Internet Engineering Task Force I. Hussain
Internet-Draft R. Valiveti
Intended status: Informational K. Pithewan
Expires: January 8, 2017 Infinera Corp
July 7, 2016
FlexE Usecases
draft-hussain-ccamp-flexe-usecases-01
Abstract
Traditionally, Ethernet MAC rates were constrained to match the rates
of the Ethernet PHY(s). OIF's implementation agreement [OIFMLG3] was
the first step in allowing MAC rates to be different than the PHY
rates. OIF has recently approved another implementation agreement
[OIFFLEXE1] which allows complete decoupling of the MAC data rates
and the Ethernet PHY(s) that support them. This includes support for
(a) MAC rates which are greater than the rate of a single PHY
(satisfied by bonding of multiple PHY(s)), (b) MAC rates which are
less than the rate of a PHY (sub-rate), (c) support of multiple FlexE
client signals carried over a single PHY, or over a collection of
bonded PHY(s). This draft catalogs the usecases that are encountered
when these Flexible rate Ethernet client signals are transported over
OTN networks.
Status of This Memo
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This Internet-Draft will expire on January 8, 2017.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. FlexE Transport Usecases . . . . . . . . . . . . . . . . . . 4
3.1. FlexE unware transport . . . . . . . . . . . . . . . . . 4
3.2. FlexE Aware . . . . . . . . . . . . . . . . . . . . . . . 6
3.2.1. FlexE Aware Case - No Resizing . . . . . . . . . . . 6
3.3. FlexE Termination - Transport . . . . . . . . . . . . . . 9
3.3.1. FlexE Client at Both endpoints . . . . . . . . . . . 9
3.3.2. Interworking of FlexE Client w/ Native Client at the
other endpoint . . . . . . . . . . . . . . . . . . . 10
3.3.3. Interworking of FlexE client w/ Client from OIF_MLG . 11
3.3.4. FlexE Client BW Resizing . . . . . . . . . . . . . . 12
3.3.5. Back-to-Back FlexE . . . . . . . . . . . . . . . . . 13
4. FlexE Transport over Wavelength(s) Usecases . . . . . . . . . 14
5. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 16
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
8. Security Considerations . . . . . . . . . . . . . . . . . . . 17
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
9.1. Normative References . . . . . . . . . . . . . . . . . . 17
9.2. Informative References . . . . . . . . . . . . . . . . . 17
Appendix A. Additional Stuff . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction
Traditionally, Ethernet MAC rates were constrained to match the rates
of the Ethernet PHY(s). OIF's implementation agreement [OIFMLG3] was
the first step in allowing MAC rates to be different than the PHY
rates standardized by IEEE. OIF has recently approved another
implementation agreement [OIFFLEXE1] which allows complete decoupling
of the MAC data rates and the Ethernet PHY(s) that support them.
This includes support for (a) MAC rates which are greater than the
rate of a single PHY (satisfied by bonding of multiple PHY(s)), (b)
MAC rates which are less than the rate of a PHY (sub-rate), (c)
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support of multiple FlexE client signals carried over a single PHY,
or over a collection of bonded PHY(s). The capabilities supported by
the OIF FlexE implementation agreement version 1.0 are:
a. Support a large rate Ethernet MAC over bonded Ethernet PHYs, e.g.
supporting a 200G MAC over 2 bonded 100GBASE-R PHY(s)
b. Support a sub-rate Ethernet MAC over a single Ethernet PHY, e.g.
