YANG Data Model for FlexE
ManagementChina MobileNo.32 Xuanwumen west street100053BeijingChinawangminxue@chinamobile.comChina MobileNo.32 Xuanwumen west street100053BeijingChinahanliuyan@chinamobile.comHuawei TechnologiesHuawei Campus, No. 156 Beiqing Rd.Beijing100095Chinashirley.yangfan@huawei.comZTEZTE, No.5 Anding Road.Beijing100029Chinaniu.xiaobing@zte.com.cnTelefonicaRonda de la Comunicacion, s/nSur-3 building, 3rd floorMadrid28050Spainluismiguel.contrerasmurillo@telefonica.comhttp://lmcontreras.com/IBM Corporation2300 Dulles Station Blvd.Herndon, VA 20171United States of Americaxufeng.liu.ietf@gmail.comCCAMP Working GroupThis document defines a service provider targeted YANG data model for
the configuration and management of a Flex Ethernet (FlexE) network,
including FlexE groups. It also supports the configuration of each FlexE
client as an interface. The YANG module in this document conforms to the
Network Management Datastore Architecture (NMDA).From a service provider's point of view, a transport network with
Flex Ethernet (FlexE) support is usually deployed with all FlexE Groups
configured at first, and then FlexE clients are added one by one at a
later stage. This document defines a service provider targeted YANG data
model for the configuration and management of FlexE, including FlexE
groups and FlexE clients. It supports the configuration of FlexE client
as an interface as the data model of FlexE client is augmented based on
the generic interfaces data model as defined in . Furthermore, when a FlexE transport network is used
to backhaul 5G mobile services, synchronization channel can also be
imbedded in a FlexE PHY. The specific PHY used for synchronization
channel can be retrieved for management. Other FlexE attributes are
based on the FlexE 2.1 Implementation Agreement as specified in .Note that this document would only focus on the configuration and
maintenance of the FlexE interfaces. Cross connection of FlexE timeslots
in a network node is tentatively out of the scope of this document.The YANG modules in this document conforms to the Network Management
Datastore Architecture (NMDA) .The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 when, and only
when, they appear in all capitals, as shown here.A simplified graphical representation of the data model is used in
this document. The meaning of the symbols in the YANG data tree
presented later in this document is defined in . They are provided below for reference.o Brackets "[" and "]" enclose list keys.o Abbreviations before data node names: "rw" means configuration
(read-write) and "ro" state data (read-only).o Symbols after data node names: "?" means an optional node, "!"
means a presence container, and "*" denotes a list and leaf-listo Parentheses enclose choice and case nodes, and case nodes are
also marked with a colon (":").o Ellipsis ("...") stands for contents of subtrees that are not
shown.o Some of the key terms used in this document are listed as
follow.The terminology for describing YANG data models is found in .Most terminologies used in this document are extracted from
[FLEXE].Calendar: The total capacity of a FlexE Group is represented as a
collection of slots. The calendar for a FlexE Group composed of n
PHYs is represented in each PHY as an array of slots (e.g., each
representing 5Gbps of bandwidth), i.e., timeslot-list string.Ethernet PHY: an entity representing Ethernet Physical Coding
Sublayer (PCS), Physical Media Attachment (PMA), and Physical Media
Dependent (PMD) layers. Each PHY is consisted of one or more FlexE
Instance (e.g., a 400GBASE-R PHY has four FlexE Instances).FlexE: Flex Ethernet.FlexE Client: An Ethernet flow based on a MAC data rate that may
or may not correspond to any Ethernet PHY rate.FlexE Group: A FlexE Group is composed of from 1 to n Ethernet
PHYs.FlexE PHY: 50GBASE-R, 100GBASE-R, 200GBASE-R, 400GBASE-R are
defined as FlexE PHY by OIF FlexE IA.In following sections, the requirements are summarized according to
the descriptions in OIF FlexE Implementation Agreement and ITU-T FlexE
related standards e.g. . FlexE YANG data
model targets to provide the configurations of the functions, as well as
to report the real states and verify the consistency between the
configuration and the real states. The requirements of FlexE groups and
FlexE clients are summarized and illustrated as follows.Requirements of the FlexE group include,R-Group-01 The model SHALL support the management of the FlexE
group, consisting of one or more Ethernet PHY(s).R-Group-02 The model SHOULD be able to verify that the collection
of Ethernet PHY(s) included in a FlexE group have the same
characteristics (e.g. number of PHYs, timeslots of PHYs, etc.) at the
local FlexE shims. If inconsistency exists, notifications (e.g.
errors) SHOULD be invoked.Requirements of the FlexE client include,R-Client-01 The model SHALL support to assign required calendar
slots to transport the FlexE clients. The assigned calendar slots MAY
be in different FlexE timeslots with different ETH PHYs.R-Client-02 The model SHALL support to add FlexE client(s) into or
remove FlexE client(s) from the FlexE group, without affecting the
other existing FlexE clients whose size and calendar slot assignments
are not changed.This section describes the hierarchy of the YANG modules for the
FlexE management.Configuration management of FlexE group includes:flexe-groups specifies management configuration of all FlexE
groupsflexe-phys specifies management configuration of a list of PHYs
in a specific FlexE groupConfiguration management of a FlexE client includes:flexe-client specifies the FlexE slots used for the FlexE Client
in FlexE groupA simplified YANG tree diagram
representing the data model is typically used by YANG modules. This
document uses the same tree diagram syntax as described in .A tree diagram of FlexE group is depicted as the following:A tree diagram of FlexE client is depicted as the following:The following YANG data module augments the interface container
defined in for a FlexE group interface. It
imports iana-if-type and ietf-interfaces .The YANG module specified in this document defines a schema for data
that is designed to be accessed via network management protocols such as
NETCONF or RESTCONF .
