SlideShare une entreprise Scribd logo
1  sur  17
Télécharger pour lire hors ligne
LTE-Default and dedicated bearer
By : Manish Arora
EPS
• EPS stands for Evolved packet system.
• whole LTE system is developed to provide all types services through
packet switching.
• To achieve this GTP (GPRS tunneling protocol is being used).
• GTP is application layer protocol which differentiate session based
on TEID (tunnil end identifier).
• UDP is used as a transport layer protocol.
• A bearer is a pipe that carry data from one node to another node.
• There are two types of GTP messages used one for control plane
and one for user plane.
• EPS bearer has following components like TEID , Transport layer
address, etc
GPRS Tunneling Protocol (GTP) in LTE
• GPRS Tunneling protocol is an important
IP/UDP based protocol used in GSM, UMTS
and LTE core networks.
• It is used to encapsulate user data when
passing through core network and also carries
bearer specific signalling traffic
between various core network entities.
• This protocol has several advantages which
will be discussed later.
Bearer in LTE
• UE <------------------------------>enb<---------------------------------->SGW <---------------------->PGW<------->Internet
• The pipes, which are carrying data from PGW to UE and vice versa called
EPS bearer.
• when data reaches at PGW from external world it process and create a
GTP-U packet and sent to SGW.
• SGW does the same thing it remove the GTP-U header received from PGW
and create a new GTP-U header then forward packet to eNB.
• Once eNB receives GTP-U packet it removes header GTP-U header and
then PDCP layer at enodeb performs IP header compression and ciphering
and map to logical channel
• then message sent to UE through radio channel. radio bearers identified
by bearer Identity (1-32) and logical channel identity(3-11).
GPRS Tunneling Protocol Types
Why is GTP used in LTE?
• It provides mobility. When UE is mobile, the IP
address remains same and packets are still
forwarded since tunneling is provided between PGW
and eNB via SGW
• Multiple tunnels (bearers) can be used by same UE
to obtain different network QoS
• Main IP remains hidden so it provides security as
well
• Creation, deletion and modification of tunnels in
case of GTP-C
GTP Interfaces in LTE
• In LTE, version 2 is used for GTP-C and version 1 is used for GTP-U
• In simple LTE network implementation, GTP-v2 is used on S5 and S11 interfaces and GTPv1 is used on S1-
U, S5, X2-U interfaces (as shown below). In inter-RAT and inter PLMN connectivity, S3, S4, S8, S10, S12 and
S16 interfaces also utilize GTP protocols
version 1 GTP-U
version 2 GTP-C
How GTP-U Works ?
• GTP-U encapsulation of UE user plane traffic can be easily understood by taking any simple example. Lets
see what happens when IP packet generated by UE reaches to eNodeB and is then forwarded to SGW.
• Consider any application on UE creates an IP/TCP packet. This packet consist of actual data by application,
TCP or UDP header and then IP field information which has source address of UE and destination address
of application server (e.g. Facebook)
• When the eNodeB receives this packet over air interface, it will put the IP packet inside GTP header which
has information related to tunnel IDs. Then further, it is encapsulated inside UDP and IP header and
forwarded as ethernet frame towards SGW. Here the IP header contains eNodeB IP as a source address
and SGW IP as a destination address
GTP-C signalling messages
As GTP-Cv2 in LTE is used for tunnel management,
some of the signalling messages are listed below
which use GTP-Cv2 protocol
What is Bearer..??
• Bearer is just a virtual concept.
• It defines how the UE data is treated when it travels across the network.
• Network might treat some data in a special way and treat others normally.
• Some flow of data might be provided guaranteed bit rate while other may
face low transfer.
• In short, bearer is a set of network parameter that defines data specific
treatment
• e.g. Person A will always get at least 256 Kbps download speed on his LTE
phone while for person B there is no guaranteed bit rate and might face
extremely bad download speed at times
