Cisco LAG vs LACP: Difference and Comparison

In the 1980s, Ethernet was developed to connect local devices in a region. It was called the Local Area Network. The purpose was to transmit and receive data from different people in the area.

By connecting Ethernet devices using Ethernet switches, we can now connect over a larger Ethernet network. Link aggregation is a common terminology that can describe bridging well.

Key Takeaways

1. LAG is a link aggregation technique, while LACP is a protocol used for link aggregation.
2. LACP supports dynamic link aggregation, while LAG does not.
3. LAG can be used with or without LACP, while LACP requires LAG.

Cisco LAG vs LACP

The difference between Cisco LAG and LACP is that Cisco LAG is an instance for link aggregation, while LACP is the action that creates an instance of link aggregation. If we look at LAG as a process, LACP is the protocol that governs the process.

Cisco LAG is the combination of two devices with more than one link. With the Link Aggregation Group, we can combine multiple network interfaces into a single intellectual interface that increases the speed of the network.

In addition to LAG, it is also known as Ethernet bonding, as it groups Ethernet links between two ethernet devices.

LACP is the monitoring unit that controls the operation of the LAG. Link Aggregation Control Protocol justifies its name as the protocol that allows LAG to function independently.

On the other hand, we can create a static link aggregation group without implementing any link aggregation control policy. Optionally, we can use LACP to protect the connection.

Comparison Table

Parameters of comparison	Cisco LAG	LACP
Known as	Link Aggregation Group.	Link Aggregation Control Protocol.
Definition	Cisco lag is a technique.	LACP is a protocol that controls the technique.
Purpose	Clubs multiple ports between two ethernet devices.	Monitors the function of LAG.
Static mode	LAG is required.	During static mode, LACP is not required.
Dependency	LAG can operate without LACP, that is, it is independent.	Dependent, i.e. it is a protocol, and you need some technique (like LAG) that you can use to start your control.

What is Cisco LAG?

Cisco LAG or Link Aggregation Group combines numerous interfaces into one main interface. LAG is also known as Ethernet bonding, link pooling, network interface controller bonding, and port aggregation.

The interfaces or ports are connected in parallel between the Ethernet switches. 

You can connect two switches or a huge network or multiple ports, or a server. Network devices see the LAG or a combination of multiple links as a single link. LAG can be inserted into VLAN.

In addition, multiple LAGs can be formed on a specific switch. You can also add more Ethernet ports to the specified LAG. The capability of the device decides the number of links that can be attached or grouped.

There are a few perks of link aggregation, and they are as follows

• Link aggregation is inexpensive. We could improve connectivity by increasing bandwidth, whereas it would have cost a lot if we had to install new cable runs.
• Link aggregation allows for the expansion of bandwidth that serves as a single link but is actually an aggregation of numerous links.
• Link aggregation balances the traffic load by dividing it among the physical links.
• The other will not be broken if one link is lost or broken. Networking is not delayed, and the damage can be repaired until then.

What is LACP?

In the 1980s, Ethernet was developed to connect local devices in a region. It was called the Local Area Network. The purpose was to transmit and receive data from different people in the area.

By connecting Ethernet devices using Ethernet switches, we can now connect over a larger Ethernet network. Link aggregation is a common terminology that can describe bridging well. 

LACP needs to be supported on both devices in order to implement its service. LACP converts a static link aggregation group to a dynamic link aggregation group.

On the other hand, you can establish a non-dynamic configuration without linking LACP into your link aggregation group.

When laying the connections, it should be noted that the connections should have a similar resistance. For example, if one link is 100 Mbit / s, the other must also be 100 Mbit/s, otherwise, the LACP would indicate this as a bad configuration.

The links should be either full-duplex or half-duplex; otherwise, it would not support the configuration of the link aggregation group.

Dynamic-link aggregation is appreciated over static link aggregation because LAG can not detect faulty configuration on its own, it needs a link aggregation control protocol to detect it. It is also economical.

Main Differences Between Cisco LAG and LACP

1. LAG is known as Link Aggregation Group, and LACP is known as Link Aggregation Control Protocol.
2. Cisco LAG is the combination of two devices with more than one link, whereas LACP is the monitoring unit that controls the operation of the LAG.
3. The purpose of LAG is to club multiple ports between two ethernet devices, while the purpose of LACP is to monitor the function of LAG.
4. Cisco LAG can exist without LACP, and then it is known as the static configuration of LAG.
5.  LAG isn’t always dependent on LACP, while LACP is depending on LAG.

References

1. https://repository.unad.edu.co/handle/10596/41996
2. https://link.springer.com/chapter/10.1007/978-1-4842-6672-4_5