Enabling the Future Network Adtran Inc 2012 All

ADTRAN at a Glance Broad Portfolio of Solutions – More than 1, 700 products 2011 Revenues - $717 million – Carrier Division - $569 million – Enterprise Division - $148 million Strong Financials – Over 20 years of continuous profitability 1, 750 Employees Global Presence – Headquartered in Huntsville, AL – Development centers: ® Adtran, Inc. 2012 All rights reserved Phoenix, AZ Ottawa, Canada Mountain View, CA Hyderabad, India Boston, MA NSN BBA Acquisition ADTRAN Headquarters, Huntsville, AL NASDAQ: ADTN 2

Global Market Trends Broadband / Ethernet Access – Exponential growth in bandwidth access – IP traffic will increase 4 x over next five years – Vo. IP proven and continues significant growth Mobility – Mobile data demand growing 15 -25 x over next three years – Users have growing number of end-points 3 to 5 devices person Smartphone, i. Pad, laptop, machine-tomachine Cloud Services & Applications – Shift to cloud computing drives demand for Enterprise and SMB connectivity Virtualization – Applications running on virtual machines increase efficiency, reduce space and carbon footprint ® Adtran, Inc. 2012 All rights reserved 3

New Devices and Applications New Mobile Devices – i. Pad, tablets, smart phones, etc. . New Applications – Video, gaming, etc. . – Cloud services – Voice over Wi-Fi Major Usage Changes – Netflix is now 30% of Internet traffic – Over 50% of the 800 M Facebook users are active daily – Over 350 M users access Facebook on their mobile device – Two-way video chat Skype Apple’s Facetime ® Adtran, Inc. 2012 All rights reserved 4

Mobility Demand is Exploding 5 B Mobile Phones Globally Smart phones are Pervasive True Mobility is no Longer a Convenience – Voice over Wi-Fi, Facetime New Devices Rely on Wireless Connectivity – i. Pads Mobile Data Traffic is Growing Exponentially Wi-Fi Data Offload to Fixed Network is Necessary Source: FCC ® Adtran, Inc. 2012 All rights reserved 5

Cloud is the Future Cloud services level the playing field for businesses of all sizes and deliver global scalability IDC estimates the market for public cloud products and services will grow to $56 billion by 2014 Amazon’s S 3 Cloud Storage Service skyrocketed from 262 billion in 2010 to over 566 billion in 2011 – Over 370, 000 requests per second Small business public cloud computing spending is estimated to reach $6 billion by 2014 – (Source: In-Stat - December 2010) ® Adtran, Inc. 2012 All rights reserved 6

ADTRAN Areas of Focus Broadest Portfolio of Broadband Solutions – Fiber-to-the-Home/Node/Curb, Ultra Broadband Mobile Infrastructure Broadband – Fixed access from exchange to cell tower – Optical access, Carrier Ethernet access, Broadband access Cloud Connectivity – – Enterprise converged access Hosted service provider solutions Carrier Ethernet, broadband connectivity Virtualization enables unlimited scalability Mobility Cloud ® Adtran, Inc. 2012 All rights reserved 7

ADTRAN – Complete Connectivity Exchange Provider’s Access Infrastructure Business & Residential Customers ® Adtran,

ADTRAN – Complete Connectivity • Broadband Access Industry’s most widely adopted access platform • Ethernet Aggregation Cost-effective for high-density Ethernet deployment Exchange • Optical Access Specifically designed for the access edge Redefining the packet optical edge ® Adtran, Inc. 2012 All rights reserved 9

ADTRAN – Complete Connectivity • Mobile Backhaul Efficient fiber Ethernet services • Business Ethernet Services Full range of service rates and service reach • Business Service Migration Extend product lifecycle Provider’s Access Infrastructure ® Adtran, Inc. 2012 All rights reserved 10

ADTRAN – Complete Connectivity • Cloud Connectivity Industry leadership in service provider bundles • Enterprise Communications Solutions which enable businesses to become more capable and efficient • Virtual Mobility Complete end-point freedom throughout the Enterprise • Residential Deliver Ultra Broadband for premium services Business & Residential Customers ® Adtran, Inc. 2012 All rights reserved 11

Core Product Performance $600 $500 Internetworking Optical Access Broadband Access 36% growth Thousands $400 48% growth $300 25% growth $200 65% growth $100 ADTRAN Core Products $0 2011 • Solid performance in Core Products • Broadband Access • Optical Access • Internetworking ® Adtran, Inc. 2012 All rights reserved 12

Broadband Access Opportunity Market Characteristics • Carrier consolidation ‒ Releases investment • Competitive push by non-wireless carriers • Government mandates ‒ US ‒ Other regions • Over the top video • Continual bandwidth upgrades ® Adtran, Inc. 2012 All rights reserved Ultra Broadband Fiber to the Home Premium internet and Ultra flexible, high video to more customers capacity deep fiber at the lowest TCO solutions 13

Core Product Growth – Broadband Access ADTRAN's Broadband Access Performance • Proven market share growth (2007 -11) • Increasing demand for premium internet, video delivery and business services • Leveraging healthy forecast for high-speed services globally Thousands $ 300 $ 250 $ 200 $ 150 $ 100 $ 50 $2007 2009 2010 2011 $2. 5 $2. 0 $1. 5 $1. 0 $0. 5 $0. 0 2011 MSAP ® Adtran, Inc. 2012 All rights reserved 2008 ADTRAN's Broadband Addressable Market Equipment Revenue ($ B) – #1 DSL & MSAP in NA – #3 DSL Globally – #4 MSAP Globally $ 350 DSLAM 2012 GPON OLT 2013 2014 Ethernet FTTH UBE Source: Infonetics 14