supportnig a 50G MAC over a 100GBASE-R PHY
c. Support a collection of flexible Ethernet clients over a single
Ethernet PHY, e.g. supporting two MACs with the rates 25G, 50G
over a single 100GBASE-R PHY
d. Support a sub-rate Ethernet MAC over bonded PHYs, e.g. supporting
a 150G Ethernet client over 2 bonded 100GBASE-R PHY(s)
e. Support a collection of Ethernet MAC clients over bonded Ethernet
PHYs, e.g. supporting a 50G, and 150G MAC over 2 bonded Ethernet
PHY(s)
Optical Transport Networks (defined by [G709] and [G798]) have, until
recently, only dealt with bit (or codeword) transparent transport of
Ethernet client signals. The introduction of the FlexE capabilities
at the OTN client interfaces requires the OTNs to examine the various
usecases. This Internet-Draft examines the various usecases that
arise when transporting the Flexible Rate Ethernet signals in Optical
transport networks. This list of usecases will help identify the
Control Plane (i.e. Routing and Signaling) extensions that may be
required).
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. Terminology
a. Ethernet PHY: an entity representing 100G-R Physical Coding
Sublayer (PCS), Physical Media Attachment (PMA), and Physical
Media Dependent (PMD) layers.
b. FlexE Group: a group of from 1 to 254 bonded Ethernet PHYs.
c. FlexE Client: an Ethernet flow based on a MAC data rate that may
or may not correspond to any Ethernet PHY rate (e.g., 10, 40, m x
25 Gb/s).
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d. FlexE Shim: the layer that maps or demaps the FlexE clients
carried over a FlexE group.
e. FlexE Calendar: Representation of a FlexE group of n PHYs as a
calendar of 20n slots logical length with 20 slots per PHY for
scheduling of slots (i.e., a PHY bandwidth) among the FlexE
clients.
3. FlexE Transport Usecases
3.1. FlexE unware transport
The FlexE shim layer in a router maps the FlexE client(s) over the
FlexE group. The transport network is unware of the FlexE. Each of
the FlexE group PHY is carried independently across the transport
network over the same fiber route. The FlexE shim in the router
tolerates end-to-end skew across the network. This usecase allows to
utilize Network Processor Unit (NPU) and router port rate full
capacities with legacy transport equipment that provides PCS-codeword
transparent transport of 100GbE. It allows striping of PHYs in the
FlexE group over multiple transport line cards.
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==================================================================
+ FlexE Ethernet Client(s) +
+-----------------------------------------------------------+
+ +
+ FlexE skew tolerance
+----------------------------------------+
+ for end-to-distance +
+-----------+ 2x100GE +---------+ +----------+ +------------+
| | | | | | | |
| Router1 | | | | | | |
|FlexE Shim +---------+ A-end | | Z-end +-----+Router 2 |
| | | (FlexE | | (FlexE | |(FlexE Shim)|
| +---^-----+ unaware)| | unaware)+-----+ |
| | | | | | | | |
| | | | | | | | |
+-----------+ + +---------+ +----------+ +------------+
FlexE Group
\----------Transport----------/
network
+--------------+ +----------------+
| FlexE Clients| | FlexE Client(s)|
+--------------+ +----------------+
| FlexE Shim | | FlexE Shim |
+----+----+----+ +----+------+----+
|PHY | | PHY | | PHY | | PHY |
+---+---+--+---+ +---+--+ +--+--+
| | +-----+ +-----+ | |
| +----------+ PHY | | PHY |-------+ |
| +-----+ +-----+ |
| | ODU4+-----------+ ODU4| |
| +-----+ +-----+ |
| |
| +-----+ +-----+ |
+-----------------+ PHY | | PHY +-----------------+
+-----+ +-----+
| ODU4+-----------+ ODU4|
+-----+ +-----+
==================================================================
Figure 1: FlexE unaware transport
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3.2. FlexE Aware
3.2.1. FlexE Aware Case - No Resizing
This scenario represents an optimization of the FlexE unaware
transport presented in Section 3.1, and illustrated in Figure 1. In
this application (see Figure 2), the devices at the edge of the
transport network do not terminate the FlexE shim layer, but are
aware of the format of the FlexE overhead. They "snoop" the FlexE
overhead to determine the subset of the set of all calendar slots
that are available for use (i.e. these calendar slots may be used, or
unused). The transport network edge removes the unavailable calendar
slots at the ingress to the network, and adds the same unavailable
calendar slots back when exiting the network. The result is that the
FlexE Shim layers at both routers see exactly the same input that
they saw in the FlexE unware scenario -- with the added benefit that
the line (or DWDM) side bandwidth has been optimized to be sufficient
to carry only the available calendar slots in all of the Ethernet
PHY(s) in the FlexE group. This mode may be used in cases where the
bandwidth of the Ethernet PHY is greater than the bit rate supported
by a wavelength (and it is known that that all calendar slots in the
PHY are not "available").
