VLANS
This logical network division isolates unicast, multicast, and broadcast traffic into smaller broadcast domains on a Layer 2 switch
What is a Virtual Local Area Network (VLAN)
This standardized IEEE framing protocol inserts a 4-byte header tag into Ethernet frames to identify VLAN membership across trunk links
What is IEEE 802.1Q
Because Layer 2 switches isolate broadcast domains, devices on different VLANs cannot exchange data without this service
What is Layer 3 routing?
This obsolete routing method required a separate physical router port for every individual VLAN, severely limiting network scalability
What is Legacy Inter-VLAN Routing?
Dedicated to user-generated web and email traffic, this type of VLAN defaults to VLAN 1 on unconfigured switch ports
What is a Data VLAN?
Inside the 802.1Q header tag, this 12-bit field supports up to 4,096 distinct VLAN identification numbers
What is a VLAN Identifier (VID)
In Router-on-a-Stick, these software-based virtual interfaces are configured on a single physical router interface to route multiple VLAN subnets
What are subinterfaces
Although effective for small networks, the Router-on-a-Stick architecture fails to scale efficiently beyond this maximum number of VLANs
What is 50 VLANS?
By default, this specific VLAN carries all untagged traffic across an 802.1Q trunk link
What is the Native VLAN
This Cisco-proprietary point-to-point protocol dynamically manages and negotiates trunk link creation between switches
What is Dynamic Trunking Protocol (DTP)
Issued on a router subinterface, this command configures 802.1Q tagging and specifies the destination VLAN ID
What is "encapsulation dot1q <vlan-id>"?
This virtual interface configured on a Layer 3 switch acts as the default gateway for a local VLAN subnet
What is a Switched Virtual Interface (SVI)
Traffic belonging to this specialized VLAN requires high QoS priority, guaranteed bandwidth, and an end-to-end delay of less than 150 ms
What is a Voice VLAN
If both connected switch ports are set to this default DTP mode, the interconnecting link will form an access link rather than a trunk
What is Switchport mode Dynamic Auto
This global configuration command must be executed on a Layer 3 switch to enable IPv4 packet forwarding between SVIs
"What is ip routing"
Layer 3 switches achieve significantly faster forwarding rates and lower latency than routers because packet routing is handled by this component
What is hardware-based switching/routing?
Stored in vlan.dat, these four specific normal range VLAN IDs are automatically created on Catalyst switches for legacy networks and cannot be deleted
What is VLANs 1002, 1003, 1004, 1005
Executing this interface configuration command prevents a switchport from actively sending DTP negotiation frames to neighboring devices
What is Switchport nonegotiate
Executing this interface command converts a Layer 2 switchport on a multilayer switch into a dedicated Layer 3 routed port
What is "no switchport"?
Unlike Router-on-a-Stick which relies on a single link, Layer 3 switches can bundle trunk ports using this Layer 2 technology to increase inter-switch bandwidth
What is EtherChannel (or Layer 2 EtherChannel)