| Network Working Group | X. Geng |
| Internet-Draft | M. Chen |
| Intended status: Experimental | Huawei |
| Expires: May 3, 2018 | October 30, 2017 |
DetNet Configuration YANG Model
draft-geng-detnet-conf-yang-00
This document describes configuration model for Deterministic Networking(DetNet). It defines DetNet configuration attribute and the corresponding YANG model, which is used for DetNet capabilities configuration/discovery, DetNet flow configuration and DetNet flow status collection in the network.
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.
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.
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A Deterministic Networking (DetNet) [I-D.ietf-detnet-architecture] provides a capability to carry a unicast or a multicast data flow for an application with strict service quality requirements, e.g., extremely low packet loss rate and bounded latency. The DetNet service is provided either for a Layer 3 (L3) flow or a Layer 2 (L2) flow by an IP/MPLS network.
This document describes configuration model for Deterministic Networking(DetNet). It defines DetNet configuration attribute and the corresponding YANG model, which is used for DetNet capabilities configuration/discovery, DetNet flow configuration and DetNet flow status collection in the network.
This draft includes three parts: DetNet configuration model defined in section 3, DetNet configuration attribute defined in section 4 and DetNet configuration YANG model defined in section 5.
This documents uses the terminologies defined in[I-D.ietf-detnet-architecture].
This section introduces three kinds of DetNet configuration models. The models can cover different network architectures, showing how configuration information exchanges between various entities in the network. Example with candidate control plane protocol is attached to each configuration model to show how DetNet may work in current Layer 3 network. To make the configuration model complete, user/network interface(UNI) information is also included in this section. UNI Information is out of scope of this draft, and more discussions about DetNet UNI information can be found in [I-D.farkas-detnet-flow-information-model].
In a fully distributed configuration model, UNI information is transmitted over DetNet UNI protocol from the user side to the network side; then UNI information and network configuration information propagate in the network over distributed control plane protocol. For example:
1) IGP collects topology information and DetNet capabilities of network([I-D.geng-detnet-info-distribution]);
2) Control Plane of the Edge Node(Ingress) receives a flow establishment request from UNI and calculates a/some valid path(s);
3) Using RSVP-TE, Edge Node(Ingress) sends a PATH message with explicit route. After receiving the PATH message, the other Edge Node(Egress) sends a Resv message with distributed label and resource reservation request.
Current distributed control plane protocol,e.g., RSVP-TE[RFC3209], SRP[IEEE802.1Qcc], can only reserve bandwidth along the path, while the configuration of a fine-grained schedule, e.g.,Time Aware Shaping(TAS) defined in [IEEE802.1Qbv], is not supported.
The fully distributed configuration model is not covered by this draft. It should be discussed in the future DetNet control plane work.
In the fully centralized configuration model, UNI information is transmitted from Centralized User Configuration (CUC) to Centralized Network Configuration(CNC). Configurations of routers for DetNet flows are performed by CNC with network management protocol.For example:
1) CNC collects topology information and DetNet capability of network through Netconf;
2) CNC receives a flow establishment request from UNI and calculates a/some valid path(s);
3) CNC configures the devices along the path for flow transmission.
In the hybrid configuration model, controller and control plane protocols are used together to offer DetNet service, and there are a lot of possible combinations. For example:
1) CNC collects topology information and DetNet capability of network through IGP/BGP-LS;
2) CNC receives a flow establishment request from UNI and calculates a/some valid path(s);
3) Based on the calculation result, CNC distributes flow path information to Edge Node(Ingress) and other information(e.g. replication/elimination) to the relevant nodes.
or
1) IGP collects topology information and DetNet capability of network through IGP/BGP-LS;
2) Control Plane of Edge Node(Ingress) receives a flow establishment request from UNI;
3) Edge Node(Ingress) sends the path establishment request to CNC through PCEP;
4) After Calculation, CNC sends back the path information of the flow to the Edge Node(Ingress) through PCEP;
5) Using RSVP-TE, Edge Node(Ingress) sends a PATH message with explicit route. After receiving the PATH message, the other Edge Node(Egress) sends a Resv message with distributed label and resource reservation request.
There are also other variations that can included in the hybrid model. The hybrid configuration model is not covered by this draft. It should be discussed in the future DetNet control plane work.
Note: [IEEE802.1Qcc] also defines three TSN configuration models: fully-centralized model, fully-distributed model, centralized Network / distributed User Model. This section defines the configuration model roughly the same, to keep the design of L2 and L3 in the same structure. Hybrid configuration model is slightly different from the 'centralized Network / distributed User Model' , which intends to contain more variations.
