Press Release

Harmonic's cOS Virtualized Broadband Platform Powers Multi-Gigabit Speeds
and Future-Ready Network Enhancements

SAN JOSE, Calif., Sept. 2, 2025 /PRNewswire/ -- Harmonic (NASDAQ: HLIT) today announced a landmark partnership with GCI, Alaska's largest telecommunications company, to modernize its extensive DOCSIS network and accelerate the delivery of high-speed broadband services across the state. Harmonic's industry-leading cOS™ virtualized broadband platform transforms GCI's existing infrastructure to deliver DOCSIS 4.0 services with faster speeds, greater reliability and enhanced scalability to GCI customers across Alaska.

"At GCI, we're building a network that's not only fast today, but is also ready for what's next," added Troy Goldie, senior vice president and chief technology officer at GCI. "Our partnership with Harmonic enables us to deploy advanced technologies that support both our current multi-gig speeds and future scalability as we work toward our long-term goal of bringing 10-gig consumer internet speeds to our customers. GCI's network is better positioned than ever before to meet Alaska's future connectivity needs."

Harmonic is fast-tracking GCI's DOCSIS 4.0 services with a turnkey solution spanning every stage of deployment — from high-level to low-level design and outside plant construction. This includes critical enhancements to cables and passive components, and the installation of new 1.8 GHz amplifiers. Harmonic's deep project management expertise ensures GCI's seamless transition to the new network infrastructure while minimizing service disruptions for customers.

The comprehensive Harmonic solution features the cOS broadband platform in a distributed access architecture (DAA) with Pebble Unified DOCSIS 4.0 Remote PHY Devices (RPDs) inside the Ripple modular DAA nodes. The advanced solution allows GCI to extend the operational life of its existing DOCSIS infrastructure while supporting future service innovations.

In addition, Harmonic's cOS Central services elevate GCI's network operations by enabling real-time insights and proactive maintenance to ensure consistently high-quality broadband experiences for subscribers. Harmonic services empower GCI to offer customers a significantly enhanced broadband experience characterized by faster speeds and robust connectivity.

"Our collaboration with GCI modernizes their network and paves the way for the delivery of high-quality, high-bandwidth broadband services to communities across Alaska," said Yaniv Ben-Soussan, senior vice president of customer experience at Harmonic. "With our market-leading solutions, deep expertise in Unified DOCSIS 4.0 and unparalleled deployment capabilities, we're committed to ensuring GCI's success."

Harmonic is the market share leader in cable broadband equipment, virtual CMTS and DAA, according to Dell'Oro Group, the trusted source for market information about the telecommunications, networks and data center IT industries. Harmonic's cOS platform powers next-gen broadband services through more than 35 million CPE devices worldwide for leading operators in North America, Europe, Latin America and Asia. 

Harmonic will demonstrate its cOS virtualized broadband platform at SCTE TechExpo25, Sept. 29 - Oct.1 in booth H1065. To schedule a meeting with the company, visit www.harmonicinc.com/scte-2025. To learn more about Harmonic's broadband solutions, visit www.harmonicinc.com/broadband.

About Harmonic
Harmonic (NASDAQ: HLIT), the worldwide leader in virtualized broadband and video delivery solutions, enables media companies and service providers to deliver ultra-high-quality video streaming and broadcast services to consumers globally. The company revolutionized broadband networking via the industry's first virtualized broadband solution, enabling operators to more flexibly deploy gigabit internet services to consumers' homes and mobile devices. Whether simplifying OTT video delivery via innovative cloud and software platforms, or powering the delivery of gigabit internet services, Harmonic is changing the way media companies and service providers monetize live and on-demand content on every screen. More information is available at www.harmonicinc.com. 

Legal Notice Regarding Forward-Looking Statements
This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Statements concerning Harmonic's business and the anticipated capabilities, advantages, reliability, efficiency, market acceptance, market growth, specifications and benefits of Harmonic products, services and technology are forward-looking statements. These statements are based on our current expectations and beliefs and are subject to risks and uncertainties, including the risks and uncertainties more fully described in Harmonic's filings with the Securities and Exchange Commission, including its Annual Report on Form 10-K for the year ended Dec. 31, 2024, its Quarterly Reports on Form 10-Q and its Current Reports on Form 8-K. The forward-looking statements in this press release are based on information available to Harmonic as of the date hereof, and Harmonic disclaims any obligation to update any forward-looking statements.

Harmonic, the Harmonic logo and other Harmonic marks are owned by Harmonic Inc. or its affiliates. All other trademarks referenced herein are the property of their respective owners.

About GCI
Headquartered in Alaska, GCI provides data, mobile, voice and managed services to consumer, business, government, and carrier customers throughout Alaska, serving more than 200 communities. The company has invested $4.7 billion in its Alaska network and facilities over the past 45 years. Through a combination of ambitious network initiatives, GCI continues to expand and strengthen its statewide network infrastructure to deliver the best possible connectivity to its customers and close the digital divide in Alaska. GCI is an independent publicly traded company (Nasdaq: GLIBA, GLIBK, GLIBB) Learn more at www.gciliberty.com.

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SOURCE Harmonic Inc.

Netra Ghosh, Corporate Communications Manager, +1 425-215-5525, netra.ghosh@harmonicinc.com; David Hanover, KCSA Strategic Communications, Investor Relations, +1 212-896-1220, investor@harmonicinc.com