Some terminology will be covered first, followed by descriptions of certain network functions and devices. A description of how data travels through a network should complete the foundation, for a basic understanding of computer data networking. Next, an example network configuration will be described. The sample network shares a two-way satellite connection to the Internet. We will also discuss a few things that can cause problems, if they are not set up properly.

The best way to understand why networks exist is, with a little history. When PCs started being used in the workplace, they were not connected by a network, but each was an independent island. Peripheral devices connected to one PC could not be used, by a user at a different PC.

Not too long after PCs started appearing on individuals desktops, laser printers started becoming affordable, even to smaller companies, though they were still quite expensive. In fact, if a small company had a laser printer, the chances are, that it had ONLY ONE laser printer...in the entire company.

Now, at that time, everyone knew that a copy of a resume that was laser printed had a higher probability of leading to an interview – it was just considered to be “more professional”, at least in the technology sector.So, if an employee was thinking about finding a job with another company, that employee might want to get laser-printed copies of his resume, to give to prospective employers. But, the only laser printer was sitting on the desk of the President’s secretary.

So, the employee would copy the resume to a floppy disk and walk (wearing sneakers, of course) to the secretary’s desk, possibly stopping to chat with a couple of co-workers, on the way. Once there, the employee would lean over and whisper, in a conspiritorial tone, “Will you please print me 25 copies of this?” Then, the employee would go to the break room, to get a cup of coffee. There might be a friend present in the break room, so the employee would stand and chat, while drinking the coffee and killing time, until the secretary gets the resumes printed. After awhile, the employee would wander back to the secretary’s desks, pick up the resumes, and head back.

The worker lost from 30 minutes to an hour of productivity, getting the copies. Well, it didn’t take management long to figure out that if you put all the PCs and the peripherals on a cable, then everyone could access the resources — without ever leaving their desk! Not only that, but they could now cost-justify the resource across all members of the LAN. So, at this point, networking really took off! A network went from being a “nice” frill to a “necessary” investment” to a “business essential”!

As PCs proliferated and the value of networks became common knowledge, more and more PCs were put onto local area networks (LANs). Ethernet LANs dominated the landscape and Ethernet LANs can only support a limited number of users. When there are too many users on an Ethernet LAN, the number of data “collisions” (more about this later) becomes excessive, sometimes to the point of the LAN becoming almost useless. At best, the network works, but very slowly.

Everyone is said to be in the same collision domain. This means that if more than one PC transmit at a time, a collision will occur. Then, all transmissions become garbage. Bridges segment the network into multiple collision domains, one per port. This means one PC on each port can transmit at the same time, without problems. Bridges typically have two or three ports. Switches, which came much later, have many ports: at least 8, typically, and perhaps hundreds.

There is one type of message called a broadcast. A broadcast is a message that is for all hosts on the network. Bridges and switches will always forward broadcasts out all ports. When bridged networks grew to be quite complex, and especially if there were backup (redundant) bridges in place, a new problem arose in the network environment: broadcast storms. Because all bridges forwarded all broadcasts out all ports, these messages to everyone could sometimes hog all of the available bandwidth. This tended to happen in the mornings, when many employees all turned on their PCs at about the same time and their PCs would all start sending out broadcast messages, to try and locate network resources. As said earlier, each port of a bridge defines a collision domain. However, all ports are said to be int he same broadcast domain.

One of the primary reasons for the creation of the router was to contain broadcast – to eliminate broadcast storms. Each port or interface of a router defines both a collision domain and a broadcast domain. Broadcast messages on one port are not forwarded out any other interfaces, by default. As it turns out, routers can also provide additional security. In fact, the original firewall was nothing more than filters configured on a router.

The laws of physics and of radio frequency (RF) transmission say that perfectly horizontal signal propagation will not interfere with perfectly vertical signal propagation. In reality, there is always some amount of interference, whenever radio waves are involved.

The best way to think of cross-polarization, or cross-pol, is that it is a measure of the interference potential of your transmitter. Whereas, co-polarization, or co-pol, is a measure of the clean signal strength of your transmitter.

ASI stands for adjacent satellite interference. Like cross-pol, it is an interfering potential of your transmitter, but on an adjacent satellite, in this case.

How these values are tested and reported varies, across technologies and implementations. For example, when pointing a HughesNet satellite dish, the cross-pol number must be maximized, but for StarBand®, it must be minimized and less than 3.0.

