Why Would a Layer 2 Switch Need an IP Address?

A layer 2 switch is a network device that carries Ethernet traffic between two networks.

Its IP address is used to access its administrative interface and configure the device.

It also allows administrators to turn up or down ports on the device.

IP addresses are not used to route traffic other than administrative traffic.


A Layer 2 switch is a type of network device that acts as a bridge between several devices.

It works on the Data Link Layer and uses MAC addresses to distinguish between data packets.

These switches help reduce the collision domain in networks, which can occur when two network devices attempt to send data packets to each other at the same time.

A layer 2 switch can be used to route a large number of packets to different destinations.

It can be configured to perform flooding or unicast routing.

In addition, it can support multiple interfaces, which can be configured for different protocols.

This configuration is particularly useful for networks that experience high traffic.

In the past, LANs were designed to be connected to one central device called a hub.

While hubs were great for network connectivity, they came with distinct drawbacks.

In addition to limited ports, they did not know what traffic was going through them.

A switch, on the other hand, can inspect incoming traffic and make forwarding decisions.

In addition, each port on a switch has its own collision domain.

Depending on the requirements of your network, you may need to use more than one layer of switching.

For example, one network may be more important than another. A layer 2 switch allows you to use both.

The most important thing to remember when choosing a switch is that you have to choose a subnet that is large enough to accommodate all of the traffic on the network.

If you use a /24 network, you can support up to 254 hosts.

A /25 network, on the other hand, can support a larger number.

A /25 network can be used to support IP phones, printers, and SAN infrastructure.

Using sub-interface syntax, a layer 2 switch can create a VLAN by creating one physical interface for each sub-interface.

A VLAN ID will be specified as the number following the physical interface.

Then, you can select this interface as the default gateway for packets from host A to host B.

This way, packets from host A to host B will be routed through the same VLAN without going through L3 processing.

Default gateway

The Default gateway of a layer 2 switch is the first port that a remote host can connect to.

By default, the default gateway is enabled.

This means that multiple inputs can all proceed simultaneously on the same output path.

This feature is called an automatic metric. This feature determines how fast the network can travel to a destination. This is done by allocating a metric to each route.

Default gateway addresses are required when devices that require a router cannot be directly connected.

This is true whether the devices are on the same network or in different networks.

However, if a switch is not configured to be a router, it must use its default gateway in order to perform management functions.

Otherwise, it has to adjust the routing protocol, rules, or policy to handle the traffic it receives.

To configure a default gateway for a layer 2 switch, you can use the ip default-gateway command.

The default gateway will be the IP address of the switch’s interface with the router.

Once you’ve configured this setting, you can back up the configuration with the copy running-config startup-config command.

You can also use the show IP interface brief command to see the status of each physical and virtual interface.

Default gateways are not required if your switch supports layer 3 functionality.

In layer 2 networks, devices can communicate with each other but cannot communicate with each other outside the VLAN.

Therefore, a layer 3 switch is needed if you need to route traffic outside a single subnet.

Layer 2 switches are more efficient than their counterparts and can be used to improve network performance.

Layer 3 switches perform routing functions on a network and act as a virtual LAN.

A layer 2 switch is faster than a router and can route traffic between two devices on the same subnet.

Priority of traffic

Priority of traffic is a feature that a Layer 2 switch can use to prioritize inbound and outbound traffic.

Priority numbers are assigned to data packets based on a priority level.

Generally, higher priority values are delivered first, and lower priority values wait in a queue.

Priority numbers are particularly important for real-time streaming data, which can be affected by network jitter or stuttering.

Higher priority values are also available for data flows such as File Transfer Protocol (FTP) and other high-speed networks.

Layer 2 switches also implement filtering rules to prevent unnecessary traffic.

For example, unicast traffic can cause network congestion and even network service loss if the destination MAC address is unknown.

By enabling filtering for unicast traffic, network administrators can keep tighter control of the amount of traffic going through their network.

Layer 3 switches support traffic marking to differentiate high-priority and low-priority applications.

Typically, QoS values are assigned to eight different traffic classes.

The switches can then place packets into queues according to the class assigned.

This helps to reduce congestion in choke points.

A Layer 2 switch should support both broadcast and multicast traffic.

In both cases, a broadcast domain is a logical division of a network.

It is used to send data to multiple devices in one network. Unlike multicasting, unicasting is sent to one node, while multicasting sends it to multiple nodes.

QoS helps organizations prioritize applications and resources.

It guarantees high performance for critical applications while simultaneously ensuring low latency and reduced jitter.

QoS also helps enterprises prioritize other types of traffic and ensure optimal network performance.

Its benefits include enabling better resource utilization, reduced latency, and improved network security.

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