Default Bearer
• When LTE UE attaches to the network for the first time, it will be assigned
default bearer which remains as long as UE is attached.
• Default bearer is best effort service.
• Each default bearer comes with an IP address.
• UE can have additional default bearers as well.
• Each default bearer will have a separate IP address.
• QCI 5 to 9 (Non- GBR) can be assigned to default bearer.
• Default bearer is one of the main bearer which is created at the time of
initial attach procedure or at the time of new PDN connection. Default
bearer represents a PDN connection and exists until UE gets detached
from network or UE initiated PDN dis-connectivity explicitly or network
force fully trigger release for the default bearer due to policy control.
Default bearer is a non-GBR bearer and provide always on IP connectivity.
Dedicated Bearer
• To put it simple, dedicated bearers provides dedicated tunnel to one or more
specific traffic (i.e. VoIP, video etc).
• Dedicated bearer acts as an additional bearer on top of default bearer.
• It does not require separate IP address due to the fact that only additional default
bearer needs an IP address and therefore dedicated bearer is always linked to one
of the default bearer established previously.
• Dedicated bearer can be GBR or non-GBR (whereas default bearer can only be
non-GBR).
• For services like VoLTE we need to provide better user experience and this is
where Dedicated bearer would come handy.
• Dedicated bearer uses “Traffic flow templates (TFT)” to give special treatment to
specific services
• Dedicated bearer is created when the requested service can't be fulfilled through
default bearer. Some services required a high level of QoS like voice call. so
network create a dedicated bearer with required QoS . Dedicated bearer may be
Non-GBR or GBR depend of qci(QoS class identifier) value. dedicated bearer can be
created/release based on requirement but default bearer is created only all on IP
connectivity and released only at the time of detach/PDN disconnection.
Two default and One dedicated
bearer
• Usually LTE networks with VoLTE implementations has
two default and one dedicated bearer
•
Default bearer 1: Used for signaling messages (sip
signaling) related to IMS network. It uses qci 5
•
Dedicated bearer: Used for VoLTE VoIP traffic. It uses
qci 1 and is linked to default bearer 1
•
Default bearer 2: Used for all other smartphone traffic
(video, chat, email, browser etc)
Why dont we use dedicated bearer
for ims signaling as well ?
•
IMS network is separate network from normal
internet.
• And it comes with its own APN.
• Therefore we need separate default bearer
for IMS network.
• This also helps in separating IMS traffic from
normal internet traffic as well
How it is decided to send voip traffic
on dedicated bearer?
•
Both UE and eNB has TFT which has rules for
certain services. For example, incase of VoLTE
voip traffic, the rule are defined on the basis
of protocol number , destination network ip
network etc
• TFT----Traffic flow Template
How is dedicated bearer linked to
default bearer?
• The value of "Linked EPS bearer identity" defined in setup info
of dedicated bearer is used to link dedicated bearer to default
bearer
FAQ
• What are the information that Default EPS has but Dedicated EPS bearer does not ?
• The answer is "APN Name" and "PDN type/PDN Address".
• Then What kind of PDN address does Dedicated EPS Bearer will use ?
• The answer is "Dedicated EPS Bearer uses the PDN address of Default EPS Bearer it is linked to".
• Then how a Dedicated EPS Bearer knows which Default EPS Bearer it is linked to ?
• The answer is that it is via a information element called "Linked EPS Bearer Identity" (See the arrow
shown in the picture above)
• What are the information that both Default EPS Bearer and Dedicated EPS Bearer has ?
• The answer is "QCI".
• Can Default EPS Bearer and Dedicated EPS Bearer can have the same QCI value ?
• The answer is "No, they must have different QCI value".
• What is the relation between Default EPS Bearer and an APN ?
• The answer is "there is one-to-one relationship between them. One Default EPS Bearer is alllocated
for one APN.

