Ethernet Switching
Ethernet Switching

RSTP issue with ex4300 and ex2300 in 18.4 version

‎06-03-2019 03:11 AM

Hi all,


It´s the first time I write here.

I´m having strange behaviours with a 4300 stack configuration and spannig tree between the other nodes connected to this Stack.

I´ve configured different "ae" between this 4300 virtual chassis and the satellites nodes.

If I type a show spanning-tree interfaces" in the 4300 virtual chassis that is the root in the RSTP topology , I see all the ae interfaces configured against the satellites switches are blocked.

Sorry if I say any stupid thing , but I´m new in the switching world Smiley Happy .

Is it supposed all the ports in the root should be in forwarding state, isnt it?

What could be the reason to have root ports in blocked state, any idea?

The only difference between this configuration and other I´ve configures is the version of all the switches, in this case is the JunOS 18.4.

Any idea or command I can try to find the problem?







Ethernet Switching

Re: RSTP issue with ex4300 and ex2300 in 18.4 version

‎06-03-2019 08:35 AM

Suggest maybe you sent the outputs of:


show spanning-tree bridge detail


show spanning-tree interface detail

Ethernet Switching

Re: RSTP issue with ex4300 and ex2300 in 18.4 version

‎06-03-2019 02:09 PM

Hi Manuel,


When the root bridge has more than one port on a single LAN segment, the bridge ID is effectively tied, as are all root path costs (all equal zero). The designated port then becomes the port on that LAN segment with the lowest port ID. It's put into Forwarding mode while all other ports on the root bridge on that same LAN segment become non-designated ports and are put into blocking mode


Please check if this is the situation you are facing, if yes, this is expected. 




Please mark my solution as accepted if it helped, Kudos are appreciated as well. Smiley Happy