Exhibit 99.1

Ixia Announces 2011 First Quarter Results
26 Percent Year-Over-Year Revenue Growth

CALABASAS, CA, April 21, 2011 — Ixia (Nasdaq:XXIA) today reported its financial results for the first quarter ended March 31, 2011.

Total revenue for the 2011 first quarter grew to a record $78.5 million, an increase of 26 percent compared with $62.0 million reported for the 2010 first quarter and up $0.7 million compared with $77.8 million reported in the immediately preceding quarter.

On a GAAP basis, the company recorded net income for the 2011 first quarter of $7.1 million, or $0.10 per diluted share, compared with net income of $0.9 million, or $0.01 per diluted share, for the 2010 first quarter.

Non-GAAP net income for the 2011 first quarter increased 268 percent to $12.2 million, or $0.16 per diluted share, compared with non-GAAP net income of $3.3 million, or $0.05 per diluted share, for the 2010 first quarter.

Additional non-GAAP information and reconciliation of our non-GAAP measures to comparable GAAP measures for the 2011 and 2010 first quarters may be found in the attached financial tables.

“We are very pleased to report strong results for our first quarter of 2011, including non-GAAP gross margin of over 80 percent and non-GAAP operating margin of over 22 percent,” commented Atul Bhatnagar, Ixia’s president and chief executive officer. “We continue to realize more operating leverage out of our model as we scale our business and in the first quarter of 2011, we reported our highest non-GAAP operating margin in over four years.

“Ixia is benefiting from global communication trends that have propelled our growth and the market’s growth over the past year,” continued Mr. Bhatnagar. “Key performance metrics of networks have changed from the bits and bytes of Layer 1-2 transport to more complex Layer 3-7 network services, such as application performance, quality of video and monetizing media. These protocol rich higher layers of the network are where Ixia’s test and simulation solutions excel and lead the market in innovation and performance. Additionally, barring another macroeconomic setback, we believe that the recent increased momentum for LTE proof of concept testing, as well as the convergence of data center, storage and server testing, will help drive our momentum throughout 2011.”

Ixia ended the first quarter with approximately $354 million in cash and investments, compared with $339 million at December 31, 2010.

Conference Call and Webcast Information

Ixia will host a conference call today, at 5:00 p.m., Eastern Time, for analysts and investors to discuss its 2011 first quarter results and its business outlook for the 2011 second quarter. Open to the public, investors may access the call by dialing (678) 825-8347. A live webcast of the conference call, along with supplemental financial information, will be accessible from the “Investors” section of Ixia’s web site (www.ixiacom.com). Following the live webcast, an archived version will be available in the “Investors” section on the Ixia web site for 90 days.

Non-GAAP Information

To supplement our consolidated financial results prepared in accordance with Generally Accepted Accounting Principles (“GAAP”), we have included certain non-GAAP financial measures in this press release and in the attachments hereto. Specifically, we have provided non-GAAP financial measures (e.g., non-GAAP cost of revenues, non-GAAP gross margin, non-GAAP operating expenses, non-GAAP operating margin, non-GAAP interest income and other, net, non-GAAP income tax expense, non-GAAP net income, and non-GAAP diluted earnings per share) that exclude certain non-cash and/or non-recurring income and expense items such as proceeds and expenses from certain legal and contractual settlements, stock-based compensation expenses, acquisition and other related costs, the amortization of acquisition-related intangible assets, restructuring expenses, certain inventory adjustments, and the related income tax effects of these items, as well as the income tax impacts of the valuation allowance recorded against certain deferred tax assets. The aforementioned items represent income and expense items that may be difficult to estimate from period to period or that we believe are not directly attributable to the underlying performance of our business operations. These non-GAAP financial measures are provided to enhance the user’s overall understanding of our financial performance. We believe that by excluding these items, our non-GAAP measures provide supplemental information to both management and investors that is useful in assessing our core operating performance, in evaluating our ongoing business operations and in comparing our results of operations on a consistent basis from period to period. These non-GAAP financial measures are also used by management to plan and forecast future periods and to assist in making operating and strategic decisions. The presentation of this additional information is not prepared in accordance with GAAP. The information therefore may not necessarily be comparable to that of other companies and should be considered as a supplement to, not a substitute for, or superior to, the corresponding measures calculated in accordance with GAAP. Investors are encouraged to review the reconciliations of GAAP to non-GAAP financial measures which are included below in the attached financial tables.

