The Internet Protocol is the principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet. IP has the task of delivering packets from the source host to the destination host solely based on the IP addresses in the packet headers.
Watch the Video lectures on IPv4 (click the following links)
IPv4 Header Checksum and its calculation
Expertvision 
Hi everyone,
I have question related to topic Datagram framgentation.
In video lecture, in service type (8bits) block => 6 blocks are represents for codepoint and 2 others unused, so my question is, why in category 1 of codepoint it’s possible to define 24 services, where from 5 bits we can define 2^5 = 32 services?
Out of 8 bits defined for field ‘service type’, 2 bits are not defined and only 6 are defined.
in category 1, one bit is fixed (last bit 0), that means with remaining 5 bits, you will have 2^5 = 32 services.,
Also have Precedence interpretation which is defined using last 3 bits, in which last 3 bits are set to 0. In this case with remaining 3 bits we can define 2^3 = 8 combinations.
Therefore, out of total 32 services,actually 8 are already defined for Precedence Interpretation.
This means that actual services available for 1st category will be 32 – 8 = 24 services.