lte e-utran overview

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LTE EPS &E-UTRAN Access Overview

Liao, Yu Hsiang

廖于翔2011/06/16

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Outline

• Architecture for Evolved Packet System (EPS)• Reference Point Interface• Control plane & User plane protocol stack• Functions between Control-plane and User-plane

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Architecture for Evolved Packet System (EPS)

SGi

S12

S3 S1-MME

PCRF

Gx

S6a

HSS

Operator's IP Services

(e.g. IMS, PSS etc.)

Rx

S10

UE

SGSN

LTE-Uu

E-UTRAN

MME

S11

S5 Serving Gateway

PDN Gateway

S1-U

S4

UTRAN

GERAN

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Functional split between E-UTRAN and EPC

EPS -- Evolved Packet System EPC - Evolved Packet Cores (Core Network)E-UTRAN -- Evolved UMTS Terrestrial Radio Access Network

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EPS Elements functions

SGi

S12

S3 S1-MME

PCRF

Gx

S6a

HSS



Rx

S10

UE

SGSN

LTE-Uu

E-UTRAN

MME

S11

S5 Serving Gateway

PDN Gateway

S1-U

S4

UTRAN

GERAN

The core network (called EPC in SAE) is responsible for the overall control of the UE and establishment of the bearers. The main logical nodes of the EPC are:• PDN Gateway (P-GW)• Serving Gateway (S-GW)• Mobility Management Entity (MME)

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Reference Point Interface

S-GW

MME

HSS

P-GW

Internet(Operator’s IP

Services)

3GPP EPC

S5

SGi

S6a

S1-MME: Reference point for the control plane protocol between E-UTRAN and MME.

S1-U: Reference point between E-UTRAN and Serving GW for the per bearer user plane tunnelling and inter eNodeB path switching during handover.

S5: It provides user plane tunnelling and tunnel management between Serving GW and PDN GW. It is used for Serving GW relocation due to UE mobility and if the Serving GW needs to connect to a non-collocated PDN GW for the required PDN connectivity.

S8: Inter-PLMN reference point providing user and control plane between the Serving GW in the VPLMN and the PDN GW in the HPLMN. S8 is the inter PLMN variant of S5

S11: Reference point between MME and Serving GW.

3GPP E-UTRAN

eNodeB

eNodeBS-GW

MME

3GPP EPC

S1-MME

S1-MME

S1-U

S1-U

X2

s11

(S8)

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Control plane protocol stack

S1-AP (S1 Application Protocol): Application Layer Protocol between the eNodeB and the MME.NAS (Non - Access Stratum ) : Main functions of the protocols that are the support of mobility of UE and the support of session management procedures to establish and maintain IP connectivity between the UE and a packet data network gateway. NAS control protocol performs followings:

•EPS bearer management;•Authentication;•ECM-IDLE mobility handling;•Paging origination in ECM-IDLE;•Security control.

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Control plane protocol stack

UDP

L2

L1

IP

L2

L1

IP

UDP

S5 or S8 S - GW P - GW

GTP - C GTP - C

UDP

L2

L1

IP

L2

L1

IP

UDP

S11 MME S-GW

GTP-C GTP-C

GTP‑C (GPRS Tunnelling Protocol for the Control plane) :

This protocol tunnels signalling messages between

S‑GW and P‑GW (S5 or S8)

MME and S‑GW (S11).

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User Plane Protocol Stack

GTP-UGTP-U protocol is used over S1-U, X2, S4, S5 and S8 interfaces of the Evolved Packet System (EPS). GTP-U Tunnels are used to carry encapsulated T-PDUs and signalling messages between a given pair of GTP-U Tunnel Endpoints. The Tunnel Endpoint ID (TEID) which is present in the GTP header indicates which tunnel a particular T-PDU belongs to.

