IP addresses are unique identifiers for devices connected to a network. They allow information to be specifically routed to the intended destination similar to mailing addresses. There are two main IP address standards, IPv4 and IPv6, with IPv6 addressing anticipated space limitations of IPv4 by expanding the number of available addresses. IP addresses can be static, configured manually, or dynamic, assigned automatically by a DHCP server.

1. Jesús Adrián Suarez López
2014-Febrero-18
What is an IP?
Every machine on a network has a unique identifier. Just as you would address a letter
to send in the mail, computers use the unique identifier to send data to specific computers on a
network. Most networks today, including all computers on the Internet, use the TCP/IP protocol
as the standard for how to communicate on the network. In the TCP/IP protocol, the unique
identifier for a computer is called its IP address.
There are two standards for IP addresses: IP Version 4 (IPv4) and IP Version 6 (IPv6). All
computers with IP addresses have an IPv4 address, and many are starting to use the new IPv6
address system as well. Here's what these two address types mean:
 IPv4 uses 32 binary bits to create a single unique address on the network. An IPv4 address is
expressed by four numbers separated by dots. Each number is the decimal (base-10)
representation for an eight-digit binary (base-2) number, also called an octet. For example:
216.27.61.137
 IPv6 uses 128 binary bits to create a single unique address on the network. An IPv6 address is
expressed by eight groups of hexadecimal (base-16) numbers separated by colons, as in
2001:cdba:0000:0000:0000:0000:3257:9652. Groups of numbers that contain all zeros are
often omitted to save space, leaving a colon separator to mark the gap (as in 2001:cdba::
3257:9652).
At the dawn of IPv4 addressing, the Internet was not the large commercial sensation it is today,
and most networks were private and closed off from other networks around the world. When
the Internet exploded, having only 32 bits to identify a unique Internet address caused people
to panic that we'd run out of IP addresses. Under IPv4, there are 232 possible combinations,
which offer just fewer than 4.3 billion unique addresses. IPv6 raised that to a panic-relieving
2128 possible addresses. Later, we'll take a closer look at how to understand your computer's
IPv4 or IPv6 addresses.
How does your computer get its IP address? An IP address can be either dynamic or static. A
static address is one that you configure yourself by editing your computer's network settings.
This type of address is rare, and it can create network issues if you use it without a good
understanding of TCP/IP. Dynamic addresses are the most common. They're assigned by the
Dynamic Host Configuration Protocol (DHCP), a service running on the network. DHCP typically
runs on network hardware such as routers or dedicated DHCP servers.
Dynamic IP addresses are issued using a leasing system, meaning that the IP address is only
active for a limited time. If the lease expires, the computer will automatically request a new
lease. Sometimes, this means the computer will get a new IP address, too, especially if the

2. computer was unplugged from the network between leases. This process is usually transparent
to the user unless the computer warns about an IP address conflict on the network (two
computers with the same IP address). An address conflict is rare, and today's technology
typically fixes the problem automatically.
Conclusion: IP addresses are like house addresses, but for computers and networks to
allow such mentioned networks to function at optimal speeds. If IP addresses were not in place
it would be as if you and your neighbor had the exact same address and when the mail man
came along to deliver a letter or someone came to visit, it would be confusing to be able to
decipher which house is yours. The same thing can be applied for networks as they allow for a
system of identification to be able to know which network is which and take the information
requested or sent to the network it is meant to go to. I learned about the IPv4 and IPv6 IP
addresses that are very similar, but IPv6 addresses are like a step up from the IPv4 addresses as
they allow for more variety of network identifiers. As time moves forward and technology
becomes more and more the standard, we may see that they come up with a new version of IP
like they did with the IPv6; maybe IPv8?
What is a Subnet?
Definition: A subnet is a logical grouping of connected network devices. Nodes on a
subnet tend to be located in close physical proximity to each other on a LAN.
Network designers employ subnets as a way to partition networks into logical segments for
greater ease of administration. When subnets are properly implemented, both the
performance and security of networks can be improved.
In Internet Protocol (IP) networking, devices on a subnet share contiguous ranges of IP address
numbers. A mask (known as the subnet mask or network mask) defines the boundaries of an IP
subnet. The correspondence between subnet masks and IP address ranges follows defined
mathematical formulas. IT professionals use subnet calculators to map between masks and
addresses.
A subnetwork, or subnet, is a logically visible subdivision of an IP network. The practice of
dividing a network into two or more networks is called subnetting.
All computers that belong to a subnet are addressed with a common, identical, most-significant
bit-group in their IP address. This results in the logical division of an IP address into two fields, a
network or routing prefix and the rest field or host identifier. The rest field is an identifier for a
specific host or network interface.

