Add VLAN to trunk causes switch to drop

[Terren_Crider]

Hi all, I've got two switches separated by about 7 miles of fiber and an Internet link at each site. I need a certain number of VLANs to extend between the sites for HA purposes. VLANs: tagged 243, 923-925, 927, 1000, untagged 4040 All of these VLANs span the trunk no problem except for 927. When I apply 927 the distant switch drops. When I remove 927, it comes back. Spantree is applied and enabled at the HA site, but not the main site. Where do I need to look to solve this problem?

[Jeremy_Gibbs]

Do you have spangaurd on or adminedge turned on? Also, what hardware and code are you running at each site? Also, what version. Take a look at this, depending on what you are running.

https://community.extremenetworks.com/extreme/topics/connecting-s-series-with-x450-g2-rstp-error-mul...

[Terren_Crider]

We may be barking up the wrong spantree here. It doesn't make much sense to me why 927 has problems, but the other six VLANs are fine.

[Terren_Crider]

SID Port State Role Cost Priority --- ---------- ---------------- ----------- -------- -------- 0 tg.11.1 Forwarding Designated 20000 128 0 tg.11.2 Blocking Backup 20000 128

[Terren_Crider]

STP Diagnostic Port Counters for SID 0 Port tg.11.1 ------------------------------------------------------------ Message Expiration Count - 0 Invalid BPDU Count - 0 Disputed BPDU Count - 2209 STP BPDU Rx Count - 0 STP BPDU Tx Count - 0 STP TCN BPDU Rx Count - 0 STP TCN BPDU Tx Count - 0 STP TC BPDU Rx Count - 0 STP TC BPDU Tx Count - 0 RST BPDU Rx Count - 2209 RST BPDU Tx Count - 0 RST TC BPDU Rx Count - 0 RST TC BPDU Tx Count - 0 MST BPDU Rx Count - 3544 MST BPDU Tx Count - 2295794 MST CIST TC BPDU Rx Count - 0 MST CIST TC BPDU Tx Count - 11 SPT BPDU Rx Count - 0 SPT BPDU Tx Count - 0 SPT TC BPDU Rx Count - 0 SPT TC BPDU Tx Count - 0

[Jeremy_Gibbs]

Also, another good command is, show spantree stats active

See if there is anything being blocked already etc...