The lowest NETCONF layer is the secure transport layer, and the
mandatory-to-implement secure transport is Secure Shell (SSH) . The lowest RESTCONF layer is HTTPS, and the
mandatory-to-implement secure transport is TLS .The NETCONF access control model provides
the means to restrict access for particular NETCONF or RESTCONF users to
a preconfigured subset of all available NETCONF or RESTCONF protocol
operations and content.There are a number of data nodes defined in the YANG data modules in
this document are writable, and the involved subtrees that are sensitive
include:/flexe/flexe-groups/flexe-group/flexe/flexe-groups/flexe-group/flexe-phys/flexe-phy-list/flexe-client/timeslot-listsWrite operations (e.g., edit-config) to these data nodes without
proper protection can have a negative effect on network operations.
Specifically, an inappropriate configuration of them may cause an
interrupt of a FlexE client flow, drop of all Ethernet frames of a FlexE
client, or even break down of a whole FlexE group interface.It is proposed that IANA should assign new URIs from the "IETF XML
Registry" as follows:It is proposed that IANA register the following YANG module in the
"YANG Module Names" registry:It is proposed that IANA register the following YANG module
in the "YANG Module Names" registry:It is proposed that IANA register a new IANAifType TBD for the
interface type of Flex Ethernet client in the "IANA Interface Type YANG
Module" .The authors would like to thank Weiqiang Cheng and Yuanlong Jiang for
their valuable suggestions.Flex Ethernet 2.1 Implementation AgreementITU-TITU-T G.8023: Characteristics of equipment functional blocks
supporting Ethernet physical layer and Flex Ethernet interfaces;
11/2018ITU-TA FlexE group must be configured first before any client signals are
carried over it. The initial configuration commands could be from
external management system, SDN controller etc.Currently, the FlexE configuration model shows the necessary
parameters about the FlexE group and the FlexE client. That is the base
model for further augments or extensions.In this section, more details about parameters in the model are
elaborated, and some examples are illustrated based on following
figure.The FlexE group YANG tree is shown in section 4. More explanations
for the flexe-group data node include,The leaf index provides an index to the FlexE group. The value
of the index may be generated by local network device or network
management system, so the values in FlexE mux and demux may be
different.The leaf group-num is transported between FlexE mux and FlexE
demux.The leaf negotiation-mode includes dynamic mode and static
mode, and the default value is dynamic mode. For the dynamic mode,
the calendar slot information for the FlexE client is only sent to
the FlexE mux. While for the static mode, the calendar slot
information for the FlexE client is configured both to the FlexE
mux and demux.The leaf sync-phy-number is used for the synchronization
management channel.The list flexe-phys includes all the PHYs bonded in a FlexE
group. Each of the PHYs is identified by the port-name and
phy-number in the group. Both ends of each PHY in the FlexE group
should use the same PHY number.While in the FlexE demux, part of the configuration for FlexE group
is shown as follows,Based on the configuration above, the running states in the FlexE
device can be gotten by using NETCONF Get command. To FlexE group, the
running states include total-bandwidth and free-bandwidth of the FlexE
group, and free-timeslot-list and used-timeslot-list of each PHY in
the FlexE group.he FlexE client YANG tree is shown in section 4. More explanations
for the flexe-client data node include,The leaf client-index provides an index to the FlexE client.
The value of the client-index may be configured by the network
device or network management system or controller, and the values
in FlexE mux and demux may be different.The leafref group-index references the FlexE group with the
specific group index. It means that the FlexE group should be
created before configuring the FlexE client, and the FlexE client
will be transported by the specific FlexE group.The leaf client-num is used to indicate the FlexE client. The
value of the client-num should be configured by the network
management system or controller, and the values in FlexE mux and
demux should be the same.The container timeslot-lists shows all the calendar slots
assigned to the FlexE client. In the list timeslot-list, the total
assignment of slots in each PHY, which is indicated by the leaf
port-name, are indicated by the slots in the leaf time-slot.For example, two FlexE clients are configured to be transported by
the FlexE group in section 4.1.The bandwidth of the first FlexE client is 10Gb/s, and the assigned
calendar slots include two 5G slots.The bandwidth of the second FlexE client is 200Gb/s, and the
assigned calendar slots include 40 5G slots, exactly located in two
100G PHYs. This configuration shows the capability of FlexE
bonding.Part of the configuration for the first and second FlexE client in
FlexE mux is shown as follows,Part of the configuration for the first and second FlexE client in
FlexE demux is shown as follows,