Applying Methodology to a Design Part 4 — Transcript

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1. 0:04characterizing the existing network and
2. 0:06sites
3. 0:07this is the fourth segment of applying
4. 0:10methodology to a design video
5. 0:16the existing network insights the second
6. 0:19step
7. 0:20of the design methodology is
8. 0:21characterizing the existing network
9. 0:23insights
10. 0:24information collected and documented in
11. 0:27this step is important
12. 0:29because the design might depend on the
13. 0:31existing network's hardware
14. 0:34software and link capacity so in many
15. 0:37cases
16. 0:38a network already exists and the network
17. 0:41design relies on
18. 0:42reconstructing and upgrading the
19. 0:44existing network insights
20. 0:47even when a network does not exist the
21. 0:49sites that will be networked still
22. 0:51should be examined
23. 0:53so the following section presents
24. 0:55insights
25. 0:57into the process of examining the
26. 0:59existing network and sites and describe
27. 1:01the tools
28. 1:02used to gather the data assess the
29. 1:05network and analyze the network
30. 1:07so a checklist to assess the network's
31. 1:10health is presented
32. 1:12guidelines for creating a summary report
33. 1:14are introduced
34. 1:16the discussion concludes with a draft
35. 1:19design document
36. 1:21and estimates of the time required to
37. 1:23complete the entire characterization
38. 1:25process
39. 1:27let's get started
40. 1:30the first step in characterizing the
41. 1:32existing network and sites is to gather
42. 1:35as much information about them
43. 1:37okay so typically based on the following
44. 1:39input
45. 1:41so customer support okay that's step one
46. 1:45so review the existing document about
47. 1:46the network and
48. 1:48use verval input from the customer to
49. 1:51obtain a first impression about the
50. 1:52network
51. 1:54although this step is mandatory it is
52. 1:57usually insufficient
53. 1:59and some results might be incorrect
54. 2:02okay so you could have
55. 2:05step two instead okay so network audio
56. 2:10so perform a network audit also called
57. 2:13an assessment which reveals details
58. 2:17of the network and augments the
59. 2:19customer's description
60. 2:21okay third would be traffic analysis
61. 2:26all right so if possible use traffic
62. 2:29analysis to provide information
63. 2:32about the applications and protocols
64. 2:34used to reveal the shortcomings
65. 2:37of the network so take note that all the
66. 2:40traffic analysis is a good idea in
67. 2:42principle
68. 2:43it is often too costly in terms of time
69. 2:47and effort to do it in practice
70. 2:50okay now let's focus on
71. 2:53the first one which is the customer
72. 2:55input okay
73. 2:57now customer input includes all
74. 2:59pertinent network and site
75. 3:01documentations
76. 3:02some items the designer could request
77. 3:05depending on the scope of the project
78. 3:07includes the following should ask
79. 3:08for site contact information
80. 3:12specially needed if remote deployments
81. 3:14are planned
82. 3:16you could also ask for the existing
83. 3:18network infrastructure
84. 3:20from physical diagrams and documents
85. 3:25okay so to logical diagrams if there
86. 3:28would be any
87. 3:29okay so the locations and types
88. 3:34of servers including a list of network
89. 3:37applications supported
90. 3:39locations and types of network devices
91. 3:42okay what else um
92. 3:45cabling okay so that is currently in
93. 3:47place
94. 3:49including interface connections
95. 3:53okay tables and worksheets is also
96. 3:56important
97. 3:57so wiring closets are the
98. 3:58telecommunication closets
99. 4:00environmental controls including heating
100. 4:03ventilation and air conditioning
101. 4:05requirements and
102. 4:06filtration locations
103. 4:09of telephone service demarcation points
104. 4:13one speeds and location of one
105. 4:16connection feeds
106. 4:17locations of power receptacles and
107. 4:20availability of additional receptacles
108. 4:23and power
109. 4:24sources okay
110. 4:28so existing network okay
111. 4:31from logical topology diagrams including
112. 4:34the addressing scheme that's very
113. 4:35important
114. 4:36and routing protocols in use
115. 4:40so you also have to consider
116. 4:41infrastructure services supported such
117. 4:43as
118. 4:43voice storage and wireless services
119. 4:47now information about expected network
120. 4:50functionality
121. 4:52okay should also be considered so this
122. 4:54documentation
123. 4:56should allow the designer to determine
124. 4:58information about the planned
