There are two Adva Fibre Service Platforms located at "The Cattery". A FSP150CCf-825 [1] and a FSP150CC-GE112 [2] (the far left hand of the four devices shown in the video).
In the simplest of terms they can be considered as extensively configurable media converters. Both have dual network ports (either optical or electrical), access ports (either optical or electrical), a management LAN port and a management serial port.
For convenience, both are configured with a management tunnel through their first network port and both devices have their first network port connected via Ethernet patch cables to LAN ports of my ZyXEL VMG1312-B10A. Both are configured such that they synchronise their clocks via the management tunnel and the VMG1312-B10A with public NTP servers.
Both devices have been used singly with other equipment and also in conjunction with each other. In experiments of the latter configuration the two FSPs have been used back to back (network port to network port), front to front (access port to access port) and in tandem (access port of the first device to the network port of the second device).
Yesterday I decided to perform an experiment using both FSPs connected back to back via the bridge of the VMG1312-B10A. Both devices were powered on and, while they went through their POST routine (& synchronised their clocks), I continued to read new posts to this forum. However upon attempting to read the next unread post the browser was unable to make any progress. It was rather like a DOS attack. Turning and looking across the room at the VMG1312-B10A it appeared that all the relevant LEDs were green. Walking to the ZyXEL and observing the LEDs closely it was seen that both LAN ports, to which the FSPs were connected, were flashing vigorously. Quckly looking at the two FSPs, it was seen that all relevant LEDs were green, with both the network ports and the access ports flashing vigorously. A closer look disclosed the reason . . . an 18 inch Ethernet patch lead was connecting an access port of one FSP with an access port of the other FSP. There was a manic storm involving the two FSPs and the ZyXEL, with the end result being a self-inflicted DOS attack on the ZyXEL. Oops . . .
A simple mistake. Upon removing the Ethernet patch lead linking the two FSPs access ports, the storm abated and normality prevailed, once again, in "The Cattery".
Postscript: All three devices' logs showed that nothing abnormal had occurred. So I have no idea which device initially triggered the storm.
[1]
https://www.youtube.com/watch?v=HtSlLv9ntMs[2]
https://www.youtube.com/watch?v=WzkBOsU72UE