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Architecture for 3gpp access (EPS)

SGi

S12

S3 S1-MME

PCRF

Gx

S6a

HSS



Rx

S10

UE

SGSN

LTE-Uu

E-UTRAN

MME

S11

S5 Serving Gateway

PDN Gateway

S1-U

S4

UTRAN

GERAN

S1-AP

GTP-U

GTP-CGTP-C

NAS

GTP-U

User Plane Control Plane

SGi

S12

S3 S1-MME

PCRF

Gx

S6a

HSS



Rx

S10

UE

SGSN

LTE-Uu

E-UTRAN

MME

S11

S5 Serving Gateway

PDN Gateway

S1-U

S4

UTRAN

GERAN

S1-AP

GTP-U

GTP-CGTP-C

NAS

GTP-U

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Functions between Control-plane and User-plane

• Control–plane ( MME in charge ):– For MME

• Manage the Attach and Detach of UE.• Manage the security-related authentication, authorization and accounting.• Manage building, updating or deleting EPS bearer, which is used to transmit the pack

ets of UE.• Manage the roaming of UE, including Handover between eNB, Idle mode, Traking ar

ea update, and paging.• User–plane (S-GW&P-GW in charge):

– For S-GW• Routes and forwards user data packets• Acts as the mobility anchor for the user plane

– -During inter-eNB handovers– -Between LTE and other 3GPP technologies

• Pages idle state UE when DL data arrives for the UE– For P-GW

• Provides connectivity to the UE to external packet data networks (UE IP Address Allocation)

• Performs policy enforcement, packet filtering, and charge support• Acts as mobility anchor between 3GPP and no-3GPP technologies (such as WiMAX)

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Attach Procedure

後端 EPC 對於整個 LTE 的 attach 的連線建立程序扮演相當重要的角色，在成功建立的流程中，主要可以分成四個程序 :

• control-plane 的– Initial Attach with Authentication 、– Create Default Bearer 、– Create Dedicated Bearer

• 以及 user-plane 的– User Plane Transport 這

四大主要內容。 MME 負責與 eNode-B 及 UE 傳遞控制面上的訊息，從系統端角度看分別是由 S1AP 以及 NAS 來處理。

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3. Identification Request

1. Attach Request

new MME Old MME/SGSN

Serving GW PCRF HSS

3. Identification Response

PDN GW

2. Attach Request

eNodeB UE

4. Identity Request 4. Identity Response 5a. Authentication / Security

17. Initial Context Setup Request / Attach Accept

First Uplink Data

19. RRC Connection Reconfiguration Complete 18. RRC Connection Reconfiguration

20. Initial Context Setup Response

24. Modify Bearer Response

23. Modify Bearer Request

First Downlink Data 25. Notify Request

26. Notify Response

(B)

(A)

16. Create Session Response

12. Create Session Request

8. Update Location Request 9. Cancel Location

11. Update Location Ack

9. Cancel Location Ack

10. Delete Session Request 10. Delete Session Response



7. Delete Session Response

7. Delete Sesion Request

First Downlink Data (if not handover)

(C)

EIR

5b. ME Identity Check

5b. Identity Request/Response

10. PCEF Initiated IP-CAN Session Termination


14. PCEF Initiated IP-CAN Session Establishment/Modification

6. Ciphered Options Request

6. Ciphered Options Response

23a. Modify Bearer Request

23b. Modify Bearer Response

(D)

21. Direct Transfer 22. Attach Complete

(E)

(F)

Attach Request Identification Request

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1. Attach Request


Serving GW PCRF HSS


PDN GW

2. Attach Request

eNodeB UE



First Uplink Data






26. Notify Response

(B)

(A)












(C)

EIR










(D)


(E)

(F)

Authentication/SecurityCiphered Options

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1. Attach Request


Serving GW PCRF HSS


PDN GW

2. Attach Request

eNodeB UE



First Uplink Data






26. Notify Response

(B)

(A)












(C)

EIR










(D)


(E)

(F)

Delete Session Update Location

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1. Attach Request


Serving GW PCRF HSS


PDN GW

2. Attach Request

eNodeB UE



First Uplink Data






26. Notify Response

(B)

