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CCNA 3 Chapter 1 Review: The OSI Reference Model and Routing. By Your Name. Objectives. Describe the overall function of the OSI reference model and the problems it solves Describe the characteristics of the: OSI physical layer OSI data link layer OSI network layer OSI transport layer
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CCNA 3 Chapter 1Review: The OSI Reference Model and Routing By Your Name
Objectives • Describe the overall function of the OSI reference model and the problems it solves • Describe the characteristics of the: • OSI physical layer • OSI data link layer • OSI network layer • OSI transport layer • Describe the function of routing in networks • Understand the different classes of routing protocols
Types of Ethernet • Ethernet and IEEE 802.3—LAN specifications, which operate at 10 Mbps over coaxial and twisted-pair cable. • 100-Mbps Ethernet— A single LAN specification, also known as Fast Ethernet, which operates at 100 Mbps over twisted-pair cable. • 1000Mbps Ethernet — A single LAN specification, also known as Gigabit Ethernet, which operates at 1000 Mbps (1 Gbps) over fiber and twisted-pair cables. • 10 Gigabit Ethernet is only supported over fiber optic media.
Three Varieties of 10Mbps Ethernet • 10BASE-2 • Known as thin Ethernet or thinnet • Allows network segments up to 185 meters on coaxial cable • 10BASE-5 • Known as thick Ethernet or thicknet • Allows network segments up to 500 meters on coaxial cable • 10BASE-T • Carries Ethernet frames on inexpensive twisted-pair wiring
The Data Link Layer The Ethernet/802.3 Interface
Path Switching The network layer (3) address does not change. The data link layer (2) MAC address changes for each segment.
Static Versus Dynamic Routes • The purpose of a static route • Why dynamic routing is necessary • Dynamic routing operations • How distances on network paths are determined by various metrics • Classes of routing protocols • Time for convergence
Routing Protocols • A routing protocol defines the set of rules used by a router when it communicates with neighboring routers, including the following: • How to send updates • What knowledge these updates contain • When to send this knowledge • How to locate recipients of the updates
DistanceVector Routing Basics • Routing updates explained • The problem of routing loops • The problem of counting to infinity • Link-state routing basics • How link-state protocols exchange routing information • How topology changes propagate through the network of routers
Hybrid Protocols Cisco’s EIGRP
The Transport Layer • Segmenting upper-layer applications • Establishing a connection • Data transfer • Reliability with windowing • Acknowledgment techniques