The MPLS WG Archive

[Brian E Carpenter <brian@hursley.ibm.com>]

No, end-to-end is very explicit in the Internet and not at all
subjective. Please see RFC 1958.

   Brian

neil.2.harrison@bt.com wrote:
> 
> All,
> 
> End-to-end is subjective since it depends on your perspective....think about
> nested LSPs, we have to cater for these.  LER-to-LER is architecturally
> restrictive being just one specific case of an LSP, and (as Eric points out)
> related to 'current box names'.  I believe we need a generic term that
> captures the essence of the LSP entity at whatever level it exists in a
> label stacked hierarchy of LSPs.  If we borrow from functional modelling
> terminology developed in G.805 by the ITU for SDH and ATM, I suspect that
> 'trail termination points' (ie an LSP exists between them) is the closest
> match to the function we are trying to describe. I attach the extracted
> references from G.805 below for your information.
> 3.1     trail termination sink: A "transport processing function" which
> accepts the characteristic information of the layer network at its input,
> removes the information related to "trail" monitoring and presents the
> remaining information at its output.
> 3.2     trail termination source: A "transport processing function" which
> accepts adapted "characteristic information" from a client layer network at
> its input, adds information to allow the "trail" to be monitored and
> presents the characteristic information of the layer network at its output.
> The trail termination source can operate without an input from a client
> layer network.
> 
> Whilst these are not perfect matches we could start to use them I guess (or
> invent our own).  Also note that as MPLS expands to cover other technologies
> (eg optical networks) then we need a common architectural term for the LSP
> object irrespective of the technology.
> BTW....I understand the ITU are going to develop a functional model of
> optical and IP/MPLS networks in due course.
> 
> So perhaps we could use LSP_TTP-LSP_TTP (or LTTP-LTTP, or indeed whatever
> looks nice) to define this entity.....and to be honest I don't think its
> name is that important, just so long as we agree on (functionally) what that
> entity is.
> 
> The only thing that concerns me now is PHP......as I said in a mail several
> weeks ago (wrt defect detection and consequent action, eg restoration) I
> really don't like the idea that the LSP (sink) trail termination point is a
> moveable feast.
> 
> Regards, Neil
> 
> > -----Original Message-----
> > From: Eric Gray [SMTP:ewgray@mindspring.com]
> > Sent: Monday, August 07, 2000 4:57 AM
> > To:   Loa Andersson
> > Cc:   David Allan; Scott Brim; David R. Oran; mpls; IESG; IAB
> > Subject:      Re: Use of the term "end-to-end"
> >
> > Loa,
> >
> >     I distinctly remember your proposing the term and
> > its more-or-less being rejected.  Never-the-less, it has
> > come to be accepted as a real term.  Many slides and
> > charts now contain some subset of this picture:
> >
> >   LER -- LSR -- ... -- LSR -- LER
> >
> > While it is still debatable that a box which is exclusively
> > either an LER or an LSR will be a long-term survivor
> > in the market place, it is useful to think of LSR verses
> > LER functionality.
> >
> > Loa Andersson wrote:
> >
> > > This is fine with me, but the last time (back in the childhood of MPLS)
> > > I tried to propose the term LER as part of the MPLS vocabulary it was
> > > not considered necessary. SO either we add it or use something else.
> > >
> > > /Loa
> > >
> > > David Allan wrote:
> > > >
> > > > Agreed
> > > >
> > > >      -----Original Message-----
> > > >      From:   Scott Brim [SMTP:sbrim@cisco.com]
> > > >      Sent:   Thursday, August 03, 2000 11:37 AM
> > > >      To:     David R. Oran
> > > >      Cc:     mpls; IESG; IAB
> > > >      Subject:        Re: Use of the term "end-to-end"
> > > >
> > > >      LER-to-LER
> > > >
> > > >      <snip>
> > >
> > > --
> > >
> > > Loa Andersson
> > > Director Routing Architecture Lab, EMEA
> > > St Eriksgatan 115A, PO Box 6701
> > > 113 85 Stockholm, Sweden
> > > phone: +46 8 50 88 36 34,   mobile + 46 70 522 78 34
> > > e-mail: loa.andersson@nortelnetworks.com