Configuring address resolution methods – Dell POWEREDGE M1000E User Manual
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Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
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Chapter 38 Configuring IP Unicast Routing
Configuring IP Addressing
To restore the default so that the switch forwards packets destined for a subnet of a network without a
network default route to the best possible supernet route, use the ip classless global configuration
command.
Configuring Address Resolution Methods
You can control interface-specific handling of IP by using address resolution. A device using IP can have
both a local address or a MAC address, which uniquely defines the device on its local segment or LAN,
and a network address, which identifies the network to which the device belongs.
Note
In a switch stack, network communication uses a single MAC address and the IP address of the stack.
The local address or the MAC address is known as a data-link address because it is contained in the
data-link layer (Layer 2) section of the packet header and is read by data-link (Layer 2) devices. To
communicate with an Ethernet device, the software must learn the MAC address of the device. The
process of learning the MAC address from an IP address is called address resolution. The process of
learning the IP address from the MAC address is called reverse address resolution.
The switch uses these types of address resolution:
•
Address Resolution Protocol (ARP) associates IP address with MAC addresses. Using an IP address
as input, ARP learns the associated MAC address and then stores the IP address/MAC address
association in an ARP cache for rapid retrieval. Then the IP datagram is encapsulated in a link-layer
frame and sent over the network. Encapsulation of IP datagrams and ARP requests or replies on
IEEE 802 networks other than Ethernet is specified by the Subnetwork Access Protocol (SNAP).
•
Proxy ARP helps hosts with no routing tables learn the MAC addresses of hosts on other networks
or subnets. If the switch (router) receives an ARP request for a host that is not on the same interface
as the ARP request sender, and if the router has all of its routes to the host through other interfaces,
it generates a proxy ARP packet giving its own local data-link address. The host that sent the ARP
request then sends its packets to the router, which forwards them to the intended host.
The switch also uses the Reverse Address Resolution Protocol (RARP), which functions the same as
ARP does, except that the RARP packets request an IP address instead of a local MAC address. Using
RARP requires a RARP server on the same network segment as the router interface. Use the ip
rarp-server address interface configuration command to identify the server.
For more information on RARP, see the Cisco IOS Configuration Fundamentals Configuration Guide,
Release 12.2 under Documentation > Cisco IOS Software > 12.2 Mainline > Configuration Guides
from the Cisco.com page.
You can perform these tasks to configure address resolution:
•
Define a Static ARP Cache, page 38-11
•
Set ARP Encapsulation, page 38-11
•
Step 4
show running-config
Verify your entry.
Step 5
copy running-config startup-config
(Optional) Save your entry in the configuration file.
Command
Purpose