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. • Trunk links must be configured to allow trunking on each end of the link. • Certain types of switches can negotiate trunk links. • Trunk links provide VLAN identification for frames traveling between switches.1Q. and VLAN information is not passed between switches. Trunking Network • VLANs are local to each switch's database. • Cisco switches have two Ethernet trunking mechanisms: ISL and IEEE 802. • Trunks carry traffic from all VLANs to and from the switch by default but can be configured to carry only specified VLAN traffic.

• Support for VLAN numbers up to 4096. . • Support for a structured and secure VLAN environment (Private VLAN. • Configuration option on a per port base instead of only a global scheme. • Optimized resource handling and more efficient transfer of information. VLAN Trunk Protocol (VTP) • Protection from unintended database overrides during insertion of new switches. • Support for interaction with VTP Version 1 and VTP Version 2. or PVLAN). • Option of clear text or hidden password protection.

Benefits • VLAN configuration consistency across the network • Mapping scheme that allows a VLAN to be trunked over mixed media • Accurate tracking and monitoring of VLANs • Dynamic reporting of added VLANs across the network • Plug-and-play configuration when adding new VLANs .

It works on the Layer 2 of the OSI model. VLAN trunks formed using DTP may utilize either IEEE 802. Neither protocol transmits the data frames that trunks carry. VTP communicates VLAN existence information between switches. Dynamic Trunking Protocol The Dynamic Trunking Protocol (DTP) is a proprietary networking protocol developed by Cisco Systems for the purpose of negotiating trunking on a link between two VLAN-aware switches. as they serve different purposes. and for negotiating the type of trunking encapsulation to be used. . DTP aids with trunk port establishment.1Q or Cisco ISL trunking protocols. DTP should not be confused with VTP.

A switch can be configured in one of .VTP uses a hierarchy of advertisements to distribute and synchronize VLAN configurations across the network. • A router or Layer 3 switch defines the boundary of each domain. • All switches in a domain share VLAN configuration details using VTP advertisements. VTP Advertisements . VTP Modes . • 2. • 3.VTP Components • VTP Domain: It consists of one or more interconnected switches.

VTP clients function the same way as VTP servers. VTP Client . or delete VLANs on a VTP client. but you cannot create. • 6.VTP servers advertise the VTP domain VLAN information to other VTP-enabled switches in the same VTP domain. • VTP servers store the VLAN information for the entire domain in NVRAM. • The server is where VLAN can created. • 5. • You must configure VTP client mode on a switch. deleted. VTP Transparent . renamed. • VLANs that are created. change. VTP Server .Transparent switches forward VTP advertisements to VTP clients and VTP servers. or deleted on transparent switches are local to that switch only. or renamed for the domain.• 4. • A VTP client only stores the VLAN information for the entire domain while the switch is on. • A switch reset deletes the VLAN information. . • Transparent switches do not participate in VTP.

• 7. it reconfigures the trunk link based o which ports are configured with which VLANs . • When VTP pruning is enabled on a network. VTP Pruning-VTP pruning increases network available bandwidth by restricting flooded traffic to those trunk links that the traffic must use to reach the destination devices. • Or • It prevents unnecessary flooding of broadcast information from one VLAN across all trunks in a VTP domain.