Re: constant FEC errors juniper mpc10e 400g

[Mark Tinka <mark@tinka.africa>]

On 4/20/24 13:25, Saku Ytti wrote:

> In most cases, modern optical long haul has a transponder, which
> terminates your FEC, because clients offer gray, and you like
> something a bit less depressing, like 1570.42nm.
>
> This is not just FEC terminating, but also to a degree autonego
> terminating, like RFI signal would be between you and transponder, so
> these connections can be, and regularly are, provided without proper
> end-to-end hardware liveliness, and even if they were delivered and
> tested to have proper end-to-end HW liveliness, that may change during
> operation, so line faults may or may not be propagated to both ends as
> RFI assertion, and even if they are, how delayed they are, they may
> suffer delay to allow for optical protection to engage, which may be
> undesirable, as it eats into your convergence budget.
>
> Of course the higher we go in the abstraction, the less likely you are
> to get things like HW livelines detection, like I don't really see
> anyone asking for this in their pseudowire services, even though it's
> something that actually can be delivered. In Junos it's a single
> config stanza in interface, to assert RFI to client port, if
> pseudowire goes down in the operator network.

In our market (Africa), for both terrestrial and submarine services, 
OTN-type circuits are not typically ordered. Network operators are not 
really interested in receiving the additional link data that OTN or 
WAN-PHY provides. They truly want to leave the operation of the 
underlying transport backbone to the transport operator.

The few times we have come across the market asking for OTN is if they 
want to groom 10x 10G into 1x 100G, for example, to deliver structured 
services downstream.

Even when our market seeks OTN from European backhaul providers to 
extend submarine access into Europe and Asia-Pac, it is often for 
structured capacity grooming, and not for OAM benefit.

It would be interesting to learn whether other markets in the world 
still make a preference for OTN in lieu of Ethernet, for the OAM 
benefit, en masse. When I worked in Malaysia back in the day (2007 - 
2012), WAN-PHY was generally asked for for 10G services, until about 
2010; when folk started to choose LAN-PHY. The reason, back then, was to 
get that extra 1% of pipe bandwidth :-).

Mark.