Unicast is a communication between a single sender and a single receiver over a network i.e. one-to-one connection that uses TCP (Transmission Control Protocol) for delivering streams over the internet. i.e. transmitting packet will be received by a single device on the network . A user requests information from a server/website/another user and the other party sends it after establishing a unique connection. Example: Browsing a website, Downloading a file from FTP Server. All Cloud Provider Supports Unicasting. All LANs (e.g. Ethernet) and IP networks support the unicast transfer mode
Multicast is a communication between a Single/Multi sender and a group of receivers i.e. transmitting packet will be received by group of devices on the network. Data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to-many communication. IP multicast traffic are sent to a group and only members of that group can receive or process the Multicast traffic. Example : Sending an e-mail message to a mailing list, Teleconferencing, videoconferencing etc
Multicast Addresses:
- 224.0.0.0 to 224.0.0.255 (Local Subnetwork)
- 224.0.1.0 to 224.0.1.255 (Internetwork control block)
- 232.0.0.0/8 – IPv4 and ff3x::/32 – IPv6 (Source-specific multicast)
Broadcast is a communication between a single sender and all receivers within range on a network i.e. transmitting packet will be received by every device on the network. Example TV channel is delivering to all devices attached to the network
Types and Addresses
Limited Broadcast : A packet is sent to a specific network or series of networks. 255.255.255.255
Directed Broadcast : A packet is sent to a specific destination address where only the host portion of the IP address is either all ones or all zeros. 192.20.255.255 or 190.20.0.0. 192.168.10.255/24 is the broadcast address for the network 192.168.10.0/24
Anycast address is an address that is assigned to a set of interfaces that typically belong to different nodes i.e. transmitting packet will be received by one of many (nearest device on the network) . A packet sent to an anycast address is delivered to the closest interface (as defined by the routing protocols in use) identified by the anycast address.
Anycast Characteristics: one-to-many & any-to-many communication model. Delivery of packets to the group interface that is closest to the sending device. A unique IPv6 address for each device in the group.
IPv4 – Anycast can be implemented by using Border Gateway Protocol (BGP).
BGP (Border Gateway Protocol) is the protocol underlying the global routing system of the internet which manages how packets get routed from network to network through the exchange of routing and reachability information among edge routers.
IPv6 – Anycast is supported explicitly in IPv6. which covers IPv6 addressing architecture, reserves Interface Identifier 0 within an IPv6 subnet as the “Subnet Router” anycast address.
Types of address:
Unicast – Identifies a single interface
Multicast – Packets sent to a multicast address are delivered to all interfaces for that address
Anycast – Packets sent to an anycast address are delivered to a single “nearest’ interface