According to section 3, different configuration model with different control plane protocol or yang model use different configuration attribute. This section tries to cover the possible attributes that is used in fully centralized configuration model. Some of the attributes can also be used as reference of the definition of other two configuration models in the future work.
Note: When the working group get the control plane into consideration, other yang models that cooperate with or configure the control plane protocols should also be included in this draft
DetNet Topology Attribute is the basis of path computation, describing the DetNet relative topology and capability of the network.
There are three kinds of DetNet nodes defined in [I-D.ietf-detnet-architecture]: Edge Node, Relay Node and Transit Node.
Edge node includes either a DetNet service layer proxy function for DetNet service protection (e.g. the addition or removal of packet sequencing information) for one or more end systems, or starts or terminates congestion protection at the DetNet transport layer. Boundary of a DetNet Domain SHALL be an edge note.
Relay node includes a service layer function that interconnects different DetNet transport layer paths to provide service protection. A DetNet relay node can be a bridge, a router, a firewall, or any other system that participates in the DetNet service layer. It typically incorporates DetNet transport layer functions as well, in which case it is collocated with a transit node.
Transit node operates at the DetNet transport layer, that utilizes link layer and/or network layer switching across multiple links and/or sub-networks to provide paths for DetNet service layer functions. Optionally provides congestion protection over those paths. An MPLS LSR is an example of a DetNet transit node.
NodeType specifies which type a DetNet node belongs to, which also indicates its role in the DetNet service.
ReplicationCapability specifies whether a DetNet node has the capability of packet replication. Replication Capability requirements include: 1) identify the packets that need to be replicated; 2) do packet replication; 3) encapsulate the replicated packets and send them to different next hop.
EliminationCapability specifies whether a DetNet node has the capability of packet elimination. Elimination Capability requirements include: 1) record the packets that have been received from different port; 2) eliminate the redundant packets; 3) encapsulate the first-received packets and send them to the next hop.
IEEE defines some queuing management algorithms to guarantee TSN service quality, most of them can be used in DetNet, for example:
This attribute specifies what kind of Queuing Management Algorithm(s) is(are) used in the output queue for DetNet (except for IEEE802.1Qci, which is always used in input queue) .
There is a set of parameters that describe reservation operation for the entire device. Those parameters are contained in Reservation Base attribute, including the following parameters:
[I-D.ietf-teas-yang-te-topo] defines the following parameters for bandwidth reservation:
Considering the features of DetNet, bandwidth reservation parameters for DetNet are defined as follows to augment the te-topology:
For example, there are three classes of DetNet service A, B, and C, with A the lowest latency and C the highest. 'Maximum DetNet Reservable Bandwidth(N)' can be presented as 'MaxBw(N)'; DetNet Unreserved Bandwidth(N) can be presented as 'UnBw(N)'. MaxBw(A) can be used by A; MaxBw(B) can by used by A&B, and MaxBw(C) can be used by A&B&C. So, if MaxBw(A)=10, MaxBw(B)=25, MaxBw(C)=40, and we allocate 15 to A, 30 to B and 10 to C, then UnBw(A)=0, UnBw(B)= 0, UnBw(C)=20.
Delay Metric is used to describe the delay of every hop, which includes the following parameters:
Link Delay specifies the delay along the network media for a packet transmitted from the specified Port of this station to the neighboring Port on a different station.
Packet Processing Delay includes: Per-Stream Filtering and Policing([IEEE802.1Qci]), Flow Classification, Looking up in Forwarding Information Base, and etc. It covers the process from the packet being received by the node to the packet being sent to the output queue. It is packet length dependent.
Queuing Delay specifies the delay for a packet in the output queue. It is determined by the Queuing Management Algorithm and Port Transmission Rate.
The delay of every hop is the sum of link delay, packet processing delay and output queuing delay.
Notes: The delay metric is also discussed in IEEE with other considerations, which can be found: <http://www.ieee802.org/1/files/public/docs2017/cr-finn-timing-model-0617-v00.pdf> and <http://www.ieee802.org/1/files/public/docs2017/cr-specht-bridge-timing-0917-v01.pdf>. More discussions are needed here.
Most of the DetNet service requires clock synchronization. Synchronization Accuracy is necessary for queuing algorithm configuration and delay prediction. For example, Synchronization Accuracy is an important parameter when calculating the guard band for CQF[IEEE802.1Qch].
