I have four EX4300-48T switches -- two in a VC, and two stand-alone -- both running JunOS 13.2X51-D35.3. I have, because I miraculously found some budget, added to these switches a pair of EX4550-32F switches in a second VC. I installed 13.2X51-D35.3 on this VC so that it will be consistent with my 4300s. (In the long run I'm going to bring the rest of my switches, a fleet of EX2200-48T switches, up to the same firmware.)

Topology wise, I'm using the two stand-alone EX4300s as concentrator switches, with runs from each of them to each edge switch. The 4550 VC is an edge switch in this topology. I'm relying on Spanning Tree to prevent loops from forming.

However, when I go to configure spanning tree, I discover that these switches apparently speak different dialects of this firmware.

On the 4300s, unless I explicitly enable spanning tree on a port as so:

set protocols rstp interface ge-0/0/47

...spanning tree isn't active on that port and it will form a loop (discovered in a lab). However, when I try the same thing on the EX4550:

root@sa3-40# set protocols rstp interface xe-0/0/31
missing argument.

The EX4550 seems to want me to say:

set protocols rstp interface xe-0/0/31 mode point-to-point

...which it then records in the config as:

set protocols rstp interface xe-0/0/31.0 mode point-to-point

...which kind of implies to me that when you turn on rstp, it is turned on for all ports by default.

I have not plugged this in yet because I don't want to create a 10G loop as that might be somewhat detrimental to my network. However since I'm using spanning-tree to provide redundant paths here (been burned by the VC in the core once already which is why I'm not VC everywhere) I need to get this right.

The only other configuration on the switches with regards to STP is setting the bridge priority (16K on the stand-alone EX4300s, 32K on the EX4550 VC).

Any historically, all I've done with my EX2200 switches (currently all running 12.3 versions of varying vintages) is to say

set protocols rstp

...and rstp is enabled on all ports.

So, to my questions:

  1. Is RSTP enabled automatically on my xe ports without me explicitly asking for it (ie the same way that it was in JunOS 12 on my EX2200s)?
  2. Should I be explicitly defining the rstp mode as point-to-point on my up/down/crosslinks?
  3. Is there, perhaps, something else I'm missing?
  4. Is there, perhaps, a better way to do this?
  5. Is there a way to get these switches to all speak the same dialect of JunOS?

The answer boils down to: EX4300s (and some newer switches) speak a dialect of JunOS called Enhanced Layer 2 Services (ELS). Older switches, of which the EX4550 is one, do not. With respect to RSTP in particular, EX4550 switches follow the "classic" behaviour that anyone familiar with EX2200 or EX4200s will understand.

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