Contenu connexe

Tendances

190937694 csfb-call-flows
190937694 csfb-call-flows190937694 csfb-call-flows
190937694 csfb-call-flowsamakRF
 
SGSN- serving gprs support node - Platform - HW, SW and CLI
SGSN- serving gprs support node  - Platform - HW, SW and CLI SGSN- serving gprs support node  - Platform - HW, SW and CLI
SGSN- serving gprs support node - Platform - HW, SW and CLI Mustafa Golam
 
LTE Architecture and LTE Attach
LTE Architecture and LTE AttachLTE Architecture and LTE Attach
LTE Architecture and LTE Attachaliirfan04
 
End to End volte ims sip call flow Guide - Mobile originating and Mobile term...
End to End volte ims sip call flow Guide - Mobile originating and Mobile term...End to End volte ims sip call flow Guide - Mobile originating and Mobile term...
End to End volte ims sip call flow Guide - Mobile originating and Mobile term...Vikas Shokeen
 
Tti bundling in fdd and tdd
Tti bundling in fdd and tddTti bundling in fdd and tdd
Tti bundling in fdd and tddLaxman Mewari
 
Lte ue initial attach & detach from networkx
Lte ue initial attach & detach from networkxLte ue initial attach & detach from networkx
Lte ue initial attach & detach from networkxtharinduwije
 
VoWifi 03 - vowifi epdg aaa and architecture (pdf ppt)
VoWifi 03 - vowifi epdg aaa and architecture (pdf ppt)VoWifi 03 - vowifi epdg aaa and architecture (pdf ppt)
VoWifi 03 - vowifi epdg aaa and architecture (pdf ppt)Vikas Shokeen
 
Call flow and MS attach in LTE
Call flow and MS attach in LTECall flow and MS attach in LTE
Call flow and MS attach in LTEShashank Asthana
 
LTE Training Course
LTE Training CourseLTE Training Course
LTE Training CourseChiehChun
 
Packet core network basics
Packet core network basicsPacket core network basics
Packet core network basicsMustafa Golam
 
LTE - Long Term Evolution
LTE - Long Term EvolutionLTE - Long Term Evolution
LTE - Long Term EvolutionArief Gunawan
 
Simplified Call Flow Signaling: 2G/3G Voice Call
Simplified Call Flow Signaling: 2G/3G Voice CallSimplified Call Flow Signaling: 2G/3G Voice Call
Simplified Call Flow Signaling: 2G/3G Voice Call3G4G
 
Lte principles overview
Lte principles  overviewLte principles  overview
Lte principles overviewNdukwe Amandi
 
Lte protocol Stack
Lte protocol StackLte protocol Stack
Lte protocol StackShoeb Ahmed
 
VoLTE Interfaces , Protocols & IMS Stack Explained
VoLTE Interfaces , Protocols & IMS Stack ExplainedVoLTE Interfaces , Protocols & IMS Stack Explained
VoLTE Interfaces , Protocols & IMS Stack ExplainedVikas Shokeen
 

Tendances (20)

190937694 csfb-call-flows
190937694 csfb-call-flows190937694 csfb-call-flows
190937694 csfb-call-flows
 
SGSN- serving gprs support node - Platform - HW, SW and CLI
SGSN- serving gprs support node  - Platform - HW, SW and CLI SGSN- serving gprs support node  - Platform - HW, SW and CLI
SGSN- serving gprs support node - Platform - HW, SW and CLI
 
LTE Architecture and LTE Attach
LTE Architecture and LTE AttachLTE Architecture and LTE Attach
LTE Architecture and LTE Attach
 
End to End volte ims sip call flow Guide - Mobile originating and Mobile term...
End to End volte ims sip call flow Guide - Mobile originating and Mobile term...End to End volte ims sip call flow Guide - Mobile originating and Mobile term...
End to End volte ims sip call flow Guide - Mobile originating and Mobile term...
 
Tti bundling in fdd and tdd
Tti bundling in fdd and tddTti bundling in fdd and tdd
Tti bundling in fdd and tdd
 
LTE KPI
LTE KPILTE KPI
LTE KPI
 
Lte ue initial attach & detach from networkx
Lte ue initial attach & detach from networkxLte ue initial attach & detach from networkx
Lte ue initial attach & detach from networkx
 
3 g call flow
3 g call flow3 g call flow
3 g call flow
 
VoWifi 03 - vowifi epdg aaa and architecture (pdf ppt)
VoWifi 03 - vowifi epdg aaa and architecture (pdf ppt)VoWifi 03 - vowifi epdg aaa and architecture (pdf ppt)
VoWifi 03 - vowifi epdg aaa and architecture (pdf ppt)
 
LTE Air Interface
LTE Air InterfaceLTE Air Interface
LTE Air Interface
 
Call flow and MS attach in LTE
Call flow and MS attach in LTECall flow and MS attach in LTE
Call flow and MS attach in LTE
 
LTE Training Course
LTE Training CourseLTE Training Course
LTE Training Course
 
UMTS/WCDMA Call Flows for Handovers
UMTS/WCDMA Call Flows for HandoversUMTS/WCDMA Call Flows for Handovers
UMTS/WCDMA Call Flows for Handovers
 
Packet core network basics
Packet core network basicsPacket core network basics
Packet core network basics
 