One good description of a network and networking says that there are three essential elements:

• Something to Share – In the case of a computer data network, this is data. In the Public Switched Telephone Network (PSTN), it is voice.
  
• Pathway – There must be a pathway connecting the entities that have something to share. For computer networks, this is the media and all intervening devices. For the PSTN, it is the twisted pair wires that connect each home to the central-office telephone switch at each end, and all connecting wires and switches in-between.
• Rules – Rules, or protocols, define how something is accomplished. At an instructor-led course, for example, the usual protocol is that a listerner will raise his/her hand or otherwise get the presenter’s attention, if there is a question, rather than just blurt it out.
  For computer networks, there are many, many protocols in use, many of which have commonly used TLAs (Three-Letter Acronyms), like TCP and FTP. Some, of course, have only two, or more than three letters, like IP and SMTP. These acronyms and others will be defined later.

Half- or Full-Duplex

Half-duplex and full-duplex refer to whether transmission can only go in one direction at a time (half-duplex), or in both directions at the same time (full-duplex). A walkie talkie operates in half-duplex, while a standard telephone is full-duplex. This is sometimes a factor, when an Ethernet Network Interface Card (NIC) or a new hub or switch is installed and it doesn’t seem to work. This will happen if one end of the connection is set to one mode, and the other end to a different mode. Though the correct mode is often determined automatically, problems also occur when one end is set to automatic, but the other end is not.

DTE or DCE

The terms DTE (Data Terminal Equipment) and DCE (Data Communications Equipment) are often used in networking discussions to define the “role” that a device plays in communicating. Most often, the term DTE (Data Terminal Equipment) refers to the PC or the router, whereas DCE (Data Communication Equipment) refers to the modem or other device that connects the DTE device to the service provider’s network.

The distinction most often refers to physical functions, such as on which pin the device transmits or receives. There are different cable types used for connecting “like” devices (i.e., DTE to DTE or DCE to DCE) than for connecting different device types (DTE to DCE). Since connecting a DTE device to a DCE device is considered the “normal” situation, a straight-through cable is used. When connecting like-to-like, however, what is known as a crossover cable is used.This cable crosses certain signals, such that the devices on each end communicate normally, unaware that they are not actually connected to the “other” device type.

This section will describe certain network functions and devices in relation to something called the OSI (Open Systems Interconnection) Reference Model, which is described next.

OSI Reference Model

The OSI Model is about functions of networking and where they typically exist in a network. It takes all of the tasks that must occur, in order to deliver data in a network, and it breaks all of this complexity down into small “chunks” of functionality. This makes each chunk, or layer, as it’s called, much easier to understand. And, for network developers, it makes it easier to define a function in detail and implement it. There are other advantages that the modular approach of the OSI Model brings, but they will not be discussed here.

The OSI Model architecture also creates a hierarchy of functionality, such that lower layers must be working properly, in order for higher layers to work. This is similar to the idea of the foundation of a building needing to be complete, before the first floor can can be built. Then, the second floor can be built, and so on. In the OSI Model, the Physical Layer must be working properly, before the Data Link Layer can function, and both of these, before the Network Layer will work, etc.

Within this modular networking environment, the actual communication is said to be peer-to-peer. Each layer is said to use the services of the layer below and provide services to the layer above. Perhaps, an anology can help clarify this.

Kings and Pages

Imagine that there are two castles, each with a king at the top of a castle tower. The first king writes a message for the second king. When he is finished, he rolls up the scroll, seals it with wax bearing his symbol, and calls for his page. He hands the scroll to the page and asks him to deliver it to the second king.

The page runs down the tower steps and to his horse, onto which he jumps. He rides the horse across the medium (a dirt road in this case), to the second castle. There, he interfaces with the second page and hands him the scroll, asking him to deliver it to his king. The second page runs up the tower steps and hands the scroll to his king, who opens it and reads it.

So, who has communicated? The two kings have communicated, though indirectly, using the services of the pages. And, the two pages have communicated. In fact, they interfaced, with each other directly. This is what is meant by peer-to-peer communication.

Job Description: Physical Layer

This is probably the easiest layer to understand. It’s also easy to see why nothing “higher” can possibly work, if this layer is not in place and functional. If, for example, you pull the cable that connects the printer to the computer, you cannot print (assuming no wireless connection). Some of the functions defined at the Physical Layer are described next.

