[DMM] 回复: [Apn] Regarding APN Usecase in Mobile Core

[刘 鹏]

Hi Sridhar and Xuesong,

If the IP network can obtain the QCI, TEID and other information of GTP, it can 
be considered as 5g's natural support for APN, and can also provide 
fine-grained services combined with N6 interface and edge computing. However, 
based on the previous discussion, it may not be able to directly obtain them. 
The value of DSCP alone may not be enough for APN.

It may need 5g network or UPF to make some additional support. Although it is 
not sure whether it is feasible, I think this information still has the 
possibility of potential support in the furture?

Regards,
Peng Liu


发件人: Apn  代表 Sridhar Bhaskaran 

发送时间: 2021年1月29日 20:05
收件人: Gengxuesong (Geng Xuesong) 
抄送: a...@ietf.org ; Uma Chunduri ; 
Kaippallimalil John ; dmm ; 
Lizhenbin 
主题: Re: [Apn] [DMM] Regarding APN Usecase in Mobile Core

Hi Gengxuesong,

QFI (mapped to 5QI) and TEID are to identify QoS flows and PDU sessions within 
UPF and gNB. They are not meant for transport network to look into. UPF and gNB 
map QFI to DSCP marking in the outer IP header which the transport network can 
use for differentiated services.

Regards
Sridhar

On Fri, Jan 29, 2021 at 3:37 PM Gengxuesong (Geng Xuesong) 
mailto:gengxues...@huawei.com>> wrote:

Hi Sridhar,



Thank you for your additional information. Can I come to a conclusion that: 
both 5QI and TEID have the potential to provide additional information for 
differentiated services in transport network, although the two parameters act 
in different scopes?



Best

Xuesong



From: Sridhar Bhaskaran 
[mailto:sridhar.bhaska...@gmail.com]
Sent: Friday, January 22, 2021 12:39 PM
To: Kaippallimalil John 
mailto:john.kaippallima...@futurewei.com>>
Cc: Gengxuesong (Geng Xuesong) 
mailto:gengxues...@huawei.com>>; Uma Chunduri 
mailto:umac.i...@gmail.com>>; Lizhenbin 
mailto:lizhen...@huawei.com>>; 
a...@ietf.org; dmm mailto:dmm@ietf.org>>
Subject: Re: [DMM] [Apn] Regarding APN Usecase in Mobile Core



Hi Xuesong,



In addition to what John said, in 3GPP networks there is one GTP-u tunnel per 
bearer (in case of 4G) and one GTP-u tunnel per PDU session (in case of 5G).



One UE (user equipment - i.e mobile device) may have multiple PDU sessions and 
hence in the network there may be more than one tunnel for a UE. The scope of 
GTP-u tunnel is from UPF to gNB only. GTP-u does not go all the way upto UE. 
The GTP-u header has a field called "TEID" (tunnel endpoint identifier). The 
TEID in the header identifies a context in UPF and gNB. The context gets 
established through signalling plane. The context provides information on the 
QoS to be provided for the bearer,  PDCP ciphering keys applicable for the 
bearer context etc.,. If there are a million UE that are getting connected to a 
UPF, there could be few million GTP-u tunnels (TEID).



In summary:

1. The 5QI / QFI marking in the GTP-u extension header provides a lookup for 
the general QoS characteristic applicable for that 5QI

2. TEID in the GTP-u header provides a lookup for UE and bearer specific 
contextual information for any differentiated treatment.



Regards

Sridhar



On Fri, Jan 22, 2021 at 2:55 AM Kaippallimalil John 
mailto:john.kaippallima...@futurewei.com>> 
wrote:

Hi Xuesong,



Traffic policy for subscribers is managed per PDU session at the UPF (and gNB).

GTP-u does provide encapsulation between the end points, but its control fields 
are meant for conveying control semantics between the GTP endpoints: they were 
not intended for IP transport/ traffic underlays. 5QI/QCI etc are in the GTP 
extension header which may not be ideal to lookup to classify each packet in 
the transport network.



