I see on Cisco guide that:
Each EtherChannel can consist of up to eight compatibly configured
Ethernet interfaces. All interfaces in each EtherChannel must be the
same speed, and all must be configured as either Layer 2 or Layer 3
interfaces
But when I try combining 2 fast ethernet link and 1 gigabit link in packet tracer, there is no error:
Group: 1
----------
Port-channels in the group:
---------------------------
Port-channel: Po1 (Primary Aggregator)
------------
Age of the Port-channel = 00d:00h:06m:15s
Logical slot/port = 2/1 Number of ports = 3
GC = 0x00000000 HotStandBy port = null
Port state = Port-channel
Protocol = LACP
Port Security = Disabled
Ports in the Port-channel:
Index Load Port EC state No of bits
------+------+------+------------------+-----------
0 00 Gig1/1 Active 0
0 00 Fa0/2 Active 0
0 00 Fa0/1 Active 0
can anyone explain this ? thank you.
Best Answer
Packet tracer is a simulation for Network academy not a IOS emulator (like say GNS3) if there is a conflict between the doc and packet tracer, packet tracer looses. If you read further in the documentation a LOT of things have to match for an etherchannel bundle can form and link speed is one of them.
A corner case MAY be etherchannel autonegotated ports that end up at different speeds, but etherchannel will react to dynamic changes and drop ports out of the etherchannel so I don't think that will work.
Nor do you want it to as with non nexus hardware the load balance is power of 2 (3 ports will result in 1 of them getting 50% of the traffic) and there is no variable load balancing (a gig port gets 2x traffic of say 5 100 meg ports)