Tom Mock Vice President, Strategic Planning May 5, 2004

1. JP Morgan 32nd Annual Technology & Telecom Conference CIENA: Beyond Optical Tom MockVice President, Strategic Planning May 5, 2004

2. Forward-Looking Statements This presentation may contain “forward-looking statements.” These statements are based on our expectations and are naturally subject to uncertainty and changes in circumstances. Actual results could vary materially from these expectations. More detailed information about the risks involved in investing in CIENA’s stock are set forth in CIENA’s Quarterly Report on Form 10-Q for the quarter ended January 31, 2004. CIENA is under no obligation (and expressly disclaims any such obligation) to update or alter its forward-looking statements, whether as a result of new information, future events or otherwise.

3. Agenda • Where we were • What changed? • CIENA: Beyond optical • CIENA’s Transformation: Beyond the product portfolio

4. Long Haul DWDM Transport Long Haul DWDM Transport Long Haul DWDM Transport Long Haul DWDM Transport Long Haul DWDM Transport Long Haul DWDM Transport Core Optical Switching Core Optical Switching Core Optical Switching Core Optical Switching Core Optical Switching Core Optical Switching Long Haul DWDM Transport Long Haul DWDM Transport Long Haul DWDM Transport Long Haul DWDM Transport Long Haul DWDM Transport Long Haul DWDM Transport Core Optical Switching Core Optical Switching Core Optical Switching Core Optical Switching Core Optical Switching Core Optical Switching $50 $50 $50 $50 $50 $50 $50 $50 $50 $50 $50 $50 700 700 700 700 700 700 600 600 600 600 600 600 43% 43% 43% 43% 43% 43% 43% 43% 43% 43% 43% 43% 500 500 500 500 500 500 $ / Mbps $ / Mbps $ / Mbps $ / Mbps $ / Gb/s 400 400 400 400 400 400 99% 99% 99% 99% 99% 99% 99% 99% 99% 99% 99% 99% $ Millions $ Millions $ Millions $ Millions $ Millions $ Millions $ Millions $ Millions $ Millions $ Millions $ Millions $ Millions $25 $25 $25 $25 $25 $25 $25 $25 $25 $25 $25 $25 300 300 300 300 300 300 16% 16% 16% 16% 16% 16% 16% 16% 16% 16% 16% 16% 36% 36% 36% 36% 36% 36% 36% 36% 36% 36% 36% 36% 200 200 200 200 200 200 Capex Capex Capex Capex Capex Capex 100 100 100 100 100 100 $5 $5 $5 $5 $5 $5 $5 $5 $5 $5 $5 $5 0 0 0 0 0 0 CAPEX CAPEX CAPEX CAPEX CAPEX CAPEX CAPEX CAPEX CAPEX CAPEX CAPEX CAPEX CAPEX CAPEX CAPEX CAPEX CAPEX CAPEX OPEX OPEX OPEX OPEX OPEX OPEX REVENUE REVENUE REVENUE REVENUE REVENUE REVENUE CAPEX CAPEX CAPEX CAPEX CAPEX CAPEX OPEX OPEX OPEX OPEX OPEX OPEX REVENUE REVENUE REVENUE REVENUE REVENUE REVENUE Traditional Traditional Traditional Traditional Traditional Traditional Traditional Traditional Traditional Traditional Traditional Traditional CIENA CIENA CIENA CIENA CIENA CIENA CIENA CIENA CIENA CIENA CIENA CIENA 1996 1996 1996 1996 1996 1996 - - - - - - 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 - - - - - - 2003 2003 2003 2003 2003 2003 1996 1996 1996 1996 1996 1996 - - - - - - 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 2000 - - - - - - 2003 2003 2003 2003 2003 2003 Acq’d Lightera, January, 1999 CIENA Led the Optical Core Revolution Success driven by disruptive economics Core Network CoreStream™ CoreDirector™

5. Acq’d ONI June 2002 ONLINE™ Metro MetroDirectorK2™ Acq’d Cyras Dec 2000 ONLINE Edge CIENA’s Optical Portfolio Expansion Access Network Core Network Metro Network CoreStream™ CoreDirector™

6. …and spending has shifted to service delivery The Operators’ “pain point” has moved… Core Optical Market is in Decline Relative cost of equipment $650 / Mbps $18 / Mbps $650 / Mbps Alpharetta Linthicum • The core is no longer the primary challenge. • Carriers shifting emphasis from CAPEX/OPEX reduction to top-line growth. • Protecting voice revenues remains a priority. • Service providers looking for strategic partners to deliver profitable broadband services originating from the edge. Source: Infonetics, Dell’Oro, CIENA Internal Estimates

7. Capture revenues by increasing service bundle Converge functionality to reduce CAPEX Control network to reduce OPEX Network Philosophy

8. VoD/HDTV Services Voice/video/ DSL Services MPLS/ATM/FR Services IP Services Storage Services ONLINE™ Metro Ethernet Services Private Line Services MetroDirectorK2™ ONLINE Edge Capturing Services Revenue Access Network Core Network Metro Network An intelligent optical core enables an all-service network, but CIENA’s portfolio lacked service delivery platforms customers needed to capture new revenue growth CoreStream™ CoreDirector™