LTE - Long Term Evolution
LTE - Long Term EvolutionLTE - Long Term Evolution
LTE - Long Term Evolution
 
Simplified Call Flow Signaling: 2G/3G Voice Call
Simplified Call Flow Signaling: 2G/3G Voice CallSimplified Call Flow Signaling: 2G/3G Voice Call
Simplified Call Flow Signaling: 2G/3G Voice Call
 
LTE Air Interface
LTE Air InterfaceLTE Air Interface
LTE Air Interface
 
Lte principles overview
Lte principles  overviewLte principles  overview
Lte principles overview
 
Lte protocol Stack
Lte protocol StackLte protocol Stack
Lte protocol Stack
 
VoLTE Interfaces , Protocols & IMS Stack Explained
VoLTE Interfaces , Protocols & IMS Stack ExplainedVoLTE Interfaces , Protocols & IMS Stack Explained
VoLTE Interfaces , Protocols & IMS Stack Explained
 

Similaire à Lte default and dedicated bearer / VoLTE

Mobile computing – module 6
Mobile computing – module 6  Mobile computing – module 6
Mobile computing – module 6 JIGNESH PATEL
 
ETE405-lec7.pdf
ETE405-lec7.pdfETE405-lec7.pdf
ETE405-lec7.pdfmashiur
 
LTE Basic Guide _ Structure_Layers_Protocol stacks_LTE control channels
LTE Basic Guide _ Structure_Layers_Protocol stacks_LTE control channels LTE Basic Guide _ Structure_Layers_Protocol stacks_LTE control channels
LTE Basic Guide _ Structure_Layers_Protocol stacks_LTE control channels senthil krishnan
 
15EC81 - Robin Singla.pdf
15EC81 - Robin Singla.pdf15EC81 - Robin Singla.pdf
15EC81 - Robin Singla.pdfsantosh147365
 
MulteFire End-to-End Architecture & Neutral Host
MulteFire End-to-End Architecture & Neutral HostMulteFire End-to-End Architecture & Neutral Host
MulteFire End-to-End Architecture & Neutral HostMFA
 
4 lte access transport network dimensioning issue 1.02
4 lte access transport network dimensioning issue 1.024 lte access transport network dimensioning issue 1.02
4 lte access transport network dimensioning issue 1.02saeed_sh65
 
Transport SDN @ OIF
Transport SDN @ OIFTransport SDN @ OIF
Transport SDN @ OIFCPqD
 
ETE405-lec4.pdf
ETE405-lec4.pdfETE405-lec4.pdf
ETE405-lec4.pdfmashiur
 
Unit1_4G-5G_Part1.pptx
Unit1_4G-5G_Part1.pptxUnit1_4G-5G_Part1.pptx
Unit1_4G-5G_Part1.pptxdevicaf983
 
ETE405-lec9.pdf
ETE405-lec9.pdfETE405-lec9.pdf
ETE405-lec9.pdfmashiur
 
Analyzing and optimizing mpls technology at Reliance Jio
Analyzing and optimizing mpls technology at Reliance JioAnalyzing and optimizing mpls technology at Reliance Jio
Analyzing and optimizing mpls technology at Reliance JioTusharSaxena53
 

Similaire à Lte default and dedicated bearer / VoLTE (20)

Mobile computing – module 6
Mobile computing – module 6  Mobile computing – module 6
Mobile computing – module 6
 
Fttx arcitectures
Fttx arcitecturesFttx arcitectures
Fttx arcitectures
 
Lte model drx
Lte model drxLte model drx
Lte model drx
 
ETE405-lec7.pdf
ETE405-lec7.pdfETE405-lec7.pdf
ETE405-lec7.pdf
 
LTE Basic Guide _ Structure_Layers_Protocol stacks_LTE control channels
LTE Basic Guide _ Structure_Layers_Protocol stacks_LTE control channels LTE Basic Guide _ Structure_Layers_Protocol stacks_LTE control channels
LTE Basic Guide _ Structure_Layers_Protocol stacks_LTE control channels
 
IPTV Basics
IPTV BasicsIPTV Basics
IPTV Basics
 
15EC81 - Robin Singla.pdf
15EC81 - Robin Singla.pdf15EC81 - Robin Singla.pdf
15EC81 - Robin Singla.pdf
 
