Layer 2 vs. Layer 3 VPN – Learn the Key Differences

Layer 2 and Layer 3 are two critical layers of the OSI (Open System Interconnection) model.

Key Takeaways:

Layer 2

• Layer 2 VPN operates at the second data link layer of the OSI model using only device MAC addresses for data transfer. 

• Layer 2 switches are faster and require minimal configuration, making them common in homes and small businesses.

Layer 3

• Layer 3 VPN operates at the data link and network layers via IP addresses and inter-VLAN communication using the devices’ MAC and IP addresses. 

• Layer 3 switches combine some of the router’s capabilities but are more complex and expensive than layer 2 switches. 

Layer 2 and Layer 3 are responsible for network communication between different devices. Both layers have their own characteristics, advantages, and disadvantages.

Let’s discuss layer 2 vs layer 3 vpn in detail.

Layer 2 vs Layer 3: Quick Comparison

Here’s a quick comparison on Layer 2 vs Layer 3 VPN, similar to the one we did with TCP vs UDP.

What is an OSI Model?

An OSI (Open System Interconnection) is a conceptual framework that divides network communication into seven layers. It works like a universal language for computer networking systems and allows diverse technologies to communicate with each other.

The OSI model helps to describe each component within the data communication, establishing rules and standards for applications and network infrastructure.

Here are some key characteristics of the OSI model:

• Seven layers: The OSI model has seven layers, each is responsible for a function in the communication process.

1. Application layer
2. Presentation layer
3. Session layer
4. Transport layer
5. Network layer
6. Data link layer
7. Physical layer

• Standardization: The OSI model provides a standardized framework for network communication, allowing different systems to communicate with each other.

• Protocol-independent: The OSI model is protocol-independent, meaning it doesn’t specify specific communication protocols but provides a framework for developing protocols.

• Generic: The OSI model is a generic model that applies to all forms of network communication, including local area networks (LAN) and wide area networks (WAN).

Source: Siem Xpert

The 7 Layers of Networking

To better understand the concept of layer 2 vs layer 3 mpls VPN let’s break down the seven layers of the OSI model.

Application Layer

The Application layer, the seventh layer, provides services to end-user applications, such as email, file transfer, and web browsing. Moreover, it manages the interaction between the application and the network to ensure efficient data transmission.

Presentation Layer

The presentation layer compresses, encrypts, and formats the data into a format the receiving device can understand and process.

Session Layer

The session layer establishes, maintains, and terminates connections between applications on different devices. It manages the application dialogue, including session establishment, maintenance, and termination.

Transport Layer

The transport layer provides reliable data transfer between devices and controls the data flow, including segmentation, acknowledgment, and reassembly.

Network Layer (layer 3)

The network layer is responsible for routing data between devices on different networks. It provides logical addressing, routing, and congestion control. Additionally, it manages the data flow between devices, including packet switching and routing.

Data Link Layer (layer 2)

The data link layer provides error-free transfer of data frames between two devices on the same network. I manage data flow between devices, including addressing, framing, error detection, and correction.

Physical Layer

The physical layer defines the physical means of data transmission, such as electrical signals, light waves, or radio waves. It specifies the physical devices and media used for communication, such as cables, fiber optic cables, or wireless transmissions.

What is a Virtual Lan (VLan)?

VLANs, or Virtual Local Area Networks, logically connect devices regardless of physical location to improve security and traffic management. 

They allow network administrators to isolate traffic between departments without moving hardware. VLANs are implemented by designating specific switch ports, and creating smaller broadcast domains to alleviate network congestion.

What is a Layer 2 or Data Link Layer?

Layer 2 is also known as the Data Link layer of the OSI model. It is primarily responsible for transferring data between devices on the same network. It ensures error-free and reliable data transfer between nodes on the network.

Source: Layer 2 of OSI Model

Here are the key functions of Layer 2/Data Link layer:

1. Reliable data transfer: The Data Link layer ensures the data delivery to the correct destination between devices on the same network.

2. Frame formatting: Layer 2 formats data into a frame and transmits it over the network to the devices.

3. Addressing: Layer 2 uses MAC addresses to identify devices on the network and ensures the data delivery to the addressed devices.

4. Flow control: The Data Link layer regulates the data flow between devices and prevents network congestion to improve data transfer efficiency.

5. Error detection and correction: Layer 2 detects and corrects errors that may occur during the data transfer between devices.

There are also sublayer of Layer 2/Data Link layer:

1. Media Access Control (MAC) sublayer: The MAC sublayer controls network medium access and data frame transmission.

2. Logical Link Control (LLC) sublayer: LLC is responsible for error-free data transfer and flow control.

Network protocols used at Layer 2:

1. Ethernet: Common protocol for local area networks (LANs) that uses the data link layer to transmit data frames.

2. Point-to-Point (PPP): A protocol for point-to-point connections, such as dial-up internet connections.

3. Frame Relay: This protocol typically transmits data using the Data Link layer within Wide Area Networks (WANs).

Summary: The Data Link Layer, or Layer 2, of the OSI model is responsible for transferring data between devices on the same network. It ensures reliable and error-free data transfer, formatting into frames, and addressing devices on the network.

What Is Layer 3 or Network Layer?

