Etherchannel

[cciepending]

Hi All

What is the real difference between L2 and L3 etherchannels?

[cadet alain]

Hi,

The same difference there is between a L2 port and a L3 port.

Regards.

Alain.

[Rahul Kachalia · Accepted solution]

Hello,

Some are identical and some are different:

Operational:

- Common mechanic between L2 and L3 EtherChannel is link bundling technique - PAgP, LACP. They function independently in which mode the EtherChannel is deployed in.

Control-Plane:

- L2 EtherChannel - Certain protocols like STP operates on logical EtherChannel interface. However certain protocols like DTP, CDP, PAgP, LACP etc operates on each individual member-link of same EtherChannel. Some of these protocols operate in independent interface mode.

- L3 EtherChannel - All protocols like OSPF/EIGRP/PIM etc operates on logical Layer 3 EtherChannel. All L2 protocols like CDP for example operates on each individual L3 member-links

Forwarding-Plane:

Answer really depends. If the system is standalone L2/L3 system then common fwding mechanic.

But if system is in virtual-switch mode like VSS, then unique hw based traffic-engg to load-share traffic intelligently between two systems.

Refer to Chapter 2 for more details in following guide:

http://www.cisco.com/en/US/docs/solutions/Enterprise/Campus/Borderless_Campus_Network_1.0/Borderless_Campus_1.0_Design_Guide.pdf

thanks,

rahul.