Test of Boxes




[this is the Box Top; position relative, no float] [the buttons don't show if there is any background color]

A. Box Other

1. Attributes

[this is Box Other; position relative; float blank]


2. General

All boxes with margin and padding set

the boxes automatically line up above and below

Float means that it immediately follows the last box anywhere on the page, even on top of other boxes.

And if you set its margins, they work off of the margin set for the precceding box, if they are inside another element.

[float seems to have no effect on these boxes; try it with a photograph.]

setting contents_right to right float threw off the left margin; float left solves the problem

there is a gap between other1 and contents_left;set margin top in contents_left to zero; pad to give some blank colored space

Setting margin right in contents_left narrows the column, but the next column still doesn't move up. Even increasing the left margin in contents_right narrows the column but does NOT move it up.

Setting width in the contents_left effectively overides the right margin setting. But the second box still does not move up

setting the width of each box to 40% and the left margin to 10% and right margin to 10% does it!The footer box floats to after the contents_right which is not at the bottom of the page. Clear: left, without any float, solves that problem.

B. Box Other1

1. Attributes

Position relative; float center

2. General

Routers are advanced networking components that can divide a single network into two logically separate networks. While Ethernet broadcasts cross bridges in their search to find every node on the network, they do not cross routers, because the router forms a logical boundary for the network. Routers operate based on protocols that are independent of the specific networking technology, like Ethernet or token ring (we'll discuss token ring later). This allows routers to easily interconnect various network technologies, both local and wide area, and has led to their widespread deployment in connecting devices around the world as part of the global Internet. A hub or a switch will pass along any broadcast packets they receive to all the other segments in the broadcast domain, but a router will not. Think about our four-way intersection again: All of the traffic passed through the intersection no matter where it was going. Now imagine that this intersection is at an international border. To pass through the intersection, you must provide the border guard with the specific address that you are going to. If you don't have a specific destination, then the guard will not let you pass. A router works like this. Without the specific address of another device, it will not let the data packet through. This is a good thing for keeping networks separate from each other, but not so good when you want to talk between different parts of the same network. This is where switches come in.

C. Box Other2

1. Attributes

(a) Routers

Routers are advanced networking components that can divide a single network into two logically separate networks. While Ethernet broadcasts cross bridges in their search to find every node on the network, they do not cross routers, because the router forms a logical boundary for the network. Routers operate based on protocols that are independent of the specific networking technology, like Ethernet or token ring (we'll discuss token ring later). This allows routers to easily interconnect various network technologies, both local and wide area, and has led to their widespread deployment in connecting devices around the world as part of the global Internet.

A hub or a switch will pass along any broadcast packets they receive to all the other segments in the broadcast domain, but a router will not. Think about our four-way intersection again: All of the traffic passed through the intersection no matter where it was going. Now imagine that this intersection is at an international border. To pass through the intersection, you must provide the border guard with the specific address that you are going to. If you don't have a specific destination, then the guard will not let you pass. A router works like this. Without the specific address of another device, it will not let the data packet through. This is a good thing for keeping networks separate from each other, but not so good when you want to talk between different parts of the same network. This is where switches come in.

2. Switch

[this is Box Contents_Left; 10% marginL & 0% marginR; position relative; float left; width = 40%]

In a fully switched network, switches replace all the hubs of an Ethernet network with a dedicated segment for every node. These segments connect to a switch, which supports multiple dedicated segments (sometimes in the hundreds). Since the only devices on each segment are the switch and the node, the switch picks up every transmission before it reaches another node. The switch then forwards the frame over the appropriate segment. Since any segment contains only a single node, the frame only reaches the intended recipient. This allows many conversations to occur simultaneously on a switched network.

Fully switched networks employ either twisted-pair or fiber-optic cabling, both of which use separate conductors for sending and receiving data. In this type of environment, Ethernet nodes can forgo the collision detection process and transmit at will, since they are the only potential devices that can access the medium. In other words, traffic flowing in each direction has a lane to itself. This allows nodes to transmit to the switch as the switch transmits to them -- it's a collision-free environment.

Packet-based switches use one of three methods for routing traffic:

Cut-through switches read the MAC address as soon as a packet is detected by the switch. After storing the 6 bytes that make up the address information, they immediately begin sending the packet to the destination node, even as the rest of the packet is coming into the switch.

[this is Box Contents_Right; 0% marginL, 10% marginR; width =40%; position relative; float left]

In a fully switched network, switches replace all the hubs of an Ethernet network with a dedicated segment for every node. These segments connect to a switch, which supports multiple dedicated segments (sometimes in the hundreds). Since the only devices on each segment are the switch and the node, the switch picks up every transmission before it reaches another node. The switch then forwards the frame over the appropriate segment. Since any segment contains only a single node, the frame only reaches the intended recipient. This allows many conversations to occur simultaneously on a switched network.

Fully switched networks employ either twisted-pair or fiber-optic cabling, both of which use separate conductors for sending and receiving data. In this type of environment, Ethernet nodes can forgo the collision detection process and transmit at will, since they are the only potential devices that can access the medium. In other words, traffic flowing in each direction has a lane to itself. This allows nodes to transmit to the switch as the switch transmits to them -- it's a collision-free environment.