Yes, Cisco Layer 2 switches support VLANs (Virtual Local Area Networks). VLANs allow network segmentation by creating separate broadcast domains within the same physical network infrastructure. This capability enhances network performance and security by isolating traffic among different groups of users or devices. Cisco's implementation of VLANs follows the IEEE 802.1Q standard, enabling the tagging of Ethernet frames for proper routing between VLANs.
VLAN
I believe there is no such thing as switching "from layer 3 to layer 2". Switching is either done within layer 3, or within layer 2.
AnswerVLANs are created on Layer 2 switches to control broadcasts and enforce the use of a Layer 3 device for communications. Each VLAN is created in the local switch's database for use. If a VLAN is not known to a switch, that switch cannot transfer traffic across any of its ports for that VLAN. VLANs are created by number, and there are two ranges of usable VLAN numbers (normal range 1-1000 and extended range 1025-4096). When a VLAN is created, you can also give it certain attributes such as a VLAN name, VLAN type, and its operational state. To create a VLAN, use the following steps.1) Configure VTP. VTP is a protocol used by Cisco switches to maintain a consistent database between switches for trunking purposes. VTP is not required to create VLANs; however, Cisco has set it up to act as a conduit for VLAN configuration between switches as a default to make administration of VLANs easier. Because of this, you must first either configure VTP with a domain name or disable VTP on the switch.2) Create the VLAN. VLANs are created by number. The two ranges of VLANs are as follows: The standard range consists of VLANs 1 to 1000. The extended range consists of VLANs 1025 to 4096. Extended VLANs are currently supported only on switches running COS software version 6.1 or greater. When you create a VLAN, you have many options to consider. Many options are valid only for FDDI and Token Ring VLANs. Some of the items configured deal with options, such as private VLANs, which are discussed in other sections in this book. VLANs are created using the set vlan command for COS devices or with the vlan command in vlan database mode for IOS switches.
A layer 2 switch can be either manageable or unmanaged, depending on its design and features. Managed layer 2 switches offer advanced functionalities such as VLAN support, traffic monitoring, and remote configuration, allowing for better network management. Unmanaged layer 2 switches, on the other hand, provide basic connectivity without the ability to configure or manage them. Therefore, whether a layer 2 switch is manageable or not depends on the specific model and its capabilities.
A Cisco CCNA lab helps Cisco IT learners get access and perform routing and Layer 2 core switching lab configurations over the internet from a personal computer.
Hubs and Switches
Depending on the IOS on the switch it will have either layer 3 functionality (EMI) or just layer 2 functionality (SMI).
Layer 2 Tunneling Protocol (L2TP)
VLANs provide the capability so virtually segregate traffic on a network. VLANs work by tagging traffic packets and ensuring that packets with separate VLAN IDs are only available at ports which have been configured for that VLAN ID.
PPP with CHAP
PPP with PAP
Performance is increased by keeping all users in the same Layer 2 network