Note: The method used to achieve time synchronization is not specified in this draft.
Path Attribute is used for path configuration in DetNet Edge Node(Ingress).
DetNet path constrains are mainly based on the application requirement, including maximum latency/number of replication trees, and traffic specification, which can be used to calculate bandwidth requirement[I-D.farkas-detnet-flow-information-model]. There may be other path constrains when the path is established, which can be added in this attribute in the future version.
Explicit routing attribute describes an end-to-end path for DetNet flow, by listing nodes along the path in order and specifying their types. The DetNet node type has been specified in section 4.1.1. If service protection is needed, DetNet flow is replicated in relay node, going through different paths, and eliminated in another relay node. It makes the DetNet route a point-to-multipoint-to-point (P-MP-P) path. In [RFC4875], explicit routing of a P-MP LSP is represented by a P-MP tree. Similarly, a P-MP-P tree is needed in DetNet, and the rules of building the tree is to be defined.
DetNet Configuration Attribute is used for path configuration after the path has been calculated, preparing for the DetNet Flow Transportation.
Flow Identification is data plane relevant, and it is defined in [I-D.farkas-detnet-flow-information-model].
Traffic Specification is defined in[I-D.farkas-detnet-flow-information-model] .
[I-D.dt-detnet-dp-sol] defines more than one data plane protocols for DetNet service, and DetNet Encapsulation attribute specifies the type of encapsulation used in the node, including:
Notes: In one DetNet domain, the encapsulation should be the same; When a flow goes across different domains, the encapsulation needs to be changed. For example, when an DetNet Edge Node connects two TSN domains, at the entry or exit boundary of the DetNet domain, the encapsulation needs to be changed accordingly. Parameters in the encapsulation also needs to do the mapping. for example, the translation from flow Unique ID defined [IEEE802.1Qcc] to DetNet flow ID defined in [I-D.dt-detnet-dp-sol] should be defined in the configuration of the edge node .
Flow Priority attribute specifies the priority reserved for DetNet flow in PSN header. The intermediate node can distinguish DetNet flow from non-DetNet flow by DetNet priority. And, if more than one DetNet priority is defined, it can also be used to describe DetNet flows with different quality requirements, e.g. , low latency DetNet flows and high latency DetNet flows.
Notes: In one DetNet domain, the priority reserved for DetNet should be the same. When crossing DetNet domains, the priority should be translated accordingly. For example, the priority translation from TSN domain to DetNet domain is defined in [I-D.varga-detnet-service-model] Annex 2 "Integrating Layer 3 and Layer 2 QoS".
This attribute is also data plane relevant. If there is no priority reserved for DetNet, other attribute should be specified to distinguish DetNet flows. The mapping from flow priority to output queue also makes it necessary to take queuing management algorithm(section 4.1.4) into consideration when defining the DetNet priority.
Queuing Management Algorithm Type is described in section 4.1.4. Different algorithm use different parameters to manage queue. In a fully-centralized configuration model, the parameters can be distributed by CNC; in a distributed configuration model, the device can configure itself based on the application requirement and flow traffic specification information.
The queuing management configuration parameters and the corresponding YANG model are being defined in IEEE. For example, when stream policing and filtering defined in[IEEE802.1Qci] is deployed in one node, the parameter of Stream filter instance table (IEEE P802.1Qci 8.6.5.1.1), Stream gate instance table (IEEE P802.1Qci 8.6.5.1.2), Flow meter instance table (IEEE P802.1Qci 8.6.5.1.3) should be configured by CNC or other control plane protocol.
This attribute specifies whether the node will do replication to the packet of this flow. Configuration of Replication in relay node is defined in [IEEE802.1CB].
This attribute specifies whether the node will do elimination to the packet of a flow. For a multicast flow, elimination can be performed on some ports, but not on others in one node. Configuration of Elimination in relay node is defined in [IEEE802.1CB].
Routing configuration is data plane relevant, but no matter what the encapsulation is, the following attributes should be contained:
The DetNet status attributes are provided by the device for each DetNet flow. The Status Attributes describe the status of the flow when it is transmitted in the network.
Performance Status contains:
Detailed discussion of Replication/Elimination status is specified in [IEEE802.1CB].
This section specifies the network management information that is used for the fully centralized DetNet configuration model. YANG model for other configuration model is to be defined in the future version of the draft.
