A
DDRESS
R
ESOLUTION
P
ROTOCOL
17-9
CLI -
This example sets a primary IP address for VLAN 1, and then adds
a secondary IP address for a different subnet also attached to this router
interface.
Address Resolution Protocol
If IP routing is enabled (page 17-5), the router uses its routing tables to
make routing decisions, and uses Address Resolution Protocol (ARP) to
forward traffic from one hop to the next. ARP is used to map an IP
address to a physical layer (i.e., MAC) address. When an IP frame is
received by this router (or any standards- based router), it first looks up the
MAC address corresponding to the destination IP address in the ARP
cache. If the address is found, the router writes the MAC address into the
appropriate field in the frame header, and forwards the frame on to the
next hop. IP traffic passes along the path to its final destination in this way,
with each routing device mapping the destination IP address to the MAC
address of the next hop toward the recipient, until the packet is delivered
to the final destination.
If there is no entry for an IP address in the ARP cache, the router will
broadcast an ARP request packet to all devices on the network. The ARP
request contains the following fields similar to that shown in this example:
Console(config)#interface vlan 1
Console(config-if)#ip address 10.1.0.253 255.255.255.0
36-4
Console(config-if)#ip address 10.1.9.253 255.255.255.0 secondary
Console(config-if)#
Table 17-1 Address Resolution Protocol
destination IP address
10.1.0.19
destination MAC
address
?
source IP address
10.1.0.253
source MAC address
00-00-ab-cd-00-00
Summary of Contents for WPCI-G - annexe 1
Page 2: ......
Page 26: ...TABLE OF CONTENTS xxvi ...
Page 36: ...GETTING STARTED ...
Page 72: ...MANAGING SYSTEM FILES 2 24 ...
Page 74: ...SWITCH MANAGEMENT ...
Page 90: ...CONFIGURING THE SWITCH 3 16 ...
Page 245: ...SHOWING PORT STATISTICS 8 33 Figure 8 12 Port Statistics ...
Page 252: ...ADDRESS TABLE SETTINGS 9 6 ...
Page 318: ...CLASS OF SERVICE 12 16 ...
Page 330: ...QUALITY OF SERVICE 13 12 ...
Page 348: ...DOMAIN NAME SERVICE 15 8 ...
Page 404: ...IP ROUTING 17 44 ...
Page 406: ...COMMAND LINE INTERFACE ...
Page 608: ...MIRROR PORT COMMANDS 26 4 ...
Page 644: ...SPANNING TREE COMMANDS 29 28 ...
Page 668: ...VLAN COMMANDS 30 24 ...
Page 686: ...CLASS OF SERVICE COMMANDS 31 18 ...
Page 700: ...QUALITY OF SERVICE COMMANDS 32 14 ...
Page 792: ...IP INTERFACE COMMANDS 36 50 ...
Page 818: ...APPENDICES ...
Page 824: ...SOFTWARE SPECIFICATIONS A 6 ...
Page 828: ...TROUBLESHOOTING B 4 ...
Page 844: ...INDEX Index 6 ...
Page 845: ......