In the field of Networking, a communications protocol is the set of standard rules for data representation, signalling, authentication and error detection required to send information over a communications channel.Protocols can be understood as an standard of agreement among networks and within networks.

The following are some of the protocols used:

1.Layer 2 and Layer 3 protocols: Address Resolution Protocol (ARP), IPCP, IP forwarding, IP host, IP Multicast, PPP-over-ATM, TCP, Telnet, Trivial File Transfer Protocol (TFTP), User Datagram Protocol (UDP), transparent bridging, virtual LAN (VLAN), MPLS, and IPv6.

2.Address Resolution Protocol(ARP): Determines the destination MAC address of a host using its known IP address.

3.Internet Control Message Protocol(ICMP): Allows hosts to send error or control messages to other hosts.

Reverse Address Resolution Protocol(RARP): Determines an IP address knowing only a MAC address.

PPP: Provides host-to-network and switch-to-switch connections over synchronous and asynchronous circuits.

Simple Network Management Protocol(SNMP): Agents that process requests for network management stations and report exception conditions when they occur; requires access to information stored in a MIB.

Telnet: A terminal emulation protocol that allows remote access to the administrative interface of a switch over the network.

UDP: Enables an application on one system to send a datagram to an application on another system; uses IP to deliver datagram’s.

Dynamic Host Connection Protocol(DHCP): Lets a host automatically obtain their IP address, subnet mask, and default route from a pre-configured DHCP server on the network.