MulteFire End-to-End Architecture & Neutral Host
MulteFire End-to-End Architecture & Neutral HostMulteFire End-to-End Architecture & Neutral Host
MulteFire End-to-End Architecture & Neutral Host
 
ACN.pptx
ACN.pptxACN.pptx
ACN.pptx
 
4 lte access transport network dimensioning issue 1.02
4 lte access transport network dimensioning issue 1.024 lte access transport network dimensioning issue 1.02
4 lte access transport network dimensioning issue 1.02
 
Transport SDN @ OIF
Transport SDN @ OIFTransport SDN @ OIF
Transport SDN @ OIF
 
Gpon
GponGpon
Gpon
 
Lte technology
Lte technologyLte technology
Lte technology
 
ETE405-lec4.pdf
ETE405-lec4.pdfETE405-lec4.pdf
ETE405-lec4.pdf
 
Cellular touch
Cellular touchCellular touch
Cellular touch
 
LTE (Long-term Evolution) [Shakeeb A.]
LTE (Long-term Evolution) [Shakeeb A.]LTE (Long-term Evolution) [Shakeeb A.]
LTE (Long-term Evolution) [Shakeeb A.]
 
Unit1_4G-5G_Part1.pptx
Unit1_4G-5G_Part1.pptxUnit1_4G-5G_Part1.pptx
Unit1_4G-5G_Part1.pptx
 
ETE405-lec9.pdf
ETE405-lec9.pdfETE405-lec9.pdf
ETE405-lec9.pdf
 
Analyzing and optimizing mpls technology at Reliance Jio
Analyzing and optimizing mpls technology at Reliance JioAnalyzing and optimizing mpls technology at Reliance Jio
Analyzing and optimizing mpls technology at Reliance Jio
 
UNIT2_PPT.ppt
UNIT2_PPT.pptUNIT2_PPT.ppt
UNIT2_PPT.ppt
 

Dernier

Dev.bg DevOps March 2024 Monitoring & Logging
Dev.bg DevOps March 2024 Monitoring & LoggingDev.bg DevOps March 2024 Monitoring & Logging
Dev.bg DevOps March 2024 Monitoring & LoggingMarian Marinov
 
solar wireless electric vechicle charging system
solar wireless electric vechicle charging systemsolar wireless electric vechicle charging system
solar wireless electric vechicle charging systemgokuldongala
 
me3493 manufacturing technology unit 1 Part A
me3493 manufacturing technology unit 1 Part Ame3493 manufacturing technology unit 1 Part A
me3493 manufacturing technology unit 1 Part Akarthi keyan
 
Design of Clutches and Brakes in Design of Machine Elements.pptx
Design of Clutches and Brakes in Design of Machine Elements.pptxDesign of Clutches and Brakes in Design of Machine Elements.pptx
Design of Clutches and Brakes in Design of Machine Elements.pptxYogeshKumarKJMIT
 
sdfsadopkjpiosufoiasdoifjasldkjfl a asldkjflaskdjflkjsdsdf
sdfsadopkjpiosufoiasdoifjasldkjfl a asldkjflaskdjflkjsdsdfsdfsadopkjpiosufoiasdoifjasldkjfl a asldkjflaskdjflkjsdsdf
sdfsadopkjpiosufoiasdoifjasldkjfl a asldkjflaskdjflkjsdsdfJulia Kaye
 
Landsman converter for power factor improvement
Landsman converter for power factor improvementLandsman converter for power factor improvement
Landsman converter for power factor improvementVijayMuni2
 
Lecture 1: Basics of trigonometry (surveying)
Lecture 1: Basics of trigonometry (surveying)Lecture 1: Basics of trigonometry (surveying)
Lecture 1: Basics of trigonometry (surveying)Bahzad5
 
Modelling Guide for Timber Structures - FPInnovations
Modelling Guide for Timber Structures - FPInnovationsModelling Guide for Timber Structures - FPInnovations
Modelling Guide for Timber Structures - FPInnovationsYusuf Yıldız
 
Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...
Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...
Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...amrabdallah9
 
Clutches and brkesSelect any 3 position random motion out of real world and d...
Clutches and brkesSelect any 3 position random motion out of real world and d...Clutches and brkesSelect any 3 position random motion out of real world and d...
Clutches and brkesSelect any 3 position random motion out of real world and d...sahb78428
 
