[quagga-dev 11766] Re: [PATCH v2] zebra: Set link-detect on by default

Paul Jakma paul at jakma.org
Fri Nov 21 10:39:42 GMT 2014

On Fri, 21 Nov 2014, Christian Franke wrote:

> Well, there are some options that were pointed out which allow to change 
> the default with less negative impact. One of the easiest would be (as 
> you pointed out yourself) to release 0.99.24 with code that doesn't 
> change the default, but does write "no link-detect" to the 
> configuration. Then, in 0.99.25, the default could be changed to do link 
> detection, and old users would hopefully have "no link-detect" in their 
> config then, overwriting the new default.

Yes, that approach could reduce the set of affected users. However, it 
still can't guarantee reducing the set to 0. So, you ultimately still end 
up having to negatively impact some users, and relying on documenting the 
change for them.

I didn't think link-detect warranted this long approach, nor am I sure 
this approach will be as effective in this case given the kind of users 
affected. But hey..

> Discussing this, we came to the conclusion that there is one other issue
> with the patch:
> There is no way to disable link-detect permanently for some interface,
> as "no link-detect" is currently not written out to the configuration.

Ah, oops. The vty code still think link-detect is the default. See 
zebra/interface.c::if_config_write :) - the sense of the config write-out 
also needs to be reversed in the patch. :) Doh. :)

Paul Jakma	paul at jakma.org	@pjakma	Key ID: 64A2FF6A
People are like onions -- you cut them up, and they make you cry.

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