Chapter 63: Address Resolution Protocol (ARP)
970
Section X: Network Management
Overview
The Address Resolution Protocol (ARP) is used to associate an IPv4
address with a MAC address used by network nodes. ARP gathers
information about mapping between an IPv4 address and a MAC address
and stores them in the ARP cache. The ARP cache is located in the RAM
of a node. When the node receives a packet from the Network layer, then
the node encapsulates the packet into a frame. The node looks up the
ARP cache to find out the MAC address of the destination node.
Proxy ARP
Proxy ARP is a technique in which a routing device answers an ARP
request for an IP address that is not on the same network. The AT-9000
switches support Proxy ARP.
For example, when a host sends data, it tries to resolve the destination IP
address to a MAC address. In most cases, the host can use the subnet
mask to figure out whether the destination IP address is a remote or local
host. When the destination is a remote host, the host uses the MAC
address of the default gateway as the destination MAC address.
Proxy ARP allows the hosts that do not support routing, or do not have
knowledge of the network structure, to determine the physical addresses
of hosts on other networks. When receiving an ARP broadcast request
with a destination IP address on a remote network, a Proxy ARP-enabled
routing device replies to the request with the MAC address of its own.
Without Proxy ARP, the ARP request does not receive any reply.
The AT-9000 switches allow you to enable and disable Proxy ARP.
ARP on the
Switch
The AT-9000 switches uses the following settings:
Dynamic ARP entries timeout in 300 seconds
Up to 512 static ARP entries
Dynamic ARP
Entries
The dynamically gathered ARP entries that populate the ARP table in the
cache are called dynamic ARP entries. Dynamic ARP entries are updated
in two ways:
During regular operations
When a node receives frames from the media, it records the source IP
and MAC addresses.
Using ARP broadcast requests
When a node creates a frame and does not find an entry of the
destination IPv4 address in the ARP cache, ARP broadcasts a
request, including the IP address of the destination host, to all the
devices on the LAN. Only the node assigned to the IP address replies
Содержание AT-9000/28
Страница 4: ......
Страница 26: ...Contents 26...
Страница 30: ...Tables 30...
Страница 36: ...36 Section I Getting Started...
Страница 70: ...Chapter 2 Starting a Management Session 70 Section I Getting Started...
Страница 96: ...96 Section II Basic Operations...
Страница 142: ...Chapter 6 Basic Switch Management Commands 142 Section II Basic Operations...
Страница 220: ...Chapter 9 IPv4 and IPv6 Management Addresses 220 Section II Basic Operations...
Страница 244: ...Chapter 10 IPv4 and IPv6 Management Address Commands 244 Section II Basic Operations...
Страница 264: ...Chapter 12 SNTP Client Commands 264 Section II Basic Operations...
Страница 298: ...Chapter 15 Enhanced Stacking 298 Section II Basic Operations...
Страница 312: ...Chapter 16 Enhanced Stacking Commands 312 Section II Basic Operations...
Страница 318: ...Chapter 17 Port Mirror 318 Section II Basic Operations...
Страница 324: ...Chapter 18 Port Mirror Commands 324 Section II Basic Operations Example awplus show mirror...
Страница 350: ...Chapter 21 Multicast Commands 350 Section II Basic Operations...
Страница 352: ...352 Section III File System...
Страница 360: ...Chapter 22 File System 360 Section III File System...
Страница 383: ...AT 9000 Switch Command Line User s Guide Section III File System 383 Example awplus show boot...
Страница 386: ...Chapter 25 Boot Configuration File Commands 386 Section III File System...
Страница 398: ...Chapter 26 File Transfers 398 Section III File System...
Страница 406: ...Chapter 27 File Transfer Commands 406 Section III File System...
Страница 408: ...408 Section IV Event Messages...
Страница 430: ...Chapter 30 Syslog Client 430 Section IV Event Messages...
Страница 438: ...438 Section V Port Trunks...
Страница 448: ...Chapter 32 Static Port Trunks 448 Section V Port Trunks...
Страница 480: ...480 Section VI Spanning Tree Protocols...
Страница 500: ...Chapter 36 Spanning Tree and Rapid Spanning Tree Protocols 500 Section VI Spanning Tree Protocols...
Страница 520: ...Chapter 38 STP Commands 520 Section VI Spanning Tree Protocols...
Страница 542: ...Chapter 40 RSTP Commands 542 Section VI Spanning Tree Protocols Example awplus show spanning tree...
Страница 558: ...558 Section VII Virtual LANs...
Страница 600: ...Chapter 42 Port based and Tagged VLAN Commands 600 Section VII Virtual LANs...
Страница 634: ...Chapter 44 GARP VLAN Registration Protocol Commands 634 Section VII Virtual LANs...
Страница 670: ...Chapter 47 Private Port VLANs 670 Section VII Virtual LANs...
Страница 692: ...Chapter 50 VLAN Stacking 692 Section VII Virtual LANs...
Страница 698: ...Chapter 51 VLAN Stacking Commands 698 Section VII Virtual LANs...
Страница 700: ...700 Section VIII Port Security...
Страница 748: ...Chapter 54 802 1x Port based Network Access Control 748 Section VIII Port Security...
Страница 790: ...Chapter 55 802 1x Port based Network Access Control Commands 790 Section VIII Port Security...
Страница 792: ...792 Section IX Simple Network Management Protocols...
Страница 804: ...Chapter 56 SNMPv1 and SNMPv2c 804 Section X Simple Network Management Protocols...
Страница 852: ...852 Section X Network Management...
Страница 976: ...Chapter 63 Address Resolution Protocol ARP 976 Section X Network Management...
Страница 1090: ...1090 Section XI Management Security...
Страница 1114: ...Chapter 71 Telnet Server 1114 Section XI Management Security...
Страница 1122: ...Chapter 73 Telnet Client 1122 Section XI Management Security...
Страница 1126: ...Chapter 74 Telnet Client Commands 1126 Section XI Management Security...
Страница 1138: ...Chapter 75 Secure Shell SSH Server 1138 Section XI Management Security...
Страница 1158: ...Chapter 78 Non secure HTTP Web Browser Server Commands 1158 Section XI Management Security...
Страница 1186: ...Chapter 80 Secure HTTPS Web Browser Server Commands 1186 Section XI Management Security...
Страница 1202: ...Chapter 81 RADIUS and TACACS Clients 1202 Section XI Management Security...
Страница 1230: ...Chapter 82 RADIUS and TACACS Client Commands 1230 Section XI Management Security...
Страница 1244: ...Chapter System Monitoring Commands 1244...
Страница 1278: ...Index 1278 Configuration mode 644 659 VLAN SET MACADDRESS command Port Interface mode 644 661 W WRITE command 75 94 385...