IP Classes, Broadcast, and Multicast (What They Mean) GA S REGULAR Menu Lifewire Tech for Humans Newsletter! Search Close GO Internet, Networking, & Security > Home Networking 43 43 people found this article helpful
IP: Classes, Broadcast, and Multicast
A guide to internet protocol address classes, broadcast, and multicast
By Bradley Mitchell Bradley Mitchell Writer Massachusetts Institute of Technology University of Illinois An MIT graduate who brings years of technical experience to articles on SEO, computers, and wireless networking. lifewire's editorial guidelines Updated on April 10, 2020 Tweet Share Email Tweet Share Email Home Networking The Wireless Connection Routers & Firewalls Network Hubs ISP Broadband Ethernet Installing & Upgrading Wi-Fi & Wireless It can be confusing to think of an IP address as being anything other than just a random string of numbers used on the internet and in local networks. The truth is that there's a lot going on behind the scenes to assign and limit IP addresses. IP classes are used to assist in assigning IP addresses to networks with different size requirements. The IPv4 IP address space can be subdivided into five address classes called Class A, B, C, D, and E. Each IP class consists of a contiguous subset of the overall IPv4 address range. One such class is reserved only for multicast addresses, which is a type of data transmission where more than one computer is addressed information at once. Blend Images - DreamPictures / Getty Images IP Address Classes and Numbering
The values of the leftmost four bits of an IPv4 address determine its class. For example, all Class C addresses have the leftmost three bits set to 110, but each of the remaining 29 bits may be set to either 0 or 1 independently (as represented by an x in these bit positions): 110xxxxx xxxxxxxx xxxxxxxx xxxxxxxx The table below describes the IP address values and ranges for each class. Note that some of the IP address space is excluded from Class E for special reasons as described further below. Class Leftmost bits Start of Range End of Range Total Addresses A 0xxx 0.0.0.0 127.255.255.255 2,147,483,648 B 10xx 128.0.0.0 191.255.255.255 1,073,741,824 C 110x 192.0.0.0 223.255.255.255 536,870,912 D 1110 224.0.0.0 239.255.255.255 268,435,456 E 1111 240.0.0.0 254.255.255.255 268,435,456 IPv4 Address Classes IP Address Class E and Limited Broadcast
The IPv4 networking standard defines Class E addresses as reserved, meaning that they should not be used on IP networks. Some research organizations use Class E addresses for experimental purposes. However, devices that try to use these addresses on the internet will be unable to communicate properly since devices are not designed to process those kinds of addresses. A special type of IP address is the limited broadcast address 255.255.255.255. A network broadcast involves delivering a message from one sender to many recipients. Senders direct an IP broadcast to 255.255.255.255 to indicate all other nodes on the local area network should pick up that message. This broadcast is "limited" in that it does not reach every node on the internet; only nodes on the LAN. Internet Protocol officially reserves the entire range of addresses from 255.0.0.0 through 255.255.255.255 for broadcast, and this range should not be considered part of the normal Class E range. IP Address Class D and Multicast
The IPv4 networking standard defines Class D addresses as reserved for multicast. Multicast is a mechanism in Internet Protocol for defining groups of client devices and sending messages only to that group rather than to every device on the LAN (broadcast) or just one other node (unicast). Multicast is mainly used on research networks. As with Class E, Class D addresses should not be used by ordinary nodes on the internet. Was this page helpful? Thanks for letting us know! Get the Latest Tech News Delivered Every Day Subscribe Tell us why! Other Not enough details Hard to understand Submit More from Lifewire What Is an IP Address? Why There Are Only 13 DNS Root Name Servers What Is a Public IP Address? (and How to Find Yours) How to Fix an IPv6 No Network Access Error Private IP Addresses: Everything You Need to Know How to Look up an IP Address Owner 255.255.255.0 Subnet Mask for IP Networks How to Change DNS Servers in Windows How to Set Up Port Forwarding 192.168.0.1 Default Router IP Address IPv4 vs. IPv6: What's The Difference? How to Change Your IP Address IP Tutorial: Subnet Mask and Subnetting What Happened to IPv5? 127.0.0.1 IP Address Explained When to Use a Static IP Address Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. Cookies Settings Accept All Cookies