The vlan trunking protocol vtp is the protocol that switches use to communicate among themselves about vlan configuration in the image above, each switch has two vlans. Trunking theory pdf download,trunk port,isl, interswitch link, 802. Trunking means that between switch a and switch b, we will create a trunk, which is an interface that carries multiple vlans. To automatically negotiate trunking, the interfaces must be in the same vtp domain.
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. The ohio state university raj jain 2 9 layering protocols of a layer perform a similar set of functions all alternatives for a row have the same interfaces choice of protocols at a layer is independent of those of at other layers. The dynamic trunking protocol dtp is a proprietary networking protocol developed by cisco. Host a and host b are in different vlans, vlan 1 and vlan 2. Dtp dynamic trunking protocol most cisco switches today support a cisco proprietary pointtopoint protocol called dynamic trunking protocol dtp on trunk ports to negotiate the trunking state. Dynamic trunking protocol dtp difference between dtp dynamic desirable and dynamic auto modes how to confgure dynamic desirable mode. The dynamic trunking protocol dtp is used to negotiate forming a trunk between two cisco devices. If the port connected to other port is capable to form a trunk, a trunk link will be formed. Do not seek or try to form a trunk unless someone explicitly asks you using dtp. Definition le vlan ou virtual local area network, en francais reseau.
Narrator dynamic trunking protocolis an automated cisco feature. 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 vlanaware switches, and for negotiating the type of trunking encapsulation to be used. This feature negotiates a trunk between two cisco devices. Dynamic trunking protocol is used to automatically negotiate the state of switchports. Its means that whenever we receive a dtp packet that requests to form a trunk, your interface will be in trunk mode. Within the ieee specification, the link aggregation control protocol lacp provides a method to control the bundling of several physical ports together to form a single logical channel. On the first switch, vlan a and vlan b are sent through a single port trunked to the router and through another port to the second switch. Ethernet is a lowlevel protocol that spells out the electrical characteristics of the network hardware used by most localarea networks. The comparable ieee standard in use by other manufacturers is garp vlan registration protocol gvrp, and more recently multiple vlan registration protocol mvrp. What protocols are used to configure trunking on a switch.
As the name implies, the system is like a tree with one trunk and many branches. You cannot configure pruning eligibility separately for each trunk. Distributed trunking uses a proprietary protocol that allows two or more port trunk links distributed across two switches to create a trunk group. Switches use vlan trunking protocol for vlan tagging process. When it comes to securing the network one of the most overlooked items is dynamic trunking protocol, also known as dtp. Vtp is available on most of the cisco catalyst family products.
Dynamic trunking protocol is cisco proprietary protocol used for negotiating a trunk link between two switches as well as the encapsulation type of either 802. Vlan trunking protocol vtp is a cisco proprietary protocol that propagates the definition of virtual local area networks on the whole local area network. Now although dtp is a cisco protocoland it automates the trunk negotiation process,cisco still recommends to use the manual configurationwhen creating a trunk link. Isl is a ciscoproprietary trunking protocol, making it unsuitable for a multivendor environment. One large limitation of disl was that it could perform the dynamic trunking negotiation only for isl links. Dtp manage trunk negotiation between two or more cisco devices before actually forming the trunk connection. A trunk can consist of multiple wires, cables or fiber optic strands. Dtp causes increased traffic, and is enabled by default, but may be disabled. The dynamic trunking protocol dtp is a cisco proprietary protocol. Dtp is normally used on cisco ios switches to negotiate if the interface should become an access port or trunk. The interface which is configured as dtp dynamic desirable mode will generate dtp messages on the interface. Lets get down to the vlan trunking protocol, or vtp. Dynamic trunk protocol the it networking community. Tf portchannelif trunk mode is enabled in an f portchannel see the link 4 in figure 52 and that portchannel becomes operational as a trunking f portchannel, it is referred to as tf portchannel.
Dynamic desirable states aggressively, form a trunk link. The pruningeligibility configuration applies globally to all trunks on the switch. Virtual local area network vlan trunk protocol vtp reduces administration in. The signals can convey any type of communications data. This is the essence of using the dynamic dtp trunking protocol.
Yersinia, a framework for layer 2 attacks black hat. Tcpip was originally developed for unix networks and is the protocol of the internet and most localarea networks. A trunk is a communications line or link designed to carry multiple signals simultaneously to provide network access between two points. A switch port configured as dtp dynamic desirable mode will actively try to convert the link to a trunk link using dynamic trunking protocol dtp. Interested in network protocols and how to assess customer networks or how to protect your. Auto states wait patiently for dtp messages, dynamic trunking protocol messages, to arrive, asking you to form a trunk. I normally think of this protocol as something to be of utmost use to all the newbies or to people who just want to buy the device, plug in the network and get going with it. Of course, it is a layer 2 data link protocol and is enabled by default. Trunking is commonly used in veryhighfrequency vhf radio and telecommunication systems. There are two major trunking protocols you must understand and compare successfully, those being isl and ieee 802. This type of interface can carry traffic of multiple vlans. 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 vlanaware switches, and for negotiating the type of trunking encapsulation to.
Cisco dtp dynamic trunking protocol tutorial flackbox. In this tutorial well take a look at dtp dynamic trunking protocol negotiation. This cisco proprietary protocol is used to negotiate trunk links between vlan aware cisco switches using dot1q or isl and is commonly enabled by default. When a pair of cisco switches are connected together they can use ciscos proprietary dynamic trunking protocol to automatically negotiate a trunk connection between them.
