DEVNET-1152 OpenDaylight YANG Model Overview and Tools
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This document provides an overview of a workshop held by the IAB on network management. The goal of the workshop was to continue discussions between network operators and protocol developers and guide the IETF's focus on future work regarding network management.
DEVNET-1152 OpenDaylight YANG Model Overview and Tools
- 2. OpenDaylight YANG model Overview Giles Heron – Principal Engineer
- 3. Why NETCONF/YANG - Informational RFC 3535 • SNMP had failed • For configuration, that is • Extensive use in fault handling and monitoring • CLI scripting • “Market share” 70%+ Abstract This document provides an overview of a workshop held by the Internet Architecture Board (IAB) on Network Management. The workshop was hosted by CNRI in Reston, VA, USA from June 4 thru June 6, 2002. The goal of the workshop was to continue the important dialog started between network operators and protocol developers, and to guide the IETFs focus on future work regarding network management. configuration
- 4. NETCONF and YANG in Context NETCONF Manager NETCONF Yang Models YANG ModelsYANG Models YANG Models YANG Models Management Applications
- 5. What is a Data-Model? What is a Network Management Protocol? • Data-Model • A data-model explicitly and precisely determines the structure, syntax and semantics of the data… • …that is externally visible • Consistent and complete • Protocol • Remote primitives to view and manipulate the data • Encoding of the data as defined by the data-model Data-Model Protocol
- 6. Confusion and Comparison • Data-Models and information Models • Information models are for humans • Not everything • Not always detailed and precise • Starting-point for data-model • Protocol • Confusion between domain-specific network management protocols and general RPC mechanisms • NETCONF vs. CORBA, SOAP, REST, … Data-Model MIB Modules YANG Modules Protocol The SNMP Protocol NETCONF
- 7. What is YANG? • YANG – Yet Another Next-Generation... • ... Communication Protocol? • ... Messaging Bus? • ... Management Information Definition Language! • Purpose • Define management information for Netconf... • ... Original focus on configuration information, but not restricted to it • ... Can be separated from Netconf (not a goal of the specification, but an important aspect)
- 8. YANG and XML • YANG assumes an XML encoding of instantiated information • Defines XML rendering rules • Relies on XML encoding for certain advanced features (e.g. expression of constraints using Xpath) • Facilitates describing XML document hierarchies • Nicely aligned with NETCONF • YANG itself is not XML • Emphasis on readability • Familiar structure to C/C++ or Java programmers • XML notation exists: YIN (Yang-Independent Notation) • Semantic equivalence • Syntactic conversions YANG <-> YIN • Alternative encodings defined (e.g. JSON for RESTconf)
- 9. YANG compared to SNMP Definition language: YANG Information model: YANG modules Instantiated data: XML Transport: Netconf Definition language: SMIv2 Information model: MIB modules Instantiated data: ASN.1 BER Transport: SNMP “Content” “Payload” “Framework” Compare SNMP Import conversion rules exist (MIBs YANG) “instant content” Ability to express hierarchy (compare MIBs: flat + tables) Richer conditions, constraints Facilities for easier reuse RPC/Action support Human readability Dynamic extensibility B2B, Web toolkits Bulk vs only incremental ops (manipulation of config files, e.g. edit-config) Transaction support Configuration vs monitoringor possibly other (no inherent dependency but will require different bindings)
- 10. YANG in the context of Netconf Transport Remote Operations Mgmt Services Mgmt info (payload) Mgmt info (definition) XML-encoded content YANG modules Netconf operations <edit-config>, <get-config>, <get> Netconf RPC <rpc>, <rpc-reply> TLS, SSH Manager (client) XML content per YANG Conceptual Data Store Agent (server)
- 11. YANG • Data modeling language • Configuration data • State data • Tree structure • Data and Types acme-box module properties container interfaces container name: string, config name: string, config interface: list, key = name oper-state: enum, config
- 12. RESTCONF • ReSTful protocol to access YANG defined data • Remote State Transfer, i.e. server maintains no session state • HTTL URLs reflect data hierarchy in a YANG-modelled datastore RESTCONF Netconf GET <get-config>, <get> POST <edit-config> (“create”) PUT <edit-config> (“replace”) PATCH <edit-config> (“merge”) DELETE <edit-config> (“delete”) OPTIONS (discover supported operations) HEAD (get without body)
- 13. Resource URI Map /restconf /config /<top-level-data-nodes> (configuration data) /operational /<top-level-data-nodes> (operational data) /modules /module /name /revision /namespace /feature /deviation /operations /<custom protocol operations> /streams /stream /name /description /replay-support /replay-log-creation-time /events /version (field) Event streams, subscribe using “get”, can specify filters Meta-information: Capabilities etc Meta-information: Supported RPCs YANG- defined data
- 14. ODL Transport Remote Operations Mgmt Services Mgmt info (encoding) Mgmt info (definition) XML-encoded content YANG modules NETCONF operations XML RPC TLS, SSH JSON JAVA DTO I2RS ? HTTP RESTCONF TCP YANG - NETCONF, RESTCONF, I2RS & IDL
- 15. Controller YANG IDL – OpenDaylight MD-SAL MD-SAL DOM BrokerBA-BI Connector Mapping Service Codec Registry Schema Service Codec Generator Binding-Aware Broker Data Store Binding-Aware to Binding-Independent Data Translation Binding-Aware Plugin Binding-Independent Plugin/Client (NETCONF/RESTCONF) Forwarding Rules Manager, Stats Manager, BGP-LS/PCEP RESTCONF Clients Internal Clients YANG Models
- 16. Mounting Remote Datastores OpenDaylight Controller Config MD-SAL NETCONF NETCONF • Mounted under e.g. http://localhost:8181/restconf/config/opendaylight- inventory:nodes/node/controller-config • Data can be accessed using …/yang-ext:mount/… • …/yang-ext:mount/config:modules is used to configure the various plug-ins Config Store RESTCONF
- 17. Mounting Remote Datastores OpenDaylight NETCONF Node “Discovery” MD-SAL NETCONF RESTCONF Node Inventory • Nodes added by POSTing to config:modules • ODL connects to each node • ODL learns capabilities (YANG modules) and stores to model cache • Cache at ~/cache/schema. Filenames of form [email protected]. Model Cache XR1 XR2 OpenWRT
- 18. Mounting Remote Datastores OpenDaylight NETCONF Node Configuration MD-SAL NETCONF RESTCONF Node Inventory • Nodes configured by POSTing or PUTting to e.g.: • http://localhost:8181/restconf/config/opendaylight-inventory:nodes/node/XR2/yang- ext:mount/Cisco-IOS-XR-ifmgr-cfg:interface-configurations/interface- configuration/act/Loopback0/ • Can retrieve config (or operational stats) using GET Model Cache XR1 XR2 OpenWRT
- 19. Thank you