Task 10 - Configure OSPF

This task covers configuring OSPF using NETCONF following the typical workflow of module discovery, payload editing, and loading.

OSPF Model Support

SR Linux supports native and OpenConfig OSPF models but it uses the native model for configuration.

http://openconfig.net/yang/ospfv2?module=openconfig-ospfv2&revision=2024-06-17
urn:nokia.com:srlinux:ospf:ospf?module=srl_nokia-ospf&revision=2025-10-31

cEOS supports only OpenConfig OSPF model.

http://openconfig.net/yang/ospf?module=openconfig-ospf&revision=2025-02-13

cEOS Configuration

To discover the OSPF YANG module, you will need to use the openconfig-network-instance (downloaded in previous tasks) and openconfig-ospfv2

(.pyenv) automan@autobook:~/tutorial$ ./scripts/netconf_tool.py ceos-01 schema openconfig-ospfv2

Visualize the tree using a depth limit of 7 to get only the top containers in the ospfv2 branch:

pyang -f tree -p openconfig \
--tree-path network-instances/network-instance/protocols/protocol/ospfv2 \
openconfig-network-instance.yang --tree-depth=7

module: openconfig-network-instance
  +--rw network-instances
     +--rw network-instance* [name]
        +--rw protocols
           +--rw protocol* [identifier name]
              +--rw ospfv2
                 +--rw global
                 |  +--rw config
                 |  |     ...
                 |  +--ro state
                 |  |     ...
                 |  +--rw timers
                 |  |     ...
                 |  +--rw graceful-restart
                 |  |     ...
                 |  +--rw mpls
                 |  |     ...
                 |  +--rw inter-area-propagation-policies
                 |        ...
                 +--rw areas
                    +--rw area* [identifier]

From the generated tree, we are interested in the global and areas containers and their mandatory children nodes. Also notice that we need to identify the network instance name and the protocol identifier name.

Under global, we will need to set a router-id:

pyang -f tree -p openconfig \
--tree-path network-instances/network-instance/protocols/protocol/ospfv2/global/config \
openconfig-network-instance.yang --tree-depth=8

module: openconfig-network-instance
  +--rw network-instances
     +--rw network-instance* [name]
        +--rw protocols
           +--rw protocol* [identifier name]
              +--rw ospfv2
                 +--rw global
                    +--rw config
                       +--rw router-id?                    yang:dotted-quad
                       +--rw summary-route-cost-mode?      enumeration
                       +--rw igp-shortcuts?                boolean
                       +--rw log-adjacency-changes?        boolean
                       +--rw hide-transit-only-networks?   boolean

Under areas, we need to set the area's identifier, and a list if interface ids:

pyang -f tree -p openconfig \
--tree-path network-instances/network-instance/protocols/protocol/ospfv2/areas \
openconfig-network-instance.yang --tree-depth=11

module: openconfig-network-instance
  +--rw network-instances
     +--rw network-instance* [name]
        +--rw protocols
           +--rw protocol* [identifier name]
              +--rw ospfv2
                 +--rw areas
                    +--rw area* [identifier]
                       +--rw identifier       -> ../config/identifier
                       +--rw config
                       |  +--rw identifier?   oc-ospf-types:ospf-area-identifier
                       ...
                       +--rw interfaces
                       |  +--rw interface* [id]
                       |     +--rw id               -> ../config/id
                       |     +--rw config
                       |     |  +--rw id?                             oc-if:interface-id
                       |     |  +--rw network-type?                   identityref
                       |     |  +--rw priority?                       uint8
                       |     |  +--rw multi-area-adjacency-primary?   boolean
                       |     |  +--rw authentication-type?            string
                       |     |  +--rw metric?                         oc-ospf-types:ospf-metric
                       |     |  +--rw passive?                        boolean
                       |     |  +--rw hide-network?                   boolean

Generate a XML skeleton using Technique 1: pyang Sample XML Skeleton at a subtree:

pyang -f sample-xml-skeleton --sample-xml-skeleton-path=/network-instances/network-instance/protocols/protocol \
--sample-xml-skeleton-doctype=config -p openconfig openconfig-network-instance.yang -o ospf.xml

The generated skeleton does not include the network instance name so will add it using what we know from Task 7.

Edit the file ospf.xml by filling the mandatory information and remove the nodes that are not required:

  • Network Instance: default
  • Protocol Identifier: oc-pol-types:OSPF (obtained from here)
  • Protocol Name: 100
  • Router ID: 1.1.1.1
  • Area: 0.0.0.0
  • Interface ID's: Ethernet1 and Ethernet2 
<network-instances xmlns="http://openconfig.net/yang/network-instance">
<network-instance>
    <name>default</name>
    <protocols>
    <protocol>
        <identifier xmlns:oc-pol-types="http://openconfig.net/yang/policy-types">oc-pol-types:OSPF</identifier>
        <name>100</name>
        <config>
        <identifier xmlns:oc-pol-types="http://openconfig.net/yang/policy-types">oc-pol-types:OSPF</identifier>
        <enabled>true</enabled>
        </config>
        <ospfv2>
        <global>
            <config>
            <router-id>1.1.1.1</router-id>
            </config>
        </global>
        <areas>
            <area>
            <identifier>0.0.0.0</identifier>
            <config>
                <identifier>0.0.0.0</identifier>
            </config>
            <interfaces>
                <interface>
                <id>Ethernet1</id>
                <config>
                    <id>Ethernet1</id>
                </config>
                </interface>
                <interface>
                <id>Ethernet2</id>
                <config>
                    <id>Ethernet2</id>
                </config>
                </interface>
            </interfaces>
            </area>
        </areas>
        </ospfv2>
    </protocol>
    </protocols>
</network-instance>
</network-instances>

Upload the configuration payload to the candidate datastore and commit:

./nc_wrapper.sh ceos-01 --edit-config=ospf.xml --db=candidate --commit

SR Linux Configuration

SR Linux uses a native OSPF YANG. Yet, similar to cEOS, we need the following:

  • OSPF version number (v2 in this task)
  • Router ID: Each router running OSPF must be configured with a unique router ID.
  • An area: At least one OSPF area must be created. An interface must be assigned to each OSPF area.
  • Interfaces: An interface has a single IP address and mask (unless the network is an unnumbered point-to-point network).