The transport network edge device could learn of the set of
unavailable calendar slots in a variety of ways; a few examples are
listed below:
a. The set of unavailable calendar slots could be configured against
each Ethernet PHY in the FlexE group. The FlexE demux function
in the transport network edge device (A) compares the information
about calendar slots which are expected to be unavailable (as per
user supplied configuration), with the corresponding information
encoded by the customer edge device in the FlexE overhead (as
specified in [OIFFLEXE1]). If there is a mismatch between the
unavailable calendar slots in any of the PHYs within a FlexE
group, the transport edge node software could raise an alarm to
report the inconsistency between the provisioning information at
the transport network edge, and the customer edge device.
b. The Transport network edge could be configured to act in a
"slave" mode. In this mode, the FlexE demux function at the
Transport network edge (A) receives the information about the
available/unavailable calendar slots by observing the FlexE
overhead (as specified in [OIFFLEXE1]) and uses this information
to select (a) the set of wavelengths (with appropriate
capacities) or (b) the bandwidth of the ODUflex (or fixed rate
ODUs) that could carry the FlexE PCS end-to-end.
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In the basic FlexE aware mode, the transport network edge does not
expect the number of unavailable calendar slots to change
dynamically.
Note that the process of removing unavailable calendar slots from a
FlexE PHY is called "crunching" (see [OIFFLEXE1]). The following
additional notes apply to Figure 2:
a. The crunched FlexE PHYs are independently transported through the
transport network. The number of used (and unused) calendar
slots can be different across the FlexE group. In particular, if
all the calendar slots in a FlexE PHY are in use, the crunching
operation leaves the original signal intact.
b. In this illustration, the different FlexE PHY(s) are transported
using ODUflex containers in the transport network. These ODUflex
connections can be of different rates.
c. When the crunched FlexE PHY(s) have a rate that is identical to
that of a standard Ethernet PHY, it is possible that the
transport network may utilize standard ODU containers such as
ODU2e, ODU4 etc.
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================================================================
FlexE Ethernet Client(s)
+-----------------------------------------------------+
FlexE skew tolerance
+---------------------------------------------+
for end+to+distance
+--------+ 2 x 100GE +---------+ +---------+ +------+
| R1 | | | | +----+ R2 |
| (FlexE+-----------+ NE A | | NE Z | |(FlexE|
| Shim) | | (FlexE | | (FlexE +----+ Shim |
| +-----^-----+ aware) | | aware) | | |
| | | | | | | | |
+--------+ + +---------+ +---------+ +------+
FlexE Group
\+--------+Transport+--------+/
network
+-------------+ +-------------+
|FlexE clients| |FlexE clients|
+-------------+ +-------------+
| FlexE Shim | | FlexE Shim |
+------+------+ +------+------+
| PHY | PHY | | PHY | PHY |
+---+--+--+---+ +---+--+---+--+
| | | |
| | +--------+ +--------+ | |
| +-------+PHY-c | |PHY-c +-+ |
| +--------+ +--------+ |
| |ODUflex +------------+ODUflex | |
| +--------+ +--------+ |
| |
| +--------+ +--------+ |
+-------------+PHY-c | |PHY-c +--------+
+--------+ +--------+
|ODUflex +------------+ODUflex |
+--------+ +--------+
| Legend:
| R1, R2 - Routers (supporting the FlexE clients)
| NE A, Z - Transport Network Edge nodes
| PHY-c - Crunched FlexE PHY(s)
===============================================================
Figure 2: FlexE Aware Transport
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3.3. FlexE Termination - Transport
These usecases build upon the basic router-transport equipment
connectivity illustrated in Figure 1. The FlexE shim layer at the
router maps to the set of FlexE clients over the FlexE group, as
usual. This section considers various usecases in which the
equipment located at the edge of the transport network is fully aware
of the FlexE OH, and FlexE Shim layers on the transport network edge,
and the customer edge are peers. In the router to network direction,
the transport edge node terminates the FlexE shim layer, and extracts
