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System reboots


So I configured a SIP trunk from for testing, 

Trunk works, can place and recieve calls...

However if I disconnect the WAN port cable and wait a min and plug the cable back in, the system reboots along with all phones

also for a office with a preexisting WAN (no extra WAN ports), SIP does not seem to want to use the LAN connection? Is this true that all SIP connections go out the WAN port only?

Any ideas...



10 Replies 10


The UC320 reboots whenever WAN IP connectivity is lost.  Here is a comment from one of the developers

"A couple known issues that we plan to address:

1.       Currently WAN interface IP address change (e.g. unplugging the WAN interface) can cause voice module to reload. The fix requires substantial code change while it is either easy to workaround or not an issue for real life deployment. So we have prioritized the more important bug fixes over it for the last release. This is something we will fix in a later release."

Im not sure what you mean about the SIP connection.  How is your UC320 connected?

Christopher Edgeworth
Frequent Contributor
Frequent Contributor

Hi Mark,

The voice process rebooting is a known issue.  Essentially, when we get a new WAN IP the voice process reinitializes and triggers the phones to reinitialize.  We have this on our radar to address in a future release.  There are a couple of things that can be done to minimize the chance of this happening:  1)  Use a static IP address for the WAN port of the UC320W and 2) put both the UC320W and the broadband access device on an Uninterruptable Power Supply (UPS).

In the 2.0 release supports basic routing functionality meaning the UC320W know about the directly connected Voice and Data subnets on the LAN side and all other network addresses are sent out the WAN interface (default route).

Have you considered putting the UC320W inline with your existing router so the topology looks like this:

Internet  --- Modem --- Edge Router --- UC320 ---switch ---phones/PCs

Or if there are more advance data IP services in place, perhaps the UC320W Route Voice Only topology outlined here is a better fit:

We are also looking at in a future feature release the option to configure the UC320W as a network appliance instead of as a router.

Hope this helps.


Have you considered putting the UC320W inline with your existing router so the topology looks like this:

Internet  --- Modem --- Edge Router --- UC320 ---switch ---phones/PCs

Which would work, right up until you change config and the network gets cut off from the internet whilst it reboots and you get shouted at lots by end users

Another popular topology we see is:

Internet - modem - edge router - existing office switch - PC's



                                                    -- UC320 - ESW POE switch - Phones

UC320 will not be managing QoS in this topology so we recommend it only for FXO deployment. But it is probably fine for small number of simultaneous SIP calls and a fat WAN pipe relative to the number of PC's. I know a few SIP sites are configured that way with no problem.

At any rate, we will be reducing the reboot time and the number of config change scenarios requiring a reboot in the future. Out of curiosity, how often do you think the UC320 needs to change config after installation? And can those changes typically planned and done after business hours?



In a perfect world , yes changes are planned and scheduled, however add,

moves, deletes etc should not require a full system reboot, also network

status should never cause a system reboot, its expected that a product

coming out of Cisco will be polished, the UC320 is not at this stage.

It just seems to me that with the amount of man years Cisco has with VOIP

and router development they should have all this figured out.

It also seems to me that Cisco product management did not need to create yet

another platform to support VOIP for Small business, as a former product

manager I would have pushed for a UC500 based platform call it a UC510, 24

users MAX but has all the current UC500 series features, as the UC500

platform has lots of man years of development, bug fixes, and features, just


Just saying...

On Thu, Apr 14, 2011 at 10:06 PM, blaw <

Hi mlemmo,

I appreciate the criticism and has taken it in good spirit. I also appreciate the desire of "UC510" from a prodcut managment perspective. I like to share the engineering perspective as long as we are "just saying".

The same engineeirng team who devleopd UC320 also persides over UC500. We have to make a critical design decision to meet the design goals which is to be extremly affordable and easy to configure. The list price is a flat $995 with no addiitonal charge for phone licenses or interface cards. This is a few times lower than the UC500. The user interface has to be easy to use so to lower partner's staff training cost.

The objectives above could not be achieved with the UC500 base design. We have to take a radically different approach such as soft instead of hard DSP and consolidation of call control and voice mail onto one MPU. The GUI also redesigned which is many times easier to learn than CLI. It is also simpler than CCA.because we confine it to the core PBX functionality. End result is partners can train a summer intern in hours to install the system. Many partners also tell me this price allow them to reach a completely new set of customers.

I think it is natural to see UC320 as a continum of UC500 especially from a product management perspective. And frankly we like that. However UC320 is a little brother breeded for a different mission. So the family resemblance might be a little less than one expected. But they complement each other in a partner's VoIP offering portfolio.



blaw wrote:

Another popular topology we see is:

Internet - modem - edge router - existing office switch - PC's



                                                    -- UC320 - ESW POE switch - Phones

We have tried this previously. The UI wouldn't let us set the WAN address to anything in an RFC1918 range. So unless the LAN is publicly addressed this wouldn't work.


What address did you use? What is the firmware version? I remember configuring at leat two production systems with 192.168.x.x. addresses without any problem.



The UC320W does a full reboot only if a setting for the data network changes such as changing WiFi password or DHCP pool range, otherwise only the voice process restarts, leaving data services intact.  When the voice process restarts, it instructs all of the connect phones to reboot (which are very quick) but the WAN connection to the internet remains up.  There is a second or two during a phone reboot that the phone switch hardware will drop the network connection if a PC is connected to the back of the phone.  The amount of downtime of the IP network is minimal.  Because all the phones reinitialize at the same time people think the whole system rebooted.


So I have a demo system configured...  using as the VOIP provider, seems to works great, 4 phones, auto attendent. No Analog lines enabled.

I purposly use DHCP for the WAN to easily connect to a customer network and get a SIP trunk for a short demo

I go onsite for a customer demo..,  but the prospect does not have internet available for the demo,  no sweat, just no external calling...  WRONG

the sytem if FUBAR, I cannot begin to describe the failures it exibits, but here goes:

phone line buttons are randomly red.

the phone lines that are "ok" ring but you cannot anwser them, however ehrn you hang the recieving phone shows missed call

some phone seem ok but no dialtone.

if I lose WAN connectivity (not Physcial ethernet) to the system the system is unusable when the WAN is on any type of DHCP connection

Static IP seems to solve the problem.

however I strongly suggest you somehow fix this asta soimple WAN connectifivy isue when using DHCP will cause the phone to be unusable, I am not sure why this would be an issue if DHCP cannot get an IP ok so no WAN, that should not cause massive failures on the Phone... 

Perhpa a quick fix would be to give DHCP a default options stetment to set an address....

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