Terminal or gateway registration timeout

Description of the problem:
no more REGISTER packets have arrived from the terminal and \ or from the gateway and the registration session has expired.

Each physical device that uses the SIP protocol (IP phones and telephone gateways) periodically sends (every 60-120 seconds) registration packets (REGISTER) to the server, indicating the registration period in the expires field:

REGISTER sip:acme.ucloud SIP/2.0
Via: SIP/2.0/UDP 192.168.0.176;branch=z9hG4bK7ab66f99E85D248A
From: “Mario Rossi” <sip:103@acme.ucloud>;tag=A31CA19B-917771A4
Expires: 60

REGISTER sip:acme.ucloud SIP/2.0
Via: SIP/2.0/UDP 192.168.0.176;branch=z9hG4bK7ab66f99E85D248A
From: “Mario Rossi” <sip:103@acme.ucloud>;tag=A31CA19B-917771A4
Contact: <sip:103@192.168.0.176>; Expires=120

Each terminal or gateway must reappear with a new REGISTER before the expiration of the period indicated in the previous REGISTER. After this period (timeout) with a tolerance of 20%, in the absence of new registrations the server will consider the device as deregistered.

Possible causes:

Among the most probable causes we can indicate:

Connectivity problems, starting from the physical connection of the device up to the internet connection (router and / or internet provider). If the disconnection is detected simultaneously on several terminals, it is likely that the problem is due to a network device common to all devices (switches, firewalls, routers). They should be considered as contemporaneous with the events that occurred in a time interval of the order of magnitude of the registration period of the terminals considered, that is, a few tens of seconds.
Single device problems. If the phenomenon occurs often, but only to a small set of devices, it is likely that the problem is limited to the devices themselves (power socket, power supply, ethernet cable, switch port)

Possible solutions:

With reference to the possible causes of the previous point:

The simultaneous disconnection of many devices could be caused by:
Lack of power supply on one or more network devices. Make sure they are under UPS modem / router / firewall, network devices and IP phones. Using PoE switches (Power over Ethernet) to power the IP phones, just leave the switch under the UPS and all the terminals connected to it will be automatically protected. Loss of connection from the modem/router
The modem / router could lose the connection to the internet, propagating the disconnection to all devices downstream of the same. Keep the internet connection under control with a simple repeated ping, launched from any PC. The percentage of packets that may be lost should always be less than 1%.

C:\temp>ping -t -l 576 -w 200 8.8.8.8

Ping 8.8.8.8 con 576 bytes of data:

Reply from 8.8.8.8: byte=576 durata=32ms TTL=53

Reply from 8.8.8.8: byte=576 durata=33ms TTL=53

Reply from 8.8.8.8: byte=576 durata=35ms TTL=53

In case you often find connectivity “holes” lasting several seconds on an xDSL line, ask the provider to reduce the connection speed, in order to improve the signal / noise ratio and increase its stability. In some cases the provider may opt for the replacement of the copper pair.

Saturation of router NAT sessions Each router is able to manage a finite number of NAT / PAT sessions from the inside out. This number, generally very high, may in some cases not be sufficient for all connections, due to abnormal use by one or more network devices that for example share files with P2P applications (Bittorrent, eMule …). Check that there are no PCs or NAS on the network with P2P applications active during business hours.

There is always the possibility that there is a bug in the router’s management of NAT sessions that leads to the exhaustion of routing resources. If by restarting the router all devices are registered, we are probably in this scenario and all that remains is to look for an updated firmware of the router or replace the router with a different one.

The disconnection of a few devices or a single device could be caused by:

Lack of power supply.
In the event that the device is not powered by a PoE switch, but by a separate power supply, check its reliability. For example, multiple sockets arranged on the floor are the most common targets for users’ kicks and the vacuum cleaner.

Device lost connection
The IP phone or gateway may lose its connection to the internet, due to a problem with the wiring or port of the switch it is connected to. Keep the connection under control with a simple repeated ping, launched from any PC to the private IP of the device. The percentage of packets lost should be negligible

C:\temp>ping -t -l 576 -w 200 192.168.1.79
Ping 192.168.1.79 con 576 byte di dati:
Reply from 192.168.1.79: byte=576 durata=1ms TTL=53
Reply from 192.168.1.79: byte=576 durata=1ms TTL=53
Reply from 192.168.1.79: byte=576 durata=1ms TTL=53
Reply from 192.168.1.79: byte=576 durata=1ms TTL=53
Reply from 192.168.1.79: byte=576 durata=1ms TTL=53
Reply from 192.168.1.79: byte=576 durata=1ms TTL=53
Reply from 192.168.1.79: byte=576 durata=1ms TTL=53

In case you often find connectivity “holes” on the device, try to change the patches that connect it to the network and to the switch, until you change the switch port.

How Can We Help?

Terminal or gateway registration timeout