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
Содержание WPCI-G - annexe 1
Страница 2: ......
Страница 26: ...TABLE OF CONTENTS xxvi ...
Страница 36: ...GETTING STARTED ...
Страница 72: ...MANAGING SYSTEM FILES 2 24 ...
Страница 74: ...SWITCH MANAGEMENT ...
Страница 90: ...CONFIGURING THE SWITCH 3 16 ...
Страница 245: ...SHOWING PORT STATISTICS 8 33 Figure 8 12 Port Statistics ...
Страница 252: ...ADDRESS TABLE SETTINGS 9 6 ...
Страница 318: ...CLASS OF SERVICE 12 16 ...
Страница 330: ...QUALITY OF SERVICE 13 12 ...
Страница 348: ...DOMAIN NAME SERVICE 15 8 ...
Страница 404: ...IP ROUTING 17 44 ...
Страница 406: ...COMMAND LINE INTERFACE ...
Страница 482: ...SYSTEM MANAGEMENT COMMANDS 20 54 Example Console show calendar 15 12 34 February 1 2002 Console ...
Страница 608: ...MIRROR PORT COMMANDS 26 4 ...
Страница 644: ...SPANNING TREE COMMANDS 29 28 ...
Страница 668: ...VLAN COMMANDS 30 24 ...
Страница 686: ...CLASS OF SERVICE COMMANDS 31 18 ...
Страница 700: ...QUALITY OF SERVICE COMMANDS 32 14 ...
Страница 792: ...IP INTERFACE COMMANDS 36 50 ...
Страница 818: ...APPENDICES ...
Страница 824: ...SOFTWARE SPECIFICATIONS A 6 ...
Страница 828: ...TROUBLESHOOTING B 4 ...
Страница 844: ...INDEX Index 6 ...
Страница 845: ......