3. The routing prefix is expressed in CIDR notation. It is written as the first address of a network,
followed by a slash character (/), and ending with the bit-length of the prefix. For example,
192.168.1.0/24 is the prefix of the Internet Protocol Version 4 network starting at the given
address, having 24 bits allocated for the network prefix, and the remaining 8 bits reserved for
host addressing. The IPv6 address specification 2001:db8::/32 is a large address block with
296
addresses, having a 32-bit routing prefix. In IPv4 the routing prefix is also specified in the
form of the subnet mask, which is expressed in quad-dotted decimal representation like an
address. For example, 255.255.255.0 is the network mask for the 192.168.1.0/24 prefix. Traffic
between subnetworks is exchanged or routed with special gateways called routers which
constitute the logical or physical boundaries between the subnets.
The benefits of subnetting vary with each deployment scenario. In the address allocation
architecture of the Internet using Classless Inter-Domain Routing (CIDR) and in large
organizations, it is necessary to allocate address space efficiently. It may also enhance routing
efficiency, or have advantages in network management when subnetworks are administratively
controlled by different entities in a larger organization. Subnets may be arranged logically in a
hierarchical architecture, partitioning an organization's network address space into a tree-like
routing structure.
Conclusion: Subnets, like IP addresses, allow for networks to be divided and
identifiable, they allow for information to flow through the correct network and reach the
correct user. Subnets are subdivisions of IP addresses allow IP addresses to span more and
more networks without the need to use different IP addresses. I learned by reading this that IP
addresses can be divided into smaller segments to optimize the network identification and to
make it so the network is 100% unique so that there is never any kind of confusion.
What is a Gateway?
In computer networking, a gateway is a node on a TCP/IP network that serves as an
access point to another network. A default gateway is the node on the computer network that
the network software uses when an IP address does not match any other routes in the routing
table. It is usually the IP address of the router to which your PC network is connected.
In home computing configurations, an ISP often provides a physical device which both connects
local hardware to the Internet and serves as a gateway. Such devices include DSL
routers and cable routers.
In organizational systems a gateway is a node that routes the traffic from a workstation to
another network segment. The default gateway commonly connects the internal networks and
the outside network. In such a situation, the gateway node could also act as a proxy server and
a firewall. The gateway is also associated with both a router, which uses headers
and forwarding tables to determine where packets are sent, and a switch, which provides the

4. actual path for the packet in and out of the gateway. In other words, a default gateway
provides an entry point and an exit point in a network.
A gateway is a node that allows you to gain entrance into a network and vice versa. On the
Internet the node which is the stopping point can be a gateway or a host node. A computer that
controls the traffic your network or your ISP (Internet Service Provider) receives is a node. In
most homes a gateway is the device provided by the Internet Service Provider that connects
users to the internet.
When a computer server serves as a Gateway node, the gateway node also operates as a
firewall and a proxy server. A firewall is a system created to prevent unauthorized admission
into a private network. A proxy server is located right between a client application such as a
web browser and the real server. The proxy server sees if the client applications requests can
be carried out by the real server.
Usually a gateway is associated with a router. So a gateway is one of the many ways we can
communicate over the World Wide Web. The gateway allows us to enter different networks on
the internet so we can transmit data back and forth. There's also software available where you
can be able to run several networks on a computer. As you have come to see by now having a
gateway on your computer has its many benefits.
Conclusion: As the name states, a gateway is an actual “gateway” between networks,
an input/output door between the information coming in and going out. This allows for a more
effective transfer of data between connected networks. I learned that you can connect
networks via a gateway to allow faster transfer rates and a more effective transfer rate so that
the information needed to be transferred between the networks can be done so in a facilitated
fashion.
What are the Basic Functions of a Router?
A router is a device or sometimes computer software that lets you know the next
network data should be sent to next. A router can be connected to two or more networks at a
time; it decides the next destination of the data based on its comprehension of the condition of
the networks. A gateway is associated with a router because a router which uses headers and
forwarding tables to figure out where packets or data is sent provides the path through which
information is sent in and out a gateway.
The main function of a router is to enable the movement of data by a device from one network
to another. A router is actually a specialized computer connected to one or more networks.
The function of a router is to manage the paths along which information is forwarded within a
network. They are necessary to facilitate communication between computers and the Internet.

5. Internet data is transferred through the TCP/IP networking protocols that are designed to
communicate data. When it is transmitted, the data is split into fragments called packets. A
router is designed to direct these packets to the correct destination along the best possible
route, hence the name, router.
Routers range in size from the small ones we have in our homes and that are available from
computer shops and from Internet Service Providers, to absolutely huge models that manage
huge flows of data between computer networks and throughout the Internet. The smaller,
home-based models make it possible to share one Internet connection between a few
computers on the network, and this enables more than one person to use it, whereas the larger
ones are far more intricate and have many multi-function routing devices.
Routers come in two basic types: Dynamic and static. The dynamic comes already programmed
to manage data traffic across the network, which is managed by a routing protocol, whereas a
static router needs to be manually configured by a network administrator who programs all of
the necessary routes that are needed for data packets.
Essential services and utilities can be integrated into a network so that it is more secure and
responds more efficiently. For example, a router can be made to incorporate a security feature
such as a firewall for added protection against viruses and other viruses that have the ability to
destroy computers and enable hackers to gather our personal information. It is also possible to
increase network function by integrating services such as IP voice, or video capability.
Conclusion: A router takes data given to it and routes it to the correct place that it
needs to go. This device allows networks to be connected in an extremely effective fashion as it
allows information to be transferred to the correct place through the router. This device highly
optimized the transfer of data between networks and the computers receiving the data or vice
versa. I learned that routers greatly speed up transfer speeds just like gateways and subnets
and all of them together make for the extremely fast internet and network speeds we have now
in actuality.