What are the characteristics of IP address

IP is connectionless, meaning that no dedicated end-to-end connection is created before data is sent. As shown in Figure 1, connectionless communication is conceptually similar to sending a letter to someone without notifying the recipient in advance.

Índice Show

IP - Best Effort Delivery
IP - Media Independent
IPv4 Packet Header

IP - Best Effort Delivery

The figure illustrates the unreliable or best-effort delivery characteristic of the IP protocol. The IP protocol does not guarantee that all packets that are delivered are, in fact, received.

Unreliable means that IP does not have the capability to manage and recover from undelivered or corrupt packets. This is because while IP packets are sent with information about the location of delivery, they contain no information that can be processed to inform the sender whether delivery was successful. Packets may arrive at the destination corrupted, out of sequence, or not at all. IP provides no capability for packet retransmissions if errors occur.

IP - Media Independent

IP operates independently of the media that carry the data at lower layers of the protocol stack. As shown in the figure, IP packets can be communicated as electronic signals over copper cable, as optical signals over fiber, or wirelessly as radio signals.

It is the responsibility of the OSI data link layer to take an IP packet and prepare it for transmission over the communications medium. This means that the transport of IP packets is not limited to any particular medium.

IPv4 Packet Header

An IPv4 packet header consists of fields containing important information about the packet. These fields contain binary numbers which are examined by the Layer 3 process. The binary values of each field identify various settings of the IP packet. Protocol header diagrams, which are read left to right, and top down, provide a visual to refer to when discussing protocol fields. The IP protocol header diagram in the figure identifies the fields of an IPv4 packet.

Significant fields in the IPv4 header include:

Version - Contains a 4-bit binary value set to 0100 that identifies this as an IP version 4 packet.

Differentiated Services or DiffServ (DS) - Formerly called the Type of Service (ToS) field, the DS field is an 8-bit field used to determine the priority of each packet. The six most significant bits of the DiffServ field is the Differentiated Services Code Point (DSCP) and the last two bits are the Explicit Congestion Notification (ECN) bits.

Time-to-Live (TTL) - Contains an 8-bit binary value that is used to limit the lifetime of a packet. The packet sender sets the initial TTL value, and it is decreased by one each time the packet is processed by a router. If the TTL field decrements to zero, the router discards the packet and sends an Internet Control Message Protocol (ICMP) Time Exceeded message to the source IP address.

Protocol - Field is used to identify the next level protocol. This 8-bit binary value indicates the data payload type that the packet is carrying, which enables the network layer to pass the data to the appropriate upper-layer protocol. Common values include ICMP (1), TCP (6), and UDP (17).

Source IPv4 Address - Contains a 32-bit binary value that represents the source IPv4 address of the packet. The source IPv4 address is always a unicast address.

Destination IPv4 Address - Contains a 32-bit binary value that represents the destination IPv4 address of the packet. The destination IPv4 address is a unicast, multicast, or broadcast address.

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Through the years, IPv4 has been updated to address new challenges. However, even with changes, IPv4 still has three major issues:

IP address depletion - IPv4 has a limited number of unique public IPv4 addresses available. Although there are approximately 4 billion IPv4 addresses, the increasing number of new IP-enabled devices, always-on connections, and the potential growth of less-developed regions have increased the need for more addresses.

Internet routing table expansion - A routing table is used by routers to make best path determinations. As the number of servers connected to the Internet increases, so too does the number of network routes. These IPv4 routes consume a great deal of memory and processor resources on Internet routers.

Lack of end-to-end connectivity - Network Address Translation (NAT) is a technology commonly implemented within IPv4 networks. NAT provides a way for multiple devices to share a single public IPv4 address. However, because the public IPv4 address is shared, the IPv4 address of an internal network host is hidden. This can be problematic for technologies that require end-to-end connectivity.

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In this lesson, we’re going to be talking about the characteristics of the Internet protocol IP.

What is it? IP is a communications protocol whereby a host will have the ability to talk to another host, such as a computer sharing data with another computer.

IP is a communication protocol is within TCP/IP, the IP, is the Internet Protocol that squishes it together.

Characteristics.

For a long time, there was only IP. We call it IPv4 now, but that’s just to distinguish it from IPv6.

The reason why we had to go other characteristics of IP, and if we focus on because there’s so few addresses versus how many people in the need, IPv6 was introduced to drastically increase the availability of IP addresses.

From the OSI Model, we have:

Bits (Layer 1)

Frames (Layer 2)

Packets. (Layer 3)

Packets, are Layer 3 of OSI packets break data down into smaller pieces.

For example, think of Internet Protocol like a steel ball that’s bouncing around inside a pinball game. The steel ball is lost if it doesn’t have a header and it’s payload or that which it carries.

The header information has where it’s from and where it’s going. Inside that header information will be the source IP address, destination IP address, because having only one is not sufficient information.

We can see this information in Wireshark.

This is a capture that’s running, notice at the top of the window it states TCP.

Wireshark will allow you to peer into the bits of your network, notice it says Internet Protocol Version 4.

Header and Payload information – In the header we have source and destination.

If we start to expand this out, it provides a lot of information in here. What version is it, header length protocol.

In this case, it’s TCP. If you have not investigated Wireshark, it is destined to be your best friend as a network admin because you can solve problems. Especially when that argument comes up, like the server team says it’s the network’s fault. The network team says it’s a server fault. You fire up Wireshark and look at information bit by bit, to know whether or not there’s an issue with the network or otherwise.

With TCP selected in Wireshark, we can drop down scroll down ‑‑ look at the level of detail that it can grab.

Wireshark is a free download so go ahead and test it out for yourself.

That serves as a good introduction. By no means, consider yourself a guru yet on the Internet Protocol, but at least we’ve dug into it a little bit more so than at the beginning.

Until next time….

Mark Jacob
Cisco and CompTIA Network + Instructor – Interface Technical Training
Phoenix, AZ

Video Certification Training: CompTIA Network +

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