The entity that classifies data packets (upstream at gNB and downstream at 
UPF-PSA) also inserts the DSCP for that GTP packet. The classification is based 
on subscriber aspects but may also on be based on its content (e.g., using DPI).



Best Regards,

John





From: dmm mailto:dmm-boun...@ietf.org>> On Behalf Of 
Gengxuesong (Geng Xuesong)
Sent: Wednesday, January 20, 2021 8:23 PM
To: Uma Chunduri mailto:umac.i...@gmail.com>>; Lizhenbin 
mailto:lizhen...@huawei.com>>
Cc: a...@ietf.org; dmm mailto:dmm@ietf.org>>
Subject: Re: [DMM] [Apn] Regarding APN Usecase in Mobile Core



Hi Uma and all,



I have read the document and got a few questions:

In my understanding, in the UPF where traffic policy is enforced, the 
fine-granularity services are provided. Then what fields in the GTP-u 
encapsulation indicates the traffic's service requirements? When a GTP-u tunnel 
goes into a SRv6 policy, according to which fields in the GTP-u encapsulation 
the DSCP is generated? We know that there are parameters such as 5QI/QCI and 
QFI, whether they are associated with a GTP-u tunnel?



Best

Xuesong

From: Apn [mailto:apn-boun...@ietf.org] On Behalf Of Uma Chunduri
Sent: Tuesday, January 19, 2021 3:17 AM
To: Lizhenbin 

Re: [DMM] [Apn] Regarding APN Usecase in Mobile Core

[Kaippallimalil John]

Hi Xuesong,
The point on using GTP-u extension header for classifying each packet was that 
unlike classifying using DSCP (which is in the IP header), finding the QCI in 
GTP extension requires more searches. And the control fields in GTP-u are for 
signaling between the 2 GTP end points (gNB, UPF, etc).

Now with regard to DSCP, since it is a mutable field, the value can be changed 
on path. It may be suitable in some deployments but not as a general solution.
In a gNB or UPF, there is already the subscriber context for a session and 
identifiers like radio bearers or IP address (upstream/downstream) to classify 
incoming packets.
E.g., a UPF may look up session context indexed by a UE IP address, retrieve 
QoS, reliability, etc , classify and select MPLS label L (or a DSCP value in 
some cases).
However, when there is a gNB or UPF function deployed in one network and IP 
transport is provided by another network, DSCP may not be able to convey slice 
aspects for a path across two different networks (this apart from DSCP being 
mutable).

Best Regards,
John

From: Gengxuesong (Geng Xuesong) 
Sent: Friday, January 29, 2021 4:01 AM
To: Kaippallimalil John ; Uma Chunduri 
; Lizhenbin 
Cc: a...@ietf.org; dmm 
Subject: RE: [DMM] [Apn] Regarding APN Usecase in Mobile Core

Hi John,

You mentioned that "5QI/QCI etc are in the GTP extension header which may not 
be ideal to lookup to classify each packet in the transport network". This is 
slightly different from my understanding about this: 5QI/QCI belongs to control 
plane information, and when the base station encapsulates the packet with GTPu, 
it maps the 5QI/QCI into the DSCP in  IP header outside GTPu encapsulation. Do 
I have any misunderstanding about this point?

Best
Xuesong

From: Kaippallimalil John [mailto:john.kaippallima...@futurewei.com]
Sent: Friday, January 22, 2021 5:25 AM
To: Gengxuesong (Geng Xuesong) 
mailto:gengxues...@huawei.com>>; Uma Chunduri 
mailto:umac.i...@gmail.com>>; Lizhenbin 
mailto:lizhen...@huawei.com>>
Cc: a...@ietf.org; dmm mailto:dmm@ietf.org>>
Subject: RE: [DMM] [Apn] Regarding APN Usecase in Mobile Core

Hi Xuesong,

Traffic policy for subscribers is managed per PDU session at the UPF (and gNB).
GTP-u does provide encapsulation between the end points, but its control fields 
are meant for conveying control semantics between the GTP endpoints: they were 
not intended for IP transport/ traffic underlays. 5QI/QCI etc are in the GTP 
extension header which may not be ideal to lookup to classify each packet in 
the transport network.