Configuring all of the above will be done at the network instance level, so let's visit the network instance tree again:

./scripts/netconf_tool.py srl-01 schema srl_nokia-network-instance

pyang -f tree -p nokia  srl_nokia-network-instance.yang --tree-path /network-instance --tree-depth=2 --ignore-errors

Like the OpenConfig module, the OSPF fits inside the protocols container:

module: srl_nokia-network-instance
  +--rw network-instance* [name]
     +--rw name                                     srl_nokia-comm:restricted-name
     +--rw type?                                    identityref
     +--rw admin-state?                             srl_nokia-comm:admin-state
     +--ro oper-state?                              srl_nokia-comm:oper-state
     +--ro oper-down-reason?                        enumeration
     +--ro oper-mac-vrf-mtu?                        uint16
     +--ro oper-vpws-mtu?                           uint16 {srl-feat:vpws}?
     +--rw description?                             srl_nokia-comm:description
     +--rw router-id?                               srl_nokia-comm:dotted-quad
     +--rw mpls-forwarding
     |     ...
     +--rw ip-forwarding!
     |     ...
     +--rw ip-tunnel-statistics {srl-feat:gribi-host-prefix-ip-tunnel-statistics}?
     |     ...
     +--rw interface* [name]
     |     ...
     +--ro system-ipv4-address
     |     ...
     +--ro system-ipv6-address
     |     ...
     +--rw vxlan-interface* [name] {srl-feat:vxlan}?
     |     ...
     +--ro icmp
     |     ...
     +--ro icmp6
     |     ...
     +--rw protocols
     |     ...
     +--rw bridge-table! {srl-feat:bridged}?
     |     ...
     +--ro route-table
     +--ro tunnel-table
     +--ro multicast-forwarding-information-base
     +--rw connection-point* [name] {srl-feat:connection-point}?
           ...

You can also inspect the OSPF module tree, which is also large:

./scripts/netconf_tool.py srl-01 schema srl_nokia-ospf

pyang -f tree -p nokia srl_nokia-ospf.yang | head -n 15

module: srl_nokia-ospf

  augment /srl_nokia-netinst:network-instance/srl_nokia-netinst:protocols:
    +--rw ospf!
       +--rw instance* [name]
          +--rw name                           srl_nokia-comm:name
          +--rw admin-state?                   srl_nokia-comm:admin-state
          +--rw version                        identityref
          +--rw address-family?                identityref
          +--rw instance-id?                   uint32
          +--rw router-id?                     yang:dotted-quad
          +--rw max-ecmp-paths?                srl_nokia-ospf-types:ospf-ecmp
          +--rw advertise-router-capability?   enumeration
          +--rw export-policy?                 -> /srl-rpol:routing-policy/policy/name
          +--rw asbr!

It is worth mentioning that the ! symbol immediately following a node name (ospf!) indicates that the node is a presence container. A presence container exists in the configuration just by being created, even if it has no child nodes and its existence signifies that OSPF is enabled in the network instance.

Typically, what you could do next is to generate the XML skeleton file that includes the minimum configuration items mentioned above. However, for such complex configuration, we can use Technique 2: Configure via CLI, Then Read Back, similar to what we did in Task 6.

Configure OSPF using the CLI on srl-01, then retrieve the configuration.

For this configuration, we assign the router id to 2.2.2.2 in srl-01 and 3.3.3.3 in srl-02. We also create area 0.0.0.0 and assign both interfaces to it.

  • Network Instance: default
  • OSPF Instance Name: 100
  • Router ID: 2.2.2.2 and 3.3.3.3 (for srl-01 and srl-02, respectively)
  • Area ID: 0.0.0.0
  • Interface Names: Ethernet1 and Ethernet2
./nc_wrapper.sh srl-01 --get-config --filter /network-instance/protocols/ospf

<?xml version="1.0" encoding="UTF-8"?>
<data xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0">
  <network-instance xmlns="urn:nokia.com:srlinux:net-inst:network-instance">
    <name>default</name>
    <protocols>
      <ospf xmlns="urn:nokia.com:srlinux:ospf:ospf">
        <instance>
          <name>100</name>
          <version xmlns:srl_nokia-ospf-types="urn:nokia.com:srlinux:general:ospf-types">srl_nokia-ospf-types:ospf-v2</version>
          <router-id>2.2.2.2</router-id>
          <area>
            <area-id>0.0.0.0</area-id>
            <interface>
              <interface-name>ethernet-1/1.0</interface-name>
            </interface>
            <interface>
              <interface-name>ethernet-1/2.0</interface-name>
            </interface>
          </area>
        </instance>
      </ospf>
    </protocols>
  </network-instance>
</data>

Save the retrieved configuration in a file ospf.xml. Edit the file and upload it to srl-02.

./nc_wrapper.sh srl-02 --edit-config=ospf.xml --db=candidate --commit

You can verify by reading the configuration back:

./nc_wrapper.sh srl-02 --get-config --filter /network-instance[name=default]/protocols/ospf

Conclusion

As this point, you have successfully configured a functioning, yet simple, network using YANG models with NETCONF and gNMI.