Configuration Guide User guide

FastIron Configuration Guide 951
53-1002494-02
IP configuration overview
ARP cache
The ARP cache can contain dynamic (learned) entries and static (user-configured) entries. The
software places a dynamic entry in the ARP cache when the Layer 3 Switch learns a device MAC
address from an ARP request or ARP reply from the device.
The software can learn an entry when the Layer 2 Switch or Layer 3 Switch receives an ARP request
from another IP forwarding device or an ARP reply. Here is an example of a dynamic entry:
Each entry contains the destination device IP address and MAC address.
Static ARP table
In addition to the ARP cache, Layer 3 Switches have a static ARP table. Entries in the static ARP
table are user-configured. You can add entries to the static ARP table regardless of whether or not
the device the entry is for is connected to the Layer 3 Switch.
NOTE
Layer 3 Switches have a static ARP table. Layer 2 Switches do not.
The software places an entry from the static ARP table into the ARP cache when the entry interface
comes up.
Here is an example of a static ARP entry.
Index IP Address MAC Address Port
1 207.95.6.111 0800.093b.d210 1/1
Each entry lists the information you specified when you created the entry.
Displaying ARP entries
To display ARP entries, refer to the following sections:
• “Displaying the ARP cache” on page 1070 – Layer 3 Switch
• “Displaying the static ARP table” on page 1072 – Layer 3 Switch only
• “Displaying ARP entries” on page 1081 – Layer 2 Switch
To configure other ARP parameters, refer to the following sections:
• “ARP parameter configuration” on page 981 – Layer 3 Switch only
To increase the size of the ARP cache and static ARP table, refer to the following:
• For dynamic entries, refer to the section “Displaying and modifying system parameter default
settings” on page 578. The <ip-arp> parameter controls the ARP cache size.
• Static entries, “Changing the maximum number of entries the static ARP table can hold” on
page 986 (Layer 3 Switches only). The <ip-static-arp> parameter controls the static ARP table
size.
IP route table
The IP route table contains paths to IP destinations.
IP Address MAC Address Type Age Port
1 207.95.6.102 0800.5afc.ea21 Dynamic 0 6