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Let's get started
What is NETCONF?
A network managing protocol to configure network elements.
It transports xml (json) via SSH.
<rpc-reply message-id="1" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> <data> <interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"> <interface> <name>eth0</name> <type xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">ianaift:ethernetCsmacd</type> <enabled>true</enabled> <ipv6 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip"> <address> <ip>2001:db8:c18:1::3</ip> <prefix-length>128</prefix-length> </address> </ipv6> </interface> </interfaces> </data></rpc-reply>
What is YANG?
A data modeling language for the definition of data sent over the NETCONF network configuration protocol.
It is a schema to validate xml.
container interfaces { description "Interface configuration parameters."; list interface { key "name"; leaf name { type string; } leaf type { type identityref { base interface-type; } mandatory true; } leaf enabled { type boolean; default "true"; } } // list interface} // container interfaces
NetConf
NetConf was designed based on Operators Requirements, which are documented in RFC3535. It addresses security topics and operational and maintenance topics.
What is the difference?
Protocol: | SNMP | NETCONF | SOAP | REST | RESTCONF | gRPC | What comes next ... |
Transport Stack | UDP | SSH | SSL | SSL | SSL | HTTP/2 TCP | |
Encoding | BER | XML (new JSON) | XML | XML, JSON | XML, JSON | binary | |
Resources | OIDs | Path | URLs | URLs | URLs | ||
Data models | MIBs | YANG modules | WSDL, XSD | YANG modules | Protocol Buffers | ||
Data Modeling Language | SMI | YANG | WSDL, XSD | Undefined, (WSDL), WADL, text… | YANG | Protocol Buffers | |
Management Operations | SNMP operations | NETCONF operations | In the XML Schema, not standardized | HTTP operations | HTTP operations | HTTP/2 operations | |
SDO (like) | IETF | IETF | W3C | W3C | IETF |
NETCONF Datastore concept
configuration datastore:
The datastore holding the complete set of configuration data that is required to get a device from its initial default state into a desired operational state.
running configuration datastore:
A configuration datastore holding the complete configuration currently active on the device. The running configuration datastore always exists.
candidate configuration datastore:
A configuration datastore that can be manipulated without impacting the device's current configuration and that can be committed to the running configuration datastore. Not all devices support a candidate configuration datastore.
startup configuration datastore:
The configuration datastore holding the configuration loaded by the device when it boots. Only present on devices that separate the startup configuration datastore from the running configuration datastore.
NETCONF Operations
| Operation | Description |
|---|---|
| get | Retrieve running configuration and device state information. |
| get-config | Retrieve all or part of a specified configuration datastore. |
| edit-config | Loads all or part of a specified configuration to the specified target (<running>, <candidate>) configuration datastore. operation-types: merge, replace, create, delete, remove |
| copy-config | Create or replace an entire configuration datastore with the contents of another complete configuration datastore. |
| delete-config | Delete a configuration datastore. The <running> configuration datastore cannot be deleted. |
| (partly-) lock | It allows the client to lock the entire configuration datastore system of a device. |
| (partly-) unlock | Releases a configuration lock, previously obtained with the <lock> operation. |
| commit | Sets the running configuration to the current contents of the candidate configuration. |
| validate | This protocol operation validates the contents of the specified configuration. |
| close-session | Request graceful termination of a NETCONF session. |
| kill-session | Force the termination of a NETCONF session. |
| (hello-message) | (exchange of yang capabilities (yang modules) between server and client) |
How does it work?
(one of x possibilities)
YANG
- YANG is a data modeling language for NETCONF (and RESTCONF) configuration and state data.
- It defines the syntax of the exchanged xml (and json) data between a NETCONF client (e.g. OpenDaylight) and a NETCONF server (a device)
Build-in data types
Name | Description |
binary | Any binary data |
bits | A set of bits or flags |
boolean | "true" or "false" |
decimal64 | 64-bit signed decimal number |
empty | A leaf that does not have any value |
enumeration | Enumerated strings |
identityref | A reference to an abstract identity |
instance-identifier | References a data tree node |
[u]int[8|16|32|64] | [8|16|32|64] -bit [un]signed integer |
leafref | A reference to a leaf instance |
string | Human-readable string |
union | Choice of member types |
Common data types
ietf-yang-types | Equivalent SMIv2 type |
counter32 | Counter32 (SNMPv2-SMI) |
zero-based-counter32 | ZeroBasedCounter32 (RMON2-MIB) |
counter64 | Counter64 (SNMPv2-SMI) |
zero-based-counter64 | ZeroBasedCounter64 (HCNUM-TC) |
gauge32 | Gauge32 (SNMPv2-SMI) |
gauge64 | CounterBasedGauge64 (HCNUM-TC) |
object-identifier | OBJECT IDENTIFIER |
object-identifier-128 | |
yang-identifier | |
date-and-time | |
timeticks | TimeTicks (SNMPv2-SMI) |
timestamp | TimeStamp (SNMPv2-TC) |
phys-address | PhysAddress (SNMPv2-TC) |
mac-address | MacAddress (SNMPv2-TC) |
xpath1.0 | |
hex-string | |
uuid | |
dotted-quad |
ietf-inet-types | Equivalent SMIv2 type |
ip-version | InetVersion (INET-ADDRESS-MIB) |
dscp | Dscp (DIFFSERV-DSCP-TC) |
ipv6-flow-label | IPv6FlowLabel (IPV6-FLOW-LABEL-MIB) |
port-number | InetPortNumber (INET-ADDRESS-MIB) |
as-number | InetAutonomousSystemNumber |
ip-address | |
ipv4-address | |
ipv6-address | |
ip-address-no-zone | |
ipv4-address-no-zone | |
ipv6-address-no-zone | |
ip-prefix | |
ipv4-prefix | |
ipv6-prefix | |
domain-name | |
host | |
uri | Uri (URI-TC-MIB) |
References/Links
RFC 3535 Overview of the 2002 IAB Network Management Workshop (see chapter 3 – Requirements by Network Operators)
RFC 6241 Network Configuration Protocol (NETCONF)
RFC 6020 YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)
RFC 6991 Common YANG Data Types
RFC 7950 The YANG 1.1 Data Modeling Language
Overview NETCONF and YANG Overview
Tutorial YANG Tutorial
Tutorial YANG Boot Camp
pyang An extensible YANG validator and converter in python