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BRKSPM-5288

LTE Design and Deployment Strategies

www.ciscolivevirtual.com

http://www.ciscolivevirtual.com/

© 2012 Cisco and/or its affiliates. All rights reserved. Cisco Public BRKSPM-5288 2

Mobile Broadband Dynamics

LTE Overall Architecture

LTE Design Strategies

LTE E-UTRAN

EPS Gateways

DNS, IP and NAT

Mobile Transport

LTE QoS and Policy

LTE Deployment Strategies

Interworking, Roaming, Security

Deployment Best Practices

Summary, References

Agenda

EPS – Evolved Packet System

NAT – Network Address Translation


Mobile Broadband- Shifting the Focus?

Traffic projections includes only Macro network

Significant data growth in APAC compared to other regions

Dominant Mobile Technology in APAC : TD-LTE

Global mobile traffic trend Traffic breakdown – Geographies

Source - http://www.cisco.com/en/US/solutions/collateral/ns341/ns525/ns537/ns705/ns827/white_paper_c11-520862.html

http://www.cisco.com/en/US/solutions/collateral/ns341/ns525/ns537/ns705/ns827/white_paper_c11-520862.html




Smart Devices and What they Do?

Smart devices will pose equal challenges for signalling and data

Broad Traffic Categories - Video(70%), Web (20%), M2M (5%)

Over the top contents used mostly but doesn’t generate differential revenue

Source - Cisco VNI Report 2012 - 2116

Traffic breakdown – based on Apps Traffic breakdown – based on Devices






Top 10% devices generate over 60% of total traffic

Device OS and Apps have unique characteristics impacting signalling

Challenge of Smart devices

Radio signalling overload due simultaneous device updates

Bandwidth hogging, Concurrent flows, Keeping NAT pin holes

Devices are more prone to malware (DOS/DDoS) attack

Smart Device Characteristics






Mobile IPv6 Adoption

IANA IPv4 address are depleted – Regional registries are allocating IPv4 business critical

Mobile IPv6 penetration is increasing with LTE, VoLTE/IMS, M2M

Asia Pacific leads throughout the forecast period, reaching 689 million in 2016


Trend - Global IPv6-Capable overall Mobile Devices Trend - Global IPv6-Capable Smartphone





ARPU

(Revenue)

Data Traffic

(Cost)

Profitability

Gap

Increase Revenue

Developing In-house Apps

B2B2C Business Model

Enable Content and Partnerships

Reduce Costs

Manage “Over The Top” contents

Offload - Small cell, SP WiFi

Optimal use of expensive assets

Managing subscriber Churn

Innovative services

User experience, policy deployments

Mobile Operator’s Challenges and Opportunity





LTE E-UTRAN

EPS Gateways

IP and NAT

Mobile Transport

LTE QoS and Policy




Summary, References

Agenda




Mobile Network Evolution – Convergence to LTE*

<1999 2000-02 2006-07 2008-09 20010-11 2012+ 2003-04

3GPP Track

* Actual speed depend upon many factors

1xRTT

EDGE

Voice

Data (9.6 - 56k)

Voice Data

(9.6 - 56k)

Data (DL 2.4M) Voice 2x cap

Data (144k)

Data

(DL/UL 20/80k)

Voice

(DL/UL 384/384k)

e-EDGE

UMB IS-95

LTE

(DL 1Mbps)

GSM

WiMAX

EV-DO RevB Multi-carrier

Data (14.7M)

HSPA+

LTE

Advanced

3G R99 HSDPA HSUPA

Enhanced modulation

(DL 384k)

EV-DO RevA

(DL/UL 100/50M)

Optimised DL

(14.4M)

Optimised UL

(5.7M)

MIMO, 64QAM

(DL/UL 42/11M)

GPRS

3GPP2 Track

Mobile Network Transformation to All IP

Architecture Harmonisation

(3GPP R8) (3GPP R10+)

(DL/UL 1000/

500M)


LTE Functional Migration from 3G

Backhaul PDSN RNC BS

PCRF

Operator’s

IP Services

HLR

AAA

UE

Home

Agent

MSC

eNodeB

RNC/PDSN

(Control) PDSN

(Bearer)

MME

Serving Gateway

HSS

PDN Gateway

Authentication (Optional)

CDMA to LTE Migration

Signaling

Bearer

Backhaul SGSN RNC BS

PCRF

Operator’s

IP Services

HLR

AAA

UE

GGSN

MSC

eNodeB

SGSN/RNC

(Control)

SGSN

(Bearer)

MME

Serving Gateway

HSS

PDN Gateway

Authentication (Optional)

UMTS to LTE Migration

Signalling

Bearer


LTE/EPS Architecture

E-UTRAN Evolved Packet System Services UE


Non-3GPP Access

3GPP

Access

Evolved Packet System

LTE/EPS Architecture -(Ref 3GPP TS23.401, TS23.402)

E-UTRAN

PDN Gateway

Serving Gateway

eNodeB

PCRF

Operator’s IP Services

HSS

Gxc (Gx+)

S11 (GTP-C)

S1-U (GTP-U)

S2b (PMIPv6,

GRE)

MME

S5 (PMIPv6, GRE)

S6a (DIAMETER)

S1-MME (S1-AP)

GERAN

S4 (GTP-C, GTP-U) UTRAN

SGSN

Trusted Non-

3GPP IP Access

Untrusted Non-

3GPP IP Access

S3 (GTP-C)

S12 (GTP-U)

S10 (GTP-C)

S5 (GTP-C, GTP-U)

Gx (Gx+)

Gxb (Gx+)

SWx (DIAMETER)

STa (RADIUS, DIAMETER)

ePDG

3GPP AAA

SWn (TBD)

S2c (DSMIPv6)

S2c

S6b (DIAMETER)

SWm (DIAMETER)

SGi

SWa (TBD)

Gxa (Gx+)

Rx+

S2c

UE

UE

UE

SWu (IKEv2, MOBIKE, IPSec)

S2a (PMIPv6, GRE MIPv4 FACoA)

Trusted Untrusted

LTE

2G/3G

Transport (Tunnelled Traffic) IP Traffic


Hierarchical Architecture National

Regional

Market

GGSN

SGSN

MSC

BSC

IP

TDM

FR/TDM

BTS

2G/2.5G 3G UTRAN

GGSN

MSC

RNC

IP

ATM

IP

NB

SGSN

3.5G UTRAN

GGSN

MSC

RNC

IP

IP

IP

NB

SGSN

LTE E-UTRAN

HSS

PCRF

SGW

MME

IP

IP

eNB

PGW

MME – Mobility Management Entity, SGW – Serving Gateway, PGW – PDN Gateway


LTE Functional Migration from 3G LTE Term CDMA Equivalent UMTS Equivalent

eUTRAN (Evolved Universal Terrestrial

Radio Access Network)

AN (Access Network) UTRAN

eNode B (Evolved Node B) Base station + RNC Base station + RNC

EPC (Evolved Packet Core) PDN (Packet Data Network) PDN (Packet Data Network)

MME (Mobility Management Entity) RNC + PDSN (Control part) RNC + SGSN (Control Part)

SGW (Serving Gateway) PDSN + PCF (Bearer part) SGSN (Bearer Part)

PDN GW (Packet Data Network Gateway) HA (Home Agent) GGSN (Gateway GPRS Support Node)

HSS (Home Subscriber System) AAA + HLR AAA + HLR

S1-MME (eNode B <-> MME for Control) A10 / A11 / A12 Iu

S1-U (eNode B <-> SGW for Bearer) A10 + R-P Session Gn

S5/S8 Bearer (SGW <-> PDNGW) MIP (Mobile IP Tunnel) Gn, Gb

EPS Bearer Service (E2E traffic path

between UE and PDN GW)

PPP + MIP PDP Context

For your reference


LTE: New Terminologies

LTE Term Meaning

Access Point Name (APN) Identifies an IP packet data network (PDN) and service type

provided by the PDN to that user’s session.

