Frame Switching Explanation

[kuroteckie]

Good afternoon techies,

I'm doing some research on switches and I just found out that there are different Layer switches (Layer 2 and Layer 3). Layer 2 switches have a method known as Frame Switching that I can't seem to grasp. From what I've researched, it seems that it is the process in which a switch with an ARP table helps to send data from a source node to a destination node looking at it's ARP table for reference. For example

John at Comp 1 wants to send data to Kelly on Comp 2. The data from Comp 1 is sent to the switch. The switch (assuming the MACs are already in ARP) looks at the ARP table and sees that Kelly's comp is on there and sends that data from John's comp to Kelly's



Is this correct or am I off?

 

[bill001g]

The word "frame" generally means layer 2. So the switch will only use the mac address to determine the ports the data is sent out.

 

[kuroteckie]

The word "frame" generally means layer 2. So the switch will only use the mac address to determine the ports the data is sent out.

When you say ports, you mean the physical ports on a switch right?

 

[bill001g]

Yes the physical ports on the switch

 

[failboat]

It may be referring to going from a frame to a packet. Which is what a layer 3 device does. It's essentially a router with no NAT. Which is very handy if you need multiple subnets in your home that can also communicate with each other.

When a layer 3 switch has different VLANs each one gets a block of physical ports. For 2 different VLANs to communicate the packets go through each others gateways, which is all virtual. If the switch needs to communicate with another device on multiple subnets, it can us trunking so that one physical port connection to another device can carry multiple subnets packets. The need to do this in a home environment is minimal. You won't have enough devices to need it for performance reasons.

 

[camieabz]

Have a good read of this - http://www.ciscopress.com/articles/article.asp?p=357103&seqNum=4

Simply put, a layer 2 switch is a smart hub which basically forwards based on ARP requests (no ARP table), while a layer 3 switch will have an ARP table, and can route at the layer 3 level (packets). It could be termed as a poor-man's router, but without layer 3 routing functionality (e.g. WAN functions).

 

[kuroteckie]

Have a good read of this - http://www.ciscopress.com/articles/article.asp?p=357103&seqNum=4

Simply put, a layer 2 switch is a smart hub which basically forwards based on ARP requests (no ARP table), while a layer 3 switch will have an ARP table, and can route at the layer 3 level (packets). It could be termed as a poor-man's router, but without layer 3 routing functionality (e.g. WAN functions).

I actually printed this out. Thank you for this link