C
ONFIGURING
THE
S
WITCH
3-256
Proxy ARP
When a node in the attached subnetwork does not have routing or a
default gateway configured, Proxy ARP can be used to forward ARP
requests to a remote subnetwork. When the router receives an ARP request
for a remote network and Proxy ARP is enabled, it determines if it has the
best route to the remote network, and then answers the ARP request by
sending its own MAC address to the requesting node. That node then
sends traffic to the router, which in turn uses its own routing table to
forward the traffic to the remote destination.
Basic ARP Configuration
You can use the ARP General configuration menu to specify the timeout
for ARP cache entries, or to enable Proxy ARP for specific VLAN
interfaces.
Command Usage
•
The aging time determines how long dynamic entries remain the cache.
If the timeout is too short, the router may tie up resources by repeating
ARP requests for addresses recently flushed from the table.
•
End stations that require Proxy ARP must view the entire network as
a single network. These nodes must therefore use a smaller subnet
mask than that used by the router or other relevant network devices.
•
Extensive use of Proxy ARP can degrade router performance because
it may lead to increased ARP traffic and increased search time for larger
ARP address tables.
no routing,
no default
gateway
Remote
ARP Server
Proxy ARP
ARP
request
Summary of Contents for 8612XL3
Page 2: ......
Page 26: ...CONTENTS xxvi ...
Page 40: ...INTRODUCTION 1 14 ...
Page 69: ...BASIC CONFIGURATION 3 15 ...
Page 175: ...PORT CONFIGURATION 3 121 ...
Page 337: ...IP ROUTING 3 283 Web Click Routing Protocol RIP Statistics ...
Page 379: ...MULTICAST ROUTING 3 325 Command Usage ...
Page 396: ...CONFIGURING THE SWITCH 3 342 ...
Page 582: ...COMMAND LINE INTERFACE 4 186 ...
Page 806: ... 224 Command Mode Privileged Exec Example Console clear vrrp 1 interface 1 counters Console ...
Page 826: ... 6 ...
Page 828: ...TROUBLESHOOTING B 2 ...
Page 838: ...GLOSSARY Glossary 10 ...
Page 845: ......