PDN Connection The Association between an UE and PDN (APN) represented by one IPv4

Address and/or one IPv6 Prefix

GPRS Tunnelling Protocol (GTP) Signalling and Tunnelling protocol for data (between eNodeB, SGW, and PGW)

EPS Bearer An EPS bearer uniquely identifies traffic flows that receive a common QoS

treatment between UE and PDN-GW

Default Bearer First one to get established and remains established throughout the lifetime of

PDN Connection.

Dedicated Bearer Additional bearer(other than default), created for a PDN connection to provide

specific QoS treatment for Apps

Tracking Area Update (TAU) Signalling Procedure when UE move between eNodeB

QoS Class Indicator (QCI) Field indicating type of service associated with a data packet.

Traffic Flow Template (TFT) A traffic filter that identifies an application class. This is associated with a Dedicated

Bearer and QCI.

For your reference


LTE: New Terminologies LTE Term Meaning

Guaranteed Bit rate (GBR) Bearer

Dedicated network resources

Allocated permanently at bearer establishment/modification

Non-Guaranteed Bit rate (non- GBR)

Bearer

No dedicated network resource are reserved

Default bearer is always non- GBR Bearer

APN-AMBR

Aggregated maximum bit rate associated with all the non- GBR bearers across all

PDN connections connected to given APN. Stored in HSS/HLR per APN

Not applicable to GBR bearers

UE-AMBR Aggregated maximum bit rate for UE

Subscription parameter and stored in HSS/HLR per UE

QoS Access agnostic QoS definition

QoS Class Identifier (QCI)

Allocation and Retention Priority

Guaranteed and Maximum Bit Rates

For your reference





LTE E-UTRAN

EPS Gateways

DNS, IP and NAT

Mobile Transport

LTE QoS and Policy




Summary, References

Agenda




LTE Design Objectives

High Peak Data Rates

100 Mbps DL (20 MHz, 2x2 MIMO)

50 Mbps UL (20 MHz, 1x2 MIMO)

5 bps/Hz for DL, 2.5 bps/Hz in UL

Spectrum Efficiency

3-4x HSPA Rel’6 in DL

2-3x HSPA Rel’6 in UL

Reduction in Capex/ Opex

Open standard

Flat IP architecture

Low Latency

< 5ms user plane (UE to RAN edge)

<100ms camped to active

< 50ms dormant to active

Quality of Service

9 QoS classes mapped to DSCP

Tighter control between user &

transport

Interworking - UMTS/GSM/EvDO

Multimode LTE UE will Handover

HO time < 500ms for Non real time

HO time < 300ms for Real Time

Multicast/Broadcast

Capable to support

enhanced MBMS

Spectrum Allocation

Flexible spectrum

1.4, 3, 5, 10, 15, 20 MHz

18


LTE E-UTRA Frequency Bands (Ref TS36.101 (8) Table 5.5-1)

E-UTRA Operating

Band

Uplink (UL) operating band BS receive UE transmit

Downlink (DL) operating band BS transmit UE receive

Duplex Mode

FUL_low – FUL_high FDL_low – FDL_high

1 1920 MHz – 1980 MHz 2110 MHz – 2170 MHz FDD




5 824 MHz – 849 MHz 869 MHz – 894MHz FDD




9 1749.9 MHz – 1784.9 MHz 1844.9 MHz – 1879.9 MHz FDD


11 1427.9 MHz – 1447.9 MHz 1475.9 MHz – 1495.9 MHz FDD




…


...

33 1900 MHz – 1920 MHz 1900 MHz – 1920 MHz TDD








Newly proposed

2496 MHz – 2690 MHz 2496 MHz – 2690 MHz TDD


Channel bandwidth BWChannel

[MHz] 1.4 3 5 10 15 20

Transmission bandwidth

configuration NRB 6 15 25 50 75 100

Channel bandwidth (BWChannel) and the Transmission bandwidth configuration (NRB). Each

NRB is also referred as resource block and 180KHz wide.

The channel edges are defined as the lowest and highest frequencies of the carrier

separated by the channel bandwidth, i.e. at FC +/- BWChannel /2

LTE E-UTRA Channels (TS36.101, Fig 5.6-1 and table 5.6-1)


FDM - Frequency Division Multiplex

Available bandwidth is divided into sub-carriers

Sub-carriers are multiplexed and transmitted serially

Inter-channel Sufficient guard band to avoid interference

OFDM – Orthogonal Frequency Division Multiplex

Available bandwidth is divided into sub-carriers

Sub-carriers are orthogonally separated to reduce interference

Each sub-carrier is modulated using QPSK, 16 QAM, 64 QAM

OFDM symbol is linear combination of signal in each sub-carrier

OFDM symbol is preceded by cyclic prefix (CP) to reduce inter-

channel interference

Being orthogonal OFDM is best suited for multi-path transmission

OFDM and OFDMA

Saved Bandwidth

OFDMA – Orthogonal Frequency Division Multiplex Access

Multiple users symbols are multiplexed and transmitted in parallel

Scheduling is performed to allocate right resources to each user


…

FFT

5 MHz Bandwidth

Sub-carriers

Symbols

Guard Intervals

…

Frequency

OFDMA Radio Frame and Data Structure

Radio spectrum (1.4 MHz to 20 MHz) is divided into sub-carriers in frequency domain.

Each sub-carrier is divided into frame and symbols in time domain

Each OFDM symbol is independently modulated and transmitted

Guard interval is added to each symbol to overcome inter-OFDM symbol interference

Multiple users symbols are sent in parallel on available spectrum

Time

Frequency Band


EUTRAN Air Interface Overview

EUTRAN interface is very spectral efficient

Downlink: Orthogonal Frequency Division Multiple Access (OFDMA) in downlink

Uplink: Single Carrier – Frequency Division Multiple Access. Sub-carrier are still

orthogonal

Variable size FFT according to bandwidth

Variable modulations (QAM, 16 and 64 QAM)

Multiple Input Multiple Output (MIMO) technology to boot signal or send more bits


E-UTRAN Radio Frame Structure for FD-LTE

0 1 2 3 4 5 6

7 OFDM Symbols

(short cyclic prefix)

1 Frame (10 msec)

1 Sub-Frame (1.0 msec)

1 Slot (0.5 msec)

0 1 2 3 10 11

19

0 1 2 3 4 5 6

cyclic prefixes

Cyclic Prefix is added

before every symbol

LTE radio frame has fixed length of 10 ms

LTE radio frame is divided into 10 sub-frame (1 ms each)

Each sub-frame is further divided into two slots of .5 ms each

Each slot is further divided into 6 or 7 OFDM symbols .

Each OFDM symbol carry either user or control information

Cyclic Prefix is precede each of symbol so that inter-channel interference is reduced


E-UTRAN Radio Frame Structure for TD-LTE

LTE radio frame has fixed length of 10 ms

LTE radio frame is further divided into two half-frames of 5 ms each

Each half-frame is divided into 5 sub-frames of 1 ms each

Two special sub-frames for signalling, Eight ordinary sub-frames for data

Ordinary sub-frame is further divided into slot of .5 ms each

Symbols are put inside each sub-frame


EUTRAN Air Interface Overview - Adaptive Modulation

The UE estimates the quality in the downlink and signals it back to the eNodeB in the Channel Quality

Indicator (CQI).

The uplink reference signals sent by UE is used by the eNodeB to estimate the quality in the uplink.

The eNodeB decides which modulation technique should be used based on the quality of the downlink

and uplink radio environment

64 Quadrature Amplitude Modulation uses 2^6 = 64 combinations to carry 6 bits per symbol

16 Quadrature Amplitude Modulation uses 2^4 = 16 combinations to carry 4 bits per symbol

Quadrature Phase Shift Keying (QPSK) uses 2^2=4 combinations to carry 2 bits per symbol.


Bandwidth (MHz) 1.25 2.5 5 10 15 20

Radio frame (KHz) 10

Sub-carrier duration (ms) 1

Sub-carrier (spacing KHz) 15

Sampling (MHz) 1.92 3.84 7.68 15.36 23.04 30.72

FFT size 128 256 512 1024 1536 2048

Sub-carriers 76 151 301 601 901 1201

Guard sub-carriers 52 105 211 423 635 847

Resource block 6 12 25 50 75 100

Resource

element

Downlink Radio Resource


Downlink Radio Resource Resource block (RB) is allocated to each user.

