3
•
Long static ARP entry
—It contains the IP address, MAC address, VLAN, and output interface.
It is directly used for forwarding packets.
•
Short static ARP entry
—It contains only the IP address and MAC address.
{
If the output interface is a Layer 3 Ethernet interface, the short ARP entry can be directly
used to forward packets.
{
If the output interface is a VLAN interface, the device sends an ARP request whose target IP
address is the IP address in the short entry. If the sender IP and MAC addresses in the
received ARP reply match the short static ARP entry, the device performs the following
operations:
−
Adds the interface that received the ARP reply to the short static ARP entry.
−
Uses the resolved short static ARP entry to forward IP packets.
To communicate with a host by using a fixed IP-to-MAC mapping, configure a short static ARP entry
on the device. To communicate with a host by using a fixed IP-to-MAC mapping through an interface
in a VLAN, configure a long static ARP entry on the device.
OpenFlow ARP entry
ARP creates OpenFlow ARP entries by learning from the OpenFlow module. An OpenFlow ARP
entry does not age out, and it cannot be updated. It can be overwritten by a static ARP entry. An
OpenFlow ARP entry can be used directly to forward packets. For more information about OpenFlow,
see
OpenFlow Configuration Guide
.
Rule ARP entry
ARP creates Rule ARP entries by learning from the IPoE or portal module. A Rule ARP entry does
not age out, and it cannot be updated. It can be overwritten by a static ARP entry. A Rule ARP entry
can be used directly to forward packets. For more information about IPoE, see
Layer 2—WAN
Access Configuration Guide
. For more information about portal, see
Security Configuration Guide
.
Configuring a static ARP entry
A static ARP entry is effective when the device functions correctly. If a VLAN or VLAN interface is
deleted, long static ARP entries in the VLAN are deleted, and resolved short static ARP entries in the
VLAN become unresolved.
A resolved short static ARP entry becomes unresolved upon certain events. For example, it
becomes unresolved when the resolved output interface goes down.
A long static ARP entry is ineffective in either of the following situations:
•
The IP address in the entry conflicts with a local IP address.
•
No local interface has an IP address in the same subnet as the IP address in the ARP entry.
Follow these guidelines when you configure a long static ARP entry:
•
The
vlan-id
argument must be the ID of an existing VLAN where the ARP entry resides. The
specified Ethernet interface must belong to that VLAN.
•
The VLAN interface must be created. Its IP address and the IP address specified by the
ip-address
argument must be on the same subnet.
To configure a static ARP entry:
Step Command
Remarks
1.
Enter system view.
system-view
N/A