Hi, cisco still has restriction when it come to configuring etherchannel, there are restrictions on the number of ports allowed in a bundle, requirement of adjacent ports and more. Have a look at a great document on etherchanne requirements and setup below. I hope this is helpful
Catalyst 3750 Series Switches
Refer to the support page for the Catalyst 3750 Series Switches for more information on these switches.
Catalyst 3750 series switches support both Layer 2 and Layer 3 EtherChannel, with up to eight compatibly configured Ethernet interfaces. All interfaces in each EtherChannel must be the same speed. All interfaces in each EtherChannel must have a configuration as either Layer 2 or Layer 3 interfaces.
The EtherChannel can be formed with interfaces on any switch and across switches within a single switch stack. Refer to Cross-Stack EtherChannel on a Catalyst 3750 Switch Configuration Example for more information on Cross-Stack EtherChannel.
The Catalyst 3750 series switches support a maximum of 12 EtherChannels with configuration on a stack.
In order to balance the traffic load across the links in a channel, EtherChannel load balancing can use any of these addresses:
MAC addresses or IP addresses
source or destination addresses
both source and destination addresses
The default configuration is the forward of source MAC addresses. Refer to Configuring EtherChannel for more information on load balancing on the 3750.
Catalyst 3750 series switches support EtherChannels in Cisco IOS Software Release 12.1(11)AX or later.
Hi, if you are configuring the link manually all parimeters have to be set the same on both links. Since I think you have all cisco switches check your PAgP and see if the port will form there own etherchannel link.
Sounds like you have 1 or more ports that are not exactly the same as the others. All ports must be configured exactly the same for all parameters such as speed and duplex . For cross stack you must either force the channel on or you can use LACP , PAGP is not an option on cross stack.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...