One UE can be allocated multiple resource blocks based upon.

Scheduling decision is made every sub-frame level (1 ms)

Actual data is carried in physical shared channel (PDSCH)


OFDM Transmitter

OFDM Receiver

Source(s) 1: N QAM

Modulator

QAM symbol rate = N/T u symbols/sec

N symbol streams 1/ T u symbol/sec

IFFT OFDM symbols 1/ T u symbols/s

N :1 Useful OFDM symbols

E-UTRAN Downlink - Processing at eNodeB

For your reference


SC-FDMA (single carrier – frequency division multiple access)

UE doesn’t need entire spectrum so transmit on single carrier

Bandwidth of single carrier is determined by data rate required by user

Data is sent serially (Not parallel like in downlink by OFDMA)

Different modulation techniques - QPSK, 16QAM, 64QAM

Implemented using Discrete Fourier Transformation Spread OFDM transmission

Multiple antenna techniques (MIMO) – 1 (Tx) X 2 (Rx)

E-UTRAN Uplink - Processing at UE

For your reference


E-UTRAN Uplink Frame structure for Uplink is similar to downlink

Radio frame = 10 ms

Ten Sub-frame (1 ms) in Radio frame

Two slot in each sub-frame (.5 ms each)

7 SC-FDMA symbols

Each UE get Resource Block

QoS, UE buffer status, Uplink channel quality

Uplink scheduling is done by eNodeB

UE get consecutive resource blocks for uplink

User data is carried in Physical Uplink Shared Channel


EUTRAN Channel Structures

Logical channels define the type of information that is being carried (control or user data)

Transport channels define how information is transported (mapping to shared channels)

Physical channels – mapping to DL or UP physical resources (bits, symbols, modulation, radio

frames etc.) carry the transport channel data across the air interface.

Scheduling is most important - eNodeB manage DL and UL scheduling


UE Category 1 2 3 4 5

Uplink peak data rate (Mbps) 5.16 25.456 51.024 51.024 75.376

Downlink peak data rate (Mbps) 10.296 51.024 102.048 150.752 302.752

Highest downlink modulation 64 QAM 64 QAM 64 QAM 64 QAM 64 QAM

Highest uplink modulation 16 QAM 16 QAM 16 QAM 16 QAM 64 QAM

Downlink MIMO support Optional (1x2) Yes (2x2) Yes (2x2) Yes (2x2) Yes (4x4)

Maximum RF bandwidth 20 MHz 20 MHz 20 MHz 20 MHz 20 MHz

Rx diversity Yes Yes Yes Yes Yes

LTE UE Categories

Source: 3GPP TS 36.306 - E-UTRA User Equipment (UE)

Widely deployed

Wide LTE spectrum- 700 MHz to 2600 MHz

Harmonisation of radio spectrum is impacting UE capabilities

Supporting LTE band as wells as I-RAT capabilities

UE MIMO capabilities is impacting device complexities and cost


E-UTRAN Design Summary

Deciding RF spectrum (700 – 2690 MHz). FDD or TDD bands are defined

Deciding spectrum size within band (1.4 to 20 MHz)

LTE RF Design Overview

Link budget – cell radius (coverage sites)

Deciding LTE subscriber and services plan – Peak and average DL, UL

Adding capacity sites to meet subscriber bandwidth requirements

Offload scheme to optimise capacity sites

Inter-working with other technologies

Number of subs per eNodeB – Total and attached, active


LTE UE Mobility Management Three main states for mobility - IDLE, ACTIVE,DETACHED

LTE_IDLE:

State is power-conservation (No Tx and Rx from UE)

No context about the UE is stored in the eNB.

Location of the UE is only known in MME

MME knows only last Tracking Area (TA) before UE went idle

Tracking Area usually consist of multiple eNodeB

MME will page the UE if SGW has network initiated data for UE

LTE_ACTIVE:

UE has RRC connection with the eNodeB

UE is registered with the MME

UE has default PDN with PGW

MME knows the UE (Tracking Area which includes eNodeB)

UE can transmit/ receive data

LTE_DETACHED:

Transitory sate during UE power ON

UE is searching to register to network


LTE UE Mobility - Idle and Connected Mode

LTE_IDLE Mode Mobility

UE can move from one eNodeB to another

eNodeB is unaware of UE

MME know the last state based upon tracking area

information (TAI)

Idle mode mobility is controlled by MME

LTE_ACTIVE Mode Mobility

UE has RRC to eNodeB.

UE send measurement information

Source eNodeB initiate X2 handover if X2 link is up

Source eNodeB initiate MME controlled handover

eNodeB buffer data during handover


eNodeB

Operator’s

IP Services

Note: Refer to TS 36.300 and TS 23.401 for further details

UE

S2a

(PMIPv6, GRE

MIPv4 FACoA)

3GPP Access

E-UTRAN

PDN

Gateway

Serving

Gateway

PCRF

HSS

Gxc

(Gx+)

S11

(GTP-C)

S1-U

(GTP-U)

S2b

(PMIPv6,

GRE)

MME

S5 (PMIPv6, GRE)

S6a

(DIAMETER)

S1-MME

(S1-AP)

GERAN


SGSN

Trusted

Non-

3GPP IP

Access

Untrusted

Non-

3GPP IP

Access

S3

(GTP-C)

S12 (GTP-U)

S10

(GTP-C)

S5 (GTP-C, GTP-U)

Gx

(Gx+)

Gxb

(Gx+)

SWx (DIAMETER)


ePDG

3GPP

AAA

SWn

(TBD)

S6b

(DIAMETER)

SWm

(DIAMETER)

SGi

SWa

(TBD)

Gxa

(Gx+)

Rx+

eNodeB

UE

UE

SWu (IKEv2,

MOBIKE, IPSec)

• RRC Management. Layer-2 bridge between UE and EPC

• Inter-eNodeB handover using X2 interface

• IP header compression & Encryption of user data stream

• MME selection at UE attachment and update

• Routing of User Plane data towards SGW

• Routing of Control Plane data towards MME

• UL bearer level rate enforcement based on AMBR and MBR

• UL and DL bearer level admission control

• UL Transport level packet marking (EPS bearer QCI => DSCP)

• Scheduling and transmission of paging messages (from MME) and

broadcast information (from MME or O&M)

• Measurement and reporting mobility and scheduling


Comparing GSM, UMTS and LTE Air Interface

Number of states for UE (RRC states) are reduced from five to three

UTRAN (DETACHED, IDLE, URA_PCH, CELL_FACH, CELL_DCH)

EUTRAN (DETACHED, IDLE and CONNECTED)

UTRAN has two additional states CELL_FACH and CELL-PCH to optimise signalling


UTRAN Enhancement for Signalling Optimisation - 3GPP HSPA Radio Resource Control (RRC) States

1. RRC states in WCDMA RAN are designed to allow low UE power consumption, high network efficiency, low response times to services

2. Large amount of data is carried on

Cell_DCH state

3. Small amount of data is carried on Cell_FACH

4. Cell_URA and Cell_PCH state is used for UE power saving

Cell DCH

Cell FACH

IDLE

Cell/URA

PCH

>0.5 kB

Data volumes

<0.5 kB

UE power

consumption

>200 mA

>100 mA

<5 mA

<5 mA

= RRC connected = IDLE

RAB

setup





LTE E-UTRAN

EPS Gateways

DNS, IP and NAT

Mobile Transport

LTE QoS and Policy




Summary, References

Agenda




Mobility Management Entity (MME)

Operator’s

IP Services


CN Core Network

eNBs eNodeBs

HSS Home Subscriber Server

MME Mobility Management Entity

NAS Non Access Stratum

SGSN Serving GPRS Support Node

UE

S2a

(PMIPv6, GRE

MIPv4 FACoA)