(A)












(C)

EIR










(D)


(E)

(F)

Create Session

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1. Attach Request


Serving GW PCRF HSS


PDN GW

2. Attach Request

eNodeB UE



First Uplink Data






26. Notify Response

(B)

(A)












(C)

EIR










(D)


(E)

(F)

Initial Context SetupRRC Connection Reconfiguration Attach Complete

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1. Attach Request


Serving GW PCRF HSS


PDN GW

2. Attach Request

eNodeB UE



First Uplink Data






26. Notify Response

(B)

(A)












(C)

EIR










(D)


(E)

(F)

Modify Bearer

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eNB1

MME / S-GW MME / S-GW

eNB2

eNB3

S1

S1

X2 E-UTRAN

X2-based Handover

換手流程不需透過 EPC上層介入，控制訊息直接是來源 eNB 和目標 eNB 之間的傳輸，其中來源 eNB 和目標 eNB皆在同一個 MME 的管轄範圍內，意旨 MME不會被更換。

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UE Source SGW

Source MME

Source eNodeB

Target eNodeB

4.Handover Request(MME UE S1AP ID,

S1 UL TEID, NCC=0, Kenb*)

Packet DataPacket Data

1.Measurement Control

UL allocation

2.Measurement Reports

3.HO decision

0.Area Restriction Provided

5.Admission Control

6.Handover Request Ack(X2 UL Forwarding TEID, X2 DL Forwarding TEID)DL allocation

7.RRCConnectionReconfiguration( Include mobilityControlInformation IE )

Deliver buffered and in transit packets to

target eNB

Detach from old cellAnd

Synchronize to new cell8.SN Status Transfer

(Receive Status UL PDCP SDUs, DL COUNT, UL COUNT)

DL Data Forwarding(to X2 DL Forwarding TEID)

Buffer DL and UL packets from Source eNB

10.UL allocation + TA for UE

9.Synchronisation

11.RRC Connection Reconfiguration Complete

13.User Plane Update Request

12.Path Switch Request(Target eNB Addr/TEID(per E-RAB),

Source MME UE S1AP ID, UE Security Capability)

14.Switch DL Path


(to S1 UL TEID)

End Marker

Packet DataEnd Marker

15.User Plane Update Response16.Path Switch Request Ack(SGW Addr/TEID(per E-RAB),

NCC=1, NH)

17.UE Context Release

18.Release Resources

HO Decision

HO Preparation

HO Execution

HO Completion

L3 Singnaling

L1/L2 Singnaling

User Data

UL Data

DL Data

UL Data Forwarding(to X2 UL Forwarding TEID)

Handover Decision (Step0~Step3) ：According to MEASUREMENT REPORT and RRM information, Source eNB can decide whether carrying on the Handover procedure of UE.

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UE Source SGW

Source MME

Source eNodeB

Target eNodeB





UL allocation


3.HO decision


5.Admission Control




target eNB







9.Synchronisation





14.Switch DL Path


(to S1 UL TEID)

End Marker



NCC=1, NH)



HO Decision

HO Preparation

HO Execution

HO Completion

L3 Singnaling

L1/L2 Singnaling

User Data

UL Data

DL Data


Handover Preparation：(Step4~Step7)Source eNB send Handover Request to Target eNB ， and carry with MME UE S1APID. Target eNB respond Handover Request Ack to Source eNB, which contains X2 TEID UL/DL 。

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UE Source SGW

Source MME

Source eNodeB

Target eNodeB





UL allocation


3.HO decision


5.Admission Control




target eNB







9.Synchronisation





14.Switch DL Path


(to S1 UL TEID)

End Marker



NCC=1, NH)



HO Decision

HO Preparation

HO Execution

HO Completion

L3 Singnaling

L1/L2 Singnaling

User Data

UL Data

DL Data


Handover Execution：(Step8~Step11)•Then, data can be sent to target eNB: Up-link data through X2 TEID UL / Down-link data through X2 TEID DL.•The target eNB will save those data for a while.•After receiving RRC Connection Reconfiguration Complete, the target eNB will transmit the Up-link data to SGW.

