Cisco Computer Networking

Conversion of Decimal IP Address 100.235.2.2 to Binary   First Octet Second Octet Third Octet Fourth Octet Decimal octet 100 235 2 2 Each octet converted to binary (Step 1) 1100100 11101011 10 10 Binary octets, after putting 0s in front (Step 2) 01100100 11101011 00000010 00000010 Resulting 32-bit number (Step 3) 01100100111010110000001000000010 Table B-15 begins with the decimal IP address in ... [full story]

Converting 10101101 to Decimal: Multiplying Each Column and Then Adding Them Together Value associated with that digit or column 128 64 32 16 8 4 2 1 The number itself 1 0 1 0 1 1 0 1 Product of two numbers in the same column 128 0 32 0 8 4 0 1 Sum of all numbers in third row 173 The process is indeed simple, as long ... [full story]

Converting Between Binary and Decimal Numbers You read earlier in this appendix that binary was simply a different way to write numbers as compared to decimal. In some cases, it's easier to work with one format or the other. However, you ... [full story]

Converting Binary IP Addresses to Decimal IP Addresses To convert from a binary IP address to its decimal equivalent, you already know the 32-bit IP address. The process is rather simple compared to converting from decimal to binary: Step 1. Separate the 32 ... [full story]

Converting Decimal IP Addresses to Binary IP Addresses You have already read about the math behind the conversion process between decimal and binary. To convert IP addresses, you simply need to follow a few additional rules: 1. When converting from a decimal ... [full story]

Converting from Binary to Decimal Converting from binary to decimal is actually pretty straightforward, at least compared to converting from decimal to binary. In fact, you've already seen the math in the text after Table B-2. To convert a binary number ... [full story]

Converting from Decimal to Binary Converting from decimal to binary doesn't take any difficult math, but the algorithm is a little longer. In this section, you'll read about a general algorithm for converting from decimal to binary, followed by a couple ... [full story]

Converting IP Addresses IP addresses are 32-bit binary numbers, but because humans would find it inconvenient to write down 32-bit numbers, the addresses are written in decimal. The format of decimal IP addresses is often called canonical format, and sometimes called ... [full story]

Figure 8-12. Copying Inventory (Files) from the FTP Warehouse Conner repeats the same basic steps as Keith had in Figure 8-11. However, instead of issuing a PUT command, Conner issues a GET command. In FTP lingo, PUT means to copy ... [full story]

Copying myproject.doc Between Barney and Fred Fred and Barney together do a little dance called the file transfer two-step, as numbered in the figure: 1. Fred places a copy of the file onto a file transfer server, using file transfer client ... [full story]

Deciding When to Stop the Traffic Based on the facts in this short section, a firewall can look at a packet, figure out who's the initiator (client) of the connection, and determine which protocol (well-known port) is being used. Knowing those ... [full story]

Deciding Where to Go Next Routers perform routing by looking at the destination IP address of the IP packet. The term routing refers to the process by which a router examines a recently received packet, looks at the destination IP address, ... [full story]

Decimal and Binary Numbering Systems This section starts with a description of the familiar decimal numbering system, followed by the binary numbering system. [full story]

Decimal Numbering System The decimal numbering system should be familiar to everyone reading this book, because it's what you've been taught since early childhood. However, unless you love math, there are a few details that you might have forgotten about decimals ... [full story]

Decimal Numbering: 1s, 10s, and 100s Digits Value Associated with That Digit or Column 100 10 1 The digits 2 3 5 With decimal numbering, the right-most digit in a number represents a value of that digit times 1; the second from the right represents the value of ... [full story]

Decimal Powers of 2 Power of 2 Decimal Value 20 1 21 2 22 4 23 8 24 16 25 32 26 64 27 128 28 256 [full story]

Decision Process with Local Subnet Destinations [View full size image] Hosts do not always send packets to their default gateway. Instead, they start by asking a simple question: "Is the destination address of this packet in the same subnet that I ... [full story]

DECnet Emulating SNA Using a Gateway DEC created a DEC-to-SNA gateway, which allowed the DEC and IBM SNA devices to talk. The term gateway refers to a wide variety of networking devices that generally convert from one standard to another. ... [full story]

Chapter 10. Delivering the Goods to the Right Street (IP) Address What You Will Learn After reading this chapter, you should be able to Explain the basic process of routing an IP packet from one computer to another Describe the structure of IP addresses Describe ... [full story]

Delivering the Package to the Right Person, Not Just the Right Address When you ship a package, you not only put the address on the shipping label, but you put the name of the person to whom the package is intended. ... [full story]

Figure 9-6. Delivery Confirmation, No Errors In Figure 9-6, TCP confirms delivery of each segment using the sequence and acknowledgment number fields. However, the acknowledgment number looks a little funny. Wilma numbered the segments 1, 2, and 3, but notice ... [full story]

Differences Between a Cross-Over Cable and a Leased Circuit If you install an Ethernet cross-over cable between two routers and plug the cable into some type of Ethernet interface on the routers, the two routers can forward Ethernet frames to each ... [full story]

Different Names for WAN Link Term Rationale Leased circuit In telco lingo, when you pick up the phone and make a voice call, the telco sets up a temporary circuit. When a customer pays money to have a permanently up circuit between two sites, ... [full story]

Different Types of Traditional Computer Networks So far, you have seen only one simple network with just a few computers. Of course, networks come in many shapes and sizes. So, it is useful to think ... [full story]

Dirt Roads Versus the DOT You can spend a long time working around or in the networking arena and not ever need to worry about how structured cabling works. This section gives you a brief glimpse into the world of structured ... [full story]

Disallowing a TCP Connection to an Inside Web Server [View full size image] The firewall's rules, shown at the bottom of the figure, tell it two types of connections that can be initiated from the outside to the inside. This new ... [full story]

DNS Request Is Made, but DNS Server Doesn't Know the Name [View full size image] The key to understanding the problem and its solution is to know that a DNS server only knows about some of the names and addresses. For ... [full story]

Double Your Speed at No Cost By the way, you can send at full speed in both directions on a WAN linka feature called full duplex. As a result, you could argue that you get twice as much bandwidth. Talk about ... [full story]

Downloading and Transferring Files The final end user application covered here is a broad topic area, but with one central theme: moving files into and out of your computer using a network. In most cases, the end user does not have ... [full story]

Dr. Analog Voice and Mr. Hiding Digital Dr. Jekyll and Mr. Hyde had a serious split personality issue in the classic book by Robert Louis Stevenson. Dr. Jekyll used advanced chemistry to create the split. DSL creates a split personality of ... [full story]

Driving Bits Across a Wire To send one binary code from one device to another, the sending device puts some electricity on the wire. Electrical signals have many characteristics that a NIC can control and vary. By varying one of these ... [full story]

Driving Bits Across the Network Roadway I just got back from lunch at one of my favorite lunch places: La Frontera Mex-Mex Grill. When it was time for lunch, I got in my car, drove to the restaurant, ordered my usualnumero ... [full story]