one or more FlexE client signals, and transports them through the
network. That is, these usecases are distinguished from the FlexE
unaware cases in that the FlexE group, and the FlexE shim layer end
at the transport network edge, and only the extracted FlexE client
signals transit the optical network. In the network to router
direction, the transport edge node maps a set of FlexE clients to the
FlexE group (i.e. performing the same functions as the router which
connects to the transport network).The various usecases differ in the
combination of service endpoints in the transport network. In the
FlexE termination scenarios, the distance between the FlexE Shims is
limited the normal Ethernet link distance. The FlexE shims in the
router, and the equipment need to support a small amount skew.
3.3.1. FlexE Client at Both endpoints
In this scenario, service consists of transporting a FlexE client
through the transport network, and possibly combining this FlexE
client with other FlexE clients into a FlexE group at the endpoints.
The FlexE client signal can be transported in two manners within the
OTN: (i) directly over one or more wavelengths (ii) mapped into an
ODUflex (of the appropriate rate) and then switched across the OTN.
Figure 3 illustrates the scenario involving the mapping of a FlexE
client to an ODUflex envelope; this figure only shows the signal
"stack" at the service endpoints, and doesn't illustrate the
switching of the ODUflex entity through the OTN. The ODUflex mapping
will be beneficial in scenarios where the rate of the FlexE client is
less than the capacity of a single wavelength deployed on the DWDM
side of the OTN network, and allows the network operators to packet
multiple FlexE client signals into the same wavelength -- thereby
improving the network efficiency. Although Figure 3 illustrates the
scenario in which one FlexE client is transported within the OTN, the
following points should be noted:
a. When the FlexE Shim termination function recovers multiple FlexE
client signals (at node A), the FlexE signals can be transported
independently. In other words, it is not a requirement that all
the FlexE client signals be co-routed.
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b. Conversely, at the egress node, FlexE clients from different
endpoints can be combined via the FlexE shim, eventually exiting
the transport edge node over an Ethernet group.
==================================================================
+--------+ 2 x 100GE +---------+ +----------+ +--------+
| | | | | | | |
| Router1| | | | | | |
| FlexE +-----------+ A-end | | Z-end +------+Router2 |
| Shim | | (FlexE | | (FlexE | |FlexE |
| +-----^-----+ term) | term) +------+ Shim |
| | | | | | | | |
| | | | | | | | |
+--------+ + +---------+ +----------+ +--------+
FlexE Group
\+--------+Transport+--------+/
network
+-----------+ +--------------+ +-------------+ +-----------+
| Client(s) | | Client | | Client | | Client(s) |
+-----------+ +--------+-----+ +------+------+ +-----------+
| FlexE Shim| | Shim | | | | Shim | | FlexE Shim|
+-----------+ +--------+ ODU | | ODU +------+ +-----------+
| PHY(s) | | PHY(s) | flex| | flex |PHY(s)| | PHY(s) |
+---+-------+ +---+----+--+--+ +---+--+---+--+ +---+-------+
| | | | | |
+---------------+ +-----------+------+----------+
=================================================================
Figure 3: FlexE termination: FlexE clients at both endpoints
3.3.2. Interworking of FlexE Client w/ Native Client at the other
endpoint
The OIF implementation agreement [OIFMLG3] currently supports FlexE
client signals carried over one or more 100GBASE-R PHY(s). There is
a calendar of 5G timeslots associated with each PHY, and each FlexE
client can make use of a number of timeslots (possibly distributed
across the members of the FlexE group. This implies that the FlexE
client rates are multiples of 5Gbps. When the rates of the FlexE
client signals matches the MAC rates corresponding to existing
Ethernet PHYs, i.e. 10GBASE-R/40GBASE-R/100GBASE-R, there is a need
for the FlexE client signal to interwork with the native Ethernet
client received from a single (non-FlexE capable) Ethernet PHY. This
capability is expected to be extended to any future Ethernet PHY
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rates that the IEEE may define in future (e.g. 25G, 50G, 200G etc.).
