What is trunk mode of a Cisco switch?
A trunk is a point-to-point link between one or more Ethernet switch interfaces and another networking device such as a router or a switch. Ethernet trunks carry the traffic of multiple VLANs over a single link, and you can extend the VLANs across an entire network.
How do you trunk a Cisco router?
To enable trunk links, configure the ports on either end of the physical link with parallel sets of commands. To configure a switch port on one end of a trunk link, use the switchport mode trunk command. With this command, the interface changes to permanent trunking mode.
What is 802.1 Q trunking?
VLAN Trunking (802.1Q) allows physical network interfaces in a computing environment to be shared, or multi-homed. Network devices on the network then only interact with packets that have the correct tags. This allows multiple different logical networks to run on the same cable and switch infrastructure.
What is the Cisco proprietary method for trunk encapsulation?
ISL (Inter-Switch Link )is a Cisco-proprietary protocol for identifying the VLAN of frames that pass over a trunk link.
How do I know if my Cisco port is trunk or access?
Use the show interfaces trunk command to check whether the local and peer native VLANs match. If the native VLAN does not match on both sides, VLAN leaking occurs. Use the show interfaces trunk command to check whether a trunk has been established between switches. Statically configure trunk links whenever possible.
What is ISL and Dot1q?
ISL and DOT1Q are 2 encapsulation standards supporting Virtual LANs (VLANs) on an Ethernet network. These are the 2 frame tagging protocols that Cisco supports. The tagging protocol can be manually specified on a trunk port, or dynamically negotiated using Cisco’s proprietary Dynamic Trunking Protocol (DTP).
What is the difference between ISL and 802.1 Q?
802.1q encapsulation inserts a 4 byte tag into original frame and FCS (Frame Check Sequence) is re-calculated. ISL uses more processor cycles than 802.1q because of the modification of the header and recalculation of FCS.
Which protocol is a Cisco proprietary protocol used for trunking switches?
VLAN Trunking Protocol
VLAN Trunking Protocol (VTP) is a Cisco proprietary protocol that propagates the definition of Virtual Local Area Networks (VLAN) on the whole local area network. To do this, VTP carries VLAN information to all the switches in a VTP domain.
What happens if u connect PC to a trunk port?
Yes. Trunk ports can carry both tagged and untagged packets. Untagged packets get put on whatever is configured as the native vlan for the port.