EAPs ring decommisioning and STP

[dazza]

Hello! 

I have a EAPs ring to decommission and to reconfigure this topology change to a star network with trunks so that I can minimise the impact of a network refresh. The main issues to deal with are STP and native vlans for a trunk. 

Can STP be enabled with EAPS rings access ports?  So to allow one change at a time.

Would the EAPS control vlan be the ideal native port for a trunk link? (not at work so thinking ahead!)

Many Thanks

Darren

[Brent_Addis]

If you're doing a network refresh anyway, why not go fabric? That way you can have all links active all the time. We've done it across our core and backbone, works amazing.

Otherwise, I would look at a mixture of mlags and seperate eaps rings. with some overlap in your core with additional licensing.

STP/MSTP/RSTP was great in it's day, but the world has moved on, if edge loops are an issue, use ELRP.

[FredrikB-NN2]

While I agree not to use STP for rings is a good thing, I usually recommend using it for the sole purpose of protecting edge ports. ELRP has changed and in environments where you have many VLANs, you can actually fill up your FDB (MAC address table) with ELRP MAC addresses. In recent EXOS versions, each switch will create a separate MAC address on each VLAN for use with ELRP. This means that 10 switches with 20 VLANs will create 200 addresses. That's not massive, but try 1000 switches and 2000 VLANs... (yes, have seen it, had problems with it!) Even in smaller networks, if you're already approaching the MAC limit of your switches, accounting for the uneven hashing that may take place, this may become an issue sooner than you think. Also, the fact that you will not be vendor independent if using ELRP is a big issue for me. I also like the function in STP edge port that disables the port if someone connects a switch that speaks STP in your network. If you don't know about it, it doesn't belong there, right?

[FredrikB-NN2]

There is no such thing as an "EAPS rings access port". Do you mean the ring ports (that are part of EAPS) or access ports that happen to reach other switches via the EAPS ring? You should not use spanning tree on any EAPS ring ports at all.

If you're building a star topology (perhaps with LAG in access to MLAG in dist?), why enable pesky STP? That would be like going from bad to worse. Disable all spanning tree except for the access ports where you configure STP Edge port with action "block". This protects you from accidental loops and also any STP issues in the backbone. If you really, really need to build a ring and don't want to use EAPS, use RSTP on those very ports, nowhere else. Adding STP "just to be safe" is to be extremely unsafe. Are you building a ring or not? If you are, that's OK and even RSTP is OK, but only on those ports! This is my philosophy anyways 🙂