3GPP Access

E-UTRAN

PDN

Gateway

Serving

Gateway eNodeB

PCRF

HSS

Gxc

(Gx+)

S11

(GTP-C)

S1-U

(GTP-U)

S2b

(PMIPv6,

GRE)

S5 (PMIPv6, GRE)

S6a

(DIAMETER)

S1-MME

(S1-AP)

GERAN


SGSN

Trusted

Non-3GPP

IP Access

Untrusted

Non-3GPP

IP Access

S3

(GTP-C)

S12 (GTP-U)

S10

(GTP-C)

S5 (GTP-C, GTP-U)

Gx

(Gx+)

Gxb

(Gx+)

SWx (DIAMETER)


ePDG

3GPP

AAA

SWn

(TBD)

S6b

(DIAMETER)

SWm

(DIAMETER)

SGi

SWa

(TBD)

Gxa

(Gx+)

Rx+

UE

UE

MME

SWu (IKEv2,

MOBIKE, IPSec)

• Signalling anchor point for eNodeB and UE

• NAS signalling (control plane signalling to the UE)

• NAS signalling security (ciphering and integrity protection)

• PGW and SGW selection during bearer establishment

• SGSN selection for handovers to 2G/3G using S3

• Bearer management including dedicated bearer establishment

• Tracking Area list management for UE

• Paging management (Intelligent paging)

• MME pooling to reduce signalling, increase availability

• Inter-MME handover using S10 interface

• Support roaming 41


MME Interfaces Design Considerations

S1-MME (Towards eNodeB) Number of eNodeB

SCTP Multihoming

MME Pooling

TAI list management S6a (Towards HSS) Number of HSS and frontends

Logic for HSS selection

SCTP multihoming

S13 (Toward EIR) Co-located with HSS

EIR supports DIAMETER interface?

DNS Logic for gateway selection – priority, weight,

collocation etc.

Fall back logic for gateway selection

S11 (Towards SGW)

DSCP Marking

Security Gateway

DSCP Marking

LI


MME Pooling Strategy

Region B

MME POOL

MME A

MME C

Region A

MME B

Region C

eNodeB has multiple active S1-MME links to MME’s in pool

Number of MME’s clustered in pool across geographical area

MME in pool is identified by Code & Group Identifier

All MME in pool will have same Group identifier

eNodeB decide MME based upon weight, load etc.


Benefits of MME Pooling

Enables geographical redundancy, as a pool can be distributed

across sites

Increases overall capacity, as load sharing across the pool

Converts inter-MME Tracking Area Updates (TAUs) to intra-MME

TAUs for moves between the MMEs of the same pool.

Reduces signalling load & transfer delay

Easy introduction of new MME in pool.

Eliminates single point of failure for eNodeB and MME.

Increase MME availability


MME Heuristic Paging To limit the volume of unnecessary paging related signalling

MME maintains a list of n last heard from eNB‘s inside the TAI for the UE

MME uses Tracking Area Updates to build this local table

For incoming page request for the idle mode user, the MME attempts to

page the user at the last heard from eNB

If no response then MME will page last n heard eNB

If still no response then page all eNB in TAI


MME Design Parameters MME parameters Per sub/Hr

1 Initial UE Attach/Detach

2 Bearer activation/deactivation per PDN session

3 PDN connection setup/tear down

4 Ingress and Egress paging

5 Number of eNodeB

6 Idle-active/active-idle transactions

7 Number of bearer per PDN session

8 Number of PDN sessions

9 Intra-MME S1 handover with SGW relocation

10 Intra-MME S1 handover without SGW relocation

11 Intra-MME X2 handover

12 Inter-MME handover

13 Intra-MME tracking area updates

14 Inter-MME tracking area updates

For your reference


Serving Gateway (SGW)

Operator’s

IP Services

Note: Refer to TS 23.401 for further details

• One SGW at a time per UE

• Anchor point for inter- eNodeB handover if no X2 interface

• Mobility anchoring for inter-3GPP mobility (terminating S4 and

relaying traffic between 2G/3G system and PGW)

• Packet buffering during handover, normal routing and forwarding

• Uplink and Downlink transport level packet marking (DSCP)

•Lawful Interception

• Accounting ;user and QCI granularity for inter-operator charging

• Uplink and Downlink charging per UE, PDN, and QCI

• ECM-IDLE mode downlink packet buffering and initiation of

network triggered service request procedure (towards MME)

QCI QoS Class Identifier

PDN Packet Data Network

UE

S2a

(PMIPv6, GRE

MIPv4 FACoA)

3GPP Access

E-UTRAN

PDN

Gateway eNodeB

PCRF

HSS

Gxc

(Gx+)

S11

(GTP-C)

S1-U

(GTP-U)

S2b

(PMIPv6,

GRE)

MME

S5 (PMIPv6, GRE)

S6a

(DIAMETER)

S1-MME

(S1-AP)

GERAN


SGSN

Trusted

Non-3GPP

IP Access

Untrusted

Non-

3GPP IP

Access

S3

(GTP-C)

S12 (GTP-U)

S10

(GTP-C)

S5 (GTP-C, GTP-U)

Gx

(Gx+)

Gxb

(Gx+)

SWx (DIAMETER)


ePDG

3GPP

AAA

SWn

(TBD)

S6b

(DIAMETER)

SWm

(DIAMETER)

SGi

SWa

(TBD)

Gxa

(Gx+)

Rx+

UE

UE

Serving

Gateway

SWu (IKEv2,

MOBIKE, IPSec)

47


SGW Interfaces Design Considerations

S1-U (Towards eNodeB) DSCP marking

Security Gateway

S11 (Towards MME) Control signalling messages

DSCP marking

S5/S8 (Towards PGW) Control and bearer tunnels towards PGW

DSCP marking

Optional CDRs

LI


PDN Gateway (PGW)


AMBR Aggregate Maximum Bit Rate

DPI Deep Packet Inspection

MBR Maximum Bit Rate

Non-GBR Non Guaranteed Bit Rate

PDN Packet Data Network

RAT Radio Access Technology

• Provide UE IP address allocation (IPv4, IPv6, IPv4/v6 both)

• De-encapsulation GTP to IP traffic. Connectivity to IP services

• DHCPv4 and DHCPv6 functions (client, relay and server)

• UE can connect to more than one PGW

• Deep Packet and Deep Flow inspection, differentiated billing

• Lawful Interception

• Uplink and Downlink transport level packet marking (DSCP)

• Downlink rate enforcement based on AMBR (e.g. for all Non-GBR)

• Downlink rate enforcement based on MBR of same QoS

• Optional Pre-rel 8 SGSN interface Gn/Gp UE

S2a

(PMIPv6, GRE

MIPv4 FACoA)

3GPP Access

E-UTRAN

Serving

Gateway eNodeB

PCRF

Operator’s

IP Services

HSS

Gxc

(Gx+)

S11

(GTP-C)

S1-U

(GTP-U)

S2b

(PMIPv6,

GRE)

MME

S5 (PMIPv6, GRE)

S6a

(DIAMETER)

S1-MME

(S1-AP)

GERAN


SGSN

Trusted

Non-3GPP

IP Access

Untrusted

Non-3GPP

IP Access

S3

(GTP-C)

S12 (GTP-U)

S10

(GTP-C)

S5 (GTP-C, GTP-U)

Gx

(Gx+)

Gxb

(Gx+)

SWx (DIAMETER)


ePDG

3GPP

AAA

SWn

(TBD)

S6b

(DIAMETER)

SWm

(DIAMETER)

SGi

SWa

(TBD)

Gxa

(Gx+)

Rx+

UE

UE

PDN

Gateway

SWu (IKEv2,

MOBIKE, IPSec)

49


PGW Interfaces Design Considerations

Gx (Towards PCRF) Most important for LTE

Traffic based upon use cases, volume reporting

SCTP multihoming

Gy (Towards pre-paid platforms) Use cases

SCTP multihoming

Are pre-paid and post-paid subscribers sent to OCS

S5/S8 (Towards SGW) Control and user tunnels

DSCP marking

AAA (For authentication, authorisation) Requirement for AAA accounting

Delayed sending of Create-Session-Response

LI

S12 - Direct Tunnel

For 3G RNC direct tunnel


PGW General Design Considerations

CDRs Fields required in CDR

File format

Onboard storage, external CGF

Deep packet Inspections Support for enhanced charging

Dimensioning depend upon number of charging rules

IP Addressing IPv4, IPv4IPv6?