In these cases, although the bit rate of the FlexE client matches the
MAC rate of other endpoint, the 64B66B PCS codewords for the FlexE
client need to be transformed (via ordered set translation) to match
the specification for the specific Ethernt PHY. These details are
described in Section 7.2.2 of [OIFMLG3] and are not eloborated any
further in this document.
Figure 4 illustrates a scenario involving the interworking of a 10G
FlexE client with a 10GBASE-R native Ethernet signal. In this
example, the network wrapper is ODU2e.
==================================================================
+--------+ 2 x 100GE +-------+ +-------+ +--------+
| | | | | | | |
| Router1| | | | | | |
|(FlexE +-----------+ A-end | | Z-end | 10GE |Router 2|
| Shim) | |(FlexE | | +------+ |
| +-----^-----+ term) | | | | |
| | | | | | | | |
| | | | | | | | |
+--------+ + +-------+ +-------+ +--------+
FlexE Group
\+---------Transport---------+/
network
+-----------+ +---------------+
| Client(s) | | Client | +------------+ +---------+
+-----------+ +-------+-------+ | 10GE PCS | | 10GE PCS|
| FlexE Shim| | Shim | | +-------+----+ +---------+
+-----------+ +-------+ ODU | | ODU2e | PHY| | PHY |
| PHY(s) | | PHY(s)| 2e | +---+---+--+-+ +-----+---+
+---+-------+ +---+-------+---+ | | |
| | | | | |
| | | | | |
+---------------+ +-------------+ +------------+
=================================================================
Figure 4: FlexE client interop with Native Ethernet Client
3.3.3. Interworking of FlexE client w/ Client from OIF_MLG
As explained in the Introduction section (Section 1 OIFMLG3 [OIFMLG3]
introduced support for carrying 10GE and 40GE client signals over a
group of 100GBASE-R Ethernet PHY(s). While the most recent
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implementation agreement doesn't call it out explicitly, it is
expected that the FlexE clients (as defined in [OIFFLEXE1]), and
10GBASE-R/40GBASE-R clients supported by OIFMLG3 [OIFMLG3]) will
interoperate.
Figure 5 illustrates a scenario involving the interworking of a 10G
FlexE client with a 10GBASE-R client supported by an OIFMLG3
interface. In this example, the network wrapper is ODU2e.
==================================================================
+--------+ 2 x 100GE +---------+ +---------+ +---------+
| | | | | | | |
| Router1| | | | | | |
| FlexE +-----------+ A-end | | Z-end +------+Router 2 |
| Shim | | (FlexE | | | |(MLG-3.0)|
| +-----^-----+ term) | | +------+ |
| | | | | | | | |
| | | | | | | | |
+--------+ + +---------+ +---------+ +---------+
FlexE Group
\+--------+Transport+--------+/
network
+-----------+ +-------------+ +--------------+ +----------+
| Client(s) | | Client | | 10GE PCS | | 10GE Cl. |
+-----------+ +--------+----+ +------+-------+ +----------+
| FlexE Shim| | Shim | | | | MLG3 | | MLG3 |
+-----------+ +--------+ ODU| | ODU +-------+ +----------+
| PHY(s) | | PHY(s) | 2e | | 2e | PHY(s)| | PHY(s) |
+---+-------+ +---+----+--+-+ +---+--+---+---+ +---+------+
| | | | | |
+---------------+ +------------+ +------------+
=================================================================
Figure 5: FlexE client interop with Ethernet Client supported by MLG3
3.3.4. FlexE Client BW Resizing
This section covers an extension of the scenario presented in
Section 3.3.1. Each FlexE client signal defined in [OIFFLEXE1] has a
rate which is a multiple of 5G, and occupies the required number of
calendar slots (5G granularity) in the FlexE group (possibly
distributed among the PHY(s) which have been bonded. The OIF
implementation agreement defines two calendars, one currently active,
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and the future calendar to which the sender wants to transition to.
