EtherChannel - Load Balancing Between 2 Equipment ??

hitmen

Part 1:
I have some problems with the concept of etherchannel.
I understand that etherchannel is used for bundling a logical interface between equipment A and equipment B.
In other words, 2 physical link terminating at the SAME EQUIPMENT.

However, my boss now wants me to load balance from equipment A to equipment B and C.
A to B is one link. (link number 1)
A to C is another link. (link number 2)

A

---

B
|
|
C

Can I put link 1 and link 2 together as an etherchannel?
In other words, 2 physical link terminating at the DIFFERENT EQUIPMENT??
My concept of etherchannel may be incorrect. Pls kindly assist. Thanks!




Part 2:
Is it possible to do load balancing WITHOUT configuring an etherchannel? (assume single link) Thanks!

networker050184

What type/model of equipment? What types of links are these? Routed or layer 2?

All of that will determine what you can do here.

EdTheLad

It's possible to load balance, but not using etherchannel, as you pointed out, etherchannel is used to bundle links between the same endpoints.Do you have two diverse paths to a single destination? are you using a routing protocol? if yes you can modify costs to make the path an equal cost path. What type of forwarding are you using? CEF? Fast switching? process switched? this will determine if you will forward per flow or per packet.If it's per flow, do you have a large number of flows? how exactly is the traffic load spread across flows?

it_consultant

Sounds like what he WANTS is a TRILL set up where all the ISLs are load balanced in the fabric. If you don't have that type of equipment than you can't do it unless you introduce some layer 3 concepts.

xXErebuS

You could use VSS/VPC if you have the equipment. I would just do load balancing via layer 3 unless your boss has deep pockets.

Cyanic

I have never tried this and I don't recommend this in a production environment, but it may be possible if you use etherchannel in mode "on". This should force device A to send packets out both links. This will only work for traffic leaving A; return traffic should always use just one of the links.

I have seen this done in production when device A is a server. It is known as Transmit Load Balancing at least in the HP world.
ftp://ftp.compaq.com/pub/products/servers/networking/teamingwp.pdf

As far a load balancing, ehterchannel provides a pseudo balance, and depending on the type of traffic you have and the balance algorithm used, you can get some not so balanced results, i.e., never expect a 50/50 balance.

hitmen

actually I made a mistake. Load balancing was instead to be done at L3.
If I do etherchannel links, can it be between L2 and L3 devices?

After I bundle an etherchannel and assign vlans to it, am I supposed to assign ip addresses to the vlan(VSI) or etherchannel to test connectivity?

I am quite confused here

Dieg0M

Assign IP addresses on the port-channel then you have a lot of possibilities to load balance. You can use different IGP's for load balancing or even route maps and load balance specific traffic.

hitmen

Is it possible to assign vlan to a port-channel?
Should I assign ip address to vlan to test connectivity?

hitmen

Ha. mY boss wanted me to do multichasis link aggregation
https://sites.google.com/site/amitsciscozone/home/link-aggregation/multichassis-link-aggregation-group

networker050184

MC-LAG support depends on your hardware. It's not something supported on your base Cisco devices.