Ip Address
Configuring IP
The Internet Protocol (IP) is the only routed protocol that is turned on by default on a Cisco router running IOS. The acronym IP is actually an abbreviated way of writing TCP/IP (Transmission Control Protocol/Internet Protocol), which is the suite of protocols and applications used on the Internet and many private internetworks.
We are going to begin the coverage of IP configuration with a brief overview of IP and how IOS processes its traffic. Then we will delve into the configuration itself and make some modifications to the internetwork that we built in Chapter 3. The only version of IP covered in this book is IP version 4.
IP Addressing
All hosts that run IP must have a unique IP address. An IP address is a logical address that is independent of a host’s hardware. IP addressing is perhaps the most mystifying part of IP for people who are new to the networking world; however, it really is very simple. To understand, you just need to use a little bit of binary (base 2) arithmetic and decimal (base 10) arithmetic.
IP addresses are 32 bits long, and the normal way of writing them is called dotted-decimal notation. To write an address in dotted-decimal notation, we divide the 32 bits of the address into four 8-bit chunks. Each 8-bit chunk is called an octet or a byte. We then convert the octets from binary to decimal and put dots (.) between them. Figure 7-1 shows four forms of the same IP host address.
<<<J115 – Figure 7-1 IP Address Notations>>>
The first form in Figure 7-1 is normal binary, just a string of 32 ones and zeros; each one and zero is a bit. This form is difficult for people to read, but it is what a computer, like a router, sees. The decimal representation of the binary address has a rather large value; 32 bits can represent decimal numbers between 0 and 4,294,967,295. The second line is the decimal equivalent of the first line. How would you like to read a number like that every time you wanted to communicate a
The Internet Protocol (IP) is the only routed protocol that is turned on by default on a Cisco router running IOS. The acronym IP is actually an abbreviated way of writing TCP/IP (Transmission Control Protocol/Internet Protocol), which is the suite of protocols and applications used on the Internet and many private internetworks.
We are going to begin the coverage of IP configuration with a brief overview of IP and how IOS processes its traffic. Then we will delve into the configuration itself and make some modifications to the internetwork that we built in Chapter 3. The only version of IP covered in this book is IP version 4.
IP Addressing
All hosts that run IP must have a unique IP address. An IP address is a logical address that is independent of a host’s hardware. IP addressing is perhaps the most mystifying part of IP for people who are new to the networking world; however, it really is very simple. To understand, you just need to use a little bit of binary (base 2) arithmetic and decimal (base 10) arithmetic.
IP addresses are 32 bits long, and the normal way of writing them is called dotted-decimal notation. To write an address in dotted-decimal notation, we divide the 32 bits of the address into four 8-bit chunks. Each 8-bit chunk is called an octet or a byte. We then convert the octets from binary to decimal and put dots (.) between them. Figure 7-1 shows four forms of the same IP host address.
<<<J115 – Figure 7-1 IP Address Notations>>>
The first form in Figure 7-1 is normal binary, just a string of 32 ones and zeros; each one and zero is a bit. This form is difficult for people to read, but it is what a computer, like a router, sees. The decimal representation of the binary address has a rather large value; 32 bits can represent decimal numbers between 0 and 4,294,967,295. The second line is the decimal equivalent of the first line. How would you like to read a number like that every time you wanted to communicate a