Overcoming Challenges in LTE Roaming

Overcoming Challenges in LTE Roaming

View the Q&A


Tuesday 6th November

LTE network deployments around the world, along with accompanying frequency fragmentation present challenges to the network operator when it comes to reliable subscriber roaming.  This presentation will provide some solutions to LTE roaming scenarios:

Join us for this free webinar which will cover the following key areas:

  • - Usage of Diameter hubbing in LTE Roaming scenarios
  • - Outline both Home Routing and Local Breakout
  • - Outline 3G fallback
  • - IPX vs. bi-lateral agreements


Tags; Archive, Featured, LTE, LTE Roaming, Roaming, Sybase 365, telecoms.com
  • Reginald Shells November 7, 2012 at 6:22 pm

    Could a Diameter Edge Agent be used in a CSFB configuration which would act as a SS7 / Diameter protocol translator without having to buy a IMS based equipment.

    • billdudley
      billdudley November 8, 2012 at 9:57 pm

      Yes, it could… it could be offered on the Diameter hubbing service (e.g. DRA) — not necessarily the Edge Agent. In fact, several Diameter hub providers will be offering such interworking (MAP / Diameter).

  • Paul Waite November 7, 2012 at 9:31 am

    Thank you all for attending this webinar and for your questions in the Q&A session. Bill will be answering the remaining questions over the coming days.

    If you have any further questions you can forward directly to rebecca.kools@sap.com.

  • Hassan Kamal November 6, 2012 at 5:23 pm

    Can any ipx provider be a diameter gateway ? Or does it need other measures like the case of roaming hub ?

    • billdudley
      billdudley November 8, 2012 at 10:09 pm

      Certainly, having an IPX network is a primary prerequisite. But to make the business model work, you should also be a reasonably sized GRX provider AND you must make the investment in Diameter hubbing technology.

  • billdudley
    billdudley November 6, 2012 at 5:17 pm

    I’ll come back a bit later on to answer more of these questions and will keep returning until they are all answered. So keep an eye on this space.

    For those of you who have requested a copy of the PPT, it will be emailed to all participants, shortly.

  • Paul Waite November 6, 2012 at 4:57 pm

    Many thanks for all your questions, we are working through them and will answer them all as soon as we can.

    A link to the presentation slides will be emailed out to all who registered for the webinar.

  • MSinno November 6, 2012 at 4:52 pm

    Understanding that mobile roaming is both an IPX and handset/tablet requirement, when do you expect LTE mobile roaming to replace the end user from just switching SIM cards?

    • billdudley
      billdudley November 8, 2012 at 10:12 pm

      LTE Roaming will certainly grow in the coming years; however, in the short term, due to frequency fragmentation, sometimes the only way would be to switch SIM cards. As I noted in the presentation, there will be some operators that will be virtually unreachable from a roaming standpoint, due to their chosen frequency bands (or spectrum limitations of their country).

  • Hung Ha November 6, 2012 at 4:44 pm

    How do you address the diameter security from IPX perspective. Also there have been some debates about whether the IPSEC should be optional or mandatory between the operator’s diameter edge agent and IPX. What is your view?

    • billdudley
      billdudley November 8, 2012 at 10:16 pm

      The security of the IPX does not make it necessary for traffic to be encrypted between the DEA and the operator — in fact, it reduces the overall QoS. But, if an operator or pair of operators request it, it could certainly be configured. But we do not recommend it.

  • MSinno November 6, 2012 at 4:43 pm

    How does a mobile operator compare and differentiate between existing GRX providers who claim to be an IPX provider and someone such as yourselves who say you are a complete IPX provider? Why would I not stay with my current GRX/IPX provider where community/ecosystem already exists?

    • billdudley
      billdudley November 8, 2012 at 10:49 pm

      That’s a good question.

