QoS settings for the Router

    I have a perfectly good router setup and I do not want to disrupt it.  I would like to know what UDP ports are being used for T-Mobile Traffic and I will adjust my QoS Settings accordingly.


    Thanks much

      All replies

      • kdilo911

        Re: QoS settings for the Router

        I would also like to use my existing router and just include the necessary settings for my Tmobile devices to use it.

        • Re: QoS settings for the Router

          My investigation by looking at traffic on my network during WiFi calling is that it is the following:


          destination IP using UDP on port 4500

          • tmo_amanda

            Re: QoS settings for the Router

            Here’s what we could track down. The below ports need to be enabled:


            TCP 5060

            TCP 5061

            UDP 52000-59999


            Your network Admins need to enable SIP traffic, and QoS settings need to be at 85% or greater for the wifi calling traffic to work. 

              • Thanks, tmo_amanda.


                Did you get this info from user experiments, as reported for example in this thread, or from more "official" sources?

                • Using the information from tmo_Amanda and working with a GREAT T-Mobile support person I was able to get an Asus RT- AC68U, the base unit for the T-Mobile CellSpot TM AC1900, to perform just as well as the T-Mobile router does..

                  The CellSpot had eliminated the ER081/082 problem for me.


                  f you have an AC68U, N66U, or other router that has a Traffic Manager and/or QoS (Quality of Service) settings, do the following:

                  Go to your Traffic Manager.

                  Turn QoS on.

                  Go to User-defined QoS Rules.

                  Enter the following two rules giving them a meaningful name like "WiFi Calling", enter the MAC for your phone, enter at least 85% of your available bandwidth (e.g 0-42500 if your maximum transfer rate is 50 Meg), the highest priority and:

                  Rule 1: Destination port "4500" Protocol "UDP"

                  Rule 2: Destination port "5060, 5061" Protocol "TCP"


                  Doing this I went from very repeatable ER081/082 to no problems at all.

                  Good luck.

                    • buddie_mac

                      Re: QoS settings for the Router

                      I had been obtaining the err081 on my Android cellphone when using Wifi calling. The settings mentioned on this thread are fine for ensuring packet arrival time by implementing a QoS. But I had to enabling IPSEC pass-thru on the router on network which the phone connects to eliminate this error.


                      For SIP, RFC 3261 suggests TLS and IPSEC for Transport and Network Layer Security. Since IPSEC unlike TLS does not support NAT traversal, a firewall opening for IPSEC is required. Since IPSEC provides end to end security (vs hop by hop), this is the most likely reason T-MO selected it.

                      Can anyone from T-MO confirm that IPSEC is being used for Wifi Calling?

                      Another Router setting that could have Wifi calling fail is if the the router's firewall is setup to forward typical SIP ports to an IP address of another SIP client on their networks. If a user is using a VoIP service and has deployed a VoIP terminal adapter within the network with router port forwarding configurations, this would send all VoIP control/data packets from these ports to this device's IP address, thus not allowing you cell phone's wifi IP address to receive these packets causing wifi-calling to fail. The QoS suggestions within this thread are good suggestions since they apply to all IP addresses using those ports.

                      Wifi calling is great feature of Tmobile!

                    • buddie_mac

                      Re: QoS settings for the Router

                      T-Mo Wifi calling is done over a VPN-IPSEC tunnel. Only ports that should be required by your router QoS are the VPN ports 500, and 4500. All SIP ports are terminated at the phone and not the router.


                      If users desire priorities on their network router such that not to allow all phone device traffic high priority, but only the phone device Voice over wifi, then setting these ports to high priority should accomplish this. It will also provide any VPN connection in the user network this priority also.


                      It would be nice that someone at T-Mo confirm this and make it clear to users.

                      • amoeba

                        Re: QoS settings for the Router

                        Thank you for the settings Amanda. I have changed the QoS settings and added more bandwidth for the specified ports while assigning a fixed IP to my device. I noticed a slight improvement in my Wifi calling quality. But theres still 5 - 10 second silences in audio when I am on call. Any more suggestions?

                      • Great question we are getting this from user forums as well as our own internal testing. We that does the trick and please let us know if we can be of additional service!