The entity that classifies data packets (upstream at gNB and downstream at 
UPF-PSA) also inserts the DSCP for that GTP packet. The classification is based 
on subscriber aspects but may also on be based on its content (e.g., using DPI).

Best Regards,
John


From: dmm mailto:dmm-boun...@ietf.org>> On Behalf Of 
Gengxuesong (Geng Xuesong)
Sent: Wednesday, January 20, 2021 8:23 PM
To: Uma Chunduri mailto:umac.i...@gmail.com>>; Lizhenbin 
mailto:lizhen...@huawei.com>>
Cc: a...@ietf.org; dmm mailto:dmm@ietf.org>>
Subject: Re: [DMM] [Apn] Regarding APN Usecase in Mobile Core

Hi Uma and all,

I have read the document and got a few questions:
In my understanding, in the UPF where traffic policy is enforced, the 
fine-granularity services are provided. Then what fields in the GTP-u 
encapsulation indicates the traffic's service requirements? When a GTP-u tunnel 
goes into a SRv6 policy, according to which fields in the GTP-u encapsulation 
the DSCP is generated? We know that there are parameters such as 5QI/QCI and 
QFI, whether they are associated with a GTP-u tunnel?

Best
Xuesong
From: Apn [mailto:apn-boun...@ietf.org] On Behalf Of Uma Chunduri
Sent: Tuesday, January 19, 2021 3:17 AM
To: Lizhenbin mailto:lizhen...@huawei.com>>
Cc: a...@ietf.org; dmm mailto: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 
mailto: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/
 where lot more details and other references related this topic was analyzed 
(primarily started after/during REL-15, 

Re: [DMM] [Apn] Regarding APN Usecase in Mobile Core

[Sridhar Bhaskaran]

Hi Gengxuesong,

QFI (mapped to 5QI) and TEID are to identify QoS flows and PDU sessions
within UPF and gNB. They are not meant for transport network to look into.
UPF and gNB map QFI to DSCP marking in the outer IP header which the
transport network can use for differentiated services.

Regards
Sridhar

On Fri, Jan 29, 2021 at 3:37 PM Gengxuesong (Geng Xuesong) <
gengxues...@huawei.com> wrote:

