Hi David, Many excellent points below w.r.t GTP-u and the Access Point Name (APN) which defines the network path for all cellular data connectivity.
However, I presume Robin was referring to a different APN - https://datatracker.ietf.org/wg/apn/about/ -- Uma C. On Mon, Jan 18, 2021 at 12:10 PM David Lake <d.l...@surrey.ac.uk> wrote: > The APN provides the linkage between the application profile and the radio > bearers. GTP-u is manner by which the traffic is tunnelled to the anchor > point and you MAY end up with different end points for each of the GTP > bearers. > > > > Traffic at both the UE and the PGW (in LTE – UPF in 5G) are directed to > the correct APN by a Traffic Flow Template (TFT). This is to ensure that > traffic goes across both the correct radio bearer and is marked correctly > in the IP network. > > > > Users will often be unaware of multiple APNs on their UE; the most common > hidden APN is one for VoLTE which, with the use of the TFT, will ensure > that the VoIP frames (media) are put across the QCI 9 radio bearer and into > the correct class on the IP network. QCI 9 maps to a specific numerology > on the Air Interface so that quality can be maintained for the voice call. > > > > In theory, multiple APNs all with their own TFT rules and potentially > multiple GTP-u tunnels could be used but this is very rarely done. > > > > David > > > > *From:* Apn <apn-boun...@ietf.org> *On Behalf Of *Uma Chunduri > *Sent:* 18 January 2021 19:17 > *To:* Lizhenbin <lizhen...@huawei.com> > *Cc:* a...@ietf.org; dmm <dmm@ietf.org> > *Subject:* Re: [Apn] [DMM] Regarding APN Usecase in Mobile Core > > > > Hi Robin, > > > > In-line.. > > > > Cheers! > -- > > Uma C. > > > > On Mon, Jan 18, 2021 at 5:25 AM Lizhenbin <lizhen...@huawei.com> wrote: > > Hi APNers and DMMers, > > I remember that in the mobile core scenarios the GTP-u tunnel can be set > up according to the user and application requirements, but I do not > understand the details. > > > > [Uma]: Obviously, the best reference for GTP-U is TS 29.281. However, uou > should look into > https://datatracker.ietf.org/doc/draft-ietf-dmm-5g-uplane-analysis/ > <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fdraft-ietf-dmm-5g-uplane-analysis%2F&data=04%7C01%7Cd.lake%40surrey.ac.uk%7C984c8fa55bbf4ea5b98908d8bbe5aa2d%7C6b902693107440aa9e21d89446a2ebb5%7C0%7C0%7C637465942368442430%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=namC6OofWdMQvTEjFwNkZT0ornR2gx1Q%2BV8SXxIHUis%3D&reserved=0> > where lot more details and other references related this topic was analyzed > (primarily started after/during REL-15, when any other use plane other > than GTP-U is worthwhile is debated for 5G N9 interface). > > > > I think when the packet tunneled by GTP-u traverses the APN-based > transport network, it may be mapped to the corresponding tunnel according > to the user and application requirements to implement the uniform service. > If you are familiar with the principle of GTP-u in the mobile core, please > help provide some details. > > > > > > Best Regards, > > Zhenbin (Robin) > > > > > > _______________________________________________ > dmm mailing list > dmm@ietf.org > https://www.ietf.org/mailman/listinfo/dmm > <https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ietf.org%2Fmailman%2Flistinfo%2Fdmm&data=04%7C01%7Cd.lake%40surrey.ac.uk%7C984c8fa55bbf4ea5b98908d8bbe5aa2d%7C6b902693107440aa9e21d89446a2ebb5%7C0%7C0%7C637465942368452424%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=00LmTEJXUJZfwFAMcs5abdCXTBvrrVSEMFeykW175u8%3D&reserved=0> > >
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