Re: [mpls-tp] about open discussion about MIP MEP in MPLS-TP networks

[John E Drake <[e-mail]>]

Snipped...

In the context of MPLS-TP what is a 'non-drop eligible frame'?  For one thing, we deal in packets.  For another, within a packet, where is this non-drop eligibility information carried?

Also, what does 'congestion on the links' mean?

Sent from my iPhone


> > [[[Sasha]]] Let's start from the fact that in packet (and, BTW, ATM)
> > networks, frames are discarded not only due
> > To bit errors, but also (and mainly) due to congestion. Congestion
> does
> > not have any analog in SDH.
> > In addition, indication of frames discarded due to CRC errors happens
> > only at the data link layer
> > (which MPLS-TP is not), and its indications are not forwarded
> anywhere.
> 
> [maarten] I am very much aware of the discarding due to congestion. I
> am
> also aware that in transport networks the expectation is that such
> discarding will be rare conditions for the non-drop eligible frames.
> 
> [maarten] The counting of transmitted and received frames and the
> computation of the difference presents the number of non-drop eligible
> frames that have been lost due to bit errors on the links and
> congestion on
> the links. The absence of an expected frame is a very good indication
> of
> such loss at an upstream point in the connection. The absence is
> forwarded
> by means of the transmitted and received counts.
> 
> I hope this clarifies my view a bit better.
> Regards,
> Maarten
> 
o/mpls-tp