LACP (Link Aggregation Control Protocol) and PAGP (Port Aggregation Protocol) are both protocols used for link aggregation, which is the process of combining multiple physical links between network devices to increase bandwidth and provide redundancy.

LACP:

• Stand for Link Aggregation Control Protocols
• LACP is a standard protocol defined in IEEE 802.3ad
• LACP is a standardized protocol, which means that it can be used with a wider range of network devices from different vendors. PAGP, on the other hand, is specific to Cisco devices.
• LACP supports two modes of operation:

Active : LACP actively sends out LACP packets to negotiate the link aggregation

Passive : the device only responds to LACP packets it receives

• LACP supports several load balancing algorithms, including source-destination IP address, source-destination MAC address, and source-destination TCP/UDP port number. PAGP supports only the source-destination MAC address algorithm.
• LACP includes error detection mechanisms to detect and recover from link failures
• LACP includes error detection mechanisms to detect and recover from link failures,

PAGP:

• Stands for Page Aggregation Control Protocol.
• PAGP is a proprietary Cisco protocol.
• specific to Cisco devices.
• PAGP has three modes of operation: Desirable, Auto, and On.

Desirable & On :

Desirable mode actively tries to form an Ether Channel with another device in Desirable or

On mode.

Auto: In Auto mode, it waits for a PAGP packet from another device.

• PAGP supports only the source-destination MAC address algorithm.
• PAGP does not have such mechanisms.