Media Types

As mentioned earlier, the media creates the path between the devices communicating. Today, there are three media types primarily used in an Ethernet environment. A fourth is described for historical reasons:

• Coax thick and thin – Thick coaxial cable was the original media type used for Ethernet LANs. In fact, technically speaking, only thick coax is a true Ethernet. When Ethernet was standardized, it became IEEE 802.3, which has several variants. So, any of the variants, which came after the original was standardized, are actually 802.3 and not Ethernet. The original thick coax became 802.3 10Base5. Later, when the thinner and cheaper coaxial cable was defined as a standard, it became 802.3 10Base2. It was referred to as thinnet or cheapernet, because it was both. Neither of these two media types are used much any more. Both operate at 10 Mbps.
• UTP – Unshielded twisted-pair (UTP) cable is the most commonly used media type. It is essentially just a higher grade of telephone wire, called Category 5 or Cat 5. There is also a Cat 5e (enhanced) and Cat 6, for higher speed Ethernet LANs. UTP costs less than either coax or fiber, partly because it is installed like telephone cable, which means there is lots of expertise and tools available, and because of its widespread use. Whereas, on coaxial networks, all devices are connected to the network cable, on UTP LANs, all devices have a point-to-point connection to a central device called a hub or a switch. There are variations of 802.3 over UTP that operate at 10 Mbps (10BaseT), 100 Mbps (100BaseT), and 1000 Mbps (1 Gbps, 1000BaseT).
• Fiber – Fiber-optic cable as a medium type brings many advantages, including increased security, lack of susceptibility to electrical noise, and increased distance. And, as always, “The Nicer the Nice...the Higher the Price”. Fiber costs significantly more than other media types, both to purchase and to install. There are variations of 802.3 that operate over fiber at 10 Mbps, 100 Mbps, 1000 Mbps (1 Gbps), and 10 Gbps. A 50 Gbps version is currently being standardized.
• Air – Wireless technologies are starting to take off and the media type for wireless networks is the air. The freedom from cables is the obvious advantage. And, costs are now only slightly higher than wired Ethernet, for the most common type of wireless LAN, 802.11b, which operates at about the same speed as the original Ethernet. The original 802.11 operated at either 1 or 2 Mbps. The newer 802.11b operates at up to 11 Mbps. A couple of newer versions operate at up to 54 Mbps. IEEE 802.11 is not Ethernet, though it is quite similar and interoperates easily, with Ethernet LANs. In fact, it is sometimes called wireless Ethernet.

Other Jobs

The Physical Layer is responsible for several other functions, including the following:

• The voltage level for defining a 1 or a 0.
• The shape of the connector, the number of pins present, what each pin is used for, i.e., to transmit.
• The clock rate, which maps to the speed of the media - Clockrate is typically expressed in bits per second (bps).

Data

Data at the Physical Layer is just bits.

Devices – Repeaters and Hubs

Because the digital signals on a LAN will degenerate over distance (this is called attenuation), it is necessary to strengthen the signal if it needs to travel beyond a certain distance. On coaxial LANs, a device known as a repeater is used. A repeater will take the received signal, and retransmit it, so it is identical to the original signal again. One reason why the old analog networks had such high error rates, as compared to digital networks, is that to strengthen an analog signal, an amplifier was used. Unlike a repeater, an amplifier amplifies any noise present, along with the signal.

When UTP and 10BaseT are used, each device is connected, point-to-point, to a hub, which is also called a multiport repeater. When the hub receives a frame from any connected device, it will repeat it out every port, except the one on which it was received. Just as when everyone was connected to a coaxial cable, all devices connected to the hub are in a single collision domain.

Demo Network

We’re going to create a demo network in this tutorial, for the purpose of demonstrating how a computer data network works. Let’s start by defining the Physical Layer of our network. Imagine that you are seated in one of several rows of chairs...perhaps listening to this presentation. If you were to reach out and grab your neightbor’s hand on each side of you, you would be demonstrating a Physical Layer connection. You could pass a message to your neighbor, using this physical connection. This, remember, is one of the essential elements of networking: A physical path from sender to receiver. If you were sitting at the end of a row, then you could “connect” with the end person in the row just in front or in back of you, with one hand. If we say that each row represents a network, then, you would be acting as a router. We will come back to this idea, AFTER you have learned about routers.