Transforming Process Safety Management: Challenges, Benefits, and Transition ...
Transforming Process Safety Management: Challenges, Benefits, and Transition ...Transforming Process Safety Management: Challenges, Benefits, and Transition ...
Transforming Process Safety Management: Challenges, Benefits, and Transition ...soginsider
 
Guardians and Glitches: Navigating the Duality of Gen AI in AppSec
Guardians and Glitches: Navigating the Duality of Gen AI in AppSecGuardians and Glitches: Navigating the Duality of Gen AI in AppSec
Guardians and Glitches: Navigating the Duality of Gen AI in AppSecTrupti Shiralkar, CISSP
 
دليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide Laboratory
دليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide Laboratoryدليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide Laboratory
دليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide LaboratoryBahzad5
 
Best-NO1 Best Rohani Amil In Lahore Kala Ilam In Lahore Kala Jadu Amil In Lah...
Best-NO1 Best Rohani Amil In Lahore Kala Ilam In Lahore Kala Jadu Amil In Lah...Best-NO1 Best Rohani Amil In Lahore Kala Ilam In Lahore Kala Jadu Amil In Lah...
Best-NO1 Best Rohani Amil In Lahore Kala Ilam In Lahore Kala Jadu Amil In Lah...Amil baba
 
A Seminar on Electric Vehicle Software Simulation
A Seminar on Electric Vehicle Software SimulationA Seminar on Electric Vehicle Software Simulation
A Seminar on Electric Vehicle Software SimulationMohsinKhanA
 
Basic Principle of Electrochemical Sensor
Basic Principle of  Electrochemical SensorBasic Principle of  Electrochemical Sensor
Basic Principle of Electrochemical SensorTanvir Moin
 
Technology Features of Apollo HDD Machine, Its Technical Specification with C...
Technology Features of Apollo HDD Machine, Its Technical Specification with C...Technology Features of Apollo HDD Machine, Its Technical Specification with C...
Technology Features of Apollo HDD Machine, Its Technical Specification with C...Apollo Techno Industries Pvt Ltd
 

Dernier (20)

Dev.bg DevOps March 2024 Monitoring & Logging
Dev.bg DevOps March 2024 Monitoring & LoggingDev.bg DevOps March 2024 Monitoring & Logging
Dev.bg DevOps March 2024 Monitoring & Logging
 
solar wireless electric vechicle charging system
solar wireless electric vechicle charging systemsolar wireless electric vechicle charging system
solar wireless electric vechicle charging system
 
me3493 manufacturing technology unit 1 Part A
me3493 manufacturing technology unit 1 Part Ame3493 manufacturing technology unit 1 Part A
me3493 manufacturing technology unit 1 Part A
 
Design of Clutches and Brakes in Design of Machine Elements.pptx
Design of Clutches and Brakes in Design of Machine Elements.pptxDesign of Clutches and Brakes in Design of Machine Elements.pptx
Design of Clutches and Brakes in Design of Machine Elements.pptx
 
sdfsadopkjpiosufoiasdoifjasldkjfl a asldkjflaskdjflkjsdsdf
sdfsadopkjpiosufoiasdoifjasldkjfl a asldkjflaskdjflkjsdsdfsdfsadopkjpiosufoiasdoifjasldkjfl a asldkjflaskdjflkjsdsdf
sdfsadopkjpiosufoiasdoifjasldkjfl a asldkjflaskdjflkjsdsdf
 
Landsman converter for power factor improvement
Landsman converter for power factor improvementLandsman converter for power factor improvement
Landsman converter for power factor improvement
 
Lecture 1: Basics of trigonometry (surveying)
Lecture 1: Basics of trigonometry (surveying)Lecture 1: Basics of trigonometry (surveying)
Lecture 1: Basics of trigonometry (surveying)
 
Modelling Guide for Timber Structures - FPInnovations
Modelling Guide for Timber Structures - FPInnovationsModelling Guide for Timber Structures - FPInnovations
Modelling Guide for Timber Structures - FPInnovations
 
Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...
Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...
Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...
 
Clutches and brkesSelect any 3 position random motion out of real world and d...
Clutches and brkesSelect any 3 position random motion out of real world and d...Clutches and brkesSelect any 3 position random motion out of real world and d...
Clutches and brkesSelect any 3 position random motion out of real world and d...
 
