Kytos’s reserved metadata


Kytos provides a way to add extra information to a napp and other Kytos objects. From a napp developer perspective, the napp has to provide APIs to store, retrieve and manage Metadata information. From the Kytos core perspective objects like Switch, Interface and Link have their metadata managed by the Topology Kytos Napp. In addition to this, sometimes, metadata needs to be used internally and exclusively, meaning that writes and deletions should only be done by the NApp that owns this resource, and shouldn’t be allowed via APIs.

From a user perspective, you have to make sure you are using the proper metadata and also make a fair usage of it, which means:

  • check if the metadata you want is not already there before creating a new one
  • follow the metadata specification regarding data type and semantics
  • use a meaningful and expressive metadata name
  • before starting using new metadata, submit a PR for documenting the metadata on this page


Metadata Napp Object Type Description Date Used by
availability topology link float Link’s availability in % 10.15.2021 sdx napp
link_name topology link str Link’s Name 10.15.2021 sdx napp, evc_manager
packet_loss topology link float Link’s packet loss in % 10.15.2021 sdx napp
bandwidth topology link int Link’s bandwidth in Gbps 10.15.2021 sdx napp, pathfinder
address topology switch str Node’s physical address 10.15.2021 sdx napp
lat topology switch str Node’s latitude 10.15.2021 sdx napp, kytos UI
lng topology switch str Node’s longitude 10.15.2021 sdx napp, kytos UI
node_name topology switch str Node’s name 10.15.2021 sdx napp, evc_manager
mtu topology interfaces int Interface’s mtu in bytes 10.15.2021 sdx napp
port_name topology interfaces str Interface’s name 10.15.2021 sdx napp, evc_manager
int mef_eline evc str If INT is enabled for the EVC Planned int napp (prototype phase)
mirror mef_eline evc str If Mirror is enabled for the EVC Planned mirror napp (prototype phase)
metrics mef_eline evc dict EVC’s user-requested metrics Planned mef_eline
monitoring mef_eline evc dict EVC’s monitoring approaches Planned monitoring napp (planned)
notifications mef_eline evc dict EVC’s notification Planned monitoring napp (planned)
frr mef_eline evc dict If Fast ReRoute is enabled for the EVC Planned frr napp (planned)
ownership topology link dict Link’s owners 02.02.2022 pathfinder
utilization topology link float Link’s average utilization in % 02.02.2022 pathfinder
reliability topology link float Link’s reliability in % 02.02.2022 pathfinder
priority topology link float Link’s priority, used for traffic engineering 02.02.2022 pathfinder
delay topology link float Link’s latency in ms 02.02.2022 pathfinder

Internal Metadata

Metadata Napp Object Type Description Date Used by
liveness_status topology link str Link’s liveness status up|down 06.30.22 topology, core
last_status_change topology link float Link’s last status change timestamp 06.30.22 topology
last_status_is_active topology link bool Whether Link’s last status is active or not 06.30.22 topology
notified_up_at topology link datetime Link’s last notified up datetime 11.18.22 topology

Usage examples

Retrieving switch’s name:

curl -s | jq -r '.metadata.node_name'

Update Link’s name

curl -s -X POST -H 'Content-type: application/json' -d '{"link_name": "MIA-FLZ-100G"}'

Update switch’s latitude and longitude:

curl -s -X POST -H 'Content-type: application/json' -d '{"lat": "25.7553646","lng": "-80.3760393"}'