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UE Source SGW

Source MME

Source eNodeB

Target eNodeB





UL allocation


3.HO decision


5.Admission Control




target eNB







9.Synchronisation





14.Switch DL Path


(to S1 UL TEID)

End Marker



NCC=1, NH)



HO Decision

HO Preparation

HO Execution

HO Completion

L3 Singnaling

L1/L2 Singnaling

User Data

UL Data

DL Data


Handover Completion：(Step12~Step18)With MME UE S1APID (Step4), Target eNB can change the transmitting path to MME and SGW. Therefore, data will be transmitted by eNB. 。

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S1-based Handover

• 當 X2 換手無法進行時則進行 S1 換手流程。如當 UE 要換手的目標 eNB 和來源 eNB 不屬於同一個 MME 管轄，即進行 S1 換手流程。起使於來源 eNB （ Source eNodeB ）傳送 Handover Required S1AP 封包來開始換手流程。所以 S1 換手會更換 MME ，並有可能更換 SGW（ Serving Gateway ）。來源 MME （ Source MME ）選擇是否更換 MME 。若是 eNB 內的換手流程（ inter-eNodeB Handover ）則不會更換 MME 。目標 MME （ Target MME ）選擇是否更換 SGW 。底下介紹換手流程的過渡時期，對於資料轉送的通道建立。

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• 來源 eNB 會判斷哪些 EPS bearer 需要被 SGW 間接轉送（ Indirect Forwarding ），並會在 Handover Required 加以註記，這是 EPC 端無法改變的設定。來源MME 根據來源 eNB 的設定，對來源 SGW 進行 Forward Relocation Procedure ，以建立轉送通道（ Forwarding Tunnel ）。

• 目標 MME 則基於來源 MME 的只是對目標 SGW 設定間接轉送的通道 ID （ Tunnel Endpoint Identifier ），即 Create Indirect Data Forwarding Tunnel Procedure 。

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PDN GWTarget Serving

GW

Source Serving

GW

Target MME

Source MME

Target eNodeB

Source eNodeB

UE

2.Handover Required(Target eNB Id, Selected TAI,

Direct Forwarding Path Availability=0)4.Create Session Request

(PGW addr & cTEID <per PDN-Conn>, PGW addr & uTEID <per bearer>)

4a.Create Session Response(Target SGW addr & uTEID UL<per bearer>)

1.Decide initial S1-based handover to

Target eNB

5a.Handover Request Acknowledge(Target eNB addr & uTEID DL<per bearer>,

Target eNB addr & uTEID for DL receiving Forwarded<per bearer>, Target eNB addr & uTEID for UL receiving Forwarded<per bearer>(tar-eNB request),

RRC Container<NCC=1, NH>)

5.Handover Request(Target SGW addr & uTEID UL<per bearer>,

DataFwdNotPoccibleSecurity Context<NCC=1, NH>)

6.Create Indirect Data Forwarding Tunnel Request

(Target eNB addr & uTEID for DL receiving Forwarded,

Target eNB addr & uTEID for UL receiving Forwarded)

6a.Create Indirect Data Forwarding Tunnel Response

(Target SGW addr & uTEID for DL Indirect Forwarding<per bearer>,

Target SGW addr & uTEID for UL Indirect Forwarding<per bearer>)

7.Forward Relocation Response(SGW change Ind,

Target SGW addr & uTEID for DL Indirect Forwarding<per bearer>(with SGW change),

Target SGW addr & uTEID for UL Indirect Forwarding<per bearer>(with SGW change),

Target eNB addr & uTEID for DL receiving Forwarded<per bearer>(without SGW change),

Target eNB addr & uTEID for UL receiving Forwarded<per bearer>(without SGW change), RRC Container<NCC=1, NH>)

