Telematics Chapter 6: Network Layer - Freie Universität Berlin

Delivery of IP Packets
● Address Resolution Protocol (ARP)
● The Internet is a virtual network, which is build upon physical networks.
● IP addresses only offer a logical address space
● The hardware on the lower layers do not understand IP addresses
● Within a local area network, the sender must know the hardware address (MAC
address) of the receiver before sending an IP packet to the destination host
● The hardware address is with Ethernet an 48-bit address, which is assigned
to a network interface card (NIC) by the manufacturer
● With ARP, IP is mapped to the hardware address and vice versa
● ARP uses the local broadcast address to dynamically inquire for the hardware
address by indication of the searched IP address
● An ARP request is only valid in the local network
Univ.-Prof. Dr.-Ing. Jochen H. Schiller ▪ cst.mi.fu-berlin.de ▪ Telematics ▪ Chapter 6: Network Layer
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