      I will say that not all GRX providers can provide a strong IPX capability. “True” IPX takes some investment in a high QoS backbone and committment to growing that as more IP services come online. For example, a smaller GRX player may not find the necessary business case to grow and evolve their underlying network to IPX standards. And bandwidth and quality requirements will only grow. Consequently, it is our opinion that your safest bet is working with one or more of the larger IPX players.

  • rajpub November 6, 2012 at 4:41 pm

    Is LTE roaming in EVDO Rev A or B possible?

    • billdudley
      billdudley November 6, 2012 at 5:13 pm

      No, these are two different standards; HOWEVER, and let’s look at someone like Verizon, whose 3G is EVDO Rev A, but also supports LTE. An LTE subscriber roaming to another network might “fall-back” to EVDO in the visited network, if the visited network does not have compatible LTE frequencies or does not have LTE at all. Most EVDO devices that support LTE, support both standards, depending on what network they can connect to.

  • Balaji Srinivasan November 6, 2012 at 4:38 pm

    Since the routing is done through the home network, does this not diminish the importance of the TAP file from the home operator’s perspective?

    • billdudley
      billdudley November 8, 2012 at 10:43 pm

      No, it does not do away with the necessity of TAP files. Regardless of whether the subscriber is home-routed or local-break-out on the visited network, the Diameter information is not enough to complete a full TAP record.

  • S. Ali November 6, 2012 at 4:38 pm

    Is there some way I can download today’s presentation or get it emailed to me?

  • yogesh anand, November 6, 2012 at 4:36 pm

    My question is related to steering of roaming (SoR) for LTE roaming. What would be the impact and how it should be done effectively?

    • billdudley
      billdudley November 8, 2012 at 11:17 pm

      Steering of Roaming should “translate” to LTE roaming as well and it should be done though the Diameter hubbing provider. In fact, we are engaging with the appropriate partners who would work through our Diameter hub, based on the policies of the home network, to provide roaming steering to preferred networks. Of course, the concept is not different from what happens today in 3G; however, this would involve accessing the appropriate Diameter traffic to insure that the subscriber connects where the home networks desires them to.

      Bottom line, we think SoR would definitely have its place in LTE roaming scenarios.

  • dellys November 6, 2012 at 4:34 pm

    How realistic is it to expect devices to be able to support frequencies available in North America, Asia and Europe?

    • billdudley
      billdudley November 6, 2012 at 5:03 pm

      Initially, as discussed, there will be devices that will try and support some frequencies more targeted for specific regions. For example, look at the iPhone 5 / new iPads. Two of the devices support the 1800 band which should support roaming in a lot of different networks as well as supporting the US bands (e.g. 700 Mhz band). Overall, many networks will support at least one of the more “common” bands such as 800/1800/2600 in addition to AWS and some of the more off frequencies such as the 700 Mhz bands. It’s early yet. But, I think you will see devices with 5, maybe even 6 band support. More, I don’t know. Of course, there will always be some country or operator that deploys on some very odd frequency bands.

      I expect, that over time, we’ll see a strong roaming market — at least for the top 100 operators worldwide, but we are not quite there yet.

  • Don November 6, 2012 at 4:33 pm

    is it possible to et a copy of the presentation slides? I was not able to make the scren full size during the session and woud like to have a copy of several of the slides. thanks!

  • Nishant Jain November 6, 2012 at 4:33 pm

    How do you see the challenges posed by Voice over LTE networks when roaming?

    • billdudley
      billdudley November 6, 2012 at 4:55 pm

      As I understand it, the roaming LTE subscriber that will be launching a VoLTE call will trigger some additional Diameter exchanges between the visited and home networks, EACH time a call is initiated — as well as the SIP call setup.
      This certainly plays into the necessity for a very good network – e.g. an IPX — connectin the two networks — if not just for the additional Diameter traffic, but also the user data (e.g. the call itself). There is more to say about this topic — I’ll try to come back wit more detailed information.

