November 26, 2019

UPDATE! Chugach Electric’s Microwave Network Now in IP/MPLS Overlay Phase

UPDATE! Chugach Electric’s Microwave Network Now in IP/MPLS Overlay Phase
Last August, we posted a blog on Chugach Electric’s measured approach to migrating to IP/MPLS. The final phase of the migration is happening now and the proof of concept testing has met its objectives. Below is a detailed update on the migration process.


up to 10X more bandwidth in some segments

After an independent study of options for migrating their network in 2010, Chugach chose Aviat Networks’ Eclipse Hybrid and IRU 600 microwave platforms to upgrade their links, increase capacity, and take the first steps toward cost-effectively evolving legacy TDM equipment to IP-based technologies. Over the next six years, the Eclipse deployments resulted in four times the previous bandwidth across the network and up to tens times the bandwidth in some segments.

With Eclipse and supporting technologies in place, the migration project moved to the IP/MPLS overlay phase in 2017, including designing, testing, and building out the network to deliver IP-based services, while using existing antennas to keep costs down, keeping TDM technologies in place as backup, and offering a highly scalable platform for future growth. The Eclipse hybrid radios can natively transport TDM and IP, ensuring that Chugach can deploy advanced new services and continue to deliver mission-critical legacy services to users transparently.

The plan to add services and the need to handle expected increases in data traffic drove Chugach to make IP/MPLS their new routing platform and their underlying networking platform for future growth. The utility chose the versatile Aviat CTR 8540 as their new routing platform to overlay the Eclipse system. It gave them the flexibility to handle their wide array of existing and planned data and voice services while using a single, cost-saving, and latency-reducing box as the platform. And the CTR 8540 is optimized for microwave.

The final phase is happening now

Since our last blog on this migration, Chugach and Aviat have worked together to plan, design, and execute proof of concept testing for the IP/MPLS overlay. Testing included the teleprotection system, deployment of IP/MPLS-enabling technologies (including the CTR 8540 router), the network path, and service migration onto the new platforms:

  • Teleprotection circuits are the interface between a network’s fault detection system and the communication system we’re all familiar with from using services. It’s what keeps communications running smoothly even when faults occur—it operates in the background to flag problems and reroutes traffic when necessary. It’s a critical part of any network. Test objectives for all teleprotection systems were met and validated.
  • IP/MPLS technologies were deployed, and testing was completed successfully during the last quarter of 2018 and the first quarter of 2019. The network testing was non-intrusive to subscriber traffic, and network measurement recording is ongoing.
  • Services that migrated to the new platforms in 2019 include teleprotection (partial migration), analog voice to voice over IP, LMR (land mobile radio) systems, corporate networks (VPLS), telecom services, and commercial services (MPLS layer 2 VPNs—partial migration).
  • SCADA services (MPLS layer 3 VPNs) are on the agenda to be tested.


Since Chugach’s network migration started, the network has maintained its services without any issues, added ample bandwidth to handle legacy and new traffic needs, and is scalable for further growth in users, services, and applications.

The Chugach five-year growth plan includes network expansion (both fiber and microwave links), additional capacity for existing links, modulation changes, and path overbuilds. At the end of the project, native TDM will still available for backup, if needed.

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