Black Box 410T manual Workgroup Application, Particular, an Intel Express

Workgroup Application:	Standalone Switch, 16-Port
	Intel Express 410T
	(ES410T16)

10-Mbps Connections

100-Mbps Connections

Older 10-Mbps Hub or Switch
Connected to Port 1 Using
Straight-Through Cable	Stack of Express 330T Stackable Hubs (EE330TX16)
	Connected to the Switch Using Crossover Cable

10

File Server Connected Using

Straight-Through Cable

10-Mbps Clients

Shared Printer

100-Mbps Clients

The Express 410T can serve as the backbone for a small network. Its MDI/MDI-X button allows the

switch to connect to other switches and hubs using straight-through cables (instead of crossover cables).

All ports on the switch are MDI-X, and the button is used to toggle Port 1 to MDI.

Technically Speaking

Compared with traditional routers and bridges, Ethernet

switches offer distinct advantages in performance, ease of use, and cost.

In particular, an Intel® Express

410 Standalone Switch can help alleviate bottlenecks in your client/server environment. A workgroup-based switch such as the Express 410 takes a logical approach to easing congestion: It boosts performance on a portion of the network and divides the local network so fewer users occupy a segment.

The switch also provides each high-performance device (such a server or a switch uplink) with its own dedicated segment, one that

can run at the same speed as the other switched ports or at higher speeds.

To further ease the flow of traffic, the Express 410T employs flow control, which temporarily suspends a transfer of data from a sending workstation until its destination port is ready to receive it. Flow control applied during Ethernet traffic bursts—when switch buffer memory is full— helps prevent information from being dropped and, in turn, saves you from costly delays.

Many conventional bridges, routers, and switches rely on large, expensive buffers to hold packets that can’t be transmitted. However, if the destination

segment becomes overloaded, incoming data can overrun the buffer, forcing the device to drop excess packets. And, although the sending nodes’ NIC software detects dropped packets, the solution typically involves a very inefficient time-out mechanism.

Flow control goes to the

source—before the segment is flooded. When a port’s internal buffers near capacity, flow control enables the switch to transmit a mock collision (also known as a jam pattern) back to the source node. The sending node sees the interruption as a collision and backs off. When the switch has emptied its internal buffers, it directs the sender’s NIC to

retransmit the packet from its hardware buffers.

You can enable and disable flow control for each port on the Express 410T. By default, flow control is enabled. The method of flow control depends on whether the ports are set to full or half duplex. For instance, if the port is operating at full duplex, the switch sends out an 802.3x PAUSE frame, instead of a collision, to delay traffic.

And, as a store-and-forward switch, the 410T stores the incoming frame in an internal buffer and delays transmission until the switch successfully completes packet error-checking.