User Manual

24-Port and 48-Port Gigabit Ethernet PoE+ Smart Switches with 4 SFP Ports
Configure Routing User Manual290
The Configure Routes page displays.
7. Select the check box for the route that you want to delete.
8. Click the Delete button.
The route is deleted.
Configure Address Resolution Protocol
The Address Resolution Protocol (ARP) associates a Layer 2 MAC address with a Layer 3
IPv4 address. ARP is a part of the Internet Protocol (IP) and is used to translate an IP
address to a media (MAC) address, defined by a LAN such as an Ethernet LAN.
The switch supports both dynamic and manual ARP configurations. With a manual ARP
configuration, you can statically add entries to the
ARP table.
A device that sends an IP packet must learn the MAC address of the IP destination, or, if the
destination is not on the same subnet, of the next hop router. The device broadcasts an ARP
request packet, to which the intended recipient responds with a unicast ARP reply that
contains its MAC address. The device then uses the MAC address in the destination address
field of the Layer 2 header that is prepended to the IP packet and sent to the recipient. Each
device in a network maintains its ARP cache locally.
The switch learns ARP cache entries by examining the source information in the ARP packet
payload fields, regardless of whether it is an
ARP request or a response. In that way, when
an ARP request is broadcast to all stations on a LAN segment or VLAN, each recipient can
store the sender’s IP and MAC address in its ARP cache. Normally, only the requestor
receives an ARP response (a unicast message) and stores the sender’s information in its
ARP cache. The most recent information always replaces existing content in the ARP cache.
A device can be moved in a network, which means that the device’s IP address that was
associated with one MAC address is now associated with another MAC address.
A device
can also disappear from the network altogether (for example, it was reconfigured,
disconnected, or powered off). These situations cause stale information in the ARP cache.
Therefore, entries are updated or periodically refreshed to determine if an address still exists.
If an entry was identified as a sender of an ARP packet, the entry can be removed from the
ARP cache. You can configure an age-out interval that determines how long an entry that is
not updated remains in the ARP cache.