| I2RS | Z. Wang |
| Internet-Draft | Q. Wu |
| Intended status: Standards Track | S. Hares |
| Expires: September 6, 2015 | Huawei |
| March 5, 2015 |
A YANG Data Model for Service Topology
draft-wang-i2rs-yang-service-topo-dm-01
This document defines a YANG data model for Service Function Forward Topology. This I2RS yang data model is part of the I2RS protocol independent topology set of data models.
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An overlay network consists of tunnels established among designated nodes to traverse segments of networks.
This draft describes a protocol independent topology of service function forwarder nodes which augments the [I-D.clemm-i2rs-yang-network-topo] model as a specific service topology (SFF). Figure 1 shows how the SFF is an extension of the service forwarded nodes.
+---------------------------------------+
/ _[X1]_ "Service" /
/ _/ : \_ (SFF) /
/ _/ : \_ /
/ _/ : \_ /
/ / : \ /
/ [X2]__________________[X3] /
+---------:--------------:------:-------+
: : :
+----:--------------:----:--------------+
/ : : : "L3" /
/ : : : /
/ : : : /
/ [Y1]_____________[Y2] tunnels /
/ * * * /
/ * * * /
+--------------*-------------*--*-------+
* * *
+--------*----------*----*--------------+
/ [Z1]_______________[Z1] "Optical" /
/ \_ * _/ /
/ \_ * _/ /
/ \_ * _/ /
/ \ * / /
/ [Z] /
+---------------------------------------+
Figure 1
There can be many types of protocol independent service topologies such as: L2VPN, L3VPN, MPLS, EVPN, and others. The Service Function Chaining services consists of a topology of Service Function Forwarder nodes connected by links which are tunnels that connect the service nodes. Each Service Forwarder node has service functions attached to the Service Function Forwarder node.
The SFF topology is built on top of one or several underlying networks (see figure 1). In case multi-tenancy is needed, multiple SFF topologies can be built on top of the same underlying network. Each tenant can only see its own service topology. But all the tenant's service topology can be mapped into the same L3 network topology.
The I2RS protocol independent topologies are abstractions created by the I2RS Client directly or by instructions to I2RS agent to import network topologies or aggregations of the network topology. The I2RS protocol independent L3 topology is created by the client or the clients instruction to import specific information from the I2RS Agent from static configuration or IGPs (E.g. OSPF or ISIS) or information passed in EGPs (e.g. [I-D.ietf-idr-ls-distribution]. Similarly, the protocol independent SFF topology is abstraction of network topology information. Since SFF has no another control plane protocol running on top of the underlying networks, this information will need to be gathered from other sources.
This document defines a Yang data model for the SFF protocol independent topology.
Datastore: A conceptual store of instantiated management information, with individual data items represented by data nodes which are arranged in hierarchical manner.
Data subtree: An instantiated data node and the data nodes that are hierarchically contained within it.
NETCONF: Network Configuration Protocol.
URI: Uniform Resource Identifier.
YANG: A data definition language for NETCONF.
Classification: Locally instantiated policy and customer/network/ service profile matching of traffic flows for identification of appropriate outbound forwarding actions.
Classifier: An element that performs Classification.
Service Function Chain (SFC): A service function chain defines a set of abstract service functions and ordering constraints that must be applied to packets and/or frames selected as a result of classification.
Service Function (SF): A function that is responsible for specific treatment of received packets.
Service Function Forwarder (SFF): A service function forwarder is responsible for delivering traffic received from the network to one or more connected service functions according to information carried in the SFC encapsulation, as well as handling traffic coming back from the SF.
Metadata: provides the ability to exchange context information between classifiers and SFs and among SFs.
Service Function Path (SFP): The SFP provides a level of indirection between the fully abstract notion of service chain as a sequence of abstract service functions to be delivered, and the fully specified notion of exactly which SFF/SFs the packet will visit when it actually traverses 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 [RFC2119].
This section describe the architecture and the tree diagram of the service topology yang data model.
The abstract Topology yang Model contain a set of abstract nodes and a list of abstract links. Service Function Chain Topo yang model and other service topo model can be augumented from the abstract topology model with SFC base topology specifics.
The following Figure depicts the relationship of service topology yang model to the abstract topology yang model.
