Exhibit 99.1

CONTACT:
Robert Travis	Scott Larson
Investor Relations	Press Inquiries
Sycamore Networks, Inc.	Sycamore Networks, Inc.
978-250-3432	978-250-3433
bob.travis@sycamorenet.com	scott.larson@sycamorenet.com

SYCAMORE NETWORKS, INC. REPORTS FIRST QUARTER FISCAL YEAR

2009 FINANCIAL RESULTS

CHELMSFORD, Mass., November 20, 2008 – Sycamore Networks, Inc. (NASDAQ: SCMR), a leader in intelligent bandwidth management solutions for fixed line and mobile network operators worldwide, today reported its results for the first quarter ended October 25, 2008. Revenue for the first quarter of fiscal 2009 was $15.4 million, compared with $38.0 million for the first quarter of fiscal 2008.

Net loss for the first quarter of fiscal 2009, on a generally accepted accounting principles (“GAAP”) basis, was $5.8 million, or $0.02 per share, compared with net income of $7.0 million, or $0.02 per share for the first quarter of fiscal 2008. Non-GAAP net loss for the first quarter of fiscal 2009 was $3.5 million, or $0.01 per fully diluted share, compared with non-GAAP net income of $10.4 million, or $0.04 per fully diluted share for the first quarter of fiscal 2008. The reconciliation between net income (loss) on a GAAP basis and net income (loss) on a non-GAAP basis is provided in a table immediately following the Unaudited Non-GAAP Consolidated Statements of Operations included with this release.

“Against a backdrop of challenging market conditions, our results for the first quarter represent continued financial discipline, expansion of customer relationships and progress on new development initiatives,” said Daniel E. Smith, president and chief executive officer. “As we navigate our business through the current market environment, we remain focused on fostering opportunities at existing customers, expanding our customer base and advancing our technology differentiation.”

About Sycamore Networks

Sycamore Networks, Inc. (NASDAQ: SCMR) is a leading provider of intelligent bandwidth management solutions for fixed line and mobile network operators worldwide. From multiservice access networks to the optical core, Sycamore products enable network operators to lower overall network costs, increase operational efficiencies, and rapidly deploy new revenue-generating services. Sycamore’s global customer base includes Tier 1 service providers, government agencies, and utility companies. For more information, please visit www.sycamorenet.com.

Use of Non-GAAP Financial Measures

The Company provides non-GAAP financial data in addition to providing financial results in accordance with generally accepted accounting principles (GAAP). These measures are not in accordance with, or an alternative for GAAP, and may be different from

non-GAAP measures used by other companies. The Company believes that the items excluded from the non-GAAP results have one or more of the following characteristics: their magnitude and timing is largely outside of the Company’s control; they are unrelated to the ongoing operation of the business in the ordinary course; they are unusual, and the Company does not expect them to occur in the ordinary course of business; or they are non-operational, non-cash expenses involving equity grants.

The non-GAAP financial data is provided to enhance the reader’s overall understanding of the Company’s current financial performance and its prospects for the future. Specifically, the Company believes the non-GAAP results provide useful information to both management and investors by excluding certain expense and income items that the Company believes are not indicative of the Company’s core operating results. In addition, since the Company has historically reported non-GAAP results to the investment community, the Company believes the inclusion of non-GAAP numbers provides consistency in its financial reporting. Further, these non-GAAP results are one of the primary indicators management uses for planning and forecasting in future periods. The non-GAAP financial data should be considered in addition to, not as a substitute for or a more appropriate indicator of, operating results, cash flows, or other measures of financial performance prepared in accordance with GAAP.

We wish to caution you that certain matters discussed in this news release constitute forward-looking statements regarding future events that involve risks and uncertainties. Readers are cautioned that actual results or events could differ materially from those stated or implied in the forward-looking statements. Other risks and uncertainties include, but are not limited to, actions, inquiries and findings that may result from certain stock option matters, including the restatement of previously issued financial statements and certain purported shareholder derivative actions filed against the Company and certain of its current and former officers and directors; the Company’s reliance on a limited number of customers; variation in the Company’s quarterly results; industry pricing pressures and the high cost of product development required to remain competitive and keep pace with evolving features and technologies desired by customers; the consolidation of both suppliers and customers in the telecommunications marketplace and general economic conditions. Certain additional risks are set forth in more detail in the section entitled “Risk Factors” in the Company’s most recent Quarterly Report on Form 10-Q and Annual Report on Form 10-K filed by the Company with the Securities and Exchange Commission. The Company disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future results or otherwise.