Job Description: Data Link Layer

If the Physical Layer is working properly, then this next layer, the Data Link Layer can perform its jobs, which are described below.

Media Access Control

When there is only a single device at each end of a communication link, there aren’t many rules needed for the communication. However, when there are many devices that must share the media, it becomes more important to have an orderly way of sharing the media, so that everyone gets a chance to transmit. The protocols that define this are called Media Access Control or MAC protocols. Though there are many different MAC protocols. We will focus on the MAC of Ethernet (802.3) and wireless (802.11) networks.

Ethernet/802.3

Though many different 802.3 variants exist, they differ primarily at the Physical Layer and they are all referred to as Ethernet. 10BaseT, 100BaseT, 1000BaseT, 10000BaseT are all called Ethernet, for example. Some have other names, as well, such as Fast Ethernet (100 Mbps) and Gigabit Ethernet (1 Gbps).

Ethernet uses something called contention for media access control. This means that a device will just start transmitting, whenever it has data to send, as long as the media is inactive. That is, nobody else is transmitting.

Only one device can transmit at a time, or a collision will occur. Each device creates a voltage change on the cable when it transmits. If a second transmission is added, this will cause further change on the cable. This is what is meant by a collision. And, the end result is that both frames will be corrupted and will have to be retransmitted. Collisions were a normal occurence on networks with 10BaseT and hubs. As discussed earlier, when there are too many users on the LAN, the network gets slow. That is because the ratio of collisions to successful transmissions goes up and eventually, the network becomes almost useless.

If you remember from earlier, this is why bridges were first introduced — to create multiple collision domains. But, that was when coaxial cable was the normal network medium. With 10BaseT (UTP and hub) networks, switches were added to solve the same problem.

The actual protocol that is used is CSMA/CD — Carrier Sense (always monitor the cable for transmissions), Multiple Access (you can see that part - all devices are connected to the same cable or hub/Collision Detection (this part means to keep monitoring the cable, and, if a collision occurs, follow the collision procedure to deal with it).

If there is more than one device in a collision domain, such as when a hub is used, the receive circuitry must be used to sense for collisions while transmitting, so it is not possible to receive data at the same time. When switches are used and only a single device is attached to each switch port, there is no need to check for collisions, so full-duplex mode can be used.

Wireless LANs/802.11

There are many different types of wireless networks including cellular voice networks, satellite TV and data networks, Personal Area Networks (PANs), and wireless LANs (WLANs). This document will focus on 802.11 WLANs. Though there are several existing and emerging 802.11 standards, only 802.11b will be discussed. WLANs use a contention media access method that is very similar to Ethernet’s. WLANs can operate in one of two modes:

• Ad hoc – This is a peer-to-peer mode, where different devices communicate directly with one another. With only two or three devices total on the WLAN, this is the appropriate choice.
• Infrastructure mode (the default) – In this setup, there is an Access Point (AP) that is physically connected to the wired Ethernet LAN. The access point communicates with the wireless devices and with the devices on the wired LAN. It takes Ethernet frames from the wired LAN and converts them to the wireless frame format and transmits them on the wireless LAN, and vice versa. Wireless devices do not communicate with one another directly, but through the access point. This is the default mode for both access points and NICs.

The currently included security feature is called Wired Equivalent Privacy (WEP). Although, it is better than nothing, the encryption scheme WEP uses is considered easy to break. Additionally, when using WEP, throughput can be reduced significantly, perhaps by as much as 30 %.

Another interesting feature of WLANs is that the speed or bps rate decreases with distance between devices. It is 11 Mbps, almost the same as the original Ethernal LAN, at close distances. As distance increases and the signal weakens, it will be stepped down, first to 5.5 Mbps, then to 2 Mbps, and then to 1 Mbps. There is also more overhead on a wireless LAN, than on an Ethernet LAN.

Addressing

As mentioned earlier, there are many names for the addresses used at this layer, including hardware address and NIC address. In the LAN environment, the most common name is MAC (media access control) address. A unicast MAC address identifies a single device on a network. The same MAC address can be used on multiple networks, but must only appear once on any given network.

A multicast MAC address is for a group of hosts on the network. Perhaps, there is a webcast that can be watched, by double-clicking on a certain web page. All the users that clicked, would receive the multicast data. A broadcast is for every host on the network.

