Earning Your CCNP Certification And Passing The BSCI Exam Depends On Knowing The Details Of Many Cisco Technologies, ISIS Chief Among Them. To Help You Prepare For Exam Success, Here's A List Of ISIS Terminology And Basic Concepts That Will Help You Pass This Tough Exam. Enjoy!ISIS Terms:Domain: Section Of The Network Under Common Administrative ControlArea: Logical Segment Of The Network Composed Of Contiguous Routers And Their Data LinksIntermediate System: A Router.End System: A Host Device.The Four Levels Of ISIS Routing:Level 0: ES-IS Routing In The Same Subnet.Level 1: IS-IS Routing In The Same Area.Level 2: IS-IS Routing In The Same Domain.Level 3: Inter-domain Routing Performed By InterDomain Routing Protocol (IDRP).ISIS Adjacency Possibilities:L1: Can Form Adjacency With Any L1 In The Same Area And Any L1L2 In The Same Area.L2: Can Form Adjacency With Any L2 In Any Area, And With An L1L2 In Any Area.L1L2: Can Form Adjacency With Any L1 In The Same Area, L1L2 In Any Area, And L2 In Any Area.A Router Interfaces SNPA (Subnetwork Point Of Attachment) Is Its Highest DLCI Number If Its On A Frame Network, And Its MAC Address If The Interface Is On An Ethernet Segment.ISIS Hello Types:ESH: ES Hello Sent By End Systems To Discover A Router.ISH: IS Hello Send By Intermediate Systems To Announce Their Presence. End Systems Listen For These.IIH: IS-to-IS Hello Send By One IS To Be Heard By Another IS. These Hellos Makes IS-IS Adjacencies Possible.Best Of Luck On Your CCNP Exams!
