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Chat => Tech Chat => Topic started by: burakkucat on June 19, 2021, 09:17:10 PM

Title: A Simple Mistake.
Post by: burakkucat on June 19, 2021, 09:17:10 PM
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
Title: Re: A Simple Mistake.
Post by: Alex Atkin UK on June 19, 2021, 10:00:56 PM
Been there, though STP is supposed to prevent this on modern hardware.
Title: Re: A Simple Mistake.
Post by: burakkucat on June 19, 2021, 10:44:55 PM
In terms of STP, I expect that the ZyXEL VMG1312-B10A was the odd one out of the three devices.
Title: Re: A Simple Mistake.
Post by: d2d4j on June 20, 2021, 10:28:18 AM
Hi burakkucat

We have seen storms a few times, and it is generally due to storm protection disabled or devices not having ability for storm protection

I did a quick readup and if I understand correctly, your can do Level 2 or Level 3, but storm protection depends upon which level is set

Level 2 storm protection is on by default

Level 3 storm protection is off by default

I maybe reading details about the wrong device though but it is worth checking and sorry in advance if I am wrong

Many thanks

John
Title: Re: A Simple Mistake.
Post by: Alex Atkin UK on June 20, 2021, 02:48:52 PM
There's definitely still some quirks as I have to use my surround receiver over WiFi because if I wire it into my network it causes some strange issues that feel like a broadcast storm.  I can't remember exactly what happened, I think it causes the switch and everything its plugged into to drop off the network.
Title: Re: A Simple Mistake.
Post by: Black Sheep on June 20, 2021, 04:30:13 PM
I genuinely wish I knew what you guys are chatting about #likeadifferentlanguage
Title: Re: A Simple Mistake.
Post by: 4candles on June 20, 2021, 05:12:43 PM
That's two of us then BS.   :wry:
Title: Re: A Simple Mistake.
Post by: burakkucat on June 20, 2021, 05:15:36 PM
I did a quick readup and if I understand correctly, your can do Level 2 or Level 3, but storm protection depends upon which level is set

Level 2 storm protection is on by default

Level 3 storm protection is off by default

Thanks for the research, John.

My current plan of action is quite simple . . . to try not to be so unobservant of what is right in front of me.  :D
Title: Re: A Simple Mistake.
Post by: burakkucat on June 20, 2021, 05:29:54 PM
For B*Sheep and 4C I'll just mention Spanning Tree Protocol (STP) (https://en.wikipedia.org/wiki/Spanning_Tree_Protocol). To describe my mistake in terms of something of which, I think, you both would be familiar consider a four-wire amplified cable section . . . What would happen if you inadvertently connected the return pair (from the right) to the go pair (to the right)?  ;)
Title: Re: A Simple Mistake.
Post by: Black Sheep on June 20, 2021, 05:32:25 PM
That's two of us then BS.   :wry:

 :D :D :D
Title: Re: A Simple Mistake.
Post by: Black Sheep on June 20, 2021, 05:36:21 PM
For B*Sheep and 4C I'll just mention Spanning Tree Protocol (STP) (https://en.wikipedia.org/wiki/Spanning_Tree_Protocol). To describe my mistake in terms of something of which, I think, you both would be familiar consider a four-wire amplified cable section . . . What would happen if you inadvertently connected the return pair (from the right) to the go pair (to the right)?  ;)

Ha ha - thanks B*Cat -  :)
Title: Re: A Simple Mistake.
Post by: 4candles on June 20, 2021, 07:38:40 PM
+1!  :)
Title: Re: A Simple Mistake.
Post by: Chrysalis on August 12, 2021, 12:18:26 AM
Yeah sounds like same problem I had today. :) But your story much more elegantly written. :)
Title: Re: A Simple Mistake.
Post by: burakkucat on August 12, 2021, 05:24:45 PM
 :)