Address Resolution Protocol (ARP)ARP)-Ch… · Proxy ARP router . IP Address Physical Address MACA MACB Timeout TO TOB . Numbered queue where packets are waiting for address resolution

Address Resolution Protocol

(ARP)

Chapter 8

Static Mapping

Involves list of logical and physical addresses

Maintenance of list requires high overhead

Dynamic Mapping

Finds physical address given logical address

Address Resolution Protocol (ARP)

Address Mapping

2

Position of ARP in TCP/IP Protocol Suite

3

broadcast

ARP Operation

4

ARP Packet

5

Encapsulation of ARP Packet

DataPreambleand SFD

Destinationaddress

Sourceaddress

Type CRC

8 bytes 6 bytes 6 bytes 2 bytes 4 bytes

Type: 0x0806

6

Example of ARP Request and Reply

7

Four Cases using ARP

8

Proxy ARP

Request

9

Most recent address mappings are kept in cache table

Mappings in cache table have time-to-live and updated periodically

ARP Cache Table

10

ARP Cache Table

11

ARP Components

12