C
HAPTER
1 8
| General IP Routing
Address Resolution Protocol
– 486 –
ES-4500G Series
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:
When devices receive this request, they discard it if their address does not
match the destination IP address in the message. However, if it does
match, they write their own hardware address into the destination MAC
address field and send the message back to the source hardware address.
When the source device receives a reply, it writes the destination IP
address and corresponding MAC address into its cache, and forwards the IP
traffic on to the next hop. As long as this entry has not timed out, the
router will be able forward traffic directly to the next hop for this
destination without having to broadcast another ARP request.
Also, if the switch receives a request for its own IP address, it will send
back a response, and also cache the MAC of the source device's IP address.
B
ASIC
ARP
C
ONFIGURATION
Use the IP > ARP (Configure General) page to specify the timeout for ARP
cache entries, or to enable Proxy ARP for specific VLAN interfaces.
CLI R
EFERENCES
◆
◆
C
OMMAND
U
SAGE
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.
Figure 289: Proxy ARP
Table 30: 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
no routing,
no default
gateway
Remote
ARP Server
Proxy ARP
ARP
request
Summary of Contents for iPECS ES-4526G
Page 1: ...USER GUIDE User Manual ES 4550G ES 4526G Managed Layer 3 Stackable GE Switch ...
Page 38: ...CONTENTS 38 ES 4500G Series ...
Page 58: ...SECTION I Getting Started 58 ES 4500G Series ...
Page 70: ...CHAPTER 1 Introduction System Defaults 70 ES 4500G Series ...
Page 86: ...SECTION I Web Configuration 86 ES 4500G Series Multicast Filtering on page 413 ...
Page 196: ...CHAPTER 6 VLAN Configuration Configuring MAC based VLANs 196 ES 4500G Series ...
Page 204: ...CHAPTER 7 Address Table Settings Clearing the Dynamic Address Table 204 ES 4500G Series ...
Page 228: ...CHAPTER 8 Spanning Tree Algorithm Configuring Interface Settings for MSTP 228 ES 4500G Series ...
Page 230: ...CHAPTER 9 Rate Limit Configuration 230 ES 4500G Series Figure 106 Configuring Rate Limits ...
Page 260: ...CHAPTER 12 Quality of Service Attaching a Policy Map to a Port 260 ES 4500G Series ...
Page 478: ...CHAPTER 17 IP Configuration Setting the Switch s IP Address IP Version 6 478 ES 4500G Series ...
Page 528: ...CHAPTER 20 IP Services Forwarding UDP Service Requests 528 ES 4500G Series ...
Page 614: ...CHAPTER 22 Multicast Routing Configuring PIMv6 for IPv6 614 ES 4500G Series ...
Page 628: ...CHAPTER 23 Using the Command Line Interface CLI Command Groups 628 ES 4500G Series ...
Page 702: ...CHAPTER 26 SNMP Commands 702 ES 4500G Series ...
Page 710: ...CHAPTER 27 Remote Monitoring Commands 710 ES 4500G Series ...
Page 868: ...CHAPTER 34 Port Mirroring Commands Local Port Mirroring Commands 868 ES 4500G Series ...
Page 890: ...CHAPTER 37 Address Table Commands 890 ES 4500G Series ...
Page 1066: ...CHAPTER 43 LLDP Commands 1066 ES 4500G Series ...
Page 1076: ...CHAPTER 44 Domain Name Service Commands 1076 ES 4500G Series ...
Page 1286: ...CHAPTER 49 Multicast Routing Commands PIM Multicast Routing 1286 ES 4500G Series ...
Page 1288: ...SECTION I Appendices 1288 ES 4500G Series ...
Page 1294: ...APPENDIX A Software Specifications Management Information Bases 1294 ES 4500G Series ...
Page 1327: ...ES 4526G ES 4550G E042011 ST R01 150200000149A ...
Page 1328: ...APRIL 2011 ISSUE 1 0 ...