ccna core concepts

CCNA Core ConceptsChapter 1: Standard Internetworking

Models

Talton Walker

Types of Internetworks Local Area Network (LAN) Metropolitan Area Network (MAN) Wide Area Network (WAN) Storage Area Network (SAN) Virtual Private Network (VPN)

Open Systems Interconnection (OSI) Model

Application Layer (7) NTP DHCP

Telnet HTTP/HTTPS FTP TFTP DNS SMTP POP3 NFS NNTP SNMP

Presentation Layer (6)

JPEG (Joint Photographic Experts Group) ASCII (American Standard Code for Information Interchange) EBCDIC (Extended Binary Coded Decimal Interchange Code) TIFF GIF (Graphics Interchange Format) PICT MPEG MIDI QuickTime RTF

Session Layer (5) NTP DHCP

NFS SQL RPC ASP X Window DNA SCP

Transport Layer (4) Responsible for:

Fault Detection Error Recovery Establishing, maintaining, and tearing down

virtual circuits Transport layer provides reliable

networking via acknowledgements, sequencing, and flow control

Layer 4 protocols include: Transmission Control Protocol (TCP) User Datagram Protocol (UDP) Sequenced Packet Exchange (SPX)

Network Layer (3) IP Layer Controls Routing of Data Protocols include:

Internet Protocol (IP) Internet Packet Exchange (IPX) AppleTalk DDP

There are two types of packets: Data Packets – the actual data being transmitted Route Update Packets – updates sent to

neighboring routers so that

Data Link Layer (2) Broadcast Domain - group of nodes that can

receive each other’s broadcast messages, segmented by a router

Collision Domain – group of nodes that share the same media, segmented by a switch. CSMA/CD

Media Access Control (MAC) The hard-coded address on the NIC 48 bits, 12 hexadecimal digits (0-9, A-F) The first 6 hex digits identify the manufacturer The last 6 hex digits are specific to that device

Logical Link Control (LLC) Complements the MAC layer Framing, error, and flow control

Physical Layer (1) The physical media data will traverse Specification of voltage, wire speed, and

pin-out cables Capability to send/receive a signal

TCP/IP Model

Cisco 3-Layer Hierarchical Model