125. 5:00and existing network and sites
126. 5:03including network topology okay includes
127. 5:06devices
128. 5:08physical and logical links external
129. 5:10connections
130. 5:11bandwidth of connections frame types
131. 5:15ip addressing routing protocols and so
132. 5:17forth
133. 5:18okay so all of those are important
134. 5:21considerations network services
135. 5:24include security quality of service high
136. 5:28availability
137. 5:29storage service wireless and so forth
138. 5:32and of course
139. 5:32the network applications examples
140. 5:35includes
141. 5:36the messaging and the video delivery for
142. 5:38the
143. 5:39learning management systems okay
144. 5:42now all this information should be
145. 5:44included in the design document
146. 5:46it also forms the basis
147. 5:49for breaking the network into modules
148. 5:56identifying major features of the
149. 5:58network
150. 5:59so sample site contact information
151. 6:03okay so site contact information is
152. 6:06especially important for projects
153. 6:07involving remote deployments
154. 6:10when equipment delivering installations
155. 6:12must be coordinated
156. 6:14so that is the site contact information
157. 6:18the customer might provide all the
158. 6:20necessary site contact information
159. 6:22or the designer might have to be
160. 6:25or to conduct a physical site audit
161. 6:28to obtain the necessary information
162. 6:32so sample side contact questions so
163. 6:35while at site
164. 6:36the designer can also obtain other
165. 6:38information for example
166. 6:40the power availability can be determined
167. 6:43by examining the existing wiring closets
168. 6:46okay digital pictures taken by a remote
169. 6:49site
170. 6:49contact can help in getting a quick
171. 6:52sense
172. 6:52of remote environment so the table here
173. 6:56illustrates a sample site contact form
174. 6:59okay
175. 7:00so questions asked okay
176. 7:03so what is the site or location name
177. 7:05site address shipping address
178. 7:07who is the site contact okay
179. 7:11is the site owned and maintained by the
180. 7:13customer
181. 7:14is this top uh site
182. 7:18what are the arts of operations okay
183. 7:21so what are the building and room access
184. 7:23procedures
185. 7:25are there any special security or safety
186. 7:28procedures or protocols
187. 7:30are there any union labor requirements
188. 7:32or procedures
189. 7:34and what are the locations of the
190. 7:36equipment cabinets and racks
191. 7:39so those has to be considered
192. 7:43so i have here an example of a high
193. 7:46level network
194. 7:47diagram okay so this is the customer
195. 7:49network diagram here
196. 7:51so this figure shows the high level
197. 7:53topology
198. 7:54of a sample network provided by the
199. 7:57customer
200. 7:59okay so with only this diagram
201. 8:02okay so what can you see here
202. 8:06so there would be many questions remain
203. 8:08about the network
204. 8:10and expected network functionality
205. 8:13so what are those so maybe the first
206. 8:15question would be
207. 8:17where's the ip addressing or what is the
208. 8:20ip addressing scheme
209. 8:23what level of redundancy or high
210. 8:25availability currently exist in the
211. 8:27network
212. 8:29okay what level of redundancy or high
213. 8:32level
214. 8:33availability is required in the new
215. 8:35network
216. 8:37something like what are the details of
217. 8:40the security design
218. 8:43what types of links are in the network
219. 8:46it's all lines all right so it should be
220. 8:49properly labeled also
221. 8:52so what are the link speeds what are the
222. 8:55planned layer 2 and layer 3 topologies
223. 8:58how is connectivity provided to remote
224. 9:00sites
225. 9:02what network infrastructure services are
226. 9:04in use such as
227. 9:06voice and video what is the plan
228. 9:10okay so are existing wireless devices in
229. 9:13place
230. 9:14so if there are wireless devices on the
231. 9:16given diagram
232. 9:18okay or what routing protocols are in
233. 9:21use
234. 9:22are there any server form or remote data
235. 9:24center connectivity requirements
236. 9:27okay what network management tools are
237. 9:30in place
238. 9:31so it is important to get as much
239. 9:33information as possible about the
240. 9:35existing situation
241. 9:37before commencing the design
242. 9:42auditing or assessing the existing
243. 9:45network
244. 9:46so a network audit or assessment is the
245. 9:48second step in acquiring information
246. 9:50about the existing network
247. 9:53so the auditing process starts by
248. 9:55consolidating
249. 9:56existing information the customer
