Re: link monitoring

["Lady Benjamin Cannon of Glencoe, ASCE" <lb () 6by7 net>]

We monitor light levels and FEC values on all links and have thresholds for early-warning and PRe-failure analysis. 

Short answer is yes we see links lose packets before completely failing and for dozens of reasons that’s still a good 
thing, but you need to monitor every part of a resilient network. 

Ms. Lady Benjamin PD Cannon of Glencoe, ASCE
6x7 Networks & 6x7 Telecom, LLC 
CEO 
lb () 6by7 net
"The only fully end-to-end encrypted global telecommunications company in the world.”

FCC License KJ6FJJ

Sent from my iPhone via RFC1149.

> On Apr 29, 2021, at 2:32 PM, Eric Kuhnke <eric.kuhnke () gmail com> wrote:
>
> 
> The Junipers on both sides should have discrete SNMP OIDs that respond with a FEC stress value, or FEC error value. 
> See blue highlighted part here about FEC. Depending on what version of JunOS you're running the MIB for it may or may 
> not exist.
>
> https://kb.juniper.net/InfoCenter/index?page=content&id=KB36074&cat=MX2008&actp=LIST
>
> In other equipment sometimes it's found in a sub-tree of SNMP adjacent to optical DOM values. Once you can acquire 
> and poll that value, set it up as a custom thing to graph and alert upon certain threshold values in your choice of 
> NMS. 
>
> Additionally signs of a failing optic may show up in some of the optical DOM MIB items you can poll: 
> https://mibs.observium.org/mib/JUNIPER-DOM-MIB/
>
> It helps if you have some non-misbehaving similar linecards and optics which can be polled during custom graph/OID 
> configuration, to establish a baseline 'no problem' value, which if exceeded will trigger whatever threshold value 
> you set in your monitoring system.
>
> > On Thu, Apr 29, 2021 at 1:40 PM Baldur Norddahl <baldur.norddahl () gmail com> wrote:
> > Hello
> >
> > We had a 100G link that started to misbehave and caused the customers to notice bad packet loss. The optical values 
> > are just fine but we had packet loss and latency. Interface shows FEC errors on one end and carrier transitions on 
> > the other end. But otherwise the link would stay up and our monitor system completely failed to warn about the 
> > failure. Had to find the bad link by traceroute (mtr) and observe where packet loss started.
> >
> > The link was between a Juniper MX204 and Juniper ACX5448. Link length 2 meters using 2 km single mode SFP modules.
> >
> > What is the best practice to monitor links to avoid this scenarium? What options do we have to do link monitoring? I 
> > am investigating BFD but I am unsure if that would have helped the situation.
> >
> > Thanks,
> >
> > Baldur