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

[Stefan Fouant]

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

In the meantime, why not just run LACP across your LAG interface?  This 
can accomplish the goal quite easily.

> Are individual links in the LAG able to detect failures with OAM?

Should be able to but I would of course test it first... :)

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