, the VLANs are down and then up again due to the Ring Protocol restart.
4.2.2 Notes when using the Ring Protocol with STP
Consider the following when you use the Ring Protocol with STP.
(1) When the Ring Protocol restarts
When you restart the Ring Protocol, you need to check that the ring does not cause a loop if the Ring Protocol
is used with STP. When restarting the Ring Protocol, you need to perform necessary actions to prevent a loop,
such as shutting down STP ports beforehand.
(2) Temporary blocking for ports other than ring ports
When one of the following events occurs on a device using both the Ring Protocol and STP, STP-activated
ports other than the ring ports are temporarily put in Blocking status:
- Starting up devices (including device restart)
- Applying the configuration file to the running configuration
- Switching the active and standby systems
- Bringing the first BSU back up
- Executing the restart vlan command
- Executing the restart spanning-tree command
When the topology within an access network is built before control frames can be sent and received by STP
over a virtual link, a loop occurs across the ring and access networks because no STP blocking ports are defined.
For this reason, this functionality temporarily blocks the ports to avoid a loop.
This functionality blocks the ports during either of the following periods:
- for 20 seconds after any of the above events occurred
- for 6 seconds after reception of a control frame when the frame is received over a virtual link within 20
seconds after any of the above events occurred