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A network ID, in the world of Transmission Control Protocol/Internet Protocol or TCP/IP, is the portion of the TCP/IP address which identifies the network for a given host, usually composed of three octets with dotted decimal representation.
The term “network ID” can also be applied in different ways to local network resources, for user authentication, but the classic use of the term relates to the TCP/IP address itself, how that is used to route information, and how it is used in the context of modern cybersecurity.
A network ID is also known as network identification or NetID.
In TCP/IP address syntax and protocol, an address is composed of four octets that are decimal-represented, instead of represented to end users in binary form. The fourth or last octet is designated to identify the host. The preceding octets, typically, are meant to designate the network.
In the early days of the Internet and IPv4 syntax, a classful network system divided network IDs into three major classes, classes A, B, and C.
Class A networks were large commercial networks.
Class B networks were the types of networks associated with institutional users, for example, government departments or large not-for-profit stakeholders.
Class C networks were for smaller administrated networks. A class D was related to multicast networks.
After changes to the addressing system, the traditional classful network system has been seen as obsolete for some time; however, experts show how some network administrators still “trade” or utilize class A network addresses or otherwise deal with the infrastructure set up by the initial build of the IPv4 system, in which the attribution of networks has to do with representing a class of network in one of the octets of the network ID itself.
So while the original type of network ID might not be necessary anymore, evidence indicates these designations are still being used in some manner.
As the Internet grew, TCP/IP addressing began to encounter a strain in terms of addressable spaces. A new IPv6 system creates a new syntax for assigning a larger number of network IDs. Where the IPv4 addresses had a 32-bit size, IPv4 offers a 128-bit size.
Another big change is that IPv4 systems addresses used a subnet mask to implement a network and IP address. With IPv6, the subnet address is built-in, so a subnet mask is not necessary.
In a very basic sense, the network ID will always exist. It just changes in how it defines a network. Tomorrow’s network ID might not be comprised of four octets at all: that has to do with how WWW like the IETF make policy. Also, experts and others may often talk about a “network ID” differently, either as a user designation: “what’s your network ID?” or a system password or ID.
The technical aspect of a TCP/IP network ID, on the other hand, is still part of the infrastructure that makes up the Internet, a global construct that is still growing and maturing. That makes the consideration of traditional TCP/IP (including network IDs) important as we move forward.