Enlighten the darkness in your fiber topology TNC

Enlighten the darkness in your fiber topology TNC 19, Tallinn, 18. 6. 2019 Jani Myyry, Kaisa Haapala & Jani Sirpoma (CSC/Funet)

Introduction - operating environment and issues • Funet operates leased long-haul and access fiber networks nationwide • Long-haul fibers o Fiber cuts and maintenance without prenotification o Failed planned maintenance: increased attenuation, signal loss • Access fibers o No route maps or measurements o Mixture of leased and customer owned fiber o Pluggable, equipment, power etc. issues cannot be ruled out 2 NOC engineer

How we troubleshoot fiber issues? • Traditionally, use handheld OTDR measurement tools o But in practice capability limited to areas near the Helsinki region o Lots of passive CWDM filter based access links, challenging to disconnect for measurements • Then we saw an in-service OTDR demo at TNC 17 in Linz o Cool stuff, remote and automatic troubleshooting possible • Investigate, go forward! o Included as a mandatory requirement for our optical tender (after vendor discussions) 3

Measuring long-haul network in-service • All fibers, with two models: o Counter-propagating for short EDFA-only links o Bi-directional for longer EDFA/RAMAN links • OTDR couplers placed behind RAMAN amplifier + Able to see the line fiber connector - Decreases the reach OTDR Coupler • RAMAN amplifies OTDR signals o Different results if amplifiers are on OTDR AMP 4 Bi. Di OTDR measurement AMP

Measuring access fibers in-service • OTDR ports available (8 -12 after long-haul needs) • Better integration needed o Couplers not robust enough (too thin fibers) Monitor port • Solution 1: customized CWDM filter o 1650 nm OTDR filter build-in o A low loss 1310 nm wide channel & MON ports • Solution 2: dark fiber only o Shelf-based OTDR filters (NREN site) o Pluggable LC “attenuator like” reflector (customer site) 5 1650 nm OTDR port

Access fiber use cases 6

Operational experiences (so far) • Able to notify fiber cuts quicker to the fiber providers and inform the location • Verify fibers after repair work o No need to rely on 3 rd party OTDR measurements • Retain fiber quality o Located dirty connectors after site work and got those fixed before turning on amplifiers o Also removed one airgap from backbone fibers (UPC <-> APC) “why do we have extra 6 d. B loss over a 2 km link? ” 7

Example 1: dirty connector between line fiber and amplifier Fault location (3, 3 m) Reflection Reference measurement 0, 8 d. B extra attenuation Analysis measurement 8

Example 2: fiber maintenance (without prenotification) Measurement during the break Analysis afterwards Reference measurement Analysis measurement fiber cut (19 824 m) +70 m length +1, 7 d. B gain (RAMAN on) 9

Future steps • Extend coverage on access side (i. e. change CWDM filters) • Integrate into NOC processes and views • Evaluate fiber mapping solutions o KML/KMZ files for long-haul fibers and some new access fibers o Events (distances) from the OTDR devices o Preferably open-source and offline maps • We are interested to hear if you have found a solution for this? 10

Jani Myyry facebook. com/CSCfi Senior Network Specialist Funet CSC – IT Center for Science Ltd. twitter. com/CSCfi jani. myyry@csc. fi noc@funet. fi youtube. com/CSCfi linkedin. com/company/csc---it-center-for-science github. com/CSCfi 11 Kuvat CSC: n arkisto ja Thinkstock