Why was the hub faster than the switch?

The switch should be faster. The switch directs the data to a specific port while a hub makes all the lights blink when a data transfer is underway because it is broadcasting to all of the ports. This slows down data transfers. go here for more info:

What f/fgeorge says is true but not the whole story. All switches introduce some amount of throughput delay into the data transfer from input port to output port. The delay can be more or less depending on which class of switch; "store and forward", or "cut-through" is used.

SF is worst because the complete incoming frame has to be received and "stored" in the switch before it is allowed to start being sent out the output port. This is primarily for error checking purposes.

CT is faster because data starts being output as soon as switch has enough data to know which output port to send it to.

The most common mis-understanding about switches vs hubs is that switches are not faster in all applications. The worst application is where several PCs are trying to access the same one target ( ie DSL modem) (many to one network). Hubs are actually faster here because they have no delay as above.

Switches work best in applications where the PCs can access many targets in the local network(ie, DSL, file servers, networked printers, PC-PC transfer, etc) (any to any network)

--reed

Does that mean that switches which support speed switching (e.g. 10/100 Mbps) will always store and forward when moving data between a 10 Mbps port and a 100 Mbps port?

On the other hand, with a hub there is a potential for more collisions which will result in delays and re-transmissions. So while there may be an initial (very minute) hit to through-put when replacing a hub with a switch, as more devices are added, the switch becomes more and more efficient.

But if we're talking about an internet connection using a cablemodem (as would be on-topic for this group), this is largely insignificant. It's like comparing a 0.1% upgrade on a highway vs. a stop sign further up the road. Hardly worth the time it takes to consider.

Even cut through switches have to store data, while waiting for previous data to pass. So the first packet will start as cut through, but more and more of it will be stored. Any additional packets behind it, will be stored until the wire is free. However, TCP has mechanisms to detect such congestion and back off the transmission rate, to reduce that congestion. Also, some switches can cause a source to slow down.

IIRC, all 10/100 switches are store and forward, since cut-through would fail when the 10M port is the input and 100M is the output (causing an under-run condition).

Also, it appears some posters still miss the point about sw vs hub being application dependent. Switches were developed to help those local networks that had a need for any to any connectivity. When 10 (or any number more than 1) users on PCs are trying to access the same cablemodem, a switch is no help, and may actually hurt, as the OP may have learned the hard way.

--reed

From: "Reed"

| IIRC, all 10/100 switches are store and forward, since cut-through would | fail when the 10M port is the input and 100M is the output (causing an | under-run condition). | | Also, it appears some posters still miss the point about sw vs hub being | application dependent. Switches were developed to help those local | networks that had a need for any to any connectivity. When 10 (or any | number more than 1) users on PCs are trying to access the same | cablemodem, a switch is no help, and may actually hurt, as the OP may | have learned the hard way. | | --reed

It depends on the POV. The E-switch on a Cable/DSL Router is also being used to share local area networking such as IPX/SPX, SMB or NetBIOS over IP. There can be 253 nodes on such a SOHO LAN. The collision domain isolation of an E-switch will help on the LAN side very well. Additionally, since an E-Switch can send and receive at the same time and so can DSL or Cable Internet connections, there is that benefit as well.

The problem is that cheap SHO Router or cheap SOHO standalone E-switches use cheap chip-sets with higher latency than their enterprise.corporate counterparts. The trade-off is lower price for higher latency.

I bet you had a duplex mis-match on the switch. This would cause terribly slow speeds compared to a connection on the Hub that was autonegotiating fine.

I run into this all the time. The first thing I do with any ethernet connection of any kind is to force the devices to full duplex/100 Mbps. This will eliminate any device from guessing incorrectly during the N-way negotiation.

With the speeds involved with Home Broadband the various types of switching methods will have little to do with latency, assuming the switch didn't come out of a cracker jack box...