This capability can be used to coordinate a synchronized switchover
of calendars between the two FlexE Shim functions -- one located in
the customer eddge device (typically a router), and the transport
network edge. In this scenario, there are three independent resizing
domains which must be coordinated (see Figure 3).
a. Between the router 1 and Transport edge node A-end
b. Between the transport edge nodes A, Z
c. Between the transport edge node Z, and router 2
It is possible to coordinate the resize operations in these domains
in such a manner that the FlexE clients get the benefit of an end-to-
end bandwidth change (increase/decrease), without involving any
additional provisioning steps in the provider network. Note for the
FlexE unaware use case (Section 3.1), the client BW can be resized by
FlexE shim coordination between router 1 and router 2.
3.3.5. Back-to-Back FlexE
This section covers a degenerate FlexE aware scenario where router1,
router2, and router3 are interconnected through back-to-back FlexE
groups without an intermediate transport network (see Figure 6).
==================================================================
+--------+ 2 x 100GE +---------+ 3 x 100GE +---------+
| | | | | |
| Router1| | | | |
| FlexE +-----------+ Router2 +-----------+ Router3 |
| Shim | | FlexE +-----------+ FlexE |
| +-----^-----+ Shim +-----^-----+ Shim |
| | | | | | | |
| | | | | | | |
+--------+ + +---------+ + +---------+
FlexE Group FlexE Group
=================================================================
Figure 6: Back-to-Back FlexE
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4. FlexE Transport over Wavelength(s) Usecases
The list of aforementioned FlexE usecases can also be supported by
mapping FlexE directly over one or more wavelengths. An example for
the FlexE unaware transport over wavelength is depicted in Figure 7.
Equivalent network diagrams for the other usecases can be obtained by
replacing an OTN container with an Optical Channel (OCh).
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==================================================================
+ FlexE Ethernet Client(s) +
+-----------------------------------------------------------+
+ +
+ FlexE skew tolerance
+----------------------------------------+
+ for end-to-distance +
+-----------+ 2x100GE +---------+ +----------+ +------------+
| | | | | | | |
| Router1 | | | | | | |
|FlexE Shim +---------+ A-end | | Z-end +-----+Router 2 |
| | | (FlexE | | (FlexE | |(FlexE Shim)|
| +---^-----+ unaware)| | unaware)+-----+ |
| | | | | | | | |
| | | | | | | | |
+-----------+ + +---------+ +----------+ +------------+
FlexE Group
\----------Transport----------/
network
+--------------+ +----------------+
| FlexE Clients| | FlexE Client(s)|
+--------------+ +----------------+
| FlexE Shim | | FlexE Shim |
+----+----+----+ +----+------+----+
|PHY | | PHY | | PHY | | PHY |
+---+---+--+---+ +---+--+ +--+--+
| | +-----+ +-----+ | |
| +----------+ PHY | | PHY |-------+ |
| +-----+ +-----+ |
| | OCh +-----------+ OCh | |
| +-----+ +-----+ |
| |
| +-----+ +-----+ |
+-----------------+ PHY | | PHY +-----------------+
+-----+ +-----+
| OCh +-----------+ OCh |
+-----+ +-----+
==================================================================
Figure 7: FlexE unaware transport over wavelength
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5. Requirements
This section summarizes solution requirements for the usecases
described in this document to help identify the Control Plane (i.e.
