D-Link DES-5200 manual Advantages of Store and Forward, Disadvantages of Store and Forward

Fast Ethernet Switching System User’s Guide

System Rate Control

The System Rate Control panel, displayed in Figure 26, enables you to set the packet forwarding rate on the DES-5200. There are two options: Store & Forward and Cut-Through.

Figure 26: System Rate Control

The DES-5200 can be set for Store and Forward or Cut-Through. This is a global setting that affects all the ports except the RS-232 port.

Store and Forward means that when the DES-5200 receives an incoming packet it “stores” the packet until the entire data packet has been received before it “forwards” the packet to a destination.

In Cut-Through mode, packets are sent as soon as the first 128 bytes are received. The first 128 bytes contain the destination address of the packet.

Advantages of Store and Forward

Store and Forward only sends out valid data packets. Bad packets created by collisions on the network or damaged packets are filtered out.

Always use Store and Forward when some devices on the network run at 10 Mbps and others run at 100 Mbps.

Disadvantages of Store and Forward

Store and Forward requires more time because it receives the whole packet before sending it out. Every byte buffered is an additional eight microseconds of delay.

Managing the DES-5200 49