About Ixia

Ixia is a leading provider of converged IP performance test systems and service verification platforms for wireless and wired infrastructures and services. Ixia’s test systems are used by network and telephony equipment manufacturers, semiconductor manufacturers, service providers, governments and enterprises to validate the performance and reliability of complex

networks, devices and applications. Ixia’s multiplay test systems address the growing need to test voice, video and data services and network capability under real-world conditions.

For more information, contact Ixia at 26601 W. Agoura Road, Calabasas, CA 91302; (818) 871-1800, Fax: (818) 871-1805; Email: info@ixiacom.com or visit our Web Site at http://www.ixiacom.com. Ixia and the Ixia four-petal logo are registered trademarks or trademarks of Ixia.

Safe Harbor under the Private Securities Litigation Reform Act of 1995:

Certain statements made in this document are forward-looking statements, including, without limitation, statements regarding, growth, profitability and future business. In some cases, such forward looking statements can be identified by terms such as “may,” “will,” “should,” “could,” “would,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “project,” “predict,” “potential,” and variations of these words and similar expressions are intended to identify forward-looking statements. These statements reflect our current views with respect to future events and are based on assumptions and are subject to risks and uncertainties. These risks, uncertainties and other factors may cause our future results, performances or achievements to be materially different from those expressed or implied by our forward-looking statements and include, among other items: changes in the global economy, competition, consistency of orders from significant customers, our success in developing and producing new products, market acceptance of our products, and war, terrorism, political unrest, natural disasters and other circumstances that could, among other consequences, reduce the demand for our products, disrupt our supply chain or impact the delivery of our products. The factors that may cause future results to differ materially from our current expectations also include, without limitation, the risks identified in our Annual Report on Form 10-K for the year ended December 31, 2010, and in our other filings with the Securities and Exchange Commission. Many of these risks and uncertainties are outside of our control and are difficult for us to forecast or mitigate. We undertake no obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.

Financial Contact:

The Blueshirt Group
Investor Relations
Maria Riley 415-217-7722
or
Tom Miller, Chief Financial Officer
Dir: 818-444-2325
tmiller@ixiacom.com

IXIA
Condensed Consolidated Balance Sheets
(in thousands)
(unaudited)

		March 31,				December 31,
		2011				2010
Assets
Current assets:
Cash and cash equivalents		$	73,286			$	76,082
Short-term investments in marketable securities			175,766				151,696
Accounts receivable, net			65,849				67,838
Inventories			31,532				28,965
Prepaid expenses and other current assets			10,315				12,647
Total current assets			356,748				337,228
Investments in marketable securities			104,799				111,440
Property and equipment, net			23,938				22,745
Intangible assets, net			49,186				52,778
Goodwill			59,384				59,384
Other assets			6,082				6,308
Total assets		$	600,137			$	589,883
Liabilities and Shareholders’ Equity
Current liabilities:
Accounts payable		$	7,793			$	9,924
Accrued expenses			28,204				33,778
Deferred revenues			36,835				37,505
Income taxes payable			—				1,648
Total current liabilities			72,832				82,855
Deferred revenues			8,411				9,170
Other liabilities			6,790				6,378
Convertible senior notes			200,000				200,000
Total liabilities			288,033				298,403
Shareholders’ equity:
Common stock, without par value; 200,000 shares authorized at March 31, 2011 and December 31, 2010; 68,630 and 67,613 shares issued and outstanding as of March 31, 2011 and December 31, 2010, respectively			122,761				115,590
Additional paid-in capital			139,489				133,249
Retained earnings			47,296				40,187
Accumulated other comprehensive income			2,558				2,454
Total shareholders’ equity			312,104				291,480
Total liabilities and shareholders’ equity		$	600,137			$	589,883

IXIA
Condensed Consolidated Statements of Operations
(in thousands, except per share data)
(unaudited)