Address allocation – DHCP, AAA, local pool?

Requirement for NATing on PGW

Inter-mobile traffic

APN Consumer only or corporate

Defining virtual APNs

Bearers Max number of default bearers – Max PDNs

Max number of dedicated bearers – Max differentiated services


SGW/PGW Design Parameters

1 Number of Simultaneous active subs

2 Number of subs using IPv4 (% IPv4 PDN)

3 Number of subs using IPv6 (% IPv6 PDN)

4 Number of subs using IPv4v6 (% IPv4v6 PDN)

5 Number of bearer activation/deactivation per PDN/Hr

6 Number of average bearer per PDN connection

7 Number of PDN connection setup/tear down per sub/Hr

8 Number of PDN session per sub

9 Number of idle-active/active-idle transaction per sub/Hr

10 Number of intra SGW handover per sub/Hr

11 Number of Inter SGW handover per sub/Hr

12 Number of inter-system handover per sub/Hr


For your reference



PCEF (Policy Control Enforcement Function) Design

1 No of flow /subscriber

2 % of deep flow inspection

3 % of deep packet inspection

4 % of PDN connection using Gy (pre-paid)

5 % of PDN connection using Gx (Policy interface)

6 Number of Gx Transactions per PDN Connection/Hr

6 Number of Dynamic Rules

Data Subs Traffic

1 % of subs simultaneously sending/receiving data

2 Average packet size for DL

3 Average packet size for UL

SGW/PGW Design Parameters (Cont’d) For your reference


LTE standards have strict design requirements for latency

Control < 100 ms (idle to active)

User <5 ms (one way UE to RAN edge). Network latency is additional

LTE Latency is broadly divided into

E-UTRAN latency (UE to eNodeB)

Network latency (eNodeB to core network)

E-UTRAN latency depend upon

Radio quality, resources (capacity) and UE category

Network Latency depend upon

Processing delay – depend on CPU, memory and load

Serialisation delay- depend on packet size and interface speed

Queuing delay – depend upon packets in queue & serialisation

Propagation delay – Depend on distance and media

Latency Considerations for LTE Design

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_white_paper09186a00800a8993.shtml

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_white_paper09186a00800a8993.shtml


Throughput vs. Latency *

Throughput at applications layer depend many factors such as

Radio conditions – More throughput near cell compared to edge

Latency - Increased latency reduces overall throughput

Packet loss - Lead to re-transmissions and less throughput at application layer

Packet size - Larger packer size has better throughput

http://www.silver-peak.com/calculator/ * LTSi and other published references


Control Plan Latency Requirements

Camped-state (idle)

Active (Cell_DCH)

Dormant (Cell_PCH)

Less than 100msec

Less than 50msec

C-Plane Latency (ref TR25.913, V8.0.0) C-Plane Latency (ref TR36.913, V9.0.0)

Camped - state

Active (in-sync)

Active – “dormant” (un-sync)

Less than 50 ms

Less than 10 ms

• Idle to active < 100 ms when user

plane is established

• Dormant to Active <50 ms

• Idle to active <50 ms when user

plane is established

• Dormant to Active <10 ms

Control Plane (C-Plane) – Relates to completion of E-UTRAN and NAS signalling

User Plan (U-Plane) – Relates to establishment of bearer path

For your reference


User Plane Latency- (3GPP TS25.912)

User plane Latency Refers to Establishment of Bearer Path to SGW

Description Duration

LTE_IDLELTE_ACTIVE delay (C-plane establishment) 47.5ms + 2 * Ts1c

TTI for UL DATA PACKET 1ms

HARQ Retransmission (@ 30%) 0.3 * 5ms

eNB Processing Delay (Uu –> S1-U) 1ms

U-plane establishment delay (RAN edge node) 51ms + 2 * Ts1c

S1-U Transfer delay Ts1u (1ms ~ 15ms)

UPE Processing delay (including context retrieval) 10ms

U-plane establishment delay (Serving GW) 61ms + 2 * Ts1c + Ts1u

Ts1c = 2ms – 15 ms

Ts1u = 1ms – 15 ms

For your reference


QCI

Value

Resource

Type

Priority Delay Budget (1)

Error Loss

Rate (2)

Example Services

1 (3) 2 100 ms 10-2 Conversational Voice

2 (3)

GBR

4 150 ms 10-3 Conversational Video (Live Streaming)

3 (3) 3 50 ms 10-3 Real Time Gaming

4 (3) 5 300 ms 10-6 Non-Conversational Video (Buffered Streaming)

5 (3) 1 100 ms 10-6 IMS Signalling

6 (4)

6

300 ms

10-6

Video (Buffered Streaming)

TCP-based (e.g., www, e-mail, chat, ftp, p2p file sharing,

progressive video, etc.)

7 (3) Non-GBR 7 100 ms

10-3

Voice, Video (Live Streaming), Interactive Gaming

8 (5)

8

300 ms

10-6

Video (Buffered Streaming)

TCP-based (e.g., www, e-mail, chat, ftp, p2p sharing,

progressive download, etc.)

9 (6) 9

Overall Delay Budget for Applications 3GPP TR23.401 V8.1.0


Distributed

MME+SGSN

+GGSN

+SGW+PGW

Distributed

MME+SGSN

+GGSN

+SGW+PGW

Distributed

MME+SGSN

Distributed

MME+SGSN

Centralised

SGW+PGW

+GGSN

Distributed

MME+SGSN

+GGSN

SGW+PGW

IP Backbone

LTE

2.5G

3G

Centralised

SGSN+GGSN

MME+SGW+PGW

IP Backbone

LTE

2.5G

3G

IP Backbone

LTE

2.5G

3G

Distributed

SGW+PGW+GGSN

Distributed

SGW+PGW+GGSN

Centralised

MME+SGSN IP Backbone

LTE

2.5G

3G

Optimising Mobile Gateway Design

Why combo and which nodes to combine?


Gateway Placements Considerations Entity Placement Considerations

MME Moderate distribution

Latency <50ms from eNB to MME (S1-MME),

Faster signalling/call setup

Use MME pooling - scaling & geographical redundancy

SGW/PGW Distributed, close to edge

Latency <50 ms from eNB (S1-U), better user experience

Co-locate/Co-host SGW/PGW if design permit

Use Mobile Service Edge gateway (MSEG) to offload selected user traffic

HSS Centralised/Moderate distribution

Latency <100 ms. Latency impact default bearer set-up

Partition HSS as front end and backend if design permit

Front-end co-locate with MME if possible

SPR/DBE Centralised

Latency <100 ms. Latency impact database query, sync

Replicate database at multiple locations

Co-locate with HSS backend

SPR/DBE Subscriber Profile Repository , Database Entity


Gateway Placements Considerations Entity Placement Considerations

PCRF,

Balance

Manager,

OCS/OFCS

Centralised

Latency <100 ms. Latency impact policy download, updates

Can share database with HSS

Balance Manager, Online Charging co-located with PCRF

DNS Tracking Area/APN DNS – Used by MME, co-locate with MME

Mobile DNS – Used by UE, distributed. Co-located with PGW

Internet DNS – Used for inbound query, Centralised

Roam DNS – Used by roaming partners, Centralised

Infrastructure DNS – Used by internal infrastructures, Centralised

AAA Centralised

Used for ePDG (3GPP) – centralised

Infra. device authentication - centralised

DHCP Centralised

DHCPv6 for IP address allocation

OCS – Online Charging system, OFCS – Offline Charging System





LTE E-UTRAN

EPS Gateways

DNS, IP and NAT

Mobile Transport

LTE QoS and Policy




Summary, References

Agenda




DNS Design

DNS Functional description

Tracking Area/APN DNS Initial Attach

• MME perform APN query to find PGW, MME perform track Area query to find SGW

Handover with TAI change & Tracking Area Updates

• MME perform track query to determine SGW

• MME select closest SGW to PGW send create session request

Mobile DNS • LTE UE query mobile DNS to resolve “Host Name” to IP address

• Can be DNS64 (LTE UE with IPv6), DNS44 (LTE UE with IPv4)