Other Jobs

The Data Link Layer has other functions including detecting transmission errors and, in some cases, tracking frames sent and received.

Data

Data at this layer is called a frame. A frame consists of a header and the Network Layer packet, or datagram, as it is also called. The header consists of Layer 2 addressing information, which has the MAC addresses for this hop of the total path, and some control information. The packet contains the IP addresses at each end of the communication and the upper-layer data.

Devices – Bridges and Switches

Unlike the repeaters and hubs of Layer 1, which repeat a unicast message on every port, the bridges and switches of Layer 2 only repeat it on the port where the destination is. Remember: all ports of a hub are in a single collision domain, but each port of a bridge or switch defines a separate collision domain. However, there is still only a single broadcast domain for all ports. Multicasts and broadcasts are repeated out every port.

Demo Network

Let’s say that each chair in a row has a number associated with it. The number uniquely identifies that chair in the row that it is in, though the same number may also exist in the next row. This number is like a MAC address. It is also called a node, physical, burned-in (BIA), or Layer 2 address.

Some protocols have what is called a handshake: a series of messages that must be exchanged, before data can be sent. This is called a connection-oriented protocol. Shaking the hand of your neighbor and asking permission to send data, before passing the message, would be the equivalent in our network.

Job Description: Network Layer

Unlike the Data Link Layer, the Network Layer goes end-to-end. Whereas the MAC address is local to a single hop of the path, the IP address goes on at the source of the data and is removed only when the packet reaches the destination. Packet delivery is the most important job of the Network Layer.

IP Addressing

Besides the Internet Protocol (IP), there are other Network Layer addresses used, such as Novell NetWare IPX. This document will focus only on IP.

An IP address is hierarchical, like our postal addresses. On the Internet, only the domain is of concern. When the packet reaches the domain, direcway.com, for example, the next level (networks and subnets) will then be looked at, by Direcway's routers, in this case. This is analogous to a letter reaching the United States: only then will the ZIP code, and then the street and house number, be looked at. The packet will be directed towards the correct satellite dish, based on the IP address, much as the letter is directed towards the correct house, based on the address. As in the case of MAC addresses, there are unicast, multicast, and broadcast IP addresses.

A Domain Name Server (DNS) will translate the domain name, such as AlfaZed.com, to the actual IP address, that is used for routing.

Address Resolution Protocol (ARP)

Another important protocol for IP is called the address resolution protocol (ARP). Remember that the IP address goes end-to-end. However, at each hop of the path, a local MAC address must be used. ARP is the way that the router gets the MAC address of the next hop router or of the final destination. Sometimes a PC will also use ARP to get the address of the local router or of the destination, if it is on the same subnet. Sometimes, the PC is configured with a default gateway, which is the address of the local router.

Private Addresses and Network Address Translation (NAT)

At one time, it was believed that not everyone would want to be on the Internet, so a range of IP addresses were set aside as private. Anyone at all can use these addresses. However, these addresses will not be routed on the Internet. Companies that had used private addresses and later wanted to be on the Internet had a problem. That is when network address translation (NAT) was devised.

Private addresses and NAT/NAPT

Theses private addresses can connect to the Internet via something called Network Address Translation (NAT) or NAT with Network Address Port Translation (NAPT). Typically, the NAT server is on the same device as the router/firewall. So, when a private IP address request is headed for the Internet, the NAT server will translate the private address to a unique and non-private IP address, from a pool of addresses that is configured on this server. This IP address is dynamically assigned. When NAT with NAPT is used, a single non-private IP address can server literally thousands of private IP addresses. This has helped ti stretch the lifetime of IP version 4.

With a consumer satellite connection, a static, private IP address is assigned to the subscriber. This is an IP address that is in the private network of the Hughes network operation center (NOC). When you have a request for the Internet, a non-private IPaddress is dynamically assigned to the packet, by the NOC’s NAT server, and the request is forwarded to the Internet. When the reply comes back from the Internet, the NAT server translates the non-private IP address back to the static, private IP address that originally sent the request.

The business service provides a static non-private address, for an extra fee. This costs more, because it permanently assigns one of a limited number of available IP addresses. Whereas the private addresses are virtually inexhaustible, since everyone can use the same ones within their network.

Anyone using Microsoft's Internet Connection Sharing (ICS) is using one of the private IP network addresses: Class C network 192.168.0.0.

