FYI - Here's my complete experience with Verizon Wireless 4G LTE Novatel MiFi 4620L and SIP communication.
On the day 4G LTE launched in my market (Las Vegas, NV) I picked the LG USB modem, and later changed to the Pantech USB modem, and both supported SIP and other RTP streams (i.e. Video) just fine.
On April 6th 2012, in preparation for a system demo at a location that doesn't have public WiFi available, I went to a Verizon Wireless "corporate" store, and they provided me with a Samsung SCH-LC11, and upgraded my 4G line to this device. When I got back to the office to test SIPcalls, in my logs I received a 500 Server Internal Error
Warning: 399 sipalg "Internal Error".
After calling the Verizon Wireless store, they told me this is an "older device", and I should have received the one that just launched. Went back to the store, but was told the store couldn't sell me the "new device", the Novatel MiFi 4620L, since it wasn't "officially launched" in Verizon stores until April 12th 2012.
The tech at the store noticed that Best Buy had an "early release", and started selling the "new device" on March 26th.
They returned and restocked the "old device", and sent me over to Best Buy.
...I'll skip the part of the story that details my painful (but ultimately successful) experience at Best Buy Mobile, and just say that I walked out of the store with a new, activated Novatel MiFi 4620L.
When I got back to the office to test SIP calls again with the "new device", in my logs I received a 500 Server Internal Error Warning: 399 sipalg "Internal Error". Exactly the same error.
I assumed (incorrectly) that SIP ALG would have been corrected on the "new device", but proved that the latest MiFi device also throws the same errors as the old device.
Interestingly enough, I WAS able to get connected to VoIP services by running on a port OTHER than 5060 (well known SIP port)... I changed to 5080 and voila, I was able to connect, make a call, etc. without the device ruining my day.
someone suggested to "plug the mifi into the computer via usb and see if that helps."
I set the device to USB Tethered mode in the settings, but when I tried to plug in via USB, it couldn't find any drivers... after searching the internet, I STILL couldn't find any drivers, so couldn't test this fully at this time.
I can now confirm the issues related to SIP is device specific. We were trying the service with the new Verizon Wireless Novatel MiFi 4620 4G LTE wireless access point.
We have certified other 4G LTE devices (Pantech UML290 and LG VL600 USB Modems) on the Verizon network, but the device I mentioned above has all kinds of issues we've noted:
1.) SIP ALG is enabled on all traffic on destined for port 5060, which breaks SIP completely. Changing to 5080 or another port does allow SIP traffic, and allows us to create 1 call.
2.) There are other packet "manipulations" that occur with the built-in router on the device that break other SIP traffic, especially in the tear down, and also with multiple RTP streams, i.e. 2 or more calls.
3.) USB Tethered mode is not a "modem only" interface (as it is with the Pantech UML290), rather it performs the same routing that occurs when connected via Wifi... which is broken for SIP.
Basically, the device is non-operable with SIP (and possibly other services relying on multiple RTP streams) at this time, although it will allow basic "emergency" SIP (as it'll support 1 call)... just not all features.
Device is headed back to the store.
Please repost this as NEW DISCUSSION in the forum instead of in the Off-Topic Lounge. This space is meant for topics not related to Wireless.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
Terrific job reporting on the limitations of the MiFi! Thanks for posting your results, someone found this discussion and posted it in the Broadband and Netbook forums where the MiFi users hang out.