channel protocol is not mandatory. (do you mean pagp?) (do you mean LACP?)
if you're talking about pagp specifically then this protocol is used to facilitate the auto creation of ether channels by exchanging packets between ethernet ports. pagp is used for ports in Auto or Desirable modes only. pagp is not exchanged between on or off mode ports.
LACP supports the auto creation of etherChannels by exchanging packets between ports. lacp is used for ports in passive & active modes.
etherChannels can be used for portAggregation to facilitate link redundancy, increased link bandwidth and load balancing.
by default, the above is basically the same configuration.
channel-group 1 mode auto
(this is a pagp default config)
channel-protocol 1 pagp
channel-grouop 1 mode auto
(this specifies the port can only talk pagp, not lacp)
basically, both examples achieve the same results, a PAGP etherChannel in Auto mode. (the auto mode places the lan port into a passive negotiating state. the port responds to pagp packets it receives but does not initiate pagp negotiation. this is default behavior)
So you should use channel-protocol command when you would like use some dynamic method to establis etherchannel, I mean that you don't define the etherchannel with "on" option. So when you want to use some dynamic option to establish the eteherchannel you need define the protocol, if your switch support more etherechannel protocol - Cisco 2950 only support PagP (Cisco solution).
If your switch support only PagP next command is enough since channel-protocol is pagp in default:
sw1(config-if)#channel-group 1 mode auto
sw2(config-if)#channel-group 1 mode desireable
You can't use boths side auto...
I case of when switch support both LACP and PagP you should use channel-protcol command to define what kind of protocol you want use.
how to configure an etherChannel depends on the switch type/IOS/CATos you have.
the channel-group command is configured at the interface level. it defines the channel-group that the interface belongs to. this allows you to add 2 or more links to the same channel-group, there by creating a logical link of 2 or more lan ports.
the channel-protocol command is optional. it restricts the channel-group command to the etherChannel protocol configured with the channel-protocol command. in other words, it makes the specified lan port accept only one of the two channel protocols, ie: pagp or lacp.
the configuration steps vary depending on if you are creating a Layer2 etherChannel or a Layer3 etherChannel.
see the following link for steps and configuration example(s):
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.