IP and Optical domains?

Mark Tinka mark.tinka at seacom.mu
Wed Jun 22 11:49:47 UTC 2016



On 22/Jun/16 13:17, Masataka Ohta wrote:

>  
> What? "the visibility is there"?
>
> I think you mean IPoDWDM something so much different from
> usual ways to have IP over something.
>
> Do you have any reference to it?

I said "visbility" due to what IPoDWDM can offer.

But I also said IP has no real "awareness" about the physical
infrastructure. It just knows it can't send/receive packets anymore.

With IPoDWDM, one could infer that the IP layer will quickly re-route
due to DWDM characteristics (related to fibre conditions). However, in
actual fact, what IP really sees is the link going away, and thus,
triggering an IGP reconvergence. It does not really know that the
degraded optical signal quality on the fibre was the cause, it just
knows that the link disappeared.

There is no difference if IP is running directly over fibre (in
Ethernet). The difference with IPoDWDM is that the re-routing is done
before the fibre actually loses link, because the line card is
monitoring the optical signal and deciding whether to keep the port up
or not. This is to minimize (or avoid) packet loss incurred by failing
only after link failure (which would be the case with generic IP running
directly over fibre (again, in Ethernet).

Whatever the case, IP is not aware about the state of the physical link.
It just sees the link going away.

But something tells me you know all this already, so...

>
> For my definition of IPoDWDM, see, for example:
>
>     "Standardization of optical packet switching with
>     many-wavelength packets"
>     http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4542288
>
> or my newest paper in HPSR2016.

Interesting.

Do you know of any implementations?

Mark.




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