What is the difference between flexlink and LACP ?

[koushik.tadikonda]

What is the difference between flexlink and LACP ?

[Bilal Nawaz]

Flexlink is a pair of L2 links, where one is used as a backup in case the primary one fails. LACP is a protocol used to negotiate the bundling/aggregation of multiple interfaces, in to one logical link.

In short these technologies provide

Flexlink = Active / Standby

LACP = Active / Active

Hope this helps.

Bilal

[koushik.tadikonda]

I think they both are Used for Redundancy  .... am i correct ??

[Bilal Nawaz]

Yes Koushik, both are used for redundancy, though LACP does have another benefit and use.

The benefit and use is to aggregate multiple links to provide more bandwidth. e.g. we have x2 1gb connections, if we were to bundle them together, total bandwidth would be 2gb instead of 1gb.

With flexlink, only one link can be active, so only 1gb bandwidth available at any one time.

Bilal

[koushik.tadikonda]

Thank you Bilal. Which is better to use LACP or Flexlink ?

Even a bundle can be configured as Flexlink and LACP is configured on bundles 

[Bilal Nawaz]

Yes Koushik, you are correct. Even an LACP port-channel L2 can be configured as a flexlink. Which one should you use? Well it depends on what your requirement is.

[Madhukrishnan Gopinathan Nair]

I think there is a world of difference between these 2 technologies.

Port-channels is a technique which helps to increase the bandwidth between 2 nodes by using redundant links between them bundled in to one logical link. This also avoids blocking of redundant links by STP.

Flex link is a an alternate technique in place of STP which has the concept of back up links.

It disables STP, but still you have only 1 link active between 2 nodes and the redundant will be kept as back up.  On link down it enables back up very fast. 

So these are 2 different techniques.

Hope this helps.

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Thanks,

Madhu.

[Bilal Nawaz]

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[Bilal Nawaz]

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[Bilal Nawaz]

Hi Madhu, you are correct, though it could be argued that lacp can and infact is used for redundancy purposes as well as aggregated bandwidth - they no longer become redundant - they are active