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CDN 2.4

Overview

CDN 2.4 implements the following features in addition to CDN 2.1, 2.2 and 2.3:

  • CDN signaling connections monitoring
  • CDN signaling connections management

CDN signaling connections monitoring

CDN 2.4 allows to check current state of signaling connections with other CDN nodes using REST API or CLI. Thus, CDN coherence can be monitored from backend.

Using REST API

REST API query /cdn/show_nodes returns current state and statistics of signaling connection with other CDN nodes

[
  {
    "version": "2.3",
    "role": "TRANSCODER",
    "inboundConnected": true,
    "outboundConnected": false,
    "globalState": "ACTIVE",
    "processingState": "NEW_STREAMS_ALLOWED",
    "id": "192.168.1.64"
  },
  {
    "version": "2.4",
    "role": "EDGE",
    "inboundConnected": true,
    "outboundConnected": false,
    "globalState": "ACTIVE",
    "processingState": "NEW_STREAMS_ALLOWED",
    "connectionStats": {
      "lastRtt": 2,
      "lastSn": 24,
      "lastMessageSentMs": 1592359761801,
      "lastACKReceivedMs": 1592359761802,
      "maxRtt": 1224,
      "inFlightSize": 0
    },
    "id": "192.168.1.65"
  }
]

Parameters

Parameter Description Example
inboundConnected Inbound connection is established from this node `true`
outboundConnected Outbound connection is established to this node `false`
lastRtt Last packet RTT, ms `2`
lastSn Last packet sequence number `24`
lastMessageSentMs Last message sent timestamp, ms `1592359761801`
lastACKReceivedMs Last acknowlegement received timestamp, ms `1592359761802`
maxRtt Maximum RTT, ms `1224`
inFlightSize Current sending packet size, bytes `0`

Note that statistics is not available for previous CDN versions nodes, connection status only can be checked.

Using CLI

CLI v 2 command

cdn show-connections

shows CDN signaling connections statistics (for CDN 2.4 nodes only)

Ip            State  Inbound Outbound Last rtt Max rtt Last SN In flight
-------------------------------------------------------------------------
192.168.1.39  ACTIVE false   true     1        2057    127     0

CDN signaling connections management

In some cases, certain CDN node coherence may be broken, for example, due to network issues between nodes. To restore the CDN coherence, singnaling connections reset and re-establishing may require. In previous CDN versions, this can be done by node restart only. In CDN 2.4, signaling connections can be reset using REST API. This operation does not affect media streams which already passing through this node.

Connection reset using REST API

REST query should be HTTP/HTTPS POST request as follows:

  • HTTP: http://test.flashphoner.com:8081/rest-api/cdn/connection/reset_outbound
  • HTTPS: https://test.flashphoner.com:8444/rest-api/cdn/connection/reset_outbound

Where:

  • test.flashphoner.com - WCS server address
  • 8081 - REST / HTTP port
  • 8444 - HTTPS port
  • rest-api - mandatory URL part
  • /cdn/connection/reset_outbound - REST method used

REST queries should be sent to the node on which connections must be reset

REST queries and response states

REST query Request body Response status Description
`/cdn/connection/reset_inbound` 
{
    "nodeId":"192.168.1.65"
}
200 OK 404 Node not found Reset inbound connection from this node
`/cdn/connection/reset_outbound` 
{
    "nodeId":"192.168.1.65"
}
200 OK 404 Node not found Reset outbound connection to this node
`/cdn/connection/reset_all` 200 OK Reset all CDN connections on this node (since build 5.2.1222)

Parameters

Parameter Description Example
nodeId Node id (IP address) to reset connection with `192.168.1.65`

Signaling connections tuning

Inactive connections reset configuration

Signaling connection can be closed if server does not receive any packets during a certain timeout. The feature is enabled by the following parameters for incoming and outgoing signaling connections respectively

cdn_inbound_ws_read_socket_timeout=true
cdn_outbound_ws_read_socket_timeout=true

By default, the read timeout is set to 60 seconds

cdn_inbound_ws_read_socket_timeout_sec=60
cdn_outbound_ws_read_socket_timeout_sec=60

Backward compatibility with CDN 2.0-2.3

  1. Statistics is not displayed for connections with previous CDN versions nodes

  2. Connection with previous CDN version node can be reset