<CODE BEGINS> file "ietf-detnet-topology@2017-10-24.yang"
module ietf-te-detnet-topology {
yang-version 1.0;
namespace "urn:ietf:params:xml:ns:yang:ietf-detnet-topology";
prefix "detnet-to";
import ietf-network-state {
prefix "nw-s";
}
import ietf-network-topology-state {
prefix "nt-s";
}
import ietf-te-types {
prefix "te-types";
}
import ietf-te-topology{
prefix "tet";
}
organization "IETF Deterministic Networking(detnet)Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/detnet/>
WG List: <mailto:detnet@ietf.org>
WG Chair: Lou Berger
<mailto:lberger@labn.net>
Editor: Xuesong Geng
<mailto:gengxuesong@huawei.com>
Editor: Mach Chen
<mailto:mach.chen@huawei.com>";
description
"This YAGN module augments the 'ietf-te-topology'
module with detnet capability data for detnet
configuration";
grouping detnet-link-info-attributes{
description
"DetNet capability attributes in a DetNet topology";
container detnet-performance-metric-attributes{
description
"Link performance information in real time.";
uses detnet-performance-metric-attributes;
}
container detnet-queuing-management-algorithm{
description
"Detnet queuing management algorithm used in
output queue";
uses detnet-queuing-management-algorithm;
}
}
grouping detnet-performance-metric-attributes{
description
"Link performance information in real time.";
container maximum-detnet-reservable-bandwidth{
uses te-types:te-bandwidth;
description
"This container specifies the maximum bandwidth
that is reserved for DetNet on this link.";
}
container reserved-detnet-bandwidth{
uses te-types:te-bandwidth;
description
"This container specifies the bandwidth that has
been reserved for DetNet on this link.";
}
container available-detnet-bandwidth{
uses te-types:te-bandwidth;
description
"This container specifies the bandwidth that can
be used for new DetNet flows on this link.";
}
leaf minimum-detnet-device-delay{
type unit 32;
description
"Minimum delay in the device for DetNet flows";
}
leaf maximum-detnet-device-delay{
type unit 32;
description
"Maximum delay in the device for DetNet flows";
}
}
grouping detnet-queuing-management-algorithm{
description
"Detnet queuing management algorithm used in
output queue";
leaf queuing-management-algorithm{
type enumeration{
enum credit-based-shaping{
reference
"IEEE P802.1 Qav";
}
enum time-aware-shaping{
reference
"IEEE P802.1 Qbv";
}
enum cyclic-queuing-and-forwarding{
reference
"IEEE P802.1 Qch";
}
enum asynchronous-traffic-shaping{
reference
"IEEE P802.1 Qcr";
}
}
}
}
grouping detnet-node-info-attributes{
description
"DetNet capability attributes in a DetNet node";
container detnet-node-type{
description
"Three types of DetNet nodes";
reference
"draft-ietf-detnet-architecture-03:
Deterministic Networking Architecture";
uses detnet-node-type;
}
container detnet-resource-reservation-attributes{
uses detnet-resource-reservation-attributes;
}
leaf detnet-elimination-capability{
type boolean;
description
"This node is able to do DetNet packet
elimination";
}
leaf detnet-replication-capability{
type boolean;
description
"This node is able to do DetNet packet
replication";
}
}
grouping detnet-node-type{
description
"This grouping defines three types of DetNet nodes";
reference
"draft-ietf-detnet-architecture-03:Deterministic
Networking Architecture";
leaf detnet-node-type{
type enumeration{
enum edge-node{
description
"An instance of a DetNet relay node that
includes either a DetNet service layer proxy
function for DetNet service protection (e.g.