                          • ed60

                            Re: QoS settings for the Router

                            I found a video online on how to configure the Qos, actually it didn't assign ports but assigned the devices  and gave them priorities  without specifying the  related ports, etc... I followed these steps and it deteriorated the performance, so it turned it off since things are fine without the Qos being enabled

                            I also asked an IT neighbor about it ,  if I didn't specify the ports would it make a difference, he said supposedly NO

                            well who knows?????

                              • Re: QoS settings for the Router

                                tforce_rick, thanks. However, the two specific ports listed by tmo_amanda are SIP (Session Initialization Protocol) ports. It's easy to see how they would have to available to the phone (to be open; not blocked) for it to start, configure, and finish calls, but hard to see how they would figure in prioritization of voice traffic, i.e., QoS.


                                The other item in Amanda's list, ports 52000-59999 are not dedicated by the internet powers that be to any specific use. They might well be used for Wi-Fi Calling voice data, but ...  who knows?


                                To reiterate the original question: the CellSpot router is advertised to prioritize Wi-Fi Calling voice traffic so that simultaneous other internet use in the home or office (e.g., streaming a  movie, downloading a large file) does not degrade call quality. Some of us would like to know the technical details of how the prioritization works so that we can use other routers that we already have and be assured of the same prioritization (a.k.a. QoS, Quality of Service) for voice data.


                                I, for instance, have a T-Mobile iPhone 6 scheduled to be delivered to me by UPS next Thursday. The primary reason I am going with T-Mobile is that it is (for a while) the only carrier that supports Wi-Fi Calling. And I prefer not to be dependent on a specific router to be assured of reliable voice quality where I use my phone the most -- at home. (I have no landlines.) I don't even know whether I'll be able to obtain a CellSpot (for a while). So it would be great to have an authoritative, definitive answer to this thread's question.

                                  • Re: QoS settings for the Router

                                    It my review of my network's traffic logging, it appears that the actual phone call goes over UDP port 4500.


                                    If you are going with T-Mobile primarily because of the Wi-Fi calling, I urge you to be cautions. I have had a pretty bad time with WiFi calling on two iPhone 6 since September 19th. First WiFi calling would not work even when turned on in settings on one of the iPhones. Had to call T-Mobile customer service. Second, WiFi calling will just drop from time to time for no apparent reason (and completely end the call at home). Internet bandwidth is good at 20Mb down/2Mb up on a Netgear WNDR3700 with QoS settings set (tried both 2.4Ghz and 5Ghz frequencies and made sure channels were clear using WiFi analyzer tools). At work with dedicated 10.5Mb up/down synchronous on Aerohive $600 APs with QoS, voice quality can be terrible with the call dropping off WiFi to cellular unpredictably.


                                    Cell signal is also bad at the home, so I received a 4G LTE Cell Booster from T-Mobile. It did nothing to improve the signals even after working with customer service (iPhones will show full bars/circles for a brief second and then immediately drop to 1). I am sending that back and next trying their CellSpot router.

                                      • Re: QoS settings for the Router

                                        Thanks, nblack. I will indeed be cautious and do a lot of testing within the period during which I can return the phone.


                                        Also, I did get a T-Mobile Test Drive iPhone 5s and its Wi-Fi calling worked OK from my home, at least for calls of a few minutes. But we'll see...

                                      • Re: QoS settings for the Router

                                        Whoops, just a few minutes later than my previous post in this thread, I found a CNET review of the CellSpot router. And it says:

                                        [T]he CellSpot has something the RT-AC68U doesn't have. It includes T-Mobile's Evolved Packet Data Gateway (ePDG) technology, and hence supposedly offers better support for Wi-Fi calling. In my testing it seemed the CellSpot automatically prioritizes its Internet bandwidth for cell-related services no matter how you customize the router. Normally, you need to configure the router's built-in QoS feature for Internet prioritizing; the CellSpot takes care of this for you.


                                        Technically, Wi-Fi calling depends on just the carrier and the smartphone. This means a Wi-Fi-calling-enabled smartphone can place and receive voice calls or send and receive text messages using any Internet-ready Wi-Fi network. However, T-Mobile says the CellSport comes with patent-pending technology that prioritizes voice calls over other Wi-Fi traffic.

                                        Patent-pending!? I think that means we aren't going to get the kind of answer I was hoping for.

                                  • Hello! It's been more than 36 hours since our last comment so we are now marking this post as assumed answered. You can continue to post, and other community users may respond, but if you would like assistance from T-Mobile or T-Force please create a new discussion.