8.Create Indirect Data Forwarding Tunnel Request(Target SGW addr & uTEID for DL Indirect Forwarding<per bearer>(with SGW change), Target SGW addr & uTEID for UL Indirect Forwarding<per bearer>(with SGW change),

Target eNB addr & uTEID for DL receiving Forwarded<per bearer>(without SGW change), Target eNB addr & uTEID for UL receiving Forwarded<per bearer>(without SGW change))

8a.Create Indirect Data Forwarding Tunnel Response(Source SGW addr & uTEID for DL Indirect Forwarding<per bearer>, Source SGW addr & uTEID for UL Indirect Forwarding<per bearer>)

9.Handover Command(Source SGW addr & uTEID for DL Indirect

Forwarding<per bearer>, Source SGW addr & uTEID for UL Indirect

Forwarding<per bearer>, RRC Container<NCC=1, NH>)

11b.Indirect forwarding DATA11b.Indirect forwarding

DATA11b.Indirect forwarding DATA

9a.Handover Command

10.eNB Status Transfer

10c.eNB Status Transfer

10a.Forward Access Context Notification10b.Forward Access Context Acknowledge

11a.Direct forwarding DATA

12.Handover ConfirmDownlink DATA

Detach from old cell and synchronize to new cell

Uplink DATA Uplink DATAUplink DATA13.Handover Notify

(TAI, ECGI, Security Capability)

14a.Forward Relocation Complete Acknowledge(Cause)

14.Forward Relocation Complete Notification(Indication)

15.Modify Bearer Request(Target eNB addr & uTEID DL<per bearer>)

17.Modify Bearer Response()

16.Modify Bearer Request

(Target SGW addr & uTEID DL<per

bearer>)16a.Modify Bearer

Response(Charging Id)

Downlink DATA Downlink DATADownlink DATA

18.Tracking Area Update procedure

19b.Delete Session Request

19c.Delete Session Response

19a.UE Context Release Complete

19.UE Context Release Command

20a.Delete Indirect Data Forwarding Tunnel Request

20b.Delete Indirect Data Forwarding Tunnel Response

20a.Delete Indirect Data Forwarding Tunnel Request

20b.Delete Indirect Data Forwarding Tunnel Response

Downlink DATA Downlink DATA Downlink DATA

3.Forward Relocation Request(Src-SGW addr & cTEID<per UE>,

PGW addr & cTEID<per PDN-Conn>, Src-SGW addr & uTEID<per bearer>,

PGW addr & uTEID<per bearer>, MM Context<NCC=1, NH>,

Indication<DFI Flag>)

(UE Return)ukHoCancelEvt

Handover Cancel

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【步驟 1 】來源 eNB 決定進行 S1 換手流程，可能是因為沒有 X2 連線，也有可能是 X2 換手失敗。【步驟 2 】來源 eNB 傳送 Handover Required 到來源 MME 。其中會帶 Target TAI 提供給來源 MME 要換手的區域，來源 MME 來決定是否要更換 M

ME 。還有 Direct Forwarding Path Availability Indication IE 說明是否和目標 eNB 有能力作直接轉送。 RRC Container 以提供給目標 eNB 。【步驟 3 】當來源 MME 根據收到的 Target TAI 確定要選擇新的目標 MME 時，則進行 Forward Relocation Procedure 。當來源 MME 發現 Target TAI

非自己可服務的範圍，則選擇一個目標 MME 。並傳送 Forward Relocation Request 至來源 SGW 。並會將 Target TAI 帶到目標 MME ，以提供目標 MME 是否要更換 SGW 。 MME UE Context 裡面帶有 IMSI 、 UE Security Context 、 UE Network Capability 和 AMBR 。還有 EPS Bearer Context 會帶有 PGW Address 和 TEID 。

【步驟 4 】當目標 MME 根據收到的 Target TAI 確定要選擇新的目標 SGW 時，則進行 Create Session Procedure 。傳送 Create Session Request 至新的目標 SGW 為 UE 建立新的 PDN 連線，內含 PGW Control TEIDs 和 PGW Uplink/Downlink User TEIDs ，以後跟 PGW 的溝通則用此 TEIDs 。

