[j-nsp] ECMP vs LAG and OAM vs BFD

[Rafael Rodriguez]

On Fri, Jul 22, 2011 at 4:14 PM, Stefan Fouant <
sfouant at shortestpathfirst.net> wrote:

> On 7/22/2011 11:24 AM, Rafael Rodriguez wrote:
>
>>
>> Interesting, did not know that control packets were always sent on the
>> lowest numbered interface in a LAG.  Are you aware of any Juniper
>> documentation mentioning this?  I found KB10926 but this is specific to
>> EX and not MX. So LAG + BFD will do nothing in determining if individual
>> links in the LAG are actually 'up'.  Thanks.
>>
>
> I am not sure of any documentation but we do cover this in some of our
> training materials.  I will see what I can dig up.
>
> Regarding BFD's capabilities to determine member state of individual member
> links, this is not currently supported by BFD.  Take a look at IETF Draft
> 'Bidirectional Forwarding Detection (BFD) for Interface' which was just
> released a few weeks ago. It is designed to meet these requirements -
> http://tools.ietf.org/html/**draft-chen-bfd-interface-00<http://tools.ietf.org/html/draft-chen-bfd-interface-00>
>
> In the meantime, why not just run LACP across your LAG interface?  This can
> accomplish the goal quite easily.


No sub-second failure detection, its 1-3 sec range.


>
>
>  Are individual links in the LAG able to detect failures with OAM?
>>
>
> Should be able to but I would of course test it first... :)
>

Testing this now.  Found:
http://www.juniper.net/techpubs/en_US/junos11.1/topics/example/layer-2-802-1ah-ethernet-oam-lfm-example-for-aggregated-ethernet-mx-solutions.html



>
> Stefan Fouant
> JNCIE-ER, JNCIE-M, JNCIE-SEC, JNCI
>
> Technical Trainer, Juniper Networks
> http://www.shortestpathfirst.**net <http://www.shortestpathfirst.net>
> http://www.twitter.com/sfouant
>