Internetworking Opportunity Market Characteristics • Rise of Cloud Services Cloud Connectivity Market Leadership in public and private cloud connectivity ‒ Public & Private • More Communications Enabled Business Processes Enterprise Communications Premises-based solutions enabling business productivity ‒ Unified Communications • Explosion of Mobile Devices ‒ End-user (not IT) dictates the device ‒ Demand for bandwidth ® Adtran, Inc. 2012 All rights reserved Virtual Mobility End point freedom across the Enterprise 15

Core Product Growth – Internetworking ADTRAN's Internetworking Performance • Proven market share growth (2007 -11) $ 140 $ 120 Millions $ – #1 Cloud Connectivity – #1 SIP Trunking – #2 Access Routers $ 160 $ 80 $ 60 $ 40 • Market Leadership in Carrier Bundled Business Services $ 20 $2007 $ 12 Billions • Highly Differentiated Virtual Wireless LAN and Unified Communications $ 100 2008 2009 2010 2011 Internetworking Addressable Market $ 10 Carrier Ethernet Wireless LAN $8 Enterprise Security $6 IP Business Gateways Routers $4 Unified Communications Managed Ethernet Switches $2 $2011 2012 2013 2014 Source: Infonetics ® Adtran, Inc. 2012 All rights reserved 16

Optical Access Opportunity Market Characteristics • Massive Traffic Growth ‒ Limitless Optical Capacity • Simplified Operations ‒ Optical Ethernet • 5 B Mobile Devices Worldwide ‒ Computer on your hip • Mobile Broadband ‒ Exponential Bandwidth Requirements Optical Networking Edge Right-sizing Packet Optical to reduce complexity at the network edge. ® Adtran, Inc. 2012 All rights reserved Mobile Backhaul Enabling the promise of Mobile Broadband 17

Core Product Growth – Optical Access ADTRAN’s Optical Access Performance • Expanding Optical Addressable Market $ 80 Millions $ – SONET WDM – Access & Transport – U. S. Global $ 100 – ONE differentiation pulls through sales in Broadband Access ® Adtran, Inc. 2012 All rights reserved $2007 2008 2009 2010 2011 ADTRAN's Optical Addressable Market $2. 0 $1. 6 Billions $ • Pull-Thru Revenue $ 40 $ 20 • Growing Market Share – Highly Differentiated Solutions - ONE – Reducing Network Complexity – Accelerating Services Delivery $ 60 $1. 2 $0. 8 $0. 4 $0. 0 2011 2012 2013 2014 Source: Infonetics 18

International Growth Progress 2011 Revenue Contribution International Growth Domestic 165% Growth 215% Growth 2010

Planned Acquisition of NSN’s BBA Business ADTRAN announced that it plans to acquire Nokia Siemens Networks Broadband Access (BBA) business NSN BBA business includes – MSAN, GPON, DSLAM and related Network Management Solutions and associated IPR – Incumbent customer base of carriers across >20 countries in Europe, Middle East, Africa, India, Russia and Asia – Strong team of sales, service, support, and engineering Acquisition is anticipated to close by the end of April 2012 Advances ADTRAN’s Top Tier Global Supplier status in fixed broadband access EPS neutral for first full year, accretive thereafter ® Adtran, Inc. 2012 All rights reserved 20

Purpose of Acquisition Accelerates strategic plan for global growth - Incumbent supplier to top Carriers across the globe, including DT, Bezeq, Sunrise and others - Regional Diversity Complementary product portfolios - Strong global MSAN Solutions - ADTRAN adds Carrier Ethernet, Ethernet Business Services, Mobile Backhaul, Enterprise solutions… - NSN BBA adds MPLS, H. 248, ETSI voice, global services… - Combined portfolios deliver compelling global roadmap • Strengthens Engineering and Services resources to focus on global accounts • Provides word-class sales, services and customer support ® Adtran, Inc. 2012 All rights reserved 21

ADTRAN Customer Focus NORTH AMERICA EUROPE ASIA AFRICA SOUTH AMERICA AUSTRALIA ANTARCTICA ® Adtran,

NSN BBA Customer Focus NORTH AMERICA EUROPE ASIA AFRICA SOUTH AMERICA AUSTRALIA ANTARCTICA ®

Combined Customer Focus NORTH AMERICA EUROPE ASIA AFRICA SOUTH AMERICA AUSTRALIA ANTARCTICA ® Adtran,

Top Tier Global MSAP Ranking – Ports Global – MSAP Category (Port Shipments) ®

Top Tier Global DSL Ranking – Revenue Global – DSL Category (Revenue) ® Adtran,

Annual Revenue and EPS: 2007 -2011 Revenue: 2007 -2011 ($ millions) $717 $606 $501

Return on Invested Capital and Economic Value Added Spread (trailing twelve months) ROIC EVA Spread 25. 00% 20. 00% 15. 00% 10. 00% 5. 00% 0. 00% -5. 00% -10. 00% -15. 00% -20. 00% -25. 00% -30. 00% ADTRAN Cisco Ericsson Fujitsu Alcatel ZTE Westell Tellabs* Calix Ciena Zhone *Adjusted for nonrecurring tax items. Information derived from Bloomberg as of January 1, 2012 ® Adtran, Inc. 2012 All rights reserved 28