		Three months ended
		March 31,
		2011				2010
Revenues:
Products		$	64,927			$	50,669
Services			13,534				11,372
Total revenues			78,461				62,041
Costs and operating expenses:(1)
Cost of revenues — products			14,021				11,445
Cost of revenues — services			1,478				1,508
Research and development			18,519				18,639
Sales and marketing			22,918				19,161
General and administrative			8,398				8,867
Amortization of intangible assets			3,690				5,058
Acquisition and other related			—				1,123
Restructuring			—				3,490
Total costs and operating expenses			69,024				69,291
Income (loss) from operations			9,437				(7,250	)
Interest income and other, net			538				8,787
Interest expense			(1,800	)			—
Income before income taxes			8,175				1,537
Income tax expense			1,066				668
Net income		$	7,109			$	869
Earnings per share:
Basic		$	0.10			$	0.01
Diluted		$	0.10			$	0.01
Weighted average number of common and common equivalent shares outstanding:
Basic			68,121				63,496
Diluted			71,433				64,785

(1)    Stock-based compensation included in:
Cost of revenues — products		$	136			$	123
Cost of revenues — services			51				46
Research and development			1,374				1,201
Sales and marketing			1,041				835
General and administrative			1,259				591

IXIA
Non-GAAP Information and Reconciliation to Comparable GAAP Financial Measures
(in thousands, except percentages and per share data)
(unaudited)

		Three months ended March 31,
		2011								2010
						% Total								% Total
		Amount ($)				Revenues				Amount ($)				Revenues
Total revenues		$	78,461				100	%		$	62,041				100	%
Total cost of revenues — GAAP		$	15,499				19.8	%		$	12,953				20.9	%
Inventory adjustment(a)			—				—				306				0.5	%
Stock-based compensation(b)			(187	)			-0.3	%			(169	)			-0.3	%
Total cost of revenues — Non-GAAP		$	15,312				19.5	%		$	13,090				21.1	%
Gross margin — GAAP		$	62,962				80.2	%		$	49,088				79.1	%
Effect of reconciling items(c)			187				0.3	%			(137	)			-0.2	%
Gross margin — Non-GAAP		$	63,149				80.5	%		$	48,951				78.9	%
Operating expenses — GAAP		$	53,525				68.2	%		$	56,338				90.8	%
Amortization of intangible assets(d)			(3,690	)			-4.7	%			(5,058	)			-8.2	%
Acquisition and other related(e)			—				—	%			(1,123	)			-1.8	%
Restructuring(f)			—				—	%			(3,490	)			-5.6	%
Stock-based compensation(b)			(3,674	)			-4.7	%			(2,627	)			-4.2	%
Legal and contract settlements(g)			(900	)			-1.1	%			—				—	%
Operating expenses — Non-GAAP		$	45,261				57.7	%		$	44,040				71.0	%
Operating margin — GAAP		$	9,437				12.0	%		$	(7,250	)			-11.7	%
Effect of reconciling items(h)			8,451				10.8	%			12,161				19.6	%
Operating margin — Non-GAAP		$	17,888				22.8	%		$	4,911				7.9	%
Interest income and other, net — GAAP		$	538				0.7	%		$	8,787				14.2	%
Auction rate securities settlements(i)			—				—	%			(8,925	)			-14.4	%
Interest income and other, net — Non-GAAP		$	538				0.7	%		$	(138	)			-0.2	%
Income tax expense — GAAP		$	1,066				1.4	%		$	668				1.1	%
Effect of reconciling items(j)			3,391				4.3	%			796				1.3	%
Income tax expense — Non-GAAP		$	4,457				5.7	%		$	1,464				2.4	%
Net income — GAAP		$	7,109				9.1	%		$	869				1.4	%
Effect of reconciling items(k)			5,060				6.4	%			2,440				3.9	%
Net income — Non-GAAP		$	12,169				15.5	%		$	3,309				5.3	%
Diluted earnings per share — GAAP		$	0.10							$	0.01
Effect of reconciling items(l)(m)			0.06								0.04
Diluted earnings per share — Non-GAAP		$	0.16							$	0.05