Design to setup ERS 4524 and Cisco Cat6509

[alvinewe]

Hi All,

I would like to get some feedback on any team that has deployed a stacked ERS4524 LAN Switch connected to the Cisco 6509 Core switch. What is the best possible method and what would the configuration be.

As tested the spanning tree does not work well between the vendors. And trunking would be an option but this is connecting an access layer to the Core thus do not need a trunking mode.

Issue:
- Connected the stacked switch to the Cisco core, it created a loop on that VLAN.
- Spanning tree enable on the Avaya switch but the loop still happen.
- Default spanning tree enabled on the Cisco Cat6.

Please advise if you come across any such setup before.

ERS 4542GT - Ver 5.6.1

Example of the current topology.

AVAYA ERS ----------------------- CAT 6509
| Stacked |
AVAYA ERS ----------------------- CAT 6509

[sidneyd]

If you are using a untagged VLAN and STP, then this should work. You should then be able to check the STP status on ports from/to the Cat.

The default mode of spanning tree operation of Avaya switches is Avaya Spanning Tree mode, which determines how you handle STP packets on tagging on the links. This is generally compatable with most vendors, but there are ways in which Cisco can tag STP BPDU such that they will not be appropriate handles by the switch.

You may want to look at using something like MSTP mode (802.1s) on both switches which sets the switch to using standard based multiple Spanning Tree.