Sycamore Networks, Inc.

Unaudited Condensed Consolidated Balance Sheets

(in thousands)

	Oct 25, 2008			July 31, 2008
Assets
Current assets:
Cash and cash equivalents	$	272,665		$	499,922
Short-term investments		549,871			321,173
Accounts receivable, net		12,105			8,779
Inventories		23,354			23,750
Prepaids and other current assets		1,988			2,847
Total current assets		859,983			856,471
Property and equipment, net		20,167			20,437
Long-term investments		114,765			120,739
Purchased intangibles, net		3,686			4,000
Goodwill		20,334			20,334
Other assets		447			482
Total Assets	$	1,019,382		$	1,022,463
Liabilities and Stockholders’ Equity
Current liabilities:
Deferred revenue	$	13,795		$	14,300
Other current liabilities		15,728			14,043
Total current liabilities		29,523			28,343
Long term deferred revenue		5,446			4,841
Long term liability		2,050			1,904
Total liabilities		37,019			35,088
Common stock		284			284
Additional paid-in capital		2,036,037			2,034,818
Accumulated deficit		(1,053,562	)		(1,047,783	)
Other equity		(396	)		56
Total stockholders’ equity		982,363			987,375
Total Liabilities and Stockholders’ Equity	$	1,019,382		$	1,022,463

Sycamore Networks, Inc.

Unaudited Consolidated Statements of Operations

(in thousands, except per share data)

	Three Months Ended
	Oct 25, 2008			Oct 27, 2007
Revenue	$	15,431		$	37,986
Cost of revenue		9,358			19,080
Gross profit		6,073			18,906
Operating expenses:
Research and development		11,455			10,764
Sales and marketing		4,074			5,243
General and administrative		1,735			4,993
Restructuring & related impairment		628			1,975
Total operating expenses		17,892			22,975
Loss from operations		(11,819	)		(4,069	)
Interest and other income, net		5,994			11,411
Income (loss) before income taxes		(5,825	)		7,342
Income tax expense (benefit)		(46	)		331
Net income (loss)	$	(5,779	)	$	7,011
Net income (loss) per share:
Basic	$	(0.02	)	$	0.02
Diluted	$	(0.02	)	$	0.02
Weighted average shares outstanding:
Basic		283,444			280,643
Diluted		283,444			283,604

Sycamore Networks, Inc.

Unaudited Non-GAAP Consolidated Statements of Operations

(in thousands, except per share data)

	Three Months Ended
	Oct 25, 2008			Oct 27, 2007
Revenue	$	15,431		$	37,986
Cost of revenue		9,019			18,975
Gross profit		6,412			19,011
Operating expenses:
Research and development		10,950			10,474
Sales and marketing		3,718			5,027
General and administrative		1,245			4,050
Total operating expenses		15,913			19,551
Loss from operations		(9,501	)		(540	)
Interest and other income, net		5,994			11,411
Income (loss) before income taxes		(3,507	)		10,871
Income tax expense (benefit)		(46	)		457
Net income (loss)	$	(3,461	)	$	10,414
Net income (loss) per share:
Basic	$	(0.01	)	$	0.04
Diluted	$	(0.01	)	$	0.04
Weighted average shares outstanding:
Basic		283,444			280,643
Diluted		283,444			283,604

Sycamore Networks, Inc.

Reconciliation of GAAP to Non-GAAP Net Income

(in thousands, except per share data)

	Three Months Ended
	Oct 25, 2008			Oct 27, 2007
GAAP net income (loss)	$	(5,779	)	$	7,011
Stock-based compensation expense:
Cost of revenue		171			105
Research and development		505			290
Sales and marketing		356			216
General and administrative		176			200
Total stock based compensation expense		1,208			811
Amortization of purchased intangible assets		314			743
Restructuring and other asset impairments:
Operating expense		628			1,975
Cost of revenue		168			—
Tax effect		—			(126	)
Non-GAAP net income (loss)	$	(3,461	)	$	10,414