目標 SGW 則會回傳 Create Session Response 以告知建立成功，內含 Target SGW Uplink User TEIDs ，最後會提供給目標 eNB ，以告知以後資料傳給新的目標 SGW 。

【步驟 5 】目標 MME 傳送 Handover Request 至目標 eNB 。此訊息是對目標 eNB 建立 UE Context 。內含有要換手的 EPS Bearer 、 RRC Container 和 Security Context 。 EPS Bearer 內包含之前目標 MME 從目標 SGW 拿到的 Target SGW Uplink User TEIDs （圖步驟 5 ，藍色部分）還有 QoS 資訊。

若目標 eNB 被告知要間接轉送資料，則產生 Indirect Forwarding TEID ，並回傳 Handover Request Ack 至目標 MME 。若有更換 SGW ，目標 MME則會將此資訊透過 Create Indirect Data Forwarding Tunnel Procedure 傳至目標 SGW （圖步驟 6 ，紅色部分）。若沒換 SGW ，來源 MME 則會透過 Create Indirect Data Forwarding Tunnel Procedure 到來源 SGW （圖步驟 8 ，紅色部分）。

RRC Container 是目標 eNB 要轉交給來源 eNB 的訊息。【步驟 6 】有進行步驟 4 且步驟 3 時目標 MME 被告知為間接轉送時，目標 MME 則會對目標 SGW 交換間接轉送的 TEID 。【步驟 7 】目標 MME 透過 Forward Relocation Response 告知來源 MME 是否更換 SGW 、 RRC Container 以及 Forward TEID 。若有更換 SGW ，

則帶目標 SGW 的 TEID （來自步驟 6a 的藍色部分）。若沒更換 SGW ，則帶目標 eNB 的 TEID （來自步驟 5a 的紅色部分）。【步驟 8 】若為間接轉送則來源 MME 則會和來源 SGW 建立 Indirect Forwarding TEID 。【步驟 9 】當來源 MME 確認 Forward Relocarion Procedure 成功完成了，則對來源 eNB 下達 Handover Command 的指令。並將來自目標 eNB 的 R

RC Container 附在內。【步驟 10 】來源 eNB 會將 eNB Status Transfer 透過 MME 傳達給目標 eNB ，告知待會會轉送的資料序號，告知從序號多少以後才需被轉送。【步驟 11 】自步驟 10 之後，目標 eNB 則可以開始轉送上行資料（ Uplink Data ）。【步驟 12 】 UE 對目標 eNB 進行換手確認。此時確認 UE 換手到目標 eNB 的管轄之下。【步驟 13-17 】目標 eNB 對目標 MME 提醒說，此 UE 已經到我的管轄下了。因此提醒目標 MME 要將原本 UE 的資料路徑由是從來源 SGW 一路到 P

GW 轉換成目標 SGW 一路到 PGW 。【步驟 18-20 】在步驟 14 時會開始倒數一段時間，時間到了來源 MME 則會對來源 eNB 作釋放 UE 資訊的步驟（ Release UE Context Procedure ）、

刪除轉送通道流程（ Delete Indirect Data Forwarding Tunnel Procedure ）以及對來源 SGW 刪除 UE 的通道（ Delete Session Procedure ）。【步驟 21 】在步驟 14a 後倒數一段時間，時間到了目標 MME 則會刪除轉送通道流程（ Delete Indirect Data Forwarding Tunnel Procedure ）。

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Thank You

29

Appendix – PCRF & HSS • PCRF

– The Policy Control and Charging Rules Function– is responsible for policy control decision-making, as well as for controlling the f

low-based charging functionalities in the Policy Control Enforcement Function (PCEF), which resides in the P-GW.

– The PCRF provides the QoS authorization (QoS class identifier [QCI] and bit rates) that decides how a certain data flow will be treated in the PCEF and ensures that this is in accordance with the user’s subscription profile.

