In 1981, IPv4 addresses were assigned using classful addressing as defined in RFC 790 (https://tools.ietf.org/html/rfc790), Assigned Numbers. Customers were allocated a network address based on one of three classes, A, B, or C. The RFC divided the unicast ranges into specific classes as follows: • Class A (0.0.0.0/8 to 127.0.0.0/8) — Designed to support extremely…
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Routing to the Internet – 100-150 Exam Guide
Most internal networks, from large enterprises to home networks, use private IPv4 addresses for addressing all internal devices (intranet) including hosts and routers. However, private addresses are not globally routable. In Figure 9-4, customer networks 1, 2, and 3 are sending packets outside their internal networks. These packets have a source IPv4 address that is…
Broadcast – 100-150 Exam Guide
Broadcast transmission refers to a device sending a message to all the devices on a network in one-to-all communications. A broadcast packet has a destination IP address with all ones (1s) in the host portion, or 32 one (1) bits. Note IPv4 uses broadcast packets. However, there are no broadcast packets with IPv6. A broadcast…
IPv4 and Network Segmentation
Objectives Upon completion of this chapter, you will be able to answer the following questions: • What are the characteristics and uses of the unicast, broadcast and multicast IPv4 addresses? • What are public, private, and reserved IPv4 addresses? • Can you explain how subnetting segments a network to enable better communication? Key Terms This…
The IPv4 Address Structure
IPv4 addresses have a structure that identifies makes the address unique as well as identifying the network the address belongs to. Networks and Hosts (8.2.2) The logical 32-bit IPv4 address is hierarchical and is made up of two parts, the network and the host. In the figure, the network portion is blue, and the host…
The Internet Protocol – 100-150 Exam Guide
Objectives Upon completion of this chapter, you will be able to answer the following questions: • What is the purpose of an IPv4 address? • How are IPv4 addresses and subnets are used together? Introduction (8.0) Kishori is learning a lot from Rina! She understands that when she sends or receives a package in the…
The MAC Address Table
What happens when the switch receives a frame addressed to a new host that is not yet in the MAC address table? If the destination MAC address is not in the table, the switch does not have the necessary information to create an individual circuit. When the switch cannot determine where the destination host is…
Ethernet Hubs – 100-150 Exam Guide
The original Ethernet networks connected all hosts with a single cable, similar to how cable TV cables are connected in your home. All users on the network shared the bandwidth available on the cable. As Ethernet networks became more popular, connecting everyone on a single cable was no longer practical, nor even possible. Engineers developed…
The Access Layer – 100-150 Exam Guide
The access layer describes the network components used to provide an end device access to the network and the LAN. Ethernet Frame (7.2.1) The Ethernet protocol standards define many aspects of network communication including frame format, frame size, timing, and encoding. When messages are sent between hosts on an Ethernet network, the hosts format the…
The Access Layer – 100-150 Exam Guide
Objectives Upon completion of this chapter, you will be able to answer the following questions: • Can you explain the process of encapsulation and Ethernet framing? • Can you explain how to improve network communication at the access layer? Key Terms This chapter uses the following key terms. You can find the definitions in the…