DHCP

Dynamic Host Configuration Protocol (DHCP) is a protocol that automatically assigns an IP address to a PC or other host that requests one. The address is not permanently assigned, but can be reused, by a different host later. This also helps to stretch the lifetime of IPv4. Newer Windows operating systems includes DHCP functionality. This is often the easiest approach to setting up a home network. However, in some cases, you must manually assign IP addresses, to the devices on your network.

Devices – Routers

A router is a device that connects networks or subnets. Each port of a router defines not only a collision domain, but also a broadcast domain. A router will not forward multicasts or broadcasts out other ports. A router’s main purpose in life is to forward packets from one subnet to another. The router will look up the destination network for the packet, using a routing information table. In the table for each possible destination network will be information that tells the router where to send the packet next, including the port to use and the IP address of the next hop router. Remember, the router will use ARP to find out what the correct MAC address is for the next router. Then, the router will build a new frame, by adding its own MAC address (as the source) and the MAC address of the next router (as the destination). Then, the packet is transmitted to the next stop.

Demo Network

We have only one path through our simple internetwork. Nonetheless, it will help you to understand how a real network sends data from a source to a destination.

Let’s now imagine that whoever is in Seat 6 on Network 1 has written a message for the person in Seat 12 on Network 2. The message is placed inside a small envelope that says: From: Network 1, Seat 6 and To: Network 2, Seat 12. It is now called a packet and the message inside the packet will not be seen again until it reaches the destination.

Now, let’s put the small envelope inside a larger envelop that is labeled: From Seat 6 to Seat 3, since that is the next local “stop” on the way to the destination. It is now called a frame. Whoever is in Seat 6 now hands the frame to the person in Seat 3. That person takes out the smaller envelope, notes that the final destination is in Network 2, and creates a new frame by putting the packet (small envelope) into a new large envelope and marking it: From Seat 3 to Seat 1. This person now passes the frame to the person in Seat 1. Note that the frame changes at every stop, but the packet does not.

The person in Seat 1, as a router, must know which way to send a packet, when it is for another network (row). Routers have tables with this information. In our example network, the router looks up the destination and learns that it must send the frame to Seat 1 in Network 2. The frame is addressed and passed to the router in Network 2. This forwarding process continues, until the frame finally reaches the person in Seat 12 of Network 2.

This time, when the packet is taken out of the larger frame envelope, the person sitting there recognizes that it is the final destination of the packet. That person then takes the message out of the smaller envelope and reads it. If a reliable protocol is being used, that person would then send an acknowledgement back, indicating the message had been received.

Job Description: Upper Layers

We’re not really too concerned with these layers within the network. These layers functions are more important to the end systems – the PCs that send and receive the data.

Transport Layer

This is the layer that provides end-to-end reliability, at least when Transmission Control Protocol (TCP) is used. TCP just keeps track of what has been sent and what has been acknowledged by the other end. There is another protocol called User Datagram Protocol (UDP), that is also sometimes used. UDP is not reliable. Both TCP and UDP use a port number , to keep track of what application sent the data.

Process Layer

On the Internet, the protocol that comes next contains all other needed functionality and is called the Process or Application Layer. Examples of Process Layer protocols are FTP, Telnet, SMTP, and HTTP. FTP stands for File Transfer Protocol and is used to send and receive files. Telnet is used to connect to another host. SMTP is the protocol used for email. It stands for Simple Mail Transfer Protocol. And, HyperText Transport Protocol (HTTP) is used for web traffic. There are others, as well, but these are the most well-known

Yes, you can receive satellite television on the same dish as your Internet service. This is sometimes called a "bird on a wire" or BOW. But, you cannot always receive the service you want on your Internet dish - it depends on the satellite assignments. The general "rule of thumb" is that you can receive TV on the Internet dish if the television satellite is two degrees from the Internet satellite, or between about 10 and 20 degrees away.

If you have StarBand® Internet service and you subscribe to the Dish Network for TV, there was an attachment available for the Phase II outdoor equipment. However, there is currently no attachment available for the new Phase III equipment.

If you have HughesNet Internet service and you subscribe to DirecTV, there was an attachment available for the Gen V outdoor equipment. However, there is currently no attachment available for the newer Raven or Prodelin antennas.

Okay, now putting it all together, the animation shows how data can flow from one host to another.