[c-nsp] loop guard still useful?

Saku Ytti saku at ytti.fi
Mon Jan 18 05:46:07 EST 2016

On 18 January 2016 at 10:57, Michele Bergonzoni <bergonz at labs.it> wrote:


> So the dispute does half of what UDLD does, if I got it right.

Ethernet with autonegotiation on should detect unidirectional links
automatically and go down on both ends at RTT/2 delay.

On A-B link, where A=>B works but A<=B does not, A will go down and A
will assert RFI or remote fault indicator on the line. B will receive
this, and go down as well.

Some platforms can assert this RFI for non-fault reasons, like port
might be configured to assert RFI if xconnect/l2circuit goes down, so
client will see port physically down, if EoMPLS fails.


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