What is Trunking?

Voice over Internet Protocol (VoIP) and streaming media service based on the Session Initiation Protocol (SIP) by which Internet telephony service providers (ITSPs) deliver telephone services and unified communications to customers inter connection with cucm..it is a peer to peer

The network access is provided by the system to the clients by means of sharing a group of frequencies.  

Trunking is a technique used in data communications transmission systems to provide many users with access to a network by sharing multiple lines or frequencies. As the name implies, the system is like a tree with one trunk and many branches.

Trunk in the telephony system  defines the connections between tow telephony systems to pass the calls from point to other point , as well as there are may different types of trunks as SIP trunk , IP trunk , E&M Trunk , E1 trunk.

Trunking is a technique used in data communications transmission systems to provide many users with access to a network by sharing multiple lines or frequencies. As the name implies, the system is like a tree with one trunk and many branches. Trunking is commonly used in very-high-frequency (VHF) radio and telecommunication systems.Trunking can also be defined as a network that handles multiple signals simultaneously. The data transmitted through trunking can be audio, video, controlling signals or images. Telecommunication networks all across the globe are based on trunking. Trunking reduces the size of a telecom network and increases bandwidth. VHF radio used by police and control centers is also based on trunking

Trunking

• VLANs are local to each switch's database, and VLAN information is not passed between switches.

• Trunk links provide VLAN identification for frames traveling between switches.

• Cisco switches have two Ethernet trunking mechanisms: ISL and IEEE.1Q.

• Certain types of switches can negotiate trunk links.

• Trunks carry traffic from all VLANs to and from the switch by default but can be configured to carry only specified VLAN traffic.

• Trunk links must be configured to allow trunking on each end of the link.

this is a link for trunking concept  https://goo.gl/9eEmZB

is a line or link designed to handle many signals simultaneously, and that connects major switching centers or nodes in a communications system. The transmitted data can be voice (as in the conventional telephone system) data, computer programs, images, video or control signals.