Ip Table; Chapter 48 Ip Table; Ip Table Overview - ZyXEL Communications GS3700 Series User Manual

This chapter introduces the IP table.

48.1 IP Table Overview

The IP Table screen shows how packets are forwarded or filtered across the Switch's ports. When
a device (which may belong to a VLAN group) sends a packet which is forwarded to a port on the
Switch, the IP address of the device is shown on the Switch's IP Table. The IP Table also shows
whether the IP address is dynamic (learned by the Switch) or static (belonging to the Switch).
The Switch uses the IP Table to determine how to forward packets. See the following figure.
The Switch examines a received packet and learns the port from which this source IP address
1
came.
The Switch checks to see if the packet's destination IP address matches a source IP address already
2
learned in the IP Table.
• If the Switch has already learned the port for this IP address, then it forwards the packet to
that port.
• If the Switch has not already learned the port for this IP address, then the packet is flooded to
all ports. Too much port flooding leads to network congestion.
• If the Switch has already learned the port for this IP address, but the destination port is the
same as the port it came in on, then it filters the packet.
Figure 274 IP Table Flowchart
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IP Table