250. 9:58provides
251. 9:59up-to-date information can be gathered
252. 10:02from the existing management software
253. 10:04used by the customers if the customer
254. 10:07has insufficient tools
255. 10:09the designer can choose to temporarily
256. 10:11introduce additional software tools
257. 10:14if they are useful then these tools can
258. 10:17be used in the network permanently
259. 10:19during the operate and optimize phases
260. 10:22of the ppdio model
261. 10:25now in audit okay
262. 10:28an audit provides details such as the
263. 10:30following
264. 10:32a list of devices
265. 10:35okay hardware specifications and
266. 10:37versions
267. 10:39and software versions of network devices
268. 10:42configurations of network devices
269. 10:45output of various auditing tools to
270. 10:47verify and augment
271. 10:48the existing documentation link
272. 10:51cpu and memory utilization of the
273. 10:54network devices so that's also important
274. 10:57a list of unused ports modules and slots
275. 11:00in the network devices that is to be
276. 11:03used to understand
277. 11:04whether the network is expandable or not
278. 11:08okay now this figure here
279. 11:11illustrates three different sources of
280. 11:13information that can be used in auditing
281. 11:15processes
282. 11:16so you've got the existing documentation
283. 11:20the existing tools and the new tools
284. 11:24now auditing process might require minor
285. 11:27temporary network changes
286. 11:29okay automated auditing should be used
287. 11:32in large
288. 11:33networks or enterprise networks for
289. 11:36which a manual approach would take too
290. 11:38much time
291. 11:39however the audit process balances both
292. 11:42detail and effort to produce as much
293. 11:45information as needed
294. 11:47or possible so for example
295. 11:50it should not require the large set of
296. 11:53cpu heavy auditing tools
297. 11:54be purchased and installed in the
298. 11:57customer network
299. 11:58to collect configuration of network
300. 12:01devices
301. 12:02so the auditing process is typically
302. 12:04performed
303. 12:05from the central location such as
304. 12:09location in a secure environment that
305. 12:12has
306. 12:12access to all network devices
307. 12:18so this figure here illustrates a sample
308. 12:20information that a manual or automated
309. 12:23auditing process collects
310. 12:24from the network management workstation
311. 12:27the auditing process
312. 12:29should collect all information relevant
313. 12:32okay that should be relevant to the
314. 12:34design
315. 12:35the same process should be used for all
316. 12:37the network devices affected
317. 12:40by the design
318. 12:44now what are the tools for assessing the
319. 12:46network
320. 12:48okay a small network can be assessed
321. 12:50without special tools
322. 12:52monitoring commands can be used to
323. 12:53collect relevant information
324. 12:56on a small number of network devices the
325. 12:59approach
326. 13:00can be semi-automated or
327. 13:04it could be manual okay now the approach
328. 13:06on the semi automated by introducing
329. 13:08scripting tools
330. 13:10to execute the monitoring commands
331. 13:12automatically
332. 13:14will speed up the process so in a large
333. 13:16network
334. 13:17a manual auditing approach is too much
335. 13:20time consuming and less reliable
336. 13:23so the following are some of the special
337. 13:25tools
338. 13:26that can be used to collect the relevant
339. 13:28information
340. 13:30from the network devices so take note
341. 13:32you can use any available
342. 13:35proprietary and open tools like six
343. 13:38cisco works okay this is used to map
344. 13:41network and collect various types of
345. 13:43information such as network topology
346. 13:46hardware software versions
347. 13:48configurations and so on
348. 13:50okay so you could also use third-party
349. 13:53like what's up gold
350. 13:54castle rock snmpc open source captain
351. 13:59okay netgorgia net mri and net uos
352. 14:03not buoyant and so on okay
353. 14:06other tools can help characterize the
354. 14:08existing environment for example
355. 14:10instead of a full wireless site
356. 14:13survey it can be helpful to conduct a
357. 14:16brief
358. 14:17rf sample of the environment using the
359. 14:20enterprise level tools
360. 14:21such as air magnet okay
361. 14:25you've got the aero peak okay and others
362. 14:29so you also have the cogno
363. 14:33spectrum expert okay this is expect
364. 14:36a spectrum analyze or analysis tool
365. 14:40and you could also have these laptop
366. 14:42applications
367. 14:44such as the aggro peak
