Removing Entries from an ARP Table (24.1.6) For each device, an ARP cache timer removes ARP entries that have not been used for a specified period of time. The times differ depending on the operating system of the device. For example, newer Windows operating systems store ARP table entries between 15 and 45 seconds, as…
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Video – ARP Operation – ARP Reply
Video – ARP Operation – ARP Reply (24.1.4) Only the device with the target IPv4 address associated with the ARP request will respond with an ARP reply. The ARP reply is encapsulated in an Ethernet frame using the following header information: • Destination MAC address — This is the MAC address of the sender of…
ARP Functions – 100-150 Exam Guide
ARP Functions (24.1.2) When a packet is sent to the data link layer to be encapsulated into an Ethernet frame, the device refers to a table in its memory to find the MAC address that is mapped to the IPv4 address. This table is stored temporarily in RAM memory and called the ARP table or…
Address Resolution – 100-150 Exam Guide
Objectives Upon completion of this chapter, you will be able to answer the following questions: • What is the purpose of ARP? Key Terms This chapter uses the following key terms. You can find the definitions in the Glossary. ARP table ARP cache Introduction (24.0) Webster here again! I have another friend to introduce to…
IPv4 Address Structure Summary
IPv4 Address Structure Summary (23.2) The following is a summary of each topic in the chapter and some questions for your reflection. What Did I Learn in this Module? (23.2.1) An IPv4 address is a 32-bit hierarchical address that is made up of a network portion and a host portion. When determining the network portion…
The Prefix Length – 100-150 Exam Guide
The Prefix Length (23.1.3) Expressing network addresses and host addresses with the dotted decimal subnet mask address can become cumbersome. Fortunately, there is an alternative method of identifying a subnet mask, a method called the prefix length. The prefix length is the number of bits set to 1 in the subnet mask. It is written…
IPv4 Address Structure – 100-150 Exam Guide
Objectives Upon completion of this chapter, you will be able to answer the following questions: • What is the structure of an IPv4 address including the network portion, the host portion, and the subnet mask? Key Terms This chapter uses the following key terms. You can find the definitions in the Glossary. prefix length Introduction…
Network Layer Summary
Network Layer Summary (22.4) The following is a summary of each topic in the chapter and some questions for your reflection. What Did I Learn in this Module? (22.4.1) • Network Layer Characteristics—The network layer, or OSI Layer 3, provides services to allow end devices to exchange data across networks. IPv4 and IPv6 are the…
IPv6 Packet Header
IPv6 Packet Header (22.3.4) The fields for the IPv6 packet header shown in Figure 22-10 are as follows: • Version —This field contains a 4-bit binary value set to 0110 that identifies this as an IP version 6 packet. • Traffic Class — This 8-bit field is equivalent to the IPv4 Differentiated Services (DS) field….
IPv6 Packet – 100-150 Exam Guide
IPv6 Packet (22.3) This topic introduces the successor of IPv4: IPv6. Limitations of IPv4 (22.3.1) IPv4 is still in use today. This topic is about IPv6, which will eventually replace IPv4. To better understand why you need to know the IPv6 protocol, it helps to know the limitations of IPv4 and the advantages of IPv6….