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.

  • What's the actual operational speed of the portchannel and the individual ports? – Teun Vink Oct 13 '13 at 16:10
  • 1
    Speed is not the right question, latency will be driven by the line rate of an individual link.Throughput depends on hardware, Nexus uses a 512 bit algorthum so you will get number of links at best. cat uses an XOR type hash so its smallest power of 2 X number of links at best. – fredpbaker Oct 14 '13 at 2:52
  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer. – Ron Maupin Aug 8 '17 at 14:58

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)


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