7.1. Overview
In an LDS, the long-haul transmission of electricity is at high
voltages. The voltage is stepped down progressively as electricity
flows into local distribution networks and is finally delivered to
LERs at a standard voltage (e.g., 110V). Thus, the LDS is a
hierarchical network. This immediately opens up the possibility of
OSPF and ISIS extensions for routing electricity in a transmission
network, but we'll contain the urge to delve into these productive
internet draft areas until later. For the present, we limit our
discussion merely to controlling the flow of electricity in an IP-
based distribution network using MPLampS.
Under MPLampS, a voltage is equated to a label. In the distribution
network, each switching element and transformer is viewed as a load-
switching router (LSR). Each IP packet carrying an electricity flow
is assigned a label corresponding to the voltage. Electricity
distribution can then be trivially reduced to the task of label
(voltage) switching as electricity flows through the distribution
network. The configuration of switching elements in the distribution
network is done through RSVP-TE to provide electricity on demand.
We admit that the above description is vague and sounds crazy. The
example below tries to add more (useless) details, without removing
any doubts the reader might have about the feasibility of this
proposal:
Example: Turning on a Lamp
It is assumed that the lamp is controlled by an intelligent device
(e.g, a (light) switch with an MPLampS control plane). Turning the
lamp on causes the switch to issue an RSVP-TE request (a PATH message
with new objects) for the electricity flow. This PATH message
traverses across the network to the ES. The RESV message issued in
return sets up the label mappings in LSRs. Finally, electricity
starts flowing along the path established. It is expected that the
entire process will be completed within a few seconds, thereby giving
the MPLampS architecture a distinct advantage over lighting a candle
with a damp match stick.
7.2. Overlay vs Peer Models
As noted before, there are two control plane models to be considered.
Under the overlay model, the lamps and the distribution network
utilize distinct control planes. Under the peer model, a single
control plane is used. A number of arguments can be made for one
model versus the other, and these will be covered in the upcoming
framework document. We merely observe here that it is the lamp
vendors who prefer the peer model against the better judgement of the
LSR vendors. We, however, want to please both camps regardless of
the usefulness of either model. We therefore note here that MPLampS
supports both models and also migration scenarios from overlay to
peer.
The above description of the hierarchical distribution system
immediately opens up the possibility of applying OSPF and ISIS with
suitable extensions. The readers may rest assured that we are
already working on such concepts as voltage bundling, multi-area
tariff extensions, insulated LSAs, etc. Future documents will
describe the details.
7.4. Voltage Protected Networks (VPNs)
VPNs allow a customer with multiple sites to get guaranteed
electricity supply with negligible voltage fluctuations due to
interference from other customers. Indeed, some may argue that the
entire MPLampS architecture may be trashed if not for the possibility
of doing VPNs. Whatever be the case, VPNs are a hot topic today and
the readers are forewarned that we have every intention of writing
several documents on this. Specifically, BGP-support for VPNs is an
area we're presently eyeing with interest.
