Newbie question about phones and internet connectivity

[Anonymous]

Please point me in the right direction to find an answer to a vexing problem.

I'm using SoundPoint 550 phones in conjunction with Elastix (Asterisk). The phones are in an office and the server is in a remote location. The office has 2 Internet connections.

I have configured the router at the office to send the VoIP traffic out one connection, data out the other. If the VoIP-specific link fails, the router will automatically route the traffic through the other connection. Unfortunately, more often than not this knocks the phones offline. (It sometimes works fine, but it isn't seamless). Essentially, the phones just sit there, stupidly unaware that they're no long in touch with the server. (The "sip show peer" on the server command shows the extensions as unreachable.)

I've noticed something similar when I reboot the router. The phones don't always wake up to the fact that they're unreachable. We have to reboot them (or wait a really long time for them to reconnect on their own).

What I would like is for the phones to reconnect after the brief network interruption of a failover between links.

Is this a phone configuration? An Asterisk configuration? Or am I missing something obvious?

Thanks

DWLangham

[Anonymous · Accepted solution]

A phone will register for a period of time depending on how it is configured. Both the server and the phone will consider the link between server and phone active for that time period. ( ok it is a little more complicated than this but basically it works this way).

You can configure the phone  for fallback ( see admin manual) if you have different Ip addresses on the two links , or lower the reg server expires interval causuing the phone to re-register more often (like every five minute instead of the ddefault one hour).

Regards

Brian

[Anonymous]

Thanks for the reply. I will give the "reg server expires interval" a try, as that makes sense.

Something I've learned since posting this is that the problem I described is related to the use of NAT to translate the phone IP's. Nothing wrong with NAT per se, but when the router reboots it loses the translations, so when the server attempts to route a call to a phone the router drops the packets. When I test with routable IPs on the phones I find that the server can establish communication with the phones immediately after. (No surprise there, I guess.)

There aren't sufficient public IPs available for use on the phone network to support all the VoIP devices, but I'm getting around the need for NAT by using a GRE tunnel between the office and the data center, allowing me to route private address space between the two locations over the public Internet without having to NAT on the office router.

[Anonymous]

we are using Polycom Soundpoint IP335 phones.

Any and every time we have an internet outage, even for a few seconds. the phones do not come back on line.

we have to manually unplug each phone to reconnect to the internet.

Why is this happening?

How do we fix it?

[SteffenBaierUK]

Hello adj,

welcome to the Polycom Community.

It is always useful to include the currently used SIP or UC Software version as issues experienced or a question asked may already be addressed in a newer release.

Please also include if you are using a SIP server or a LYNC / Skype for Business server.

This also allows yourself and others to check against current software release notes, Administrator Guides or FAQ post’s.

The above is also stated in the "Read First"

Therefore the Polycom VoIP FAQ contains this post here:

Question: How can I find out my SIP or UC Software Version of my Phone?
Resolution: Please check here

Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.

Best Regards

Steffen Baier

Polycom Global Services