• HSS – The Home Subscriber Server – contains users’ SAE subscription data such as the EPS-subscribed QoS profile

and any access restrictions for roaming. It also holds information about the PDNs to which the user can connect.

– In addition the HSS holds dynamic information such as the identity of the MME to which the user is currently attached or registered. The HSS may also integrate the authentication center (AUC), which generates the vectors for authentication and security keys.

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Appendix – full MME functions

– MME functions include:• NAS signalling;• NAS signalling security;• Inter CN node signalling for mobility between 3GPP access networks (terminating

S3);• UE Reachability in ECM-IDLE state (including control and execution of paging

retransmission);• Tracking Area list management;• Mapping from UE location (e.g. TAI) to time zone, and signalling a UE time zone

change associated with mobility,• PDN GW and Serving GW selection;• MME selection for handovers with MME change;• SGSN selection for handovers to 2G or 3G 3GPP access networks;• Roaming (S6a towards home HSS);• Authentication;• Authorization;• Bearer management functions including dedicated bearer establishment;• Lawful Interception of signalling traffic;• Warning message transfer function (including selection of appropriate eNodeB);• UE Reachability procedures;• Support Relaying function (RN Attach/Detach).

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Appendix – Full Serving GW functions

– The functions of the Serving GW, for both the GTP-based and the PMIP-based S5/S8, include:

• the local Mobility Anchor point for inter-eNodeB handover;• sending of one or more "end marker" to the source eNodeB, source SGSN

or source RNC immediately after switching the path during inter-eNodeB and inter-RAT handover, especially to assist the reordering function in eNodeB.

• Mobility anchoring for inter-3GPP mobility (terminating S4 and relaying the traffic between 2G/3G system and PDN GW);

• ECM-IDLE mode downlink packet buffering and initiation of network triggered service request procedure;

• Lawful Interception;• Packet routing and forwarding;• Transport level packet marking in the uplink and the downlink, e.g. setting

the DiffServ Code Point, based on the QCI of the associated EPS bearer;• Accounting for inter-operator charging. For GTP-based S5/S8, the Serving

GW generates accounting data per UE and bearer;• Interfacing OFCS according to charging principles and through reference

points specified in TS 32.240 [51].

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Appendix – Full PDN GW functions PDN GW functions include for both the GTP-based and the PMIP-based S5/S8:

• Per-user based packet filtering (by e.g. deep packet inspection);• Lawful Interception;• UE IP address allocation;• Transport level packet marking in the uplink and downlink, e.g. setting the DiffServ Code Point,

based on the QCI of the associated EPS bearer;• Accounting for inter-operator charging;• UL and DL service level charging as defined in TS 23.203 [6] (e.g. based on SDFs defined by the

PCRF, or based on deep packet inspection defined by local policy);• Interfacing OFCS through according to charging principles and through reference points

specified in TS 32.240 [51].• UL and DL service level gating control as defined in TS 23.203 [6];• UL and DL service level rate enforcement as defined in TS 23.203 [6] (e.g. by rate

policing/shaping per SDF);• UL and DL rate enforcement based on APN-AMBR (e.g. by rate policing/shaping per aggregate

of traffic of all SDFs of the same APN that are associated with Non-GBR QCIs);• DL rate enforcement based on the accumulated MBRs of the aggregate of SDFs with the same

GBR QCI (e.g. by rate policing/shaping);• DHCPv4 (server and client) and DHCPv6 (client and server) functions;• The network does not support PPP bearer type in this version of the specification. Pre-Release 8

PPP functionality of a GGSN may be implemented in the PDN GW;• packet screening.

Additionally the PDN GW includes the following functions for the GTP-based S5/S8:• UL and DL bearer binding as defined in TS 23.203 [6];• UL bearer binding verification as defined in TS 23.203 [6];• Functionality as defined in RFC 4861 [32];• Accounting per UE and bearer.

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Appendix

lte e-utran overview

Documents