The default switchport mode for newer Cisco switch Ethernet interfaces is dynamic auto. Note that if two Cisco switches are left to the common default setting of auto, a trunk will never form. switchport mode dynamic desirable: Makes the interface actively attempt to convert the link to a trunk link..
Thereof, what is a Switchport?
switchport mode access - Always forces that port to be an access port with no VLAN tagging allowed EXCEPT for the voice vlan. DTP is not used and a trunk will never be formed. It will also use DTP to negotiate a neighbouring interface that is set to dynamic desirable or dynamic auto into a trunk.
Likewise, what is dynamic desirable mode? Dynamic Desirable — Makes the port actively attempt to convert the link to a trunk link. The port becomes a trunk port if the neighboring Ethernet port is set to trunk, dynamic desirable or dynamic auto mode. No-negotiate — Disables DTP.
Correspondingly, what is Switchport mode access used for?
Using the “Switchport mode access” command forces the port to be an access port while and any device plugged into this port will only be able to communicate with other devices that are in the same VLAN. Using the “Switchport mode trunk” command forces the port to be trunk port.
What does Switchport Nonegotiate mean?
switchport nonegotiate: Prevents the interface from generating DTP frames. You can use this command only when the interface switchport mode is access or trunk. You must manually configure the neighboring interface as a trunk interface to establish a trunk link.
Related Question Answers
What does no Switchport command do?
The no switchport command puts the interface in L3 mode (known as "routed port") and makes it operate more like a router interface rather than a switch port. The ip address command assigns an IP address and network mask to the interface. Routed ports can be configured with a Layer 3 routing protocol.How many ports are in switch?
basically switches comes 8 ports, 12 ports, 16 ports, 24 ports, 28 ports.What is trunking mode?
Trunking is a function that must be enabled on both sides of a link. If two switches are connected together, for example, both switch ports must be configured for trunking, and they must both be configured with the same tagging mechanism (ISL or 802.1Q).What is difference between trunk and access port?
As for the difference between Trunks and Access ports, a trunk does add dot1q or ISL tags directly to frames and can exist on all or multiple vlans. While an access port only passes traffic from a set vlan but does not modify the frame with a vlan tag.What is spanning tree used for?
The Spanning Tree Protocol (STP) is a network protocol that builds a loop-free logical topology for Ethernet networks. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them.What are two types of ports for VLANs?
There are mainly two types of ports in a Private VLAN: Promiscuous port (P-Port) and Host port. Host port further divides in two types – Isolated port (I-Port) and Community port (C-port).What is Switchport port security?
The switchport security feature (Port Security) is an important piece of the network switch security puzzle; it provides the ability to limit what addresses will be allowed to send traffic on individual switchports within the switched network.Which are types of switch ports?
Common Switch Port Types on Network Switches When the data switch resides in a VLAN, there may be three common switch port types: access port, trunk port and hybrid port. An Ethernet interface can function as a trunk port, an access port or a hybrid port.What is access mode?
access mode - Computer Definition (2) The operations that an operating system can perform, such as read, write, append, lock and execute (sometimes abbreviated RWALX).What is PortFast?
Enabling the PortFast feature causes a switch or a trunk port to enter the STP forwarding-state immediately or upon a linkup event, thus bypassing the listening and learning states. The PortFast feature is enabled at a port level, and this port can either be a physical or a logical port.What is difference between VLAN access and trunk mode?
An access port sends and receives untagged frames (i.e. all frames are in the same VLAN), while a trunk port supports tagged frames and thus allows to switch multiple VLANs.What is Switchport VLAN?
Use the switchport access vlan command to assign the port or range of ports into access ports. A port in access mode can have only one VLAN configured on the interface which can carry traffic for only one VLAN. vlan-id - Specifies the VLAN to which the port is configured.Which command disables DTP?
Use switchport nonegotiate command under that port to disable DTP.Is DTP enabled by default?
DTP is enabled by default on all modern Cisco switches. If all it takes is the right DTP packet to form a trunk from an access port, an intruder can easily inject traffic into whatever VLANs are allowed on the port (by default, all of them).What is VTP transparent mode?
The VTP Transparent mode is something between a VTP Server and a VTP Client but does not participate in the VTP Domain. In Transparent mode, you are able to create, modify and delete VLANs on the local switch, without affecting any other switches regardless of the mode they might be in.What is the difference between VTP and DTP?
In summary, VTP is a protocol used to share VLAN information within a domain among connected switches. On the other hand, DTP is a protocol used to negotiate trunking between switch ports on either ends of a link.What is CDP in networking?
From Wikipedia, the free encyclopedia. Cisco Discovery Protocol (CDP) is a proprietary Data Link Layer protocol developed by Cisco Systems in 1994 by Keith McCloghrie and Dino Farinacci. It is used to share information about other directly connected Cisco equipment, such as the operating system version and IP address.Which two protocols can detect native VLAN mismatch errors?
If there is a native VLAN mismatch, Spanning Tree Protocol (STP) places the port in a port VLAN ID (PVID) inconsistent state and will not forward on the link -> STP can detect native VLAN mismatch. 