> Hi Sridhar,
>
>
>
> Thank you for your additional information. Can I come to a conclusion
> that: both 5QI and TEID have the potential to provide additional
> information for differentiated services in transport network, although the
> two parameters act in different scopes?
>
>
>
> Best
>
> Xuesong
>
>
>
> *From:* Sridhar Bhaskaran [mailto:sridhar.bhaska...@gmail.com]
> *Sent:* Friday, January 22, 2021 12:39 PM
> *To:* Kaippallimalil John 
> *Cc:* Gengxuesong (Geng Xuesong) ; Uma Chunduri <
> umac.i...@gmail.com>; Lizhenbin ; a...@ietf.org; dmm
> 
> *Subject:* Re: [DMM] [Apn] Regarding APN Usecase in Mobile Core
>
>
>
> Hi Xuesong,
>
>
>
> In addition to what John said, in 3GPP networks there is one GTP-u tunnel
> per bearer (in case of 4G) and one GTP-u tunnel per PDU session (in case of
> 5G).
>
>
>
> One UE (user equipment - i.e mobile device) may have multiple PDU sessions
> and hence in the network there may be more than one tunnel for a UE. The
> scope of GTP-u tunnel is from UPF to gNB only. GTP-u does not go all the
> way upto UE. The GTP-u header has a field called "TEID" (tunnel endpoint
> identifier). The TEID in the header identifies a context in UPF and gNB.
> The context gets established through signalling plane. The context provides
> information on the QoS to be provided for the bearer,  PDCP ciphering keys
> applicable for the bearer context etc.,. If there are a million UE that are
> getting connected to a UPF, there could be few million GTP-u tunnels
> (TEID).
>
>
>
> In summary:
>
> 1. The 5QI / QFI marking in the GTP-u extension header provides a lookup
> for the general QoS characteristic applicable for that 5QI
>
> 2. TEID in the GTP-u header provides a lookup for UE and bearer specific
> contextual information for any differentiated treatment.
>
>
>
> Regards
>
> Sridhar
>
>
>
> On Fri, Jan 22, 2021 at 2:55 AM Kaippallimalil John <
> john.kaippallima...@futurewei.com> wrote:
>
> Hi Xuesong,
>
>
>
> Traffic policy for subscribers is managed per PDU session at the UPF (and
> gNB).
>
> GTP-u does provide encapsulation between the end points, but its control
> fields are meant for conveying control semantics between the GTP endpoints:
> they were not intended for IP transport/ traffic underlays. 5QI/QCI etc are
> in the GTP extension header which may not be ideal to lookup to classify
> each packet in the transport network.
>
>
>
> The entity that classifies data packets (upstream at gNB and downstream at
> UPF-PSA) also inserts the DSCP for that GTP packet. The classification is
> based on subscriber aspects but may also on be based on its content (e.g.,
> using DPI).
>
>
>
> Best Regards,
>
> John
>
>
>
>
>
> *From:* dmm  *On Behalf Of *Gengxuesong (Geng
> Xuesong)
> *Sent:* Wednesday, January 20, 2021 8:23 PM
> *To:* Uma Chunduri ; Lizhenbin 
> *Cc:* a...@ietf.org; dmm 
> *Subject:* Re: [DMM] [Apn] Regarding APN Usecase in Mobile Core
>
>
>
> Hi Uma and all,
>
>
>
> I have read the document and got a few questions:
>
> In my understanding, in the UPF where traffic policy is enforced, the
> fine-granularity services are provided. Then what fields in the GTP-u
> encapsulation indicates the traffic's service requirements? When a GTP-u
> tunnel goes into a SRv6 policy, according to which fields in the GTP-u
> encapsulation the DSCP is generated? We know that there are parameters such
> as 5QI/QCI and QFI, whether they are associated with a GTP-u tunnel?
>
>
>
> Best
>
> Xuesong
>
> *From:* Apn [mailto:apn-boun...@ietf.org ] *On
> Behalf Of *Uma Chunduri
> *Sent:* Tuesday, January 19, 2021 3:17 AM
> *To:* Lizhenbin 
> *Cc:* a...@ietf.org; dmm 
> *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  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/
> 

Re: [DMM] [Apn] Regarding APN Usecase in Mobile Core

[Gengxuesong (Geng Xuesong)]

Hi Sridhar,

Thank you for your additional information. Can I come to a conclusion that: 
both 5QI and TEID have the potential to provide additional information for 
differentiated services in transport network, although the two parameters act 
in different scopes?

Best
Xuesong

From: Sridhar Bhaskaran [mailto:sridhar.bhaska...@gmail.com]
Sent: Friday, January 22, 2021 12:39 PM
To: Kaippallimalil John 
Cc: Gengxuesong (Geng Xuesong) ; Uma Chunduri 
; Lizhenbin ; a...@ietf.org; dmm 

Subject: Re: [DMM] [Apn] Regarding APN Usecase in Mobile Core

Hi Xuesong,

In addition to what John said, in 3GPP networks there is one GTP-u tunnel per 
bearer (in case of 4G) and one GTP-u tunnel per PDU session (in case of 5G).

One UE (user equipment - i.e mobile device) may have multiple PDU sessions and 
hence in the network there may be more than one tunnel for a UE. The scope of 
GTP-u tunnel is from UPF to gNB only. GTP-u does not go all the way upto UE. 
The GTP-u header has a field called "TEID" (tunnel endpoint identifier). The 
TEID in the header identifies a context in UPF and gNB. The context gets 
established through signalling plane. The context provides information on the 
QoS to be provided for the bearer,  PDCP ciphering keys applicable for the 
bearer context etc.,. If there are a million UE that are getting connected to a 
UPF, there could be few million GTP-u tunnels (TEID).

