Datagram is UDP that is connectionless,best effort-delivery protocol which means it sends data and doesnot take responsibility for the data's integrity.But,it is useful when large number of data has to be sent.
Kritika Raj
Only the Network Layer (Layer 3) portion of the datagram is used by the Network Layer (Layer 3) portion of the TCP/IP Model. The network portion of the datagram includes IP Addressing information, and things such as TTL (Time to Live), and Datagram Priority markings.
datagram is used in conectionless n/w e.g. UDP Whereas packets used in connection oriented n/w e.g. ATM X.25 tcp
datagram subnet is connection oriented network.
Total number of bytes in the datagram, including the header.The length of an IP datagram itself is technically measured in bytes. The length field represents the size of both the header and the data portions of the datagram.
IP Datagram
The datagram length field in an IP header is 16 bits in length. Therefore, the maximum datagram size an IP datagram can support is 2^16 - 1 = 65,535 bytes
It uses something called a checksum to verify datagram integrity
When a client wishes to send a UDP datagram there is nothing that they are required to except to send it. The datagram will use a checksum to verify the integrity of the datagram and deliver it where it needs to go.
DiffServ
Answer B DiffServ Page 831
Differentiated Services Field
The Differentiated Services Field.