etherchannel allows to bundle multiple links and to make them appear as only one link.
The best way to build the bundle is the use of standard based LACP protocol as it permits a form of signalling on each member link ( each member link status is negotiated with the other side) and this allows to detect misconfigurations and errors in cabling that may lead to different member links connected to two different devices ( not supported).
Cisco etherchannel allows to build bundles in a silent not negotiated way, but experience says that nowdays this is not recommended as unconditional bundling cannot detect some errors like having different member links connected to two different switches. Also there is no knowledge if the other side is acting as a bundle or not.
A layer2 etherchannel is seen as a single link by STP allowing to use all the member links for better performance. Most of the times a layer2 etherchannel is configured as a trunk ( 802.1Q more often) and can carry multiple Vlans/broadcast domains.
Layer2 etherchannels are best suited for interconnection of L2 LAN switches providing at the same time better performance and link fault tolerance.
In order to setup a L2 etherchannel acting as a trunk member links have to be configured at the same way:
same trunking encapsulation protocol
same native vlan ( for 802.1Q)
the same list of Vlans permitted on each member link
A Layer3 etherchannel is like a single port configured in routed mode with no switchport, there is no concept of Vlans here, an IP address is associated to the port-channel logical interface, no ip address is configured under member interfaces. Layer3 port channel are used for interconnecting routers with routers or routers with multilayer switches for the same reasons of increased performance and link fault tolerance. No L2 signalling protocol including STP plays a role on Layer3 port channel.
In order to setup a L3 etherchannel acting as a trunk member links have to be configured at the same way:
L3 etherchannels are used in Service Provider networks to scale over 10GE speeds between core routers like CRS or ASR 9000 using bundles of 4 or more tengigabit interfaces.
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.