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What is the purpose of protocol field in IP header?
The protocol field in the IP header is an 8-bit number that defines what protocol is used inside the IP packet. TCP and UDP are only two of the possible protocols that can be filtered on, although they are most common.
Why is version the first field in an IP header?
Version: the first field tells us which IP version we are using, only IPv4 uses this header so you will always find decimal value 4 here. Header Length: this 4 bit field tells us the length of the IP header in 32 bit increments.
Which fields of IP header change from router to router?
When an IPv4 datagram passes through a router, its header checksum must change as a result of decrementing the TTL field.
What is IP header field?
An IP header is header information at the beginning of an Internet Protocol (IP) packet. IP packets consist of a header for addressing and routing, and a payload for user data. The header contains information about IP version, source IP address, destination IP address, time-to-live, etc.
Which field of IP header is used for selecting service?
Figure 3-13 IP Header Type of Service (ToS) Field This new field is called the Differentiated Services Code Point (DSCP). That gives you 64 or 26 possible values that can be used to prioritize traffic.
Which is the first field in the protocol header?
Protocol Version (4 bits) : This is the first field in the protocol header. This field occupies 4 bits. This signifies the current IP protocol version being used. Most common version of IP protocol being used is version 4 while version 6 is out in market and fast gaining popularity.
What are the fields in the IP header?
IP header. Notice the fields in the header: the IP version is IPv4, the header length is 20 bytes, the upper-level protocol used is TCP, the TTL value is set tu 128, source and destination IP addresses are listed, etc.
What does the header do in an IP packet?
IP Packet Header: Format, Fields What is IP header? IP Header is meta information at the beginning of an IP packet. It displays information such as the IP version, the packet’s length, the source, and the destination.
What do the numbers mean in the IPv4 header?
Protocol: This IPv4 header is reserved to denote that internet protocol is used in the latter portion of the Datagram. For Example, 6 number digit is mostly used to indicate TCP, and 17 is used to denote the UDP protocol. Header Checksum: The next component is a 16 bits header checksum field, which is used to check the header for any errors.