Internet DNS • Mainly root DNS. Need DNS64 capability

Infrastructure DNS • Name resolution in the OAM (e.g. admin to login to the device, SNMP)

Roam DNS • Used for roaming traffic. Need IPv6 capability of roaming transport is IPv6

E-UTRAN

PDN Gateway

Serving Gateway

eNodeB

PCRF

Operator’s IP Services

HSS

Gxc (Gx+)

S11 (GTP-C)

S1-U (GTP-U)

MME

S6a (DIAMETER)

S1-MME (S1-AP)

S5 (GTP-C,GTP-U)

Gx (Gx+)

SWx (DIAMETER)

3GPP AAA S6b

(DIAMETER)

SGi

Rx+

UE

Tracking Area/APN DNS

Mobile DNS S10 (GTP-C

Infrastructure DNS Internet DNS

Roam DNS


Greenfield LTE deployments

Introduce dual stack LTE UE

Transport – Dual stack (Preference) or 6PE, 6VPE

All LTE Gateway interfaces should be IPv6

Internal Apps (i.e. IMS, Video etc.) should be IPv6

NAT64 for IPv4 internet

Deploying LTE in existing network

Introduce dual stack LTE UE

IPv6 for MME(S1-MME, S11), SGW(S1-U, S5/S8), PGW(S5/S8, SGi)

Transport – 6PE, 6VPE to support LTE

Convert Internal Apps (i.e. IMS, Video etc.) to IPv6

Create Services islands- served by IPv4, IPv6

NAT64 for IPv4 internet

Integrate with existing 2.5/3G network on IPv4

IPv6 Planning Design Considerations


Interface ID

/32 /64 /16

128 Bits

/48

Regions (/40 256 regions)

Functions within region (/48 provides 256 functions)

(eNodeB, IP-BH, MPLS Core, MME, HSS, SGW, PGW,

Data Centre, Security etc.) Devices and subnets for each devices

(48 – 64 provides 65,000 subnet of /64)

IPv6 Subnet Considerations for Infrastructure

Infrastructure subnets are typically not announced to internet

Use proper summarisation to optimise routing scalability

Point-to-point Interface address: Choices - /127, /64

Loopback /128

Subnetting Example (Assuming - /32 for Infrastructure)


Interface ID

/32 /64 /16

128 Bits

/48

Regions (/40 256 regions)

Services/APN within region (/48 provides 256 )

(IMS, Internet, Video, M2M, Message, Enterprise etc.) Devices and subnets for each devices **

(48 – 64 provides 65K users within each service/APN)

IPv6 Subnet Considerations for Subscribers

LTE Users IPv6 subnets are announced to internet

Separate block for each service i.e. APN/virtual APN

Allocation strategy – Local Pool, AAA, DHCPv6

Subnet strategy – Ability to identify services, easy growth

Subnetting Example (Assuming /32 for LTE Users)

** For wireless routers gateway allocated smaller block i.e. /60, /56 or /48 etc.


3GPP Rel-8 onward

Dual stack User send one PDP request “IPv4v6”

Gateway will create bearer; Allocate IPv4 & IPv6 to same bearer

For GPRS network single bearer is applicable from 3GPP Rel-9 onward

Prior to 3GPP Rel-8 (LTE introduced from Rel-8 onward)

Dual-stack User sends two PDP requests- One of for IPv4 and another for IPv6

Gateway creates two unique PDP-contexts- One for IPv4 and another for IPv6.

Transport Traffic- Bearer setup for dual stack UE

Dual stack

Dual stack


Create Session Request (APN, QoS,

PDN-type=IPv6,…)

Create Session Request (APN, QoS,

PDN-type=IPv6,…)

Create Session Reply (UE Prefix,

Protocol config options (e.g. DNS-server list,…),

cause)

Create Session Reply (UE Prefix,

Protocol config options, cause)

AAA DHCP PGW SGW MME

Attach Request

Attach Accept

Router Solicitation

Router Advertisement

UE

DHCPv6 – Information Request

DHCPv6 PD Option 3

DHCPv6 – Confirm

DHCPv6 – Relay Forward

DHCPv6 – confirm

DHCPv6 – Reply forward DHCPv6 – Relay Reply

Prefix Retrieval Option 2

Option 1 /64 prefix allocation from local pool

SLAAC

Prefix communicated to SGW/MME

empty UE IP-address for dynamic allocation

/64 prefix allocation: 3 Options: Local Pool, AAA, DHCP

UE ignore IPv6 prefix

received in attach

MME compare requested PDP types

(IPv4, IPv6, IPv4v6) with HSS

RA contain the same IPv6 prefix as

the one provided during default bearer

establishment UE request additional

information

Subscriber IPv6 Address Allocation For your reference


Large Scale NAT -Where to Place the NAT Function?

PGW & NAT44/64

eNB

IPv4

private IPv4

IPv4 Public

public IPv4

SGW

NAT44/64

PGW eNB

IPv4 IPv4

private IPv4 private IPv4

IPv4 Public

public IPv4

CGN/ CGv6

SGW

NAT

NAT44/64

NAT

Option 1: NAT on Mobile Gateway (Distributed)

Option 2: NAT on Router (Centralised)

Key Benefits:

• Subscriber aware NAT

- per subscriber control

- per subscriber accounting

• Large Scale (further

enhanced by distribution)

• Highly available

(incl. geo-redundancy)

Key Benefits:

• Integrated NAT for multiple

administrative domains

(operational separation)

• Large Scale

• Overlapping private IPv4

domains (e.g. w/ VPNs)

• Intelligent routing to LSN


Intelligent Routing Large Scale NAT

LSN announce their availability with dynamic state Mobile Gateway select the best route and forward traffic

Internet

CGN2

CGN1

Mobile gateway

PGW

User

1

2

Service.Transport-Attachment: “VPN Blue”, LSN1

Service.Type: NAT64 or NAT44

Service.Load.Bandwidth.Available: 10 Gbps

Service.Load.Bandwidth.10min-average: 2.3 Gbps

Service.Load.Bindings.Available: 2.000.000

Service.Load.Bindings.10-min-average: 500.000

Service.Transport-Attachment: “VPN-Blue”, LSN2

Service.Type: NAT64 or NAT44

Service.Load.Bandwidth.Available: 10 Gbps

Service.Load.Bandwidth.10min-average: 5 Gbps

Service.Load.Bindings.Available: 3.000.000

Service.Load.Bindings.10-min-average: 500.000

For your reference

FUTURE





LTE E-UTRAN

EPS Gateways

DNS, IP and NAT

Mobile Transport

LTE QoS and Policy




Summary, References

Agenda




Transport Planning – Mobile Backhaul, Core

UE trafficserved by eNodeBs

Last mile

serves eNodeBs

aggregationcore

eNodeBs

Transport

network

External

Networks

Mobile Backhaul – Access ring

Bandwidth- Full access capacity (Peak rate)

Resiliency, failover, dual homing

Routing - L2/L3 based on requirements.

