What is needed for inter-VLAN communication on a switch? Learn how VLAN trunking (802.1Q) enables traffic between VLANs and across switches, a key concept for the Cisco Certified Support Technician (CCST) Networking 100-150 exam.
Table of Contents
Question
A network administrator is configuring VLANs on a switch. What is required for inter-VLAN communication?
A. STP
B. Port mirroring
C. ARP table
D. VLAN trunking
E. DHCP relay
Answer
D. VLAN trunking
Explanation
VLAN trunking (802.1Q) allows VLAN traffic to pass between switches and routers for inter-VLAN communication.
The requirement for inter-VLAN communication on a switch is VLAN trunking.
VLAN trunking allows multiple VLANs to share a single physical link between network devices, such as switches and routers, using VLAN tags to identify and separate traffic for each VLAN.
The most common standard for VLAN trunking is IEEE 802.1Q, which inserts a tag into Ethernet frames to indicate the VLAN ID. This ensures that traffic from different VLANs can travel across trunk links and be properly routed or switched at the destination.
For inter-VLAN communication, trunk ports are configured on switches to carry traffic for all (or specified) VLANs. This is essential when you have hosts in the same VLAN on different switches or when using a router-on-a-stick or multilayer switch for routing between VLANs.
Without VLAN trunking, each VLAN would require a separate physical connection for inter-switch or inter-VLAN communication, making the network inefficient and hard to scale.
In practice, trunking is configured with commands like switchport mode trunk and specifying the encapsulation type (dot1q) on Cisco switches.
VLAN trunking (802.1Q) enables VLAN-tagged traffic to pass between switches and routers, making inter-VLAN communication possible and efficient across network infrastructure.
Cisco Certified Support Technician (CCST) Networking 100-150 certification exam practice question and answer (Q&A) dump with detail explanation and reference available free, helpful to pass the Cisco Certified Support Technician (CCST) Networking 100-150 exam and earn Cisco Certified Support Technician (CCST) Networking 100-150 certification.