Re: Flapping Transport

[Mike Hammett <nanog () ics-il net>]

*nods* I know optical transport can be difficult to track down, but they had admitted to a faulty card, then said they 
weren't going to do anything because it hadn't faulted again. 




Yeah, it's probably just being cheap. Well, kinda. I mean they've also said the card was already delivered, just needed 
installation. 




----- 
Mike Hammett 
Intelligent Computing Solutions 

Midwest Internet Exchange 

The Brothers WISP 

----- Original Message -----

From: "Dave Cohen" <craetdave () gmail com> 
To: "Mike Hammett" <nanog () ics-il net> 
Cc: "NANOG" <nanog () nanog org> 
Sent: Tuesday, August 1, 2023 1:37:47 PM 
Subject: Re: Flapping Transport 



At a previous $dayjob, we employed a guy that was a bona fide optical guru. He had effectively memorized the 400+ page 
Nortel 6500 operating guide, and some of the hardware vendors would call him for advice when their TACs couldn't figure 
a problem out. Allegedly, he was the person who discovered that the early generations of OTU-4 line deployments were 
susceptible to problems across cable in OPGW space because of the Faraday Effect. On the rare occasion when he couldn't 
diagnose a problem he'd respond with something like "voodoo doesn't always work". 


To your question, it isn't acceptable but it is likely pretty normal. Flapping isn't often a particularly 
straightforward issue to diagnose and/or resolve in optical networks (especially ones where there's regen or in-line 
amplification), and most transport providers don't employ guys like that that can figure it out. And even then, voodoo 
doesn't always work. 


Your hope is that whatever the "card issue" was was a localized event rather than something that's now systemic, and 
while I don't really understand why they wouldn't take a maintenance window to replace the cards anyway (aside from 
being cheap, which is almost definitely the reason), if they're not seeing continued issues (and of course you'd have 
to trust them that they're not), it's equally likely as not that the problem has in fact resolved. 


On Tue, Aug 1, 2023 at 2:21 PM Mike Hammett < nanog () ics-il net > wrote: 







I have a wave transport vendor that suffered issues twice about ten days apart, causing my link to flap a bunch. I put 
in a ticket on the second set of occurrences. I was told that there was a card issue identified and would be notified 
when the replacement happened. Ticket closed. 


Three weeks later, I opened a new ticket asking for the status. The new card arrived the next day, but since no more 
flaps were happening, the card would not be replaced. Ticket closed. 




A) It doesn't seem like they actually did anything to fix the circuit. 
B) They admitted a problem and sent a new card. 
C) They later decided to not do anything. 




Is that normal? 
Is that acceptable? 




To avoid issues flapping causes, I disabled that circuit until repaired, but it seems like they're not going to do 
anything and I only know that because I asked. 



----- 
Mike Hammett 
Intelligent Computing Solutions 

Midwest Internet Exchange 

The Brothers WISP 






-- 


- Dave Cohen 
craetdave () gmail com