L3 is recommended

Core/Super backbone

Bandwidth - mean average with over subscription

Connecting backhaul from all regions

Regional and National Data Centre

Internet, roaming partners, Applications

Routing – MPLS VPN/Global routing

Mobile Backhaul – Pre-agg/Agg

Bandwidth- mean average with oversubscription

Aggregating access and pre-agg rings

Agile & resilient architecture to backhaul BW

Routing- L2/L3VPN, Any-to-any routing


Mobile Backhaul Bandwidth - Radio Behaviour

Spectral

Efficiencybps/Hz

Bandwidth, Hz

64QAM

16QAM

QPSK

cell

average

Busy TimeMore averaging

UE1

UE2

UE3

: : :

Many

UEs

Quiet TimeMore variation

UE1

64QAMCell average

UE1

bps/Hz

QPSKCell average

UE1

bps/Hz

Hz Hz

a) Many UEs / cell b) One UE with a good link c) One UE, weak link

BW is designed on per cell/sector, including each radio type

Busy time – averaged across all users

Quiet Time – one/two users (Utilise Peak bandwidth)

For multi-technology radio- sum of BW for each technology

Last mile bandwidth- Planned with Peak

Aggregation/Core – Planned with Meantime Average

Manage over subscription


Mobile Backhaul Bandwidth – Overheads

S1 User plane traffic

(for 3 cells)

+Control Plane

+X2 U and C-plane

+OA&M, Sync, etc

+Transport protocol overhead

+IPsec overhead (optional)

Core network

RAN

1 2 3 4

X-2 user & control: ~ 3-5% (Applies only to Meantime Avg.)

OA&M, Sync: <1% covering S1-MME, OAM etc.

Transport GTP /Mobile IP Tunnel: ~10%

IPSec: Overhead of ~14%. Total of 1+2+3+4 ~25%


Mean Peak overhead 4% overhead 10% overhead 25%

(as load->

infinity)

(lowest

load)

busy time

mean peak

busy time

mean peak

busy time

mean peak

busy time

mean peak

DL 1: 2x2, 10 MHz, cat2 (50 Mbps) 10.5 37.8 31.5 37.8 1.3 0 36.0 41.6 41.0 47.3

DL 2: 2x2, 10 MHz, cat3 (100 Mbps) 11.0 58.5 33.0 58.5 1.3 0 37.8 64.4 42.9 73.2

DL 3: 2x2, 20 MHz, cat3 (100 Mbps) 20.5 95.7 61.5 95.7 2.5 0 70.4 105.3 80.0 119.6

DL 4: 2x2, 20 MHz, cat4 (150 Mbps) 21.0 117.7 63.0 117.7 2.5 0 72.1 129.5 81.9 147.1

DL 5: 4x2, 20 MHz, cat4 (150 Mbps) 25.0 123.1 75.0 123.1 3.0 0 85.8 135.4 97.5 153.9

UL 1: 1x2, 10 MHz, cat3 (50 Mbps) 8.0 20.8 24.0 20.8 1.0 0 27.5 22.8 31.2 26.0

UL 2: 1x2, 20 MHz, cat3 (50 Mbps) 15.0 38.2 45.0 38.2 1.8 0 51.5 42.0 58.5 47.7

UL 3: 1x2, 20 MHz, cat5 (75 Mbps) 16.0 47.8 48.0 47.8 1.9 0 54.9 52.5 62.4 59.7

UL 4: 1x2, 20 MHz, cat3 (50

Mbps)*14.0 46.9 42.0 46.9 1.7 0 48.0 51.6 54.6 58.6

UL 5: 1x4, 20 MHz, cat3 (50 Mbps) 26.0 46.2 78.0 46.2 3.1 0 89.2 50.8 101.4 57.8

Scenario, from TUDR studyTri-cell Tput

Total U-plane + Transport overhead

No IPsec IPsecX2 OverheadSingle Cell Single base station

All values in Mbps

Mobile Backhaul Bandwidth – Last Mile Use quiet time peak for each cell

Not all cells will peak at same time- Factor this for 3/6 sector eNB

Number of eNodeB in access ring - Number of hops, total bandwidth

Access ring will have dual homing to pre-agg

Total BW = DL + UL (20MHz, 2X2 DL MIMO, 1X2 UL MIMO) 105.3+42 ~ 145 Mbps


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3 4 5 6 7 8 9 10

Gbps

Tricell eNodeBs

5: 4x2, 20 MHz, cat4 (150 Mbps)no IPsec





0.01

0.1

1

10

100

1000

1 10 100 1000 10000

Gbps

Tricell eNodeBs

single cell eNodeBs:

1 2 3 6 9 12 15 18 21 24 27 30

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3 4 5 6 7 8 9 10

Gbps

Tricell eNodeBs

5: 1x4, 20 MHz, cat3 (50 Mbps) no IPsec

4: 1x2, 20 MHz, cat3 (50 Mbps)*no IPsec




0.01

0.1

1

10

100

1000

1 10 100 1000 10000

Gbps

Tricell eNodeBs

single cell eNodeBs:

1 2 3 6 9 12 15 18 21 24 27 30

Mobile Backhaul Bandwidth – Agg & Core D

ow

n lin

k

Uplin

k

Total BW = DL + UL ; For 10,000 eNB (Tricell) = 700+500 = 1200 Gbps

Per eNB in Core ~ 1200/10,000 ~ 120 Mbps





LTE E-UTRAN

EPS Gateways

DNS, IP and NAT

Mobile Transport

LTE QoS and Policy




Summary, References

Agenda




Agg-1 Agg-3 Agg-2

S1-U, S1-C, X2

Agg-3

UE

MME

S1-C, S-10

S-11, Gn

Cell site router

P-GW

S-GW

S1-U, S-11, Gn

Regional

Data Centre

Main

Data Centre

Marks traffic with appropriate DSCP (QCI) values

Traffic shaping / queuing / prioritisation

Hierarchical Traffic shaping with policy maps

Maps DSCP values to MPLS EXP

Traffic reclassification

eNB

LTE QoS Deployment - Example


Hierarchical QoS Deployment Hierarchical QoS is a queuing framework that allows for multiple levels of

queue and different treatments for each queue

In the example below 1 Gbps can be divided into four logical link of 200

Mbps each. Separate queuing mechanism can be applied to each flow


3GPP Policy Control Architecture (PCC) General PCC Principles

Traffic classifed as Service Data Flows

Charging and QoS control, Gate control at PCEF

QoS policies propagated to the mobile edge

Push and Pull models

Session update notification

Diameter based interface (Gx, Rx, Gy)

3G PCEF

Use for enforcing policy

Co-located with PGW and SGW

Subscriber Profile repository (SPR)

Database used to store per user policy rules

Integrated with main HSS

Integrated with Top-up server (For pre-paid subs)

OCS and OFCS

Online Charging (OCS) for pre-paid subscriber billing

Offline Charging (OFCS) for post-paid subscriber billing

Mobile Gateway

(inc. PCEF)

PCRF

OCS OFCS

Gx

Rx

Sp

SPR

Gy Gz

Applications

http://www.nortel.com/


QoS Parameter in Transport – DSCP, Precedence, TOS

DSCP – differentiated services Code Points

IPv4 header contain 8 bits for

Type of Service (TOS) which is

used for QoS

Application dataTCP HeaderEthernet Header Ethernet Trailer

Ethernet frame

IP Header

version(4 bits)

header length

Type of Service/TOS(8 bits)

Total Length (in bytes) (16 bits)

Identification (16 bits)flags

(3 bits)Fragment Offset (13 bits)

Source IP address (32 bits)

Destination IP address (32 bits)

TTL Time-to-Live(8 bits)

Protocol(8 bits)

Header Checksum (16 bits)

32 bits





LTE E-UTRAN

EPS Gateways

DNS, IP and NAT

Mobile Transport

LTE QoS and Policy




Summary, References

Agenda




LTE Roaming - Infrastructures IP Exchange (IPX)

1. IP Exchange (IPX) is next-gen innovations for UMTS/LTE data roaming

2. Any-to-any roaming architecture

1. IPX combines roaming between large ecosystem service providers (mobile, fixed, ISP,

Application Service Providers etc.)