In summary:
1. The 5QI / QFI marking in the GTP-u extension header provides a lookup for 
the general QoS characteristic applicable for that 5QI
2. TEID in the GTP-u header provides a lookup for UE and bearer specific 
contextual information for any differentiated treatment.

Regards
Sridhar

On Fri, Jan 22, 2021 at 2:55 AM Kaippallimalil John 
mailto:john.kaippallima...@futurewei.com>> 
wrote:
Hi Xuesong,

Traffic policy for subscribers is managed per PDU session at the UPF (and gNB).
GTP-u does provide encapsulation between the end points, but its control fields 
are meant for conveying control semantics between the GTP endpoints: they were 
not intended for IP transport/ traffic underlays. 5QI/QCI etc are in the GTP 
extension header which may not be ideal to lookup to classify each packet in 
the transport network.

The entity that classifies data packets (upstream at gNB and downstream at 
UPF-PSA) also inserts the DSCP for that GTP packet. The classification is based 
on subscriber aspects but may also on be based on its content (e.g., using DPI).

Best Regards,
John


From: dmm mailto:dmm-boun...@ietf.org>> On Behalf Of 
Gengxuesong (Geng Xuesong)
Sent: Wednesday, January 20, 2021 8:23 PM
To: Uma Chunduri mailto:umac.i...@gmail.com>>; Lizhenbin 
mailto:lizhen...@huawei.com>>
Cc: a...@ietf.org; dmm mailto:dmm@ietf.org>>
Subject: Re: [DMM] [Apn] Regarding APN Usecase in Mobile Core

Hi Uma and all,

I have read the document and got a few questions:
In my understanding, in the UPF where traffic policy is enforced, the 
fine-granularity services are provided. Then what fields in the GTP-u 
encapsulation indicates the traffic's service requirements? When a GTP-u tunnel 
goes into a SRv6 policy, according to which fields in the GTP-u encapsulation 
the DSCP is generated? We know that there are parameters such as 5QI/QCI and 
QFI, whether they are associated with a GTP-u tunnel?

Best
Xuesong
From: Apn [mailto:apn-boun...@ietf.org] On Behalf Of Uma Chunduri
Sent: Tuesday, January 19, 2021 3:17 AM
To: Lizhenbin mailto:lizhen...@huawei.com>>
Cc: a...@ietf.org; dmm mailto: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 
mailto: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/
 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 

Re: [DMM] [Apn] Regarding APN Usecase in Mobile Core

[Gengxuesong (Geng Xuesong)]

Hi Zongpeng,

I agree that “the transport network (such as the IPRAN) should be able to 
provide proper SLA for different GTP-u sessions”, where APN may play a role.

Best
Xuesong

From: duzongp...@foxmail.com [mailto:duzongp...@foxmail.com]
Sent: Thursday, January 21, 2021 11:45 AM
To: Gengxuesong (Geng Xuesong) ; Uma Chunduri 
; Lizhenbin 
Cc: a...@ietf.org; dmm 
Subject: Re: Re: [Apn] [DMM] Regarding APN Usecase in Mobile Core

Hi Xuesong and all,

In my understanding, 5GC can establish multiple GTP-u sessions for 
different services with different requirements, and the requirements should be 
satisfied E2E.

In the backhaul network, the transport network (such as the IPRAN) should 
be able to provide proper SLA for different GTP-u sessions.

APN should be able to benefit the SLA negotiation between the 5G system and 
the underneath transport network.