368. 14:47okay so from wild packets right
369. 14:51so a lot of tools would be available
370. 14:54okay for the network assessment
371. 14:59manual information collection example so
372. 15:02commands for manual information
373. 15:04collection
374. 15:05so the auditing process can be performed
375. 15:08manually on relatively small network
376. 15:10using various monitoring commands
377. 15:12now the figure here illustrates three
378. 15:14different types of network devices
379. 15:17okay information to be collected and
380. 15:19commands that can be used to obtain
381. 15:21information
382. 15:22so on the cisco routers that francisco
383. 15:25ios software
384. 15:27the show tech support okay the show
385. 15:30processes cpu okay
386. 15:34you also have the show processes memory
387. 15:36so you can use that
388. 15:38on cisco devices on cisco switches
389. 15:41okay so you also have the show version
390. 15:44show running config and other commands
391. 15:48okay on the cisco secure pix security
392. 15:51appliances you could have show versions
393. 15:53android terminal okay now this would
394. 15:55totally depend on the available devices
395. 15:58and organization
396. 15:59so this is just an example assuming that
397. 16:02organization is using the cisco
398. 16:03equipment
399. 16:06now the feature here illustrates a
400. 16:08sample output from
401. 16:10show processor's cpu command on a cisco
402. 16:12router
403. 16:13the output displays information about
404. 16:16the network device
405. 16:17utilization which is important for
406. 16:20describing the network health
407. 16:24another example here okay so
408. 16:28this figure illustrates a sample output
409. 16:30from the show process as memory command
410. 16:32on a cisco router
411. 16:36now using other tools like the cacti
412. 16:39device uh
413. 16:40list here okay shown automatic
414. 16:43information collection example
415. 16:45okay the figure is a screenshot of an
416. 16:50open source cacti
417. 16:51application or cutting showing the list
418. 16:53of devices
419. 16:54found in the network
420. 16:58you also have here the screenshot from
421. 17:00the net mri appliance
422. 17:02from net cordia so the inventory results
423. 17:06are expanded to view the cisco cut 4506
424. 17:10devices
425. 17:11including ip addresses device names and
426. 17:14operating system versions
427. 17:19network traffic analysis so analyzing
428. 17:22network traffic
429. 17:23and applications traffic analysis
430. 17:26is the third step in characterizing a
431. 17:28network
432. 17:29so traffic analysis verifies the set of
433. 17:32applications and protocols
434. 17:34used in the network and determines
435. 17:38the application's traffic patterns
436. 17:41so it might reveal any additional
437. 17:44applications or protocols running on the
438. 17:46network
439. 17:47each discovered application and
440. 17:49protocols should be described in the
441. 17:51following terms
442. 17:54importance to the customer quality of
443. 17:58service related requirements
444. 18:00security related requirements and scope
445. 18:04okay so in other words the network
446. 18:07module in which the application or
447. 18:09protocol is
448. 18:12used
449. 18:15so use the following interactive
450. 18:16approach as illustrated in the figure
451. 18:18to create a list of applications and
452. 18:20protocols used in the network
453. 18:23so step one okay
454. 18:26use customer input to list expected
455. 18:29applications
456. 18:31step 2 use traffic analyzers
457. 18:35to verify the customer's list of
458. 18:38applications
459. 18:40step 3. present
460. 18:43the customer with a new list of
461. 18:45applications and discuss
462. 18:46discrepancies and then fourth would be
463. 18:50generate the final list of applications
464. 18:52and their requirements
465. 18:54importance quality of service security
466. 18:57as defined
467. 18:58by the customers
468. 19:02now assume that a customer requirement
469. 19:04concerns quality of service on a wide
470. 19:06area network connection with
471. 19:08limited bandwidth so in this case
472. 19:11the information collected is relevant
473. 19:13because it describes the following
474. 19:15so the application tcp port
475. 19:185151 which is required for
476. 19:22performing classification for instance
477. 19:24the importance
478. 19:25of the application this information is
479. 19:28useful
480. 19:29for evaluating how much bandwidth
481. 19:32should be allocated to the application
482. 19:35the current bandwidth consumption
483. 19:37according to the present quality of
484. 19:38service implementation