To configure a trunk interface, the switchport mode trunk interface command is used. This video gives you a brief and clear information about dtp protocol watch our free ccna classes and subscribe to get more,stay connected with us we are adding more videos,,dont. Vlan trunking protocol vlan trunking protocol vtp is a cisco layer 2 messaging protocol that manages the addition, deletion, and renaming of vlans on a networkwide basis. Vlan trunking protocol vtp is a cisco proprietary which basic aim is to manage all configured vlans across a switched network. Lacp allows a network device to negotiate an automatic bundling of links by sending lacp packets to the peer directly. The grouped links appear to the downstream device as if they are from a single device. It doesnt tell you which one it specifies but you could safely answer c anyway even without the sh interface command because the other end is dynamic desirable. Please do not make requests for copies of radio programming software which is sold or was sold by the manufacturer for any monetary value. Dtp negotiates the operational mode of directly connected switch. The two most popular protocol suites for networking are tcpip and ethernet.
Catalyst 65006000 series cisco ios softwarecatalyst 45004000 cisco ios software. Introduction to networking protocols and architecture. Spanning tree protocol this document descibes spanning tree protocol stp in a wireless environment. Trunks typically connect switching centers in a communications system.
So, in auto mode, the link just listens to its neighbor and waiting for dtp frames to be transmitted to form a trunk and if not, no trunking will happen. Dynamic trunking protocol dtp explained orbitcomputer. The tagging protocol can be manually specified on a trunk port, or dynamically negotiated using ciscos proprietary dynamic trunking. Stp overview stp is a layer 2 link management protocol that prov ides path redundancy while preventing loops in the network. The benefit of dtp is to boost traffic on a trunked link. Vtp helps to propagate and maintain vlan configurations consistency to other switches on the network. Both disl and dtp are cisco proprietary protocol that are designed to learn whether the device on the other end wants to perform trunking or not. Source address of originating host src and dest ports not parts of ip hdr ip version header length type of service total length identification flags time to live protocol header checksum destination address of target host options padding ip data fragment offset. Dynamic trunking protocol dtp is the second generation of dynamic interswitch link disl which allow switches to negotiate trunking state of the link between two switches. How to configure dtp dynamic trunking protocol modes. Louis 2008 raj jain computer networking and internet protocols. Trunk negotiation is managed by the dynamic trunking protocol dtp, which is a.
An interface can be set to trunking or nontrunking, or to negotiate trunking. Below is the switchport modes or dtp modes for easy reference. Understanding dynamic trunking protocol dtp the dynamic trunking protocol dtp is a cisco proprietary protocol that is automatically enabled on catalyst 2960 and catalyst 3560 series switches. A comprehensive introduction raj jain professor of computer science and engineering. Dynamic trunking protocol free ccna in this video imran talks about dynamic trunking protocol dtp. Moreover, in nonegotiate mode, since it disables the sending of dtp frames, there will be no trunking.
The first two layers of the open systems interconnection osi model deal with the physical structure of the network and the means by which network devices can send information from one device on a network to another. A the negotiation of trunking encapsulation the command switchport trunk encapsulation negotiate is only available for trunk mode dynamic desirable, or dynamic auto. Configure vlan trunking protocol vtp on all switches. Dtp, like disl, is a protocol that autonegotiates whether trunking can be performed on the connection. Dtp is used to negotiate forming a trunk link between two or more cisco devices before actually forming the trunk connection.
A switchport can be set to one of four modes dynamic auto default, dynamic desirable, trunk. To anyone looking to acquire commercial radio programming software. Dtp dynamic trunking protocol dtp dynamic trunking protocol is how switchports automatically negotiate their mode before you ever configure them. Is there any way to make the connection between switch a and switch b supports traffic of all vlans. Vtp is a messaging protocol that uses layer 2 trunk frames to add, delete and rename vlans on a single domain. I would like to know if referring to the dynamic trunking mode implicitely refers to the dynamic desirable mode or to the dynamic auto. The dynamic trunking protocol dtp automatically enabled on catalyst 2960 and catalyst 3560 series switches. Dtp or dynamic trunking protocol is cisco proprietery protocol.
What protocols are used to configure trunking on a switch 1. Following commands sets can be used to configure different dynamic trunking protocol dtp modes for switch interface refer folowing lessons if you are not familiar with dynamic trunking protocol dtp. These ports need to be configured as access ports and assigned to their respective vlans by. In preparation of our ccna exam, we want to make sure we cover the various concepts that we could see on. Using these different trunking modes, an interface can be set to trunking or nontrunking or even able to negotiate trunking with the neighboring interface. Vlan trunking protocol vtp was developed by cisco to reduce vlan administration effort in a switched network, making it a cisco proprietary protocol.
He also explains vlan trunking protocol vtp and show how to configure them in different. By default dtp is enabled and the interfaces of your switches will. Disl has been replaced by ciscos proprietary dynamic trunking protocol dtp. If the trunking mode is on, then it cant have the automatic negotiation of trunking protocol in fact, layer 3 switches like 3560 will not allow you to set the trunking. Dynamic trunking protocol dtp explained icnd2 200105. Do your best using dtp to form a trunk with the other side of that link. Cisco port trunking protocol ptp is used to carry tagged frames. Understanding spanning tree protocol this section describes how spanningtree features work. Vlan trunking protocol how lan switches work howstuffworks. Trunk port, dynamic desirable port, dynamic auto,dtp, dynamic trunking protocol, trunking trunk pdf file download. Tf portchannelif trunk mode is enabled in an f portchannel see the link 4 in figure 12 and that portchannel becomes operational as a trunking f portchannel, it is referred to as tf portchannel. Dtp dynamic trunking protocol is a cisco proprietary protocol.
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