Setting up etherchannel!!

Unanswered Question
Jul 17th, 2007

Hi to all,

I need some help with the setting up of etherchannel in a network setup of mine (see attached picture). I wanted to know if the load balancing done by etherchannel is per-packet using plain round-robin like with the command "ip load-sharing per-packet" or something else.

I tried to look for more info regarding the following command, but not much is stated about the type of load balancing done. It is only said that some hash algorithm is used. I dont know if the source-and-destination MAC address forwarding is what i'm looking for.

port-channel load-balance {src-mac | dst-mac | src-dst-mac | src-ip | dst-ip | src-dst-ip | src-port | dst-port | src-dst-port}

In the setup, I want to setup etherchannel between the 4 PCs(A-D) and Switch 2. How should I go about it. The PCs(A-D) have IP addresses and are connected to the ports FaEth1-4 of a 2950 Series switch. The PC are basically Linux firewalls. How do I configure the PCs for forwarding traffic to the etherchannel? Are there options for supporting Cisco's etherchannel technology in Linux?

Warm regards,


I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)


Etherchannel is used between two devices for example between two switches to increase the bandwidth by bundling up to 8 ports achieving 8*100M or 8*1G or 8*10G depends on the port type. I guess you want to configure some form of traffic distribution between four servers. if so than the SLB is your choice or NAT. What kind of switch u have?

Hope it helps,


vishamr2000 Tue, 07/17/2007 - 08:39

Hi Krisztian,

I have a Catalyst 2950 Series switch. I actually saw in certain pictures of cisco documentation where the endpoint of an etherchannel was a server with 2 channels connected to it. I basically want to load balance traffic between the 4 PCs from Host 2 in the setup diagram I attached. I am not able to find enough info about the load balancing done in an etherchannel.

By the way, do you know whether a multi-layer switch can accept static routes and commands like "ip route-cache" and " ip load-sharing per-packet". I know most routers do but is there a switch that does that as well?

If you have any info regarding this, then pls let me know..

Warm regards,


glen.grant Tue, 07/17/2007 - 09:33

The load balance is done via a hashing algorithim via either the mac or ip addresses used in a conversation . Everything in a particular conversation will always go down the same pipe .

Hi Visham,

Well, if the NIC's are in the same server then no problem, but if I understood correctly you want to connect to 4 different PC's. Furthermore your OS and NIC's have to link aggregation too. The multilayer switches are using cef (ip cef) which is the most efficient way of forwarding mechanism implemented in hardware by means of ASIC but please note that 2950 is L2 switch. As I saw the ip load-sharing per-packet is platform dependent but the per destination is supported by default.

Hope it helps,


vishamr2000 Wed, 07/18/2007 - 10:48

Hi there,

Yes I want to connect to 4 different PCs but which are found on the same subnet, hence they all are pointing towards the same network.

I read about CEF and it has to be enable in order to do per-packet load balancing (PPLB). However, while it works fine on routers, i dont know if CEF allows PPLB on multilayer switches. I came across this bit of info from a document entitled "Configuring Cisco Express Forwarding" [XC-29-XC-32, Cisco IOS Switching Services Configuration Guide]

"Note Per-packet load balancing via CEF is not supported on Engine 2 Gigabit Switch Router (GSR) line cards (LCs)."

Can someone pls explain the above statement to me. I understood it as saying that PPLB via CEF is not allowed on multilayer switches. Is there a document that states whether PPLB via CEF is allowed on multilayer switches?

One thing more, what is the maximum number of Fast Ethernet ports in existing Cisco routers?Which Cisco router is that?

Many thx to Krisztian & glen.grant for their input...much appreciated!!

Warm regards,



This Discussion