SEGMENTS AND ENTITY WIDE DISCLOSURES (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016
Revenue:
Revenue	$ 728,719	$ 670,550	$ 2,057,238	$ 1,884,382
Segment profit (loss) and the reconciliation to consolidated net income (loss)
Operating income (loss)	81,999	57,024	158,923	96,496
Less: Non-performance operating expenses
Selling and marketing	86,739	83,732	260,292	252,878
General and administrative	35,569	34,336	106,423	100,681
Amortization of intangible assets	3,837	14,529	29,368	46,957
Acquisition and integration costs	0	1,029	0	4,613
Restructuring costs	2,203	1,138	8,874	2,057
Add: Other non-performance financial items
Interest expense and other income (loss), net	(14,263)	(19,614)	(45,322)	(52,741)
Less: Provision for income taxes	7,726	3,864	11,704	7,758
Net income	60,010	33,546	101,897	35,997
Networking Platforms
Revenue:
Revenue	592,347	540,892	1,653,778	1,502,608
Networking Platforms \| Converged Packet Optical
Revenue:
Revenue	506,532	467,615	1,421,315	1,291,956
Networking Platforms \| Packet Networking
Revenue:
Revenue	82,121	63,658	220,641	180,437
Networking Platforms \| Optical Transport
Revenue:
Revenue	3,694	9,619	11,822	30,215
Software and Software-Related Services
Revenue:
Revenue	42,251	31,569	119,347	87,468
Software and Software-Related Services \| Software Platforms
Revenue:
Revenue	18,395	12,558	48,587	32,409
Software and Software-Related Services \| Software-Related Services
Revenue:
Revenue	23,856	19,011	70,760	55,059
Global Services
Revenue:
Revenue	94,121	98,089	284,113	294,306
Global Services \| Maintenance Support and Training
Revenue:
Revenue	57,902	55,996	171,133	169,123
Global Services \| Installation and Deployment
Revenue:
Revenue	27,397	31,245	84,011	92,317
Global Services \| Consulting and Network Design
Revenue:
Revenue	8,822	10,848	28,969	32,866
Operating Segments
Segment profit (loss) and the reconciliation to consolidated net income (loss)
Operating income (loss)	210,347	191,788	563,880	503,682
Operating Segments \| Networking Platforms
Segment profit (loss) and the reconciliation to consolidated net income (loss)
Operating income (loss)	159,649	150,521	423,859	390,109
Operating Segments \| Software and Software-Related Services
Segment profit (loss) and the reconciliation to consolidated net income (loss)
Operating income (loss)	11,133	38,855	23,384	(970)
Operating Segments \| Global Services
Segment profit (loss) and the reconciliation to consolidated net income (loss)
Operating income (loss)	$ 39,565	$ 2,412	$ 116,637	$ 114,543

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