2. End-to-end QoS for roaming and interworking

3. Any IP services on a bilateral basis with end-to-end QoS and interconnect charging

4. IPX-proxy provide service-interworking, intelligent routing at Application layer **

3. IPX charging – Enhanced service aware billing – volume, type, discounts etc.

Service

Provider-1

Service

Provider-2

Service

Network-3

IPX Service

Provider-1

IPX Service

Provider-2

DNS root

database,

ENUM

IPX

Proxy IPX Proxy

End-to-end SLA


LTE Roaming – Home Routed Mobile register in visited network radio

eNodeB send attach request to visited MME

Visited MME forward attach request to home HSS using S6a interface

UE is authenticated from Home HSS

Visited MME perform node selection - SGW and PGW

For home routed traffic, visited SGW will forward entire traffic, all APN to home PGW

Diameter interfaces inter-PLMN: S6a, S6d, S9

LTE roaming is new and very few case studies

Deployed by majority of LTE operators

S6a

HSS

S8

S3

S1 - MME

S10

UTRAN

GERAN

SGSN

MME

S11

Serving Gateway

UE

“ LTE

- Uu

”

E - UTRAN

S12

HPLMN

VPLMN

PCRF

Gx Rx

SGi Operator’s IP

Services

PDN

Gateway

S 1 - U

S4

Home-Routed

From TS 23.401


LTE Roaming – Local Breakout (From TS 23.401)

Mobile register in visited network radio. eNodeB send attach request to visited MME

Visited MME forward attach request to home HSS using S6a interface

UE is authenticated from Home HSS. Visited MME perform node selection - SGW

Visited MME select PGW based upon APN type

For default PDN MME select local PGW

Traffic for other PDN e.g. VoLTE, video, VPN, enterprise customer etc. routed to home PGW

Bulk of traffic is routed locally

Local Breakout for all services.

S6a

HSS

S 5

S3 S1 - MME

S10

GERAN

UTRAN

S G SN

MME

S11

Serving G ateway UE

" LTE - Uu" E - UTRAN

S4

HPLMN

VPLMN

V - PCRF

Gx

SGi

PDN G ateway

S1 - U

H - PCRF

S9

Home Operator’s IP

Services

Rx

Visited Oper ator PDN

S12

S6a

HSS

S3

S1-MME

S10

UTRAN

SGSN

MME

S11

Serving Gateway

S5

UE

LTE-Uu

E-UTRAN

S4

HPLMN

VPLMN

V-PCRF

Gx

SGi PDN

Gateway

S1-U

H-PCRF

S9

Visited Operator's IP

Services

Rx

GERAN

S12

Local Breakout default APN, other APN home routed


Se

rvin

g N

od

e

AN

Home Node

Mobile Node

Provider Apps User Apps

USIM

4

1

1

1

1

2

2

1 3

Transport

Application

Network

1

2

3

4

Network Access Security in Radio Access

Network Domain Network security for signalling & user data

User Domain Security for mobile

Application Domain User & Apps security

3GPP TS 33.401 Security Standards

UE Transport Mobile Packet Core & Apps


LTE Network Security Threats

· Rogue eNB connecting to MME.

· Resource Exhaustion on MME (too many

authentication requests from eNB)

· Mobile to Mobile Spewing Attacks

· DOS Attacks in downlink direction from Internet

· TCP based attacks from Internet (Syn, session hijack, resource exhaustion etc.)

· UDP Based attacks like Smurf attack.

· ICMP Attacks like ping of death. Fragmentation attacks.

· Layer 4 protocol anomalies attacks

· Malware/Spyware prevention

· Rogue MME connecting to HSS or PCRF

· HSS, PCRF protections against DOS/DDOS attacks

· Database (Sp) must be protected against protocol anomalies attacks

like SQL Slammer worm or resource consumption attacks.

· CDR protection against manipulation by both internal or external

attackers.


Security for Roaming Traffic

IPSec tunnel between home and visited DRA for control traffic

User authentication traffic between vHSS and hHDSS

Policy traffic between hPCRF and vPCRF

IPX/GRX firewall to for user and control plane roaming traffic

For local breakout visited network provide internet security

UE UE

vPCRF hPCRF

PGW SGW eNB

MME

PGW SGW

MME

eNB

Home Network

Transit IP Network(s)

Visited Network

Home routed (HR) traffic

Local breakout (LBO)

GRX FW (User plane)

vHSS hHSS

vDRA hDRA Control (IPSec)


Assess network readiness for LTE. This will help operationalising LTE quickly

Radio planning – Spectrum, bandwidth, re-farming existing spectrum

Base station planning - Reuse existing UTRAN, new sites

Backhaul planning – major upgrade to IP/MPLS based backhaul

Assess & Develop IP Skill set. Skill gaps among RF, BTS & Core engrs reduced

Training staff in LTE, IMS, IP Routing etc.

Business Planning

Service plan, New Applications, New Subscribers

End-to-end LTE/EPS Design

Designing whole network aligning with business objectives

Radio, Transport, Gateways, Data Centre, Applications


Prepare and Design


Market by market field trials with real users

Develop and customise LTE KPI, correlate KPI across multiple devices/vendors

Develop operations troubleshooting tools, process and guide

Integrate new infrastructures with existing NOC, OSS/BSS - Support structure

Monitor and optimise as necessary

LTE Deployment Strategies (Con‘t)

Field Trials and Deployment

Lab integration and testing – vendors facility, SP facility

System level IOT- All vendors, All related elements, All Apps

I-RAT testing - 2G/3G; Offload – WiFi, Femto

Device ecosystem testing – Different devices and Apps testing

Roaming testing with other LTE, UMTS networks

Test and Validation


Key Take Aways ….

Test & Validation is Key - Feature Certification & Interoperability Testing

Right foundations with scalable design is key for long term success

Governance Plan – Operator, Network vendors, Apps partners

Interlock at both Working and Executive Level

Use open standards (3GPP, IETF, ITU,NGMN, LTESi ), KPI’s


1. Cisco SP Mobile community - https://communities.cisco.com/community/solutions/sp

2. Cisco Mobile Packet Core portfolio www.cisco.com/go/mobile

3. NGMN http://www.ngmn.org (White paper on Gateways, backhaul, security)

4. 4G Americas http://www.4gamericas.org (Whitepapers)

5. 3GPP http://www.3gpp.org (Standards)

6. ETSI Studies on latency requirements for M2M applications

http://docbox.etsi.org/Workshop/2010/201010_M2MWORKSHOP/

7. Global Certification Forum – Testing mobile devices

http://www.globalcertificationforum.org/WebSite/public/home_public.aspx

8. White paper on Latency Improvements in LTE

http://www.ericsson.com/hr/about/events/archieve/2007/mipro_2007/mipro_1137.pdf

9. Whitepaper on Latency Analysis http://www.techmahindra.com/Documents/WhitePaper/White_Paper_Latency_Analysis.pdf

10. NGMN publications on backhaul bandwidth planning, M2M etc.

References

https://communities.cisco.com/community/solutions/sp

http://www.cisco.com/go/mobile

http://www.ngmn.org/

http://www.4gamericas.org/

http://www.3gpp.org/

http://docbox.etsi.org/Workshop/2010/201010_M2MWORKSHOP/

http://www.globalcertificationforum.org/WebSite/public/home_public.aspx

http://www.ericsson.com/hr/about/events/archieve/2007/mipro_2007/mipro_1137.pdf

http://www.techmahindra.com/Documents/WhitePaper/White_Paper_Latency_Analysis.pdf


Speaker Information Prakash Suthar,

Senior Solutions Architect , [email protected]

Prakash Suthar is Senior Solutions Architect with Cisco Systems, Service Provider Mobile Practice

team. Suthar specialises in LTE design and deployments, VoLTE, Mobile Data Centre, IPv6, network

optimisation and signalling issues in UMTS/HSPA network. Suthar work with majority of mobile service

providers on architecture, design and validations and complex issues.

Suthar has over 25 years of experience working with mobile service operators in US and international.

He has supported wireless deployments for over 15 operators in US and international. Prior to joining

Cisco he worked as Distinguished Member of technical Staff (DMTS) with Alcatel Lucent for over 10

years, Department of telecommunications, India.

Suthar hold holds industry certifications - CCIE (Service Provider), CCNP, CCIP, PMP. Suthar is MS in

Information Technology, Senior member of IEEE and fellow of Institutions of Electronics and

Telecommunications Engineers, India.

mailto:[email protected]


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