計劃趕得上變化
計劃趕得上變化計劃趕得上變化
計劃趕得上變化
 
Transforming Process Safety Management: Challenges, Benefits, and Transition ...
Transforming Process Safety Management: Challenges, Benefits, and Transition ...Transforming Process Safety Management: Challenges, Benefits, and Transition ...
Transforming Process Safety Management: Challenges, Benefits, and Transition ...
 
Guardians and Glitches: Navigating the Duality of Gen AI in AppSec
Guardians and Glitches: Navigating the Duality of Gen AI in AppSecGuardians and Glitches: Navigating the Duality of Gen AI in AppSec
Guardians and Glitches: Navigating the Duality of Gen AI in AppSec
 
Lecture 2 .pdf
Lecture 2                           .pdfLecture 2                           .pdf
Lecture 2 .pdf
 
دليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide Laboratory
دليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide Laboratoryدليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide Laboratory
دليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide Laboratory
 
Présentation IIRB 2024 Chloe Dufrane.pdf
Présentation IIRB 2024 Chloe Dufrane.pdfPrésentation IIRB 2024 Chloe Dufrane.pdf
Présentation IIRB 2024 Chloe Dufrane.pdf
 
Best-NO1 Best Rohani Amil In Lahore Kala Ilam In Lahore Kala Jadu Amil In Lah...
Best-NO1 Best Rohani Amil In Lahore Kala Ilam In Lahore Kala Jadu Amil In Lah...Best-NO1 Best Rohani Amil In Lahore Kala Ilam In Lahore Kala Jadu Amil In Lah...
Best-NO1 Best Rohani Amil In Lahore Kala Ilam In Lahore Kala Jadu Amil In Lah...
 
A Seminar on Electric Vehicle Software Simulation
A Seminar on Electric Vehicle Software SimulationA Seminar on Electric Vehicle Software Simulation
A Seminar on Electric Vehicle Software Simulation
 
Basic Principle of Electrochemical Sensor
Basic Principle of  Electrochemical SensorBasic Principle of  Electrochemical Sensor
Basic Principle of Electrochemical Sensor
 
Technology Features of Apollo HDD Machine, Its Technical Specification with C...
Technology Features of Apollo HDD Machine, Its Technical Specification with C...Technology Features of Apollo HDD Machine, Its Technical Specification with C...
Technology Features of Apollo HDD Machine, Its Technical Specification with C...
 

Lte default and dedicated bearer / VoLTE

  • 1. LTE-Default and dedicated bearer By : Manish Arora
  • 2. EPS • EPS stands for Evolved packet system. • whole LTE system is developed to provide all types services through packet switching. • To achieve this GTP (GPRS tunneling protocol is being used). • GTP is application layer protocol which differentiate session based on TEID (tunnil end identifier). • UDP is used as a transport layer protocol. • A bearer is a pipe that carry data from one node to another node. • There are two types of GTP messages used one for control plane and one for user plane. • EPS bearer has following components like TEID , Transport layer address, etc
  • 3. GPRS Tunneling Protocol (GTP) in LTE • GPRS Tunneling protocol is an important IP/UDP based protocol used in GSM, UMTS and LTE core networks. • It is used to encapsulate user data when passing through core network and also carries bearer specific signalling traffic between various core network entities. • This protocol has several advantages which will be discussed later.
  • 4. Bearer in LTE • UE <------------------------------>enb<---------------------------------->SGW <---------------------->PGW<------->Internet • The pipes, which are carrying data from PGW to UE and vice versa called EPS bearer. • when data reaches at PGW from external world it process and create a GTP-U packet and sent to SGW. • SGW does the same thing it remove the GTP-U header received from PGW and create a new GTP-U header then forward packet to eNB. • Once eNB receives GTP-U packet it removes header GTP-U header and then PDCP layer at enodeb performs IP header compression and ciphering and map to logical channel • then message sent to UE through radio channel. radio bearers identified by bearer Identity (1-32) and logical channel identity(3-11).
  • 6. Why is GTP used in LTE? • It provides mobility. When UE is mobile, the IP address remains same and packets are still forwarded since tunneling is provided between PGW and eNB via SGW • Multiple tunnels (bearers) can be used by same UE to obtain different network QoS • Main IP remains hidden so