+-----------------+
| Abstract |
| Topology Model |
| |
+--------|--------+
|
+-----------------------+
| ..... |
|
+------V----------+
| Service |
| Topology models |
| |
+--------|---------
|
+----|------------------------|---+
| |
+--------V--------+ +--------V-----------+
|Service Function | | Another protocol |
| Forwarder | | Independent Service|
| Topology Models | | Topology Models |
+-----------------+ +--------------------+
Figure 2
The relationship of service topology yang model to the abstract topology yang model
The following is the generic topology module
module: network
+--rw network* [network-id]
+--rw network-id network-id
+--ro server-provided? boolean
+--rw network-types
+--rw supporting-network* [network-ref]
| +--rw network-ref leafref
+--rw node* [node-id]
+--rw node-id node-id
+--rw supporting-node* [network-ref node-ref]
+--rw network-ref leafref
+--rw node-ref leafref
The service modules augments the network types and this data structures.
To provide context for this model, this sample augment for the
types is provided (but not normative for this draft).
module: Service Topologies
augment /nt:network-topology/nt:topology/nt:topology-types
+--rw Service-Topologies
+--rw SFF-topology
+--rw L3VPN-Service-topology
+--rw EVPN-Service-topology
Figure 3: The structure of the abstract (base) network model
The following figure provide the structure of service topology yang model. Each node is printed as:
<status> <flags> <name> <opts> <type>
<status> is one of:
+ for current
x for deprecated
o for obsolete
<flags> is one of:
rw for configuration data
ro for non-configuration data
-x for rpcs
-n for notification
<name> is the name of the node
If the node is augmented into the tree from another module, its
name is printed as <prefix>:<name>.
<opts> is one of:
? for an optional leaf or choice
! for a presence container
* for a leaf-list or list
[<keys>] for a list's keys
<type> is the name of the type for leafs and leaf-lists
Figure 4
SFF Topology Module
module: SFF topology
augment /nt:network-topology/nt:topology/nt:topology-types
+--rw Service-Topologies
+--SFF Topology!
augment /nt:network-topology/nt:topology
+--rw service-topo-id network-id
+--rw service-topology-attributes
+--rw node-count uint32
+--rw topology-extension!
augment /nt:network-topology/nt:topology/nt:node
+--rw node-type!
| +--rw classifier-node? string
| +--rw sf-node? string
| +--rw sff-node? string
+--rw next-hop*[hop-id]
| +--hop-id node-id
+--rw node-extension!
+--rw classifier-extension!
| +--rw classifier-id node-id
| +--rw sfc-policy uint32
| +--rw sfp!
| +--rw sfp-id uint32
| +--rw sf-list*[sf-id]
| +--rw sf-id node-id
| +--rw sff-list*[sff-id]
| +--rw sff-id node-id
+--rw sf-node-extension!
| +--rw sf-id node-id
| +--rw sf-node-locator uint32
| +--rw sf-type!
| | +--rw firewall? uint32
| | +--rw loadbalancer? uint32
| | +--rw NAT44? uint32
| | +--rw NAT64? uint32
| | +--rw DPI? uint32
| +--rw sf-inventory-data!
+--rw sff-node-extension!
+--rw sff-id node-id
+--rw (sffn-address)?
| +--:(ipv4-address)
| | +--rw ipv4-address? inet:ipv4-address
| +--:(ipv6-address)
| +--rw ipv6-address? inet:ipv6-address
+--rw sffn-virtual-context!
| +--rw context-id uint32
+--rw Attached-service-address!
| +--rw service-node*[service-node-id]
| | +--rw service-node-id node-id
| +--rw host-system*[host-system-id]
| +--rw host-system-id uint32
+--rw customer-support*[customer-id]
| +--rw customer-id uint32
+--rw customer-service-resource*[customer-resource-id]
| +--rw customer-resource-id node-id
+--rw sffn-vntopo!
Figure 5
The service topo yang model contains a service-topology structure. Based on the base model, this can be a list.
topology model
The generic model contains a topology leaf. The SFF augments the topology types leaf within this topology life with the SFF-topology type. The SFF module also augments the topology with topology-id leaf, and a topology attributes leaf that contains node count leaf and topology-extension container. The node-count leaf can be used to indicate the number of nodes which contained in the service-topology list. The topology-extension container can be used to augment the service topology model by topology specifics.
node structure
The generic topology structure also contains a node (nt:node), and this structure has been augmented by containers for node type, a next-hop container, and a node-extensions. The node-type container can used to indicate the type node, such classifier, a sf or a sff. The node-extension container can be used to augment the node list by node specifics, for example: classifier extension, sf extension, sff extension.
link structure
The generic link topology structure contains a link (nt:link) structure, and this generic link structure has been augmented to include a sff-link-type leaf, sff-direction container, and an segment-extension leaf. The segment-extension container can be used to augment the segment list by segment specifics. Such as netconf segment extension, i2rs segment extension.
classifier extension
In SFC, the classifier is used to locally instantiated policy and customer/network/service profile matching of traffic flows for identification of appropriate outbound forwarding actions.
sf-node-extension
The sf is a function that is responsible for specific treatment of received packets. As a logical component.
sff-node-extension
The service function forwarder is responsible for delivering traffic received from the network to one or more connected service functions according to information carried in the SFC encapsulation, as well as handling traffic coming back from the SF.
