Before and After of EtherChannel

[Plutodelic]

yes guys this is a question if you wondered what i meant by the title.

My question though relys on the sense of etherchannel rather then any technical help.

I am currently working on my dissertation project for my university, and my topic is all about EtherChannel. So far from what i've read (yes, it is new to me, new for my level), i can tell that what EC offers is High Speed at Low Cost with configurable load balancing, thats the aggregation part, the other part is redundancy with extreme fast convergence in case of link fail and "transparent" to higher layer services (STP).

my question is, what are the default questions i should be asking myself before implementing EC. a good question that helped me was identifying bottlenecks on the network (imagine a mid size enterprise presented on the hierarchical layers) though the more i "researched" for traffic the more stupid it got since the idea of having redundancy everywhere is just RIGHT, so i ended up having a L3 EC between two core switches, L2 EC between Access and Distribution (and of course Distribution to Core), and another EC between a Server and an Access Switch (i am trying to show all possible scenarios of EC), in one word, i ended up with quite a lot of EtherChannels.

to ease the question, what should be undertaken first before implementing EC on an existing mid size business network?

best regards

Memli.

[Mahesh Gohil]

Hello Memli,

I can recall two goof up while designing etherchannel for my network. Just briefing them , may be useful to you

Think of

> Which hardware to use , as many hardware do not support source-destination based load balancing where you end up in

    only one link forwarding traffic   and other is ideal.

> Do you have any backup of this bundle. for example if total requirement of traffic is 200meg and there is

  backup bundle of 200meg.

      Now say if one link goes down from first bundle and the ability of first bundle will be   decreased to 100meg

  though you have backup bundle available. Here you should use minimum-active facility
  whereby if one link goes down whole of the bundle will go down and traffic will fallback to backup bundle

Hope this input will help you

Regards

Mahesh

[Plutodelic]

Mahesh thank you for your fast reply.

I did recon those steps, but they're more from e technical nature, though thanks for the backup idea, it sounds brilliant.

To help the question even more, how would you divide in tasks implementing etherchannel.

I do understand the technical work, from having the ports in the same state to chossing the right protocol. But i was thinking of what do network admins actually "brainstorm" before introducing EtherChannel. As i already said, my first question to myself was "where is the bandwidth needed", and i could identify that a specific tree needs additional speed, though when it comes to redundancy, i wouldnt spare a single link for it, which brought me to the question, can a whole network be EtherChanneled, is that a possible scenario?

Regards,

Memli.

[Ganesh Hariharan]

Mahesh thank you for your fast reply.
I did recon those steps, but they're more from e technical nature, though thanks for the backup idea, it sounds brilliant.
To help the question even more, how would you divide in tasks implementing etherchannel.
I do understand the technical work, from having the ports in the same state to chossing the right protocol. But i was thinking of what do network admins actually "brainstorm" before introducing EtherChannel. As i already said, my first question to myself was "where is the bandwidth needed", and i could identify that a specific tree needs additional speed, though when it comes to redundancy, i wouldnt spare a single link for it, which brought me to the question, can a whole network be EtherChanneled, is that a possible scenario?
Regards,
Memli.

Hi Memli,

When you say about etherchannel the most desirable aspect is the bandwidth,If you use 8 active ports a total bandwidth of 800 Mbit/s, 8 Gbit/s or 80 Gbit/s is possible depending on port speed Because EtherChannel takes advantage of existing wiring it makes it very scalable. It can be used at all levels of the network to create higher bandwidth links as the traffic needs of the network increase.

Other additonal advantages are if go in technical details it prevents from switchin loops with STP which treats all the links as a single one and BPDUs are only sent down one of the links. Without the use of an EtherChannel, STP would effectively shutdown any redundant links between switches until one connection goes down.

Redundancy is also maintained when you configure etherChannel all adapters that are part of the channel share the same Layer 2 (MAC) address. This makes the EtherChannel transparent to network applications and users because they only see the one logical connection; they have no knowledge of the individual links Fault-tolerance is another key aspect of EtherChannel. Should a link fail, the EtherChannel technology will automatically redistribute traffic across the remaining links. This automatic recovery takes less than one second and is transparent to network applications and the end user.

Hope to Help !!

Ganesh.H

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