TCPIP Packet Format
This tutorial covers everything one like to know about networking basics including circuit switching vs packet switching, TCP/IP protocol fields, ARP/RARP protocol fields, what is IP address ,what is MAC address, networking devices which include hub, switch, bridge, router, gateway and firewall. This page covers This page covers TCPIP packet including fields in Ethernet header,IP header and TCP header.
• Circuit Switching vs Packet switching
• LAN vs WAN vs MAN
• What is an IP address
• What is MAC Address
• Basics of OSI and TCP-IP Layers
• What is Hub
• What is Switch
• What is Bridge
• What is Router
• What is Gateway
• Firewall basics
• TCP-IP Packet format
• ARP Protocol format
| No. of bytes | Field type | Description | Header type |
| 1-6 | DA | Destination address | Ethernet Header |
| 7-12 | SA | Source Address | Ethernet Header |
| 13-14 | Type | Type Field 0x800- IP 0x806 ARP |
Ethernet Header |
| 15 | Ver | Ver=4, No. of 4 byte words in the header | IP header |
| 16 | Type | Type of Service(typically 0) | IP header |
| 17-18 | T-len | Total length of packet in bytes including IP header |
IP header |
| 19-20 | ID | Unique Identification of packet | IP header |
| 21 | Flags | 3 bits (0-DF-MF) DF=0 May fragment,MF=0 last fragment |
IP header |
| 21-22 | Offset | Fragment offset in 64 bit blocks | IP header |
| 23 | TTL | Time to live | IP header |
| 24 | Protocol | Upper layer protocol carried in data(TCP/UDP) |
IP header |
| 25-26 | Checksum | Checksum of the header | IP header |
| 27-30 | IP SA | IP source address | IP header |
| 31-34 | IP DA | IP destination address | IP header |
| 35-36 | S-port | Source port | TCP header |
| 37-38 | D-port | destination port | TCP header |
| 39-42 | Seq. Num. | Sequence Number | TCP header |
| 43-46 | ACK | Acknowledgement number | TCP header |
| 47 | Len | 4 bit size of TCP header in 4 byte words |
TCP header |
| 47-48 | Reserved | 6 bits not used | TCP header |
| 48 | Flags | UAPRSF(U=Urgent,A=Ack,P=Push, R=Reset,S=Sync,F=Fin) |
TCP header |
| 49-50 | Window | TCP Window(for flow control) | TCP header |
| 51-52 | Checksum | Checksum for header and data | TCP header |
| 53-54 | Urgent | Urgent pointer | TCP header |
| 55 to N | DATA | TCP Data | Data Payload part |
| N+1 | FCS | CRC(4 byte) | Ethernet Header |
Networking related links
What is Bridge
What is Router
What is Gateway
Firewall basics
TCP-IP Packet format
Difference between OSI and TCPIP layers
Difference between TCP UDP
RF and Wireless tutorials
WLAN 802.11ac 802.11ad wimax Zigbee z-wave GSM LTE UMTS Bluetooth UWB IoT satellite Antenna RADAR