9. CIENA’s Acquisition/Partnership Goals • Expand addressable market with service delivery platforms • Leverage core leadership/strengths • Leverage customer base/relationships • Improve CIENA’s business model • Drive revenue growth • Improve gross margins • Push toward sustained profitability

10. Preserve the Core; Expand Service Portfolio Video on Demand HDTV VoIP Ethernet Storage Private Lines Internet Access DSL IP VPNs • Protect brand and customer base by continuing investment in the core at reduced levels • Diversify into service delivery with a coherent portfolio • Target underserved, high growth segments that leverage CIENA’s brand and customer equity

11. Disciplined Acquisition Strategy Candidates should: • Be disruptive to existing network economics • Fit with CIENA’s network vision • Have adjacency (via customer or technology) • Deliver good margin profile • Have channel fit or provide new channel • Have visible path to #3+ market share in growth market

12. VoD/HDTV Services Acq’d WaveSmith June 2003 Voice/video/ DSL Services DN™ 7 MPLS/ATM/FR Services IP Services Storage Services ONLINE™ Metro Ethernet Services Private Line Services MetroDirectorK2™ ONLINE Edge Capturing Services Revenue Access Network Core Network Metro Network CoreStream™ CoreDirector™

13.  MultiService Switching   Revenue per $ of CapEx  150% increase   Traditional DN Applications: DSL Aggregation, VoD, ATM,Frame Relay Disciplined Acquisition Strategy - WaveSmith Acquisition/Partner candidates should: • Be disruptive to existing network economics • Fit with CIENA’s network vision • Have adjacency (via customer or technology) • Deliver good margin profile • Have channel fit or provide new channel • Have visible path to #3+ market share in growth market

14. VoD/HDTV Services Voice/video/ DSL Services DN™ 7 MPLS/ATM/FR Services IP Services Acq’d Akara Aug 2003 CN™ 2000 Storage Services ONLINE™ Metro Ethernet Services Private Line Services MetroDirectorK2™ ONLINE Edge Capturing Services Revenue Access Network Core Network Metro Network CoreStream™ CoreDirector™

15.  SONET/SDH Storage   Revenue per $ of CapEx  230% increase   Traditional CN 2000 Applications Storage extension, Access WDM, Low-Cost Ethernet Transport Disciplined Acquisition Strategy - Akara Acquisition/Partner candidates should: • Be disruptive to existing network economics • Fit with CIENA’s network vision • Have adjacency (via customer or technology) • Deliver good margin profile • Have channel fit or provide new channel • Have visible path to #3+ market share in growth market

16. VoD/HDTV Services Laurel Partnership Sept 2003 Voice/video/ DSL Services Internet Photonics Catena DN™ 7 MPLS/ATM/FR Services IP Services CN™ 2000 ST™ (Laurel) Storage Services ONLINE™ Metro PacketWave™ (Luminous) Ethernet Services Private Line Services MetroDirectorK2™ Luminous Partnership Sept 2003 ONLINE Edge Capturing Services Revenue Access Network Core Network Metro Network CoreStream™ CoreDirector™

17. Background • Acquisition closed May 3, 2004. • 75.9 million shares of CIENA Common Stock issued. • Majority of shares not subject to lock-up. • A leading innovator in the broadband access market • Customers • Three RBOCs (including Bell South) • Major IOCs • CLECs • Products • CNX-5 • CN1000 • CN1000FX Yankee Group: Overall broadband equipment revenues in the access area will present a market opportunity in excess of $7.5 billion

18. Background • Acquisition closed May 3, 2004. • 24.1 million shares of CIENA Common Stock issued. • No lock-up. • A leading supplier of carrier-grade optical Ethernet transport and switching solutions • Customers • Six of the top ten U.S. cable operators (including Cablevision, Cox, Adelphia) • Carriers such as TDS Metrocom deploying Ethernet private-line services • Products • LightStack MXA • LightStack MX • LightStack GSLAM • LightHandler Infonetics Research: Worldwide Ethernet services market will grow from approximately $2.9 billion in 2003 to $7.5 billion by 2007.

19. CIENA’s Transformation: Beyond the Product Portfolio • Shifting investment to access/service delivery from core • Goal of reducing ongoing opex (exclusive of Catena/IPI) by 10% to 20% in FY ’04 • Announced facilities consolidation and associated headcount reduction affecting 425 employees (~25% of CIENA’s workforce prior to Catena/IPI) on April 20, 2004 • 2002-2003 investments will enable us to maintain core leadership • Manufacturing nearly 100% outsourced • Currently working to consolidate contract manufacturers • Services business restructured to profitability • Sales force revamped to include skills/experience required for broader portfolio • 30+ channel partners developed to target enterprise opportunities/new geographies

20. FY ’01 $1.6 billion FY ’02 $361 million Core Networking Service/Tech Support Metro Networking Solutions & Software Transforming CIENA to Encompass Broadband Service Delivery From (2003) To Include (2005) CAPEX/OPEX Savings Service Revenues Value Proposition Technologies Core Optical Broadband Edge & Access High Quality/Low Volumes Direct Sales Only Low Cost/High Volumes Channels/Enterprise Pull Competencies FY ’03 $283 million FY ’04 (stated goal prior to Catena & IPI) Data Networking/ Service Delivery T.B.D.

21. Thank You!