the addition or removal of packet sequencing
information) for one or more end systems, or
starts or terminate congestion protection at
the DetNet transport layer,analogous to a
Label Edge Router (LER).";
}
enum relay-node{
description
"A DetNet node including a service layer
function that interconnects different DetNet
transport layer paths to provide service
protection.A DetNet relay node can be a bridge,
a router, a firewall, or any other system that
participates in the DetNet service layer. It
typically incorporates DetNet transport layer
functions as well, in which case it is
collocated with a transit node.";
}
enum transit-node{
description
"A node operating at the DetNet transport layer,
that utilizes link layer and/or network layer
switching across multiple links and/or
sub-networks to provide paths for DetNet
service layer functions.Optionally provides
congestion protection over those paths.An MPLS
LSR is an example of a DetNet transit node.";
}
}
}
}
grouping detnet-resource-reservation-attributes{
description
"This grouping describs reservation operation for
the entire device";
leaf MaxFanInPorts{
type Unit32
description
"maximum number of fan-in ports in the device";
}
leaf MaxPacketSize{
type Unit32
description
"maximum Packet size the device allows";
}
leaf MaxDetNetClasses{
type Unit32
description
"maximum number of traffic classes that can be
reserved for DetNet";
}
augment "/nw-s:networks/nw-s:network/nt-s:link/tet:te/"{
container advertise-info{
description
"Advertised DetNet link information attributes.";
uses detnet-link-info-attributes;
}
}
augment "/nw-s:networks/nw-s:network/nw-s:node/tet:te/"{
description
"Advertised DetNet node information attributes.";
container{
uses detnet-node-info-attributes;
}
}
<CODE ENDS>
<CODE BEGINS> file "ietf-detnet-static @2017-10-26.yang"
module ietf-detnet-static {
yang-version 1.0;
namespace "urn:ietf:params:xml:ns:yang:ietf-detnet-static";
prefix "detnet-static";
import ietf-routing {
prefix "rt";
}
import ietf-yang-types{
prefix "yang";
}
organization "IETF Deterministic Networking(detnet)Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/detnet/>
WG List: <mailto: detnet@ietf.org>
WG Chair: Lou Berger
<mailto:lberger@labn.net>
Editor: Xuesong Geng
<mailto:gengxuesong@huawei.com>
Editor: Mach Chen
<mailto:mach.chen@huawei.com>";
description
"This YAGN module augments the 'ietf-routing'module
with detnet flow configuration attribute";
grouping flow-identfication {
description
"DetNet flow identification";
reference
"draft-farkas-detnet-flow-information-model"
leaf source-ip-address {
type yang:ip-address;
description
"Source IP address";
}
leaf destination-ip-address {
type yang:ip-address;
description
"Destination IP address";
}
leaf source-mac-address {
type yang:mac-address;
description
"Source MAC address";
}
leaf destination-mac-address {
type yang:mac-address;
description
"Destination MAC address";
}
leaf ipv6-flow-label {
;
}
leaf mpls-label {
;
}
}
grouping traffic-specification{
descprition
"traffic-specification specifies how the Source
transmits packets for the flow. This is the
promise/request of the Source to the network.
The network uses this traffic specification
to allocate resources and adjust queue
parameters in network nodes.";
reference
"draft-farkas-detnet-flow-information-model"
leaf max-packets-per-interval{
type uint16;
description
"max-packets-per-interval specifies the maximum
number of packets that the application shall
transmit in one Interval.";
}
leaf max-packet-size{
type unit16;
description
"max-packet-size specifies maximum packet size
that the Source will transmit";
}
leaf queuing-algorithm-selection{
type uint8;
descprition
"";
}
}
grouping routing-configuration{
descprition
"configuration parameters direct data plane
operations";
container flow-identification{
uses flow-identfication;
}
leaf operation{
type enumeration{
enum transmission{
description
"Operation: transmit ";
}
enum replication{
description
"Operation: packet replication";
}
enum elimination{
description
"Operation: packet elimination";
}
enum elimination-and-replication{
description
"Operation: packet elimination and
replication";
}
}
}
}
grouping queuing-parameters{
}
grouping replication-function{
}
grouping elimination-function{
}
augment "/rt:routing{
description
"DetNet node static configuration
attributes.";
container{
uses flow-identfication;
uses traffic-specificatio;
uses routing-configuration;
uses queuing-parameters;
uses replication-function;
uses elimination-function;
}
}
<CODE ENDS>
This document makes no request of IANA.
Note to RFC Editor: this section may be removed on publication as an RFC.
| [I-D.dt-detnet-dp-sol] | Korhonen, J., Andersson, L., Jiang, Y., Finn, N., Varga, B., Farkas, J., Bernardos, C., Mizrahi, T. and L. Berger, "DetNet Data Plane Encapsulation", Internet-Draft draft-dt-detnet-dp-sol-02, September 2017. |
| [I-D.farkas-detnet-flow-information-model] | Farkas, J., Varga, B., rodney.cummings@ni.com, r., Jiang, Y. and Y. Zha, "DetNet Flow Information Model", Internet-Draft draft-farkas-detnet-flow-information-model-01, June 2017. |
| [I-D.ietf-detnet-architecture] | Finn, N., Thubert, P., Varga, B. and J. Farkas, "Deterministic Networking Architecture", Internet-Draft draft-ietf-detnet-architecture-03, August 2017. |
| [RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997. |