485. 19:40okay so take note however
486. 19:44that this information might not be
487. 19:46relevant
488. 19:47should a customer requirement instead
489. 19:50concern a secure
490. 19:51and resilient internet connection
491. 19:55okay so in that case it might be
492. 19:57necessary to gather information
493. 20:00or additional information
494. 20:04network analysis tools so tools used for
495. 20:07traffic analysis
496. 20:08range from manual identification of
497. 20:12application using
498. 20:13the cisco ios software commands
499. 20:17to those in which dedicated software or
500. 20:20hardware based analyzers
501. 20:22capture live packets or use the simple
502. 20:26network management protocol snmp
503. 20:28which is an open software to gather
504. 20:31information
505. 20:32or interface information so analysis
506. 20:34tools
507. 20:35includes the following you've got the
508. 20:38end bar
509. 20:39okay this is the
510. 20:43network based application recognition
511. 20:46and bar can be used to identify the
512. 20:48presence of well-known applications and
513. 20:50protocols in the network
514. 20:53you also have the net flow net flow is
515. 20:56an integral part of the cisco io
516. 20:58software that collects and measures
517. 21:00data as it enters specific routers or
518. 21:03switch interfaces
519. 21:05so netflow allows the identification of
520. 21:08lesser known application
521. 21:11because it gathers information about
522. 21:13every
523. 21:14flow of the packet
524. 21:17now this information can be collected
525. 21:19manually by using the cisco ios
526. 21:21show ip cache flow command okay so for
527. 21:25every
528. 21:25automated process there must be a
529. 21:28corresponding manual commands that can
530. 21:31do the same
531. 21:32okay so alternatively the cisco network
532. 21:36service or cns netflow collection engine
533. 21:38or nfc
534. 21:39allows automatic information gathering
535. 21:42of its flow in the network segment
536. 21:46so third-party or software-based
537. 21:48products can be used to analyze
538. 21:50traffic in different subnets of the
539. 21:53network
540. 21:54so examples of those are this open
541. 21:57source cacti
542. 21:59okay you've got the network general
543. 22:02sniffer
544. 22:03wild packets ether peak or aero peak
545. 22:06the solar winds orion wire shark is a
546. 22:09very popular tool
547. 22:11and armon probes so remote monitoring
548. 22:15probes can also be used to support
549. 22:17traffic analysis
550. 22:18so the following section includes
551. 22:21examples of those
552. 22:24tools
553. 22:27so this diagram here shows
554. 22:31a cisco ios and bar show ipnbar protocol
555. 22:35discovery command so what it does
556. 22:39this commands or this command shows the
557. 22:42statistics gathered by envir protocol
558. 22:44discovery feature
559. 22:45which provides an easy way to discover
560. 22:48application protocols that are
561. 22:50transmitting
562. 22:51or transiting in an interface
563. 22:54so you can use also other protocols that
564. 22:57can do the same
565. 22:59so the protocol discovery feature
566. 23:01discovers
567. 23:02any protocol traffic supported by nbar
568. 23:05and can be used to monitor both input
569. 23:07and output traffic
570. 23:10okay
571. 23:13next would be this is an example of the
572. 23:15net flow printout
573. 23:17so this provides a sample output from
574. 23:21the show ipv
575. 23:22cache flow command illustrating
576. 23:24statistics gathered
577. 23:26by the net flow switching feature okay
578. 23:29so by analyzing netflow data a designer
579. 23:32can identify
580. 23:33the cause of congestions because you've
581. 23:35got the number of packets there
582. 23:37okay determine the class of service for
583. 23:40each user and application and identify
584. 23:44the traffic source and destination
585. 23:46network
586. 23:47so basically this net flow allows
587. 23:49extremely granular
588. 23:51and accurate traffic measurements and
589. 23:54high level
590. 23:54aggregated traffic connection
591. 24:00other network analysis tools like
592. 24:04here okay so this figure
593. 24:07shows a sample output from cacti tool
594. 24:10illustrating the daily throughput
595. 24:12on a link okay
596. 24:18also another example here
597. 24:21is a solar winds organ output
598. 24:24so the figure is an example of
599. 24:27utilization table
600. 24:28from solarwinds orion tool illustrating
601. 24:30the current percentage
602. 24:32utilization on the top 25 interfaces
603. 24:37okay
604. 24:41summary report the result of the network
605. 24:44characterization
606. 24:46is a summary report that describes the
