Presentation from SIEPON Seminar on 20 April in Czech Republic, sponsored by IEEE-SA & CAG. Opinions presented by the speakers in this presentation are their own, and not necessarily those of their employers or of IEEE.

1. “EPoC”:
The Art of Mixed Media
Edwin J. Mallette
04/21/2012

2. This Talk Will Cover:
(A Few) Drivers for the EPON Protocol
over a Coax (EPoC) PHY
Coaxial Network Types
EPoC Deployment Models
Coaxial Network Variability
Needed Flexibilities in the EPoC PHY
Closing Remarks.

3. (A Few) Drivers for EPoC
EPoC is the EPON Protocol over a Coax PHY. The
intent is that the EPON MAC is intended to be
common across EPoC and EPON.
Some operators have a strong desire for high line-rate
performance with features included in EPON (e.g. QoS
guarantees) where the drop to the subscriber happens
to be comprised (in full or in part) of coaxial cable.
Specific operator use cases include:
 Operators that use EPON to backhaul other Ethernet over
Coax solutions which are used to reach subscribers over
coaxial cable within a Multiple Dwelling Unit (MDU).
 Operators with DOCSIS deployments who are also
deploying EPON for higher speed first mile access and are
interested in EPON-like performance over a CxDN with
DOCSIS Provisioning of EPON (DPoETM).

4. Coaxial Network Types
There are two general types of coaxial networks
 The first is the “Passive” coaxial plant; one that does not
use line extenders, amplifiers, or other in-line powered
devices.
 The second is the “Active” coaxial plant which uses
amplifiers to extend reach, distance, supported number of
splits on the coaxial plant.
The diagram below depicts two CxDNs with an
active plant (as evidenced by the triangle-amplifier
icons.)

5. EPoC Deployment Model1
In one case the deployment might involve some
Ethernet-Optical backhaul of the Coax Line Terminal
(CLT)
The CLT has EPoC PHYs operating the EPON protocol
on the Coax Distribution Network.
Operator would directly manage the in-building CLT.
In the example below two CxDNs are shown below,
analogous to Optical Distribution Networks (ODNs).

6. EPoC Deployment Model2
In another case, as depicted with a diagram depicting service to the
MDU, the deployment might involve an Optical Line Terminal (OLT) in the
Central Office (CO) with an Optical-Coax Unit (OCU).
The OCU could operate as a layer-1 repeater / media converter to simply
convert optical to electrical and electrical to optical.
The OCU could operate as a layer-2 bridge which in addition to
converting between media types might provide other functions helpful
for aggregation, etc.
Operator would directly manage the service through the OLT in the CO.
The OLT would directly manage the Coaxial Network Units (CNUs)
through the OCUs. This model has some benefits in easing some service
management overhead (single MAC.)

7. EPoC Deployment Model3
This is similar to the previous deployment as
the OLT is centralized in the CO with an OCU
operating to perform the media conversion.
In this case, the OCU is deployed into an
active coaxial outside plant.

8. CxDN Variability1
The coaxial plant is widely variable from operator to
operator, within an operator’s networks from market to
market, even within the same market.
The coaxial plant where the EPoC PHY has to live may
be active or passive.
 In active coaxial plants the amplified bands may be as high
as 1000MHz or may be lower like 600MHz.
 This has implications W.R.T. how far amplifiers are spaced
apart.
For EPoC, a single CxDN may pass 1000 subscribers or
may pass a much smaller number like 20.
The coaxial plant distance may be small – 200 meters
or less, or large – ~2 kilometers.
Specific plant conditions, depending on how well the
coaxial plant is maintained, what kind of spurious
noise is generated into the plant, etc, vary from
deployment to deployment.

9. CxDN Variability2
In some deployments, the coaxial plant supports a single service
with all usable frequencies being allocate-able to the EPOC PHY for
a single CxDN.
In other deployments, the coaxial plant supports a multitude of
other services including:
 Video services in 6MHz or 8 MHz channels – either digitally encoded or
legacy analog TV services.
 Cable-modem (e.g. DOCSIS) services in multiple sets of channels with
channel widths between 800KHz and 8MHz channels.
 Narrow-band service management and control channels.
 These same services commonly occupy different frequency ranges
market by market.
Reference : MSO Topology Scenarios, IEEE802.3 EPoC SG 2012‐03‐13 Meeting

10. PHY Flexibility
To account for this physical layer variability, the EPoC
PHY will need to support:
 Flexible (and configurable) Upstream and Downstream
frequency placement and frequency band widths.
 Flexible (and configurable) bit-loading (bits per Hertz)
within a sub-carrier.
 Flexible upstream and downstream MAC data rates.
 Traversing in-line amplification, equalization as well as
“unimproved” (e.g. un-amplified) spectrum.
 Compatibility with other services.
 Robustness to survive in harsh (e.g. noisy) conditions even
if the MAC data rate must be reduced.
With the goal of supporting up to 1Gbps+ Upstream
and Downstream in some amount of spectrum.

11. Closing Remarks
There are many Ethernet over Coax technologies out there.
Often in-MDU EoCs that use EPON as the loop to the MDU have
two MACs – one for the EoC and a separate MAC for EPON.
This commonly means separate provisioning of both the optical
and coaxial network devices.
EPoC provides efficiency in a common MAC, shared with the
most widely deployed FTTX technology in EPON.
EPoC is expected to simplify forwarding, reduce protocol
conversion, and simplify provisioning (over other EoC+EPON
solutions).
And coax drops aren’t going away any time soon (largely due to
time and money constraints.)
The ultimate desire with EPoC is to be able to leverage the vast
EPON supplier market to hold down the costs of future EPoC
products.
And provisioning of EPON with specifications like DPoE to also
provision EPoC access is KEY.

12. Thank You!!->