📖 What is Link Aggregation Control Protocol (LACP)?
Link Aggregation Control Protocol (LACP) is a vendor-neutral standard used to bundle multiple physical network links into a single logical link. This process, known as link aggregation, increases available bandwidth and provides redundancy by automatically managing the failover between the combined physical ports.
"Remember that LACP is the industry standard (IEEE 802.3ad), whereas PAgP is Cisco-proprietary. If the exam mentions 'industry-standard aggregation,' think LACP."
📚 Certification: CompTIA Network+ Certification Exam (N10-009)
🔑 What are the Key Concepts of Link Aggregation Control Protocol (LACP)?
- ▸ LACP follows the IEEE 802.3ad standard, ensuring interoperability between networking equipment from different vendors, unlike proprietary protocols such as Cisco's PAgP.
- ▸ It provides increased aggregate bandwidth by combining multiple physical Ethernet links into one logical channel, reducing congestion between high-traffic network devices.
- ▸ The protocol offers automatic redundancy; if one physical link in the bundle fails, traffic is instantly redistributed across the remaining active links.
- ▸ LACP uses 'Active' and 'Passive' modes to negotiate the formation of the link aggregation group, determining which device initiates the connection.
- ▸ Traffic is distributed across the physical links using a load-balancing algorithm, typically based on source and destination MAC or IP addresses.
🎯 How does Link Aggregation Control Protocol (LACP) appear on the N10-009 Exam?
You may be asked to identify the best solution for increasing bandwidth between two core switches while maintaining redundancy, specifically when the hardware is from different manufacturers.
A scenario might describe a server with multiple NICs that needs a single logical connection to a switch to prevent a single point of failure and increase throughput.
Expect questions where you must distinguish between LACP and PAgP based on whether the requirement specifies an industry-standard or a vendor-specific configuration.
❓ Frequently Asked Questions
Does LACP increase the maximum speed of a single data transfer?
No, LACP increases the total aggregate capacity of the link. A single TCP session is typically limited to the speed of one physical member link to avoid out-of-order packets.
What is the difference between LACP Active and Passive modes?
Active mode actively sends LACP packets to negotiate a bundle. Passive mode only responds to LACP packets. At least one side must be set to Active for the link to form.