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What is in an IP header?
Each IP packet contains both a header (20 or 24 bytes long) and data (variable length). The header includes the IP addresses of the source and destination, plus other fields that help to route the packet. The data is the actual content, such as a string of letters or part of a webpage.
What field in the IP header is responsible for preventing a packet from endlessly looping through a network?
TTL field
Each router that receives a packet as it is forwarded towards its destination will reduce the value of the TTL field by ‘1’. If a router receives a packet with a TTL value of ‘1’, it will discard the packet. This protects the Internet from endlessly forwarding packets that have become stuck in a loop.
Which of the following are contained within each IP packet header?
The header contains information about IP version, source IP address, destination IP address, time-to-live, etc. The payload of an IP packet is typically a datagram or segment of the higher-level transport layer protocol, but may be data for an internet layer (e.g., ICMP or ICMPv6) or link layer (e.g., OSPF) instead.
What is the value of the protocol field in the IP header?
The Protocol field in the IPv4 header contains a number indicating the type of data found in the payload portion of the datagram. The most common values are 17 (for UDP) and 6 (for TCP). This field provides a demultiplexing feature so that the IP protocol can be used to carry payloads of more than one protocol type.
Is an IP address ending in 0 valid?
in general statement ‘IP addresses ending in . 0 or . 255 is invalid’ is false.
Which fields can be changed in IP header?
This is header information which is a prefix to an IP packet. An IP header contains information about the IP address of the source, IP address of the destination, IP version, header length, service type, time to live (TTL), protocols and header checksum etc.
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.
Where does IP consider the packet to be?
At the next layer, the Internet layer, IP considers the entire packet (consisting now of the TCP or UDP header and the data) to be data and now attaches its own IP header. Finally, at the network access layer, Ethernet or another network protocol considers the entire IP packet passed to it to be data and attaches its own header.
What is the maximum length of an IP header?
Header Length(4 bits) : This field provides the length of the IP header. The length of the header is represented in 32 bit words. This length also includes IP options (if any). Since this field is of 4 bits so the maximum header length allowed is 60 bytes.
What is the fragment offset in IP protocol?
Fragment offset (13 bits): In case of fragmented IP data grams, this field contains the offset ( in terms of 8 bytes units) from the start of IP datagram. So again, this field is used in reassembly of fragmented IP datagrams. Time to live (8 bits) : This value represents number of hops that the IP datagram will go through before being discarded.