<CODE BEGINS> file "sff-topology.yang"
module sff-topology{
yang-version 1;
namespace "urn:TBD:params:xml:ns:yang:sff-topology";
prefix "sff-topo";
organization "TBD";
contact
"wangzitao@huawei.com";
description
"This module defines sff topology yang data model";
import network-topology {
prefix "nt";
}
import ietf-inet-types {
prefix "inet";
}
import network { prefix nd; }
//import service-topologies{ prefix st;}
organization "IETF I2RS Working Group";
contact
"wangzitao@huawei.com";
description
"This module defines sfc topology yang data model";
typedef node-id {
type inet:uri;
}
augment "/nt:network-topology/nt:topology/nt:topology-types"{
container Service-Topologies{
container SFF-Topology{
description
"SFF topology.";
}
}
}
augment "/nt:network-topology/nt:topology"{
leaf service-topo-id{
type network-id;
}
container service-topology-attributes{
leaf node-count{
type uint32;
}
container topology-extension{
description
"can be augment/extension.";
}
}
}
augment "/nt:network-topology/nt:topology/nt:node"{
container node-type{
leaf classifier-node{
type string;
}
leaf sf-node{
type string;
}
leaf sff-node{
type string;
}
}
list next-hop{
key "hop-id";
leaf hop-id{
type node-id;
}
}
container node-extension{
container classifier-extension{
leaf classifier-id{
type node-id;
description
"The identifier of the classifier.";}
leaf sfc-policy{
type uint32;
description
"Indicate the policy of sfc.";}
container sfp{
description
"contains several sfps.";
leaf sfp-id{
type uint32;
description
"The identifier of the sfp.";}
list sf-list{
key "sf-id";
leaf sf-id{
type node-id;
description
"The identifier of the sf which include in the sfp.";}
}
list sff-list{
key "sff-id";
leaf sff-id{
type node-id;
description
"The identifier of the sff which include in the sfp.";}
}
}//end the sfp container
}
container sf-node-extension{
leaf sf-id{
type node-id;
description
"The identifier of the service function(sf).";}
leaf sf-node-locator{
type uint32;
description
"To indicate the service function (sf) locator";}
container sf-type{
leaf firewall{
type uint32;
description
"To indicate the service function (sf) is firewall.";}
leaf loadbalancer{
type uint32;
description
"To indicate the service function (sf) is loadbalancer.";}
leaf NAT44{
type uint32;
description
"To indicate the service function (sf) is NAT44.";}
leaf NAT64{
type uint32;
description
"To indicate the service function (sf) is NAT64.";}
leaf DPI{
type uint32;
description
"To indicate the service function (sf) is DPI.";}
}//end the sf-type container
container sf-inventory-data{
description
"The container of the inventory data of service function (sf).";
}
}
container sff-node-extension{
leaf sff-id{
type node-id;
description
"The identifier of the service function forward (sff).";}
choice sffn-address{
description
"The address of the service function forward (sff) node";
case ipv4-address{
leaf ipv4-address{
type inet:ipv4-address;}
}
case ipv6-address{
leaf ipv6-address{
type inet:ipv6-address;}
}
}//end the choice sffn-address
container sffn-virtual-context{
leaf context-id{
type uint32;
description
"the identifier of the sffn virtual context.";}
}
container Attached-service-address{
list service-node{
key "service-node-id";
leaf service-node-id{
type node-id;
description
"The identifier of the service node.";}
}//end the service-node list
list host-system{
key "host-system-id";
leaf host-system-id{
type uint32;
description
"The identifier of the host system.";}
}//end the service-node list
} //end the attached-service-address container
list customer-support{
key "customer-id";
leaf customer-id{
type uint32;
description
"The identifier of the customer.";}
}//end the customer-support list
list customer-service-resource{
key "customer-resource-id";
leaf customer-resource-id{
type node-id;
description
"The identifier of the customer resource.";}
}//end the customer-service-resource list
container sffn-vntopo{
description
"This container can be use to contain the virtual network topology of
Sffn. And it can be augment by specific virtual network topology.";
}
}
}
}
}
<CODE ENDS>
TBD.
TBD.