Packets and Protocols

1. Packet Life

2. Protocols

3. WireShark



Ethernet is a family of computer networking technologies for local area networks(LANs). Ethernet was commercially introduced in 1980 and standardized in 1983 as IEEE 802.3. Ethernet has largely replaced competing wired LAN technologies such as token ring,FDDI, and ARCNET.

The Ethernet standards comprise several wiring and signaling variants of the OSI physical layer in use with Ethernet. The original 10BASE5 Ethernet used coaxial cable as a shared medium. Later the coaxial cables were replaced with twisted pair and fiber optic links in conjunction with hubs or switches. Data rates were periodically increased from the original 10 megabits per second to 100 gigabits per second.

Getting Trained

Embedded Linux and Android System Development

1. Free Electrons –  Embedded Linux Experts

Free Electrons, believe in the usefulness and strong potential of embedded Linux, free and open-source software and open standards in embedded systems and mobile devices. Strongly committed to free software, by releasing all our training materials under a free documentation license and by contributing to free software projects (Linux kernel, Buildroot, QEMU, etc.).

1.a Linux courses

1.b Android courses

2. Useful Links

Network and Networking

1. MRTG –  The Multi Router Traffic Grapher

The Multi Router Traffic Grapher, or just simply MRTG, is free software for monitoring and measuring the traffic load on network links. It allows the user to see traffic load on a network over time in graphical form.

2.  Graphical Network Simulator – GNS3

GNS3, the Graphical Network Simulator. Run Cisco, Juniper and open-source virtual networks on your PC!

Packet/Traffic Generator and Analyzers

1. Ostinato is an open-source, cross-platform network packet crafter/traffic generator and analyzer with a friendly GUI. Craft and send packets of several streams with different protocols at different rates.

2. Wireshark is a free and open-source packet analyzer. It is used for network troubleshooting, analysis, software and communications protocol development, and education. Originally named Ethereal. Wireshark is a network packet analyzer. A network packet analyzer will try to capture network packets and tries to display that packet data as detailed as possible. You could think of a network packet analyzer as a measuring device used to examine what’s going on inside a network cable, just like a voltmeter is used by an electrician to examine what’s going on inside an electric cable (but at a higher level, of course). In the past, such tools were either very expensive, proprietary, or both. However, with the advent of Wireshark, all that has changed. Wireshark is perhaps one of the best open source packet analyzers available today.

3.a WinPcap is the industry-standard tool for link-layer network access in Windows environments: it allows applications to capture and transmit network packets bypassing the protocol stack, and has additional useful features, including kernel-level packet filtering, a network statistics engine and support for remotepacket capture.

3.b WinPcap Developer’s Pack

The TCP/IP Guide

The TCP/IP Guide

A Comprehensive, Illustrated Internet Protocols Reference
by Charles M. Kozierok, No Starch Press, 2005

The TCP/IP Guide is a reference resource on the TCP/IP protocol suite that was designed to be not only comprehensive, but comprehensible. Organized using a logical, hierarchical structure, The TCP/IP Guide uses a personal, easy-going writing style that lets anyone understand the technologies that run the Internet. The Guide explains dozens of protocols and technologies in over 1,500 pages. The book’s personal, user-friendly writing style lets readers of all levels understand the dozens of protocols and technologies that run the Internet, with full coverage of PPP, ARP, IP, IPv6, IP NAT, IPSec, Mobile IP, ICMP, RIP, BGP, TCP, UDP, DNS, DHCP, SNMP, FTP, SMTP, NNTP, HTTP, Telnet and much more.

From Charles M. Kozierok, the creator of the highly regarded, comes The TCP/IP Guide. This completely up-to-date, encyclopedic reference on the TCP/IP protocol suite will appeal to newcomers and the seasoned professional alike. Kozierok details the core protocols that make TCP/IP internetworks function and the most important classic TCP/IP applications, integrating IPv6 coverage throughout. Over 350 illustrations and hundreds of tables help to explain the finer points of this complex topic.

The TCP/IP Guide is a must-have addition to the libraries of internetworking students, educators, networking professionals, and those working toward certification.


Convert IP Multicast Address to Multicast MAC Address

To start, we can pick any address from the 32 IP addresses we converted above. Let’s pick a random one like

1. First convert the address to binary:

11100011 : 10001010 : 00000000 : 00000001
We’re only concerned with the red colored portion which represents the low-order 23bits of the IP address.
Notice that we are dropping the high order bit of the second octet.

2. Convert those 23 bits to hexadecimal: 


3. We already know that the first 3-bytes (24 bits) of the MAC address is 01:00:5E. This was established earlier in the article. Simply append the result on step 2 to the first 3-bytes and you have your MAC address: 

*You can pick any of the 32 Ip addresses we have on the list above and you will always get 01:00:5E:0A:00:01 as your MAC address following the steps just mentioned.