Web Caching and Replication

2.2. IP Datagram Header

The Internet Protocol was designed to be as simple as possible. The reason for this approach is to allow many hosts and existing networks to participate in the Internet with minimal effort. The consequence, however, is that the IP protocol guarantees neither in-order delivery of multiple datagrams nor the delivery of datagrams at all. The only guarantee it provides is that all parties involved will make their best effort to deliver the datagram.

What IP does support is datagram fragmentation, which is necessary to transfer IP datagrams over different physical networks with different maximum datagram sizes. For example, consider a router connected to two physical networks with maximum datagram sizes of 1500Bytes and 512Bytes. ...