Internet Domain Properties
This section describes the properties of internet domain.
Characteristics of the Internet domain are:
| Item | Description |
|---|---|
| Socket types and protocols | The SOCK_STREAM socket type is supported by the Internet TCP protocol; the SOCK_DGRAM socket type, by the UDP protocol. Each is layered atop the transport-level IP. The Internet Control Message Protocol (ICMP) is implemented atop or beside IP and is accessible through a raw socket. |
| Naming | Sockets in the Internet domain have names composed of a 32-bit Internet address and a 16-bit port number. Options can be used to provide IP source routing or security options. The 32-bit address is composed of network and host parts; the network part is variable in size and is frequency encoded. The host part can be interpreted optionally as a subnet field plus the host on a subnet; this is enabled by setting a network address mask. |
| Raw access | The Internet domain allows a program with root-user authority access to the raw facilities of IP. These interfaces are modeled as SOCK_RAW sockets. Each raw socket is associated with one IP protocol number and receives all traffic for that protocol. This allows administrative and debugging functions to occur and enables user-level implementations of special-purpose protocols such as inter-gateway routing protocols. |