The Network Layer, also known as Layer 3 in the OSI model, facilitates the transfer of variable-length data sequences. 

It accomplishes this by providing functional and procedural mechanisms from a source host on one network to a destination host on a different network.

Source: Layer 3 of OSI Model

Key functions of Layer 3 or Network Layer:

• Routing: The Network Layer handles data packets between different networks. It determines which route the data will travel from source to destination.

• Fragmentation and Reassembly: The Network Layer may fragment data packets into smaller packets if they are too large to transmit over a particular network. It also reassembles the packets at the destination.

• Error Handling: The Network Layer reports delivery errors to the Transport layer and may request retransmission of lost or corrupted packets.

• Logical Addressing: The Network Layer assigns logical addresses to devices on a network, which it uses to route data packets

Here are some sub-layers of Layer 3/Network Layer:

1. Sub-network Access: It deals with the protocols that interfere with a network such as X.25

2. Subnetwork Dependent Convergence: The sublayer is used when necessary to raise the level of a transit network to that of the network on either side.

3. Sub-network Independent Convergence: This layer transfers across multiple networks such as CLNP (Connectionless Network Protocol) or IPv7.

Summary: The Network Layer or Layer 3 is primarily responsible for routing, fragmentation, and reassembling data packets, error handling, and logical addressing. It plays a crucial role in ensuring the data is delivered correctly.

What is an MPLS VPN?

An MPLS VPN (Multiprotocol Label Switching Virtual Private Network) is a virtual private network that utilizes Multiprotocol Label Switching (MPLS) technology.

VPN providers and Internet Service Providers (ISPs) use MPLS VPNs because they offer secure and reliable connectivity to their customers. 

These VPNs use advanced networking technologies to create and manage communications within a VPN environment.

Why Use the MPLS Network?

The main advantage of MPLS VPNs is their secure and reliable connectivity. Organizations can establish private and controlled communication channels between remote sites, ensuring their traffic is routed according to their specific requirements. 

Organizations seeking to control their data and network infrastructure can take advantage of MPLS VPNs because they offer a high level of control and privacy.

Furthermore, MPLS VPNs offer a high level of customization, allowing organizations to tailor their services to their unique needs. 

This flexibility allows businesses to optimize network performance, ensure data privacy, and maintain strict access controls – all while benefiting from the scalability and cost-effectiveness inherent in a managed VPN service.

MPLS vs. VPN

MPLS (Multiprotocol Label Switching) and VPN are two technologies used to establish private and secure connections between devices or networks. 

Although both technologies provide secure and private connections, they operate differently and have unique advantages and disadvantages.

When to Use Each?

MPLS: Use MPLS when you need a high-speed, reliable, and scalable connection for large-scale networks. It is suitable for organizations with complex network infrastructure and high bandwidth requirements.

VPN: Use a VPN when you need a secure and flexible connection for remote access or small-scale networks. It is suitable for organizations with limited budgets and infrastructure.

Is VPN a layer 2 or Layer 3?

Layer 2 VPNs, also known as Virtual Private LAN Service (VPLS), are used to transport Layer 2 protocols, such as Ethernet frames, between different sites. 

It facilitates the communication of sensitive information by connecting and sharing VLANs. Layer 2 VPNs establish communication between national offices, connecting remote sites to a central location and linking multiple sites.

In contrast, Layer 3 VPNs, also called Virtual Private Routed Networks (VPRN), operate at the network layer and route traffic between sites using IP addresses. 

They primarily transmit data within the backend of the VPN infrastructure, such as VPN connections between back offices or data centers. 

Layer 3 VPNs are designed to secure peer-to-peer connections for remote workers, suppliers, or offices in different regions.

Why Use Layer 2 VPN?

Layer 2 VPN provides low latency, high performance, and scalability. It is suitable for applications that require low latency, such as gaming, VoIP calling, video conferencing, network virtualization, etc. Layer 2 VPN also offers high performance through seamless integration and high-speed data transfer. 

Why Use Layer 3 VPN?

Layer 3 VPN provides better security, flexibility, and scalability. They are suitable for applications that require high security, such as Personal Identifiable Information (PII), Personal Health Information, or classified information. These VPNs are also flexible and scalable for large-scale networks and businesses.

VPN protocols also directly impact VPN performance. Some major protocols, such as WireGuard, OpenVPN, Shadowsocks, etc., are widely used for an optimized and secure experience. Ensure that you’ve selected the appropriate VPN for your needs.

Frequently Asked Questions (FAQs)

Can Layer 2 and Layer 3 VPNs be Used Together?

Layer 2 and Layer 3 VPNs can indeed be used together to enable organizations to achieve a more comprehensive, diverse, and flexible network infrastructure.

What are The Benefits Of Combining Layer 2 and Layer 3 VPNs?

Combining the Layer 2 and Layer 3 VPNs could have potential benefits, such as Improved performance, scalability, security, customized solution, and flexibility.

Conclusion

Hope you’re now clear about Layer 2 vs Layer 3 VPN. 

Layer 2 operates at the Data Link layer of the OSI model. It allows virtualized network connections between two or more network devices as if they were physically connected.

Layer 3 operates in the Network Layer of the OSI model and provides secure communication between multiple sites by using IP routing and forwarding.