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RE: Closing the GELS Mailing List
igor,
> So, IMO IEEE should be responsible for the definition of data
> plane labels, while CCAMP for control plane labels.
a label distribution protocol is a set of procedures by which one node
informs another of the label/FEC bindings it has made
if these labels are distributed via the gmpls control plane driving
population of the LIBs to which difference are u pointing out here ? so,
not sure to see the point (whatever the number of levels of indirection
between the fwd'ing plane encoding and control plane encoding u will
always fall back on the former, the label distribution protocol
exchanges a piece of information used by the nodes to perform their
forwarding decision)
-d.
> -----Original Message-----
> From: Igor Bryskin [mailto:i_bryskin@yahoo.com]
> Sent: Friday, September 07, 2007 9:21 PM
> To: neil.2.harrison@bt.com; PAPADIMITRIOU Dimitri;
> adrian@olddog.co.uk; zali@cisco.com;
> Attila.Takacs@ericsson.com; ccamp@ops.ietf.org; gels@rtg.ietf.org
> Cc: rcallon@juniper.net
> Subject: RE: Closing the GELS Mailing List
>
> Hi Neil,
>
> I think there is a difference between a "data plane label"
> which is a Layer Information (LI) used by a given server
> layer and a "control plane label", which is a piece of
> information signaled between adjacent controllers for the
> purpose of connection provisioning. IMO the former is always
> a superset of the latter. Let's take, for instance,
> connection oriented Ethernet. MAC SA is a very important part
> of the data plane label because it identifies the source of
> the connection. However, the connection frames are forwarded
> according to MAC DA/VID, and hence connection ingress node,
> for example, needs only be signaled with this tuple by the
> downstream neighbor, hence the control plane label is MAC
> DA/VID (or just VID, for those who like the idea of the VID
> cross-connects architecture).
>
> So, IMO IEEE should be responsible for the definition of data
> plane labels, while CCAMP for control plane labels.
>
> Cheers,
> Igor
>
>
> neil.2.harrison@bt.com wrote:
>
> Dimitri wrote 07 September 2007 16:36 in response to Adrian
>
> > >
> > > This is also something we would expect to describe within
> > > CCAMP although
> > > "what is a label" would come to us from the data plane
> > specification.
> >
> > do i interpreet correctly your statement that if the
> > specification that CCAMP is going to receive from IEEE does
> > not speak about "label" and its encoding there will be no
> > place to discuss any "label processing" and "label
> > distribution" protocol in IETF - being domain-wide or
> link-local
> > -
> >
> > in that case, isn't the .1Q specification outside scope of
> > this effort since not referring - as of today at least - to
> > any "label" semantic as part of the Ethernet frame header
> > information field ?
> >
> > thanks,
> > -d.
>
> What do you think a MAC DA, MAC SA and VID are? These
> are all 'labels'.
>
> You also have to remember that the nature of the labels
> required in a
> traffic unit are determined by the type of the network
> mode one is
> dealing with.
>
> In the co-cs and co-ps modes we have a construction known as a
> 'connection'. This implies specific architectural
> requirements....but
> the most significant, for this discussion at least, is
> that a connection
> must have a single source. What this means is that one
> does not have to
> incorporate a SA label in a co mode traffic
> unit....under defect-free
> conditions it is redundant information as the
> connection itself provides
> the source information. {Compare this to the cl-ps mode
> which does not
> have connections...here having a SA in the traffic unit
> is essential}
>
> Ergo why co-cs and co-ps mode technologies to date that
> respect the
> requirements of a connection have only focussed on
> incorporating a DA
> (forwarding) label. Further, these forwarding labels
> only need to be
> distinct in resolving some number (N say) of different
> client layer
> (link-connection) instances within a server layer
> (network connection)
> resource partition. However, there are advantages from
> having both a SA
> and DA label in a co-ps traffic unit that are network
> unique and not
> just link-connection unique (ie not swapped)....the
> inherent robustness
> under misconnectivity defects (without any adjunct OAM
> flow) is one of
> these. And of course, these are the nature of the
> native labels one
> already gets in Ethernet due to its cl-ps mode origins.
> So why would
> one even contemplate not using these since they are
> already there?
>
> The VID label is slightly different in that one can
> consider it as a
> 'route discriminator label' and a local extension to
> the SA or DA, ie it
> provides the ability to identify disjoint paths between
> nodal end
> points.
>
> The mere fact IEEE may not refer to the above
> quantities as 'labels'
> does not change the fact that this is what they are. So
> I'm not clear
> what your real point is here.
>
> regards, Neil
>
>
>
>
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