Configuring Extended Edge Switching Ring Topology

The following procedure explains how to set up an Extended Edge Switching ring topology.

Extended Edge Switching rings allow two Extended Edge Switching (VPEX) cascades to be joined together to form a ring, or a single cascade to be joined back to the controlling bridge (CB). When a link breaks or a bridge port extender (BPE) otherwise leaves, the remaining BPEs form one or two new cascades that end at the ring break, thus keeping connectivity to the CB alive.

For more information about Extended Edge Switching ring topology, see Extended Edge Switching Rings.

Ensure that all BPEs are running the minimum VPEX version software to support Extended Edge Switching (see ExtremeXOS Release Notes). For information about upgrading the BPEs, see Upgrading the Controlling Bridge and Bridge Ports Extenders.

Connect the BPEs into one or two cascades.
Configure the cascades and allow them to form. You can use either:
- Full automation (Configuring Extended Edge Switching Topology with Full Automation).
- Partial automation (Configuring Extended Edge Switching Topology with Partial Automation (Auto-configuration)).
- Manual configuration (Manually Configuring Bridge Port Extenders).
  Note
  Ring re-balancing establishes two cascades of approximately equal length without regard to bandwidth consumption of a BPE. In a mixed node cascade, you should place the most bandwidth consuming BPEs as close as possible to the CB in the cascade. For example, a 48t BPE may use two-port LAGs to communicate with the CB, but a 24t BPE switch can only have one port in its upstream direction. Thus the 24-port BPEs should be placed at the tiers that are farther from the CB.
Use the show slot {slot {detail} | detail } and show vpex topology { port port_num} {summary | detail} commands to ensure that the cascades have finished forming correctly.
Connect the end BPEs of these cascades to each other, or the end of the single cascade to a port on the CB.
A message similar to the following appears:
```
<Noti:VPEX.Ring.Dtect> Slot-1: Ring detected between ports <port1> and <port2>
```
(Optional) Turn on automatic ring re-balancing. Ring re-balancing is disabled by default. For more information about ring re-balancing, see Uneven Cascade Lengths and Ring Re-balancing. If you want to enable ring re-balancing, use the following command:
configure vpex ring rebalancing [auto | off]

When a ring contains different types of BPEs that provide different amounts of bandwidth, automatic ring re-balancing may cause an undesirable balance point as seen when using the show vpex topology { port port_num} {summary | detail} command. If so, wait until the ring state is complete. You can then force the balance point by disabling a cascade port at the desired re-balance point, disabling automatic re-balancing, and then enabling the cascade port that was disabled previously.
If you are using redundant CBs with one-arm MLAGs (see One-Arm MLAGs), have each MLAG peer declare a slot on the other peer's one-arm MLAG. Use the command:
configure vpex mlag-id mlag_id peer peer_name slot slot_num
You can also set a preference for when Auto-Configuration configures the virtual MLAG ID. The default (cascade) configures the virtual MLAG ID whenever a 2nd-tier BPE is detected remotely, but not locally. To set the preference, use the command:
configure vpex auto-configuration mlag-id [cascade | ring]

For information about troubleshooting an Extended Edge Switching topology, see Troubleshooting an Extended Edge Switching Topology.