Best Regards
Zongpeng Du


duzongp...@foxmail.com & 
duzongp...@chinamobile.com

From: Gengxuesong (Geng Xuesong)
Date: 2021-01-21 10:23
To: Uma Chunduri; 
Lizhenbin
CC: a...@ietf.org; dmm
Subject: Re: [Apn] [DMM] Regarding APN Usecase in Mobile Core
Hi Uma and all,

I have read the document and got a few questions:
In my understanding, in the UPF where traffic policy is enforced, the 
fine-granularity services are provided. Then what fields in the GTP-u 
encapsulation indicates the traffic's service requirements? When a GTP-u tunnel 
goes into a SRv6 policy, according to which fields in the GTP-u encapsulation 
the DSCP is generated? We know that there are parameters such as 5QI/QCI and 
QFI, whether they are associated with a GTP-u tunnel?

Best
Xuesong
From: Apn [mailto:apn-boun...@ietf.org] On Behalf Of Uma Chunduri
Sent: Tuesday, January 19, 2021 3:17 AM
To: Lizhenbin mailto:lizhen...@huawei.com>>
Cc: a...@ietf.org; dmm mailto: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 
mailto: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/ 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
___
dmm mailing list
dmm@ietf.org
https://www.ietf.org/mailman/listinfo/dmm

Re: [DMM] [Apn] Regarding APN Usecase in Mobile Core

[Gengxuesong (Geng Xuesong)]

Hi John,

You mentioned that "5QI/QCI etc are in the GTP extension header which may not 
be ideal to lookup to classify each packet in the transport network". This is 
slightly different from my understanding about this: 5QI/QCI belongs to control 
plane information, and when the base station encapsulates the packet with GTPu, 
it maps the 5QI/QCI into the DSCP in  IP header outside GTPu encapsulation. Do 
I have any misunderstanding about this point?

Best
Xuesong

From: Kaippallimalil John [mailto:john.kaippallima...@futurewei.com]
Sent: Friday, January 22, 2021 5:25 AM
To: Gengxuesong (Geng Xuesong) ; Uma Chunduri 
; Lizhenbin 
Cc: a...@ietf.org; dmm 
Subject: RE: [DMM] [Apn] Regarding APN Usecase in Mobile Core

Hi Xuesong,

Traffic policy for subscribers is managed per PDU session at the UPF (and gNB).
GTP-u does provide encapsulation between the end points, but its control fields 
are meant for conveying control semantics between the GTP endpoints: they were 
not intended for IP transport/ traffic underlays. 5QI/QCI etc are in the GTP 
extension header which may not be ideal to lookup to classify each packet in 
the transport network.

The entity that classifies data packets (upstream at gNB and downstream at 
UPF-PSA) also inserts the DSCP for that GTP packet. The classification is based 
on subscriber aspects but may also on be based on its content (e.g., using DPI).

Best Regards,
John


From: dmm mailto:dmm-boun...@ietf.org>> On Behalf Of 
Gengxuesong (Geng Xuesong)
Sent: Wednesday, January 20, 2021 8:23 PM
To: Uma Chunduri mailto:umac.i...@gmail.com>>; Lizhenbin 
mailto:lizhen...@huawei.com>>
Cc: a...@ietf.org; dmm mailto:dmm@ietf.org>>
Subject: Re: [DMM] [Apn] Regarding APN Usecase in Mobile Core

Hi Uma and all,

I have read the document and got a few questions:
In my understanding, in the UPF where traffic policy is enforced, the 
fine-granularity services are provided. Then what fields in the GTP-u 
encapsulation indicates the traffic's service requirements? When a GTP-u tunnel 
goes into a SRv6 policy, according to which fields in the GTP-u encapsulation 
the DSCP is generated? We know that there are parameters such as 5QI/QCI and 
QFI, whether they are associated with a GTP-u tunnel?

Best
Xuesong
From: Apn [mailto:apn-boun...@ietf.org] On Behalf Of Uma Chunduri
Sent: Tuesday, January 19, 2021 3:17 AM
To: Lizhenbin mailto:lizhen...@huawei.com>>
Cc: a...@ietf.org; dmm mailto: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 
mailto: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/
 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
___
dmm mailing list
dmm@ietf.org
https://www.ietf.org/mailman/listinfo/dmm