607. 24:48network health
608. 24:50so the customer input network audit
609. 24:53and traffic analysis should provide
610. 24:56enough information
611. 24:58to identify possible problem in the
612. 25:00existing network
613. 25:02the collected information must be
614. 25:04collated into a concise
615. 25:06summary report that identifies the
616. 25:08following so you've got
617. 25:10features required in the network
618. 25:13possible drawbacks
619. 25:14of and problems in the existing network
620. 25:18actions needed to support the new
621. 25:20network's requirements and features
622. 25:23with this information the designers
623. 25:25should be able to propose
624. 25:27hardware and software upgrades to
625. 25:29support the customer requirements or
626. 25:32to influence a change in requirements
627. 25:37so the summary report conclusion should
628. 25:39identify the existing infrastructure
629. 25:41shortcomings
630. 25:43so we have here an example of equipment
631. 25:46summary report
632. 25:50okay now in the example the quality of
633. 25:53service congestion management or cubing
634. 25:55is required
635. 25:56so however the designer has identified
636. 25:59that cisco ios software version 12.0
637. 26:02does not support the newest viewing
638. 26:04technologies
639. 26:05so in addition some routers do not have
640. 26:08enough ram and flash memory for an
641. 26:11upgrade
642. 26:12so the figure presents a sample summary
643. 26:14report
644. 26:16that identifies different aspects of
645. 26:18network infrastructure
646. 26:20so summary report recommendations relate
647. 26:23the existing network
648. 26:24and the customer requirements
649. 26:29so this recommendations can be used to
650. 26:31propose upgrading
651. 26:33of hardware you've got recommended
652. 26:35actions there
653. 26:36they're not just the hardware and
654. 26:37software to support the required
655. 26:40features or modifying the customer
656. 26:42requirements
657. 26:44so in this example options include
658. 26:47evaluating the necessity of the cubing
659. 26:49requirement
660. 26:50in the wide area network
661. 26:55creating a draft design document
662. 26:59so after totally examining the existing
663. 27:02network
664. 27:03the designer creates a draft design
665. 27:05document
666. 27:06so the figure illustrates a draft design
667. 27:09documents
668. 27:10index okay not yet fully developed
669. 27:14including the section that describes the
670. 27:17existing network
671. 27:19the design requirements and existing
672. 27:20network infrastructure chapters
673. 27:23of the design document are closely
674. 27:25related
675. 27:26examining the existing network can
676. 27:28result in changes
677. 27:30to the design requirements so data from
678. 27:33both
679. 27:34chapters directly influence the network
680. 27:37design okay
681. 27:40now typical draft documentation for
682. 27:43existing network should include
683. 27:45the following items okay so there should
684. 27:48be
685. 27:49a logical legacy topology map or maps
686. 27:53divided topology into network modules if
687. 27:56the network is
688. 27:57too large to fit onto one topology map
689. 28:01okay so you also need the physical layer
690. 28:05layer one topology map or maps the
691. 28:08network audit results
692. 28:10including the types of traffic in the
693. 28:12network
694. 28:13the traffic congestion points and the
695. 28:15sub-optimal traffic path and so on
696. 28:18okay so a summary section okay
697. 28:22describing the major network services
698. 28:26used in the existing network such as
699. 28:28maybe they have utilized ospf or the
700. 28:32open shortcut
701. 28:33first routing protocol the border
702. 28:36gateway protocol or bgp
703. 28:38and the internet protocol security or
704. 28:40ipsec
705. 28:42so a summary description of applications
706. 28:45and overlay services
707. 28:47used in the network should also be
708. 28:48included
709. 28:50also a summary description of issues
710. 28:54that might affect the design or the
711. 28:56established design requirements
712. 28:59a list of existing network devices with
713. 29:02the platform and software versions
714. 29:05also you have to consider configurations
715. 29:07of existing network devices
716. 29:09so usually attached as either a separate
717. 29:12document
718. 29:13or an append appendix in a large
719. 29:16document
720. 29:18okay
721. 29:22time estimates for performing network
722. 29:25characterization
723. 29:27so this section provides some guidelines
724. 29:30to estimate how long it may take to
725. 29:33characterize the network
726. 29:35so the time required to characterize the
