Critical Concepts of the 200-120 CCNA Routing and Switching Exam
In the spring of 2013, Cisco announced major updates to their Cisco Certified Network Associate (CCNA) curricula, including a new version of the CCNA Routing and Switching exam (200-120 CCNA). This paper provides a review of the CCNA Routing and Switching exam's critical concepts, as an aid to students preparing to pass the latest version of the CCNA Routing and Switching exam.
Global Knowledge offers a CCNA Accelerated (CCNAx) Boot Camp; this boot camp is an accelerated version of the two courses that comprise the CCNA Routing and Switching exam preparation curricula: Interconnecting Cisco Networking Devices Part 1 (ICND1) and Interconnecting Cisco Networking Devices Part 2 (ICND2). All of these courses are now at version 2.0.
TCP/IP Transport Layer Protocols
TCP is a reliable, connection-oriented, protocol that uses sequence and acknowledgement numbers to provide reliability. TCP verifies that the remote end is listening prior to sending data, using a three-way handshake: SYN, SYN/ACK, ACK.
UDP is a best-effort, connectionless, protocol that does not have sequence or acknowledgement numbers, and does not do end-to-end verification.
Internet Layer Protocols
IP: Provides the logical addressing structure and offers connectionless, best-effort delivery of packets (datagrams). IPv4 and IPv6 are described in the following sections.
Internet Control Message Protocol (ICMP): Provides control and feedback messages between IP devices.
Address Resolution Protocol (ARP): Using a destination IPv4 address, ARP resolves (discovers) the appropriate destination MAC (Layer 2) address to use. Thus, ARP maps a Layer 3 IPv4 address to a Layer 2 MAC address.
Reverse Address Resolution Protocol (RARP): Using a source MAC address, RARP retrieves an IP address form the RARP Server. RARP maps source Layer 2 address to a Layer 3 address; it is an early form of Dynamic Host Configuration Protocol (DHCP).
DHCP: DHCP is built on a client-server model
Domain Name System (DNS): Resolves domain names to IP addresses.