      • Andreas Neubacher November 8, 2012 at 11:51 am

        I would be interested especially on your view especially on the call handling in case of VoLTE roaming.
        Especially in the context that in current teleco Environment the routing and charging is done primarily on E.164 numbers while in case of VoLTE roaming, the routing between the S- and P-CSCF is done based on domain names contained in SIP headers given in the registration prodecure to the UE.
        Can you comment whether the current IPX framework provides this functionality yet?
        Would be keen elaborating with you on this.

        • billdudley
          billdudley November 8, 2012 at 10:07 pm

          I am not aware that IPX framework – any IPX framework — provides this functionality – yet; however, once we start supporting VoLTE functionality (roaming or interworking), we will address the conversion between E.164 numbers, identifying the subscriber UE, and the domain names (or specifically the SIP URI). The SIP URI of the User Equipment should be unique and I’m sure we can find a way, if necessary to map that to the E.164 number.


  • Edvard November 6, 2012 at 4:32 pm

    Do you see the need for IPsec over IPX/GRX?

    • billdudley
      billdudley November 6, 2012 at 4:43 pm

      Possibly; however, I would be concerned about quality of service with an IPSec. Besides, if you already have an IPX connection, then you can certainly leverage that, without needing an IPsec connection. Some operators are asking for different VREs to differentiate the type of traffic – for example, lower bandwidth for the Diameter traffic and either re-use their GRX channels for the “user data” for home routing.

  • Peter Massam November 6, 2012 at 4:27 pm

    In exchanging Charging Control info’ is that practical when dealing with real-time balance management for pre-paid subs?

    • billdudley
      billdudley November 6, 2012 at 4:45 pm

      Yes, I think it would be. This exchange of information really happens when the subscriber firsts registers with the visited network — which, as you know, sometimes takes several minutes, even in 3G. It should only take a second or two to authenticate the subscriber. In some of our tests with live operators, that has been the case.

  • MSinno November 6, 2012 at 4:25 pm

    you have mentioned we can look at these slides later. How can we do this using this webinar format? I would like to have a copy of these slides to review offline and discuss internally with my other internal teams.

  • Mike Demler November 6, 2012 at 4:22 pm

    are slides downloadable? No way to enlarge live stream?

  • Kathleen Leach November 6, 2012 at 4:02 pm

    Can we get the slide deck post presentation please

  • Paul Waite November 6, 2012 at 4:01 pm

    If you are experiencing problems with the live streaming then please try our non streaming version here: http://webinars.telecoms.com/webinar/nostream/

  • Ahmed Kamal November 6, 2012 at 3:33 pm

    unfortunately i won’t be able to attend this webinar , can i have the outputs in presentation format ?

  • Diana Tawfik November 6, 2012 at 3:14 pm

    How testing LTE what are the challenges between operators?

    • billdudley
      billdudley November 8, 2012 at 10:39 pm

      Testing is typically done in a two-stage process: Testing between the DRA and the DEA (of the operator) and then end-to-end testing. We must accurately define the desired outcomes for both phases. We have found that some operators do not necessarily follow the standards, which becomes quite evident during the testing process; however, through our function a Diameter hubbing provider, we can provide some interworking and/or mediation to resolve these capabilities.
      A Diameter hubbing provider should also be able to simulate Diameter traffic before end-to-end testing with another or multiple operators begins. By that point, the DRA (Diameter hubbing provider) should expose a standard interface to all other operators

  • Diana Tawfik November 6, 2012 at 3:11 pm

    What is the last progress in Ir25 documents for LTE testing?
    Also what about the agreements between operators? Do we need to sign new agreements?

    • billdudley
      billdudley November 6, 2012 at 5:04 pm

      I can’t really answer the IR 25 part yet. We do not play a role in that group.

      In terms of agreements, that is up to the operators — no requirement. Many will amend existing agreements to cover LTE roaming.

  • Qasem November 6, 2012 at 8:14 am

    what will be the TAP file version that will support LTE CDR’s?

    • billdudley
      billdudley November 6, 2012 at 4:50 pm

      Not sure off the top of my head. But I can get back to you. I have your email address and will also post this here.