RE: Optical Link Interface

[Andre Fredette <fredette@photonex.com>]

Kireeti,

Thank you for helping us to focus on the technical arguments.

I agree with your comments below.

On the master-slave vs. peer issue, I think both would work, but the peer 
model is more flexible without being significantly more complex.  LMP is 
just not a complex protocol (no matter how you slice it).

Andre

At 01:39 PM 7/25/2001 -0700, Kireeti Kompella wrote:
>Hi,
>
>This email is as a router vendor/implementor.
>
>The issues (so far) are:
>
>a) LMP-WDM as an extension of LMP vs. NTIP as a new protocol.
>
>    Subject to (c) below, I much prefer having to implement LMP
>    (which I will have to) and add on the features needed for
>    the OLI, rather than implement two different protocols.  The
>    rationale is the same as was used when deciding to extend
>    link state IGPs with TE information rather than do a new TE
>    link state flooding protocol, or to do GMPLS as an extension
>    of MPLS rather than develop a new optical signaling protocol.
>
>b) Two protocols vs. one.
>
>    One.
>
>c) The model: master-slave vs. peer.
>
>    I'm not qualified to speak here; this is the domain of the
>    optical gurus.  However, I'll make two tangential points.  The
>    first is that the answer seems to depend on the architecture
>    of the component systems, which probably indicates that the
>    protocol should do both.  The second is a piece of generic
>    wisdom (?) that it is generally easier to add bells onto a
>    peer-oriented protocol to deal with the master-slave case
>    than to add whistles to a master-slave protocol to make it
>    work in the peer case.
>
>d) The transport protocol: TCP or raw over IP.
>
>    It is my understanding that the PXC-WDM link is usually one IP
>    hop; it seems that TCP is an overkill in that case.  Also,
>    building failover capability for TCP-based protocols is rather
>    more challenging.
>
>    (Side note: both protocols can be made to work either way, so
>    this is not so much of an NTIP-LMP_WDM issue as much as "what
>    transport should OLI use?")
>
>Kireeti.