Port Aggregation Protocol
Encyclopedia
Port Aggregation Protocol (PAgP) is a Cisco Systems
proprietary networking protocol, which is used for the automated, logical aggregation of Ethernet
switch ports, known as an etherchannel
. This means it can only be used between Cisco switches and/or switches from licensed vendors. A similar purpose protocol known as LACP, released by the IEEE known as 802.3ad, is an industry standard and is not tied to any specific vendor.
PAgP can be configured on a Cisco switch to operate in three different modes.
- auto : Passive negotiation of the channel.
- desirable : Active negotiation of the channel.
- on : No protocols are used, it assumes the other side has also enabled link aggregation.
On Cisco network devices running CatOS, a single switch module may only be configured to run in either LACP or PAgP modes. Cisco devices that run IOS (native and/or non-hybrid mode boxes) support individual port configuration for LACP and are not restricted to per module settings as with CatOS.
SMLT protocol removes this limitation by allowing the physical ports to be split between two switches in a triangle configuration or 4 or more switches in a mesh configuration.
Cisco Systems
Cisco Systems, Inc. is an American multinational corporation headquartered in San Jose, California, United States, that designs and sells consumer electronics, networking, voice, and communications technology and services. Cisco has more than 70,000 employees and annual revenue of US$...
proprietary networking protocol, which is used for the automated, logical aggregation of Ethernet
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
switch ports, known as an etherchannel
EtherChannel
EtherChannel is a port link aggregation technology or port-channel architecture used primarily on Cisco switches. It allows grouping of several physical Ethernet links to create one logical Ethernet link for the purpose of providing fault-tolerance and high-speed links between switches, routers and...
. This means it can only be used between Cisco switches and/or switches from licensed vendors. A similar purpose protocol known as LACP, released by the IEEE known as 802.3ad, is an industry standard and is not tied to any specific vendor.
PAgP can be configured on a Cisco switch to operate in three different modes.
- auto : Passive negotiation of the channel.
- desirable : Active negotiation of the channel.
- on : No protocols are used, it assumes the other side has also enabled link aggregation.
On Cisco network devices running CatOS, a single switch module may only be configured to run in either LACP or PAgP modes. Cisco devices that run IOS (native and/or non-hybrid mode boxes) support individual port configuration for LACP and are not restricted to per module settings as with CatOS.
Limitations
A limitation of Port Aggregation Protocol is that all the physical ports in the aggregation group must reside on the same switch. Avaya'sAvaya
Avaya Inc. is a privately held computer networking, information technology and telecommunications company that is a global provider of business communications systems. The international head quarters is in Basking Ridge, New Jersey, United States...
SMLT protocol removes this limitation by allowing the physical ports to be split between two switches in a triangle configuration or 4 or more switches in a mesh configuration.