Routing and Signaling) extensions that may be required.
a. The solution SHALL support a FlexE group to address
abovementioned usecases including FlexE unaware (where FlexE mux
and demux can be separated by longer distances), FlexE aware
(where FlexE mux and demux can be separated by shorter
distances), and FlexE partially aware.
b. The solution SHALL support a flexible mechanism for configuring a
FlexE group -- such as a signaling protocol or a SDN controller/
management system with network access to the FlexE mux/demux at
each end of the FlexE group.
c. The solution SHALL support the ability to add/remove Ethernet
PHYs to/from a FlexE group.
d. The solution SHOULD allow decoupling of FlexE group's initial
configuration and bring up operation from an addition (or
removal) of FlexE clients to the FlexE group. For instance, it
SHOULD be possible to configure and bring up a FlexE group
without any FlexE client (e.g., with all calendar slots set to
unused or unavailable).
e. The solution SHALL allow adding or removing a FlexE client to a
FlexE group without affecting traffic on other clients.
f. The solution SHALL allow resizing of FlexE client BW through
coordination of calendar updates within a single FlexE group.
There SHOULD be no expectation that FlexE client BW resizing be
hitless in all network scenarios.
g. For the FlexE unaware case, each of the 100GBASE-R PHYs in the
FlexE group SHALL be carried independently across transport
network using a PCS codeword transparent mapping. All PHYs of
the FlexE group SHALL be interconnected between the same two
FlexE shims. The Ethernet PHYs SHOULD be carried over the same
fiber route across the transport network (i.e., co-routed)
h. For the FlexE partially aware case, each of the 100GBASE-R PHYs
in the FlexE group SHALL be carried independently across
transport network. All PHYs of the FlexE group SHALL be
interconnected between the same two FlexE shims. The Ethernet
PHYs SHOULD be carried over the same fiber route across the
transport network. In the transport network, in mux direction,
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the OTN mapper SHALL be able to discard unavailable slots (e.g.,
this can be based on static configuration as the rate of a
wavelength is not expected to change in-service). In the
transport network, in the demux direction, the OTN mapper SHALL
be able to restore unavailable slots to match the original PHY
rate.
i. For the FlexE aware case, the FlexE group SHALL be terminated at
the transport network edge. It SHOULD be possible to carry
(switch) each FlexE client extracted from the FlexE group
independently across transport network using OTN mapping (e.g.,
ODUflex).
6. Acknowledgements
7. IANA Considerations
This memo includes no request to IANA.
8. Security Considerations
None.
9. References
9.1. Normative References
[G709] ITU, "Optical Transport Network Interfaces", February
2016.
[G798] ITU, "Characteristics of optical transport network
hierarchy equipment functional blocks", February 2012.
[OIFFLEXE1]
OIF, "FLex Ethernet Implementation Agreement Version 1.0
(OIF-FLEXE-01.0)", March 2016.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
9.2. Informative References
[OIFMLG3] OIF, "Multi-Lane Gearbox Implementation Agreement Version
3.0 (OIF-MLG-3.0)", April 2016.
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Appendix A. Additional Stuff
This becomes an Appendix.
Authors' Addresses
Iftekhar Hussain
Infinera Corp
169 Java Drive
Sunnyvale, CA 94089
USA
Phone: +1-408-572-5200
Email: IHussain@infinera.com
Radha Valiveti
Infinera Corp
169 Java Drive
Sunnyvale, CA 94089
USA
Phone: +1-408-572-5200
Email: rvaliveti@infinera.com
Khuzema Pithewan
Infinera Corp
169 Java Drive
Sunnyvale, CA 94089
USA
Phone: +1-408-572-5200
Email: kpithewan@infinera.com
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