727. 29:37network very significantly depending on
728. 29:40factors such as
729. 29:41the following okay so the experience of
730. 29:45the network engineer
731. 29:47the quality of documentation provided by
732. 29:49the customer
733. 29:51and the quality of the communication
734. 29:53with the customer
735. 29:55the size and complexity of the network
736. 29:57the efficiency of network management and
737. 29:59discovery tools
738. 30:01whether or not the network devices are
739. 30:02carefully managed
740. 30:04via snmp or how much
741. 30:07information is needed to scope the
742. 30:09project
743. 30:11so the figure here provides a range of
744. 30:15time estimates in ours okay
745. 30:19for characterization of networks in a
746. 30:21variety of
747. 30:22sizes so this estimates assume a highly
748. 30:26skilled
749. 30:26professional or network engineer with
750. 30:29efficient automated tools
751. 30:32for network discovery and performance
752. 30:34gathering
753. 30:35and a network in which the devices
754. 30:38communicate
755. 30:39with snmp all right
756. 30:43so the network characterization includes
757. 30:47strategic evaluation and possible
758. 30:50network
759. 30:51red design so the steps in
760. 30:55this diagram here okay
761. 30:58interviewing the management team to
762. 31:00gather the goals and constraints
763. 31:03interviewing the network team okay
764. 31:06so to gather goals constraints
765. 31:10documentations and diagrams
766. 31:14all right so you also have reviewing
767. 31:18the documentations and diagrams and
768. 31:21clarifying items
769. 31:22with the site team okay also
770. 31:26setting up the network discovery tool
771. 31:28which typically involves using automated
772. 31:30discovery or
773. 31:32entering a device list or static
774. 31:34addresses range into the tool
775. 31:37verifying the tool has found most
776. 31:39routers and switches
777. 31:40and starting to collect performance data
778. 31:44so for discovery we are using
779. 31:47the cisco discovery tool or the cisco
780. 31:49discovery product called cdp
781. 31:52you also have lldp for open systems
782. 31:56all right next would be resolving snmp
783. 32:00access and similar problems if devices
784. 32:03have not been carefully managed in the
785. 32:05past
786. 32:08allowing discovery tool to gather data
787. 32:11the time for this step will vary
788. 32:13depending on the network
789. 32:15sizes and should include seasonal or
790. 32:19cyclical factors but generally one week
791. 32:23of data is sufficient okay the network
792. 32:26engineer typically does not need to
793. 32:29oversee this process
794. 32:32next would be analyzing the captured
795. 32:34data
796. 32:35minimizing the time required is
797. 32:37dependent
798. 32:38on the use of efficient tools okay
799. 32:42next would be preparing high level or
800. 32:45layer 3
801. 32:46designs or diagrams for the proposed
802. 32:49network
803. 32:51we also have preparing the report of
804. 32:54conclusion
805. 32:55and recommendations okay
806. 32:59now consequently network
807. 33:01characterization typically takes
808. 33:04from one to many weeks
809. 33:07okay depending on the size and
810. 33:10complexity of the network
811. 33:12and other factors mentioned at the
812. 33:14beginning of this
813. 33:15video lecture
814. 33:22so summary characterizing an existing
815. 33:26network
816. 33:26entails gathering as much information
817. 33:29about the network as possible
818. 33:32so organization input the network audit
819. 33:36and traffic analysis provides the key
820. 33:38information that you need
821. 33:41identifying major features of the
822. 33:43network involves gathering network
823. 33:45documentation
824. 33:46and querying the organization data
825. 33:50gathering
826. 33:50is at most priority the auditing process
827. 33:55adds details to the initial network
828. 33:57documentation
829. 33:58that you created from existing
830. 34:00documentation and customer input
831. 34:03you can manually audit a small network
832. 34:05but you typically need automated tools
833. 34:07as presented
834. 34:09to audit a large network so traffic
835. 34:12analysis
836. 34:13verifies the set of applications and
837. 34:15protocols
838. 34:16used in the network and determines the
839. 34:18traffic patterns of the applications
840. 34:24also tools used for traffic analysis
841. 34:27range from manual identification of
842. 34:30application using
843. 34:32proprietary and non-proprietary tools
844. 34:36the result of the network
845. 34:37characterization is a summary report
846. 34:41describing the health of the network