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What is Core Networks?

Core Network

[^1] Core network or network core is part of network that interconnects the internet's end systems which exchange messages with each other. The source or host breaks long messages into smaller part of data known as packets to end system destination. Packets are transmitted over each communication links and packet switches(routers and link-layer switches) across links on path from source to destination. Core network also known as mesh of interconnected routers. [^2] In general, this term signifies the highly functional communication facilities that interconnect primary nodes. The core network delivers routes to exchange information among various sub-networks. The facilities and devices used for the core or backbone networks are usually routers and switches, with switches being used more often. The technologies used for the core facilities are mainly network and data link layer technologies, including asynchronous transfer mode (ATM), IP, synchronous optical networking (SONET) and dense wavelength division multiplexing (DWDM).

There are two fundamental approaches to build a network core: packet-switching and circuit switching . In circuit-switched networks, the resources needed along a path (buffers, link transmission rate) to provide for communication between the end systems are reserved for the duration of the communication session between the end systems. In packet-switched networks, these resources are not reserved; a session’s messages use the resources on demand and, as a consequence, may have to wait (that is,queue) for access to a communication link. [^1]

Functions

There are two key core network functions - Forwarding (switching): after the router has received all of the packet's bits, it begin to transmit (forward) the first bit of the packet onto the outbound link. [^1]

  • Routing: determine source-destination paths taken by packets. A router takers a packet arriving on one of its attached communication links and forwards that packet onto another one of its attached communication links. In the internet, every end system has an address called an IP address. The source or host includes the destination’s IP address in the packet’s header when it wants to send a packet to a destination. [^1]

core_network Credit: Prodapt Solutions

References

[^1]: Kurose, J. F., & Ross, K. W. (2017). Computer networking: a top-down approach (7th ed.). Pearson. [^2]: Technopedia(n.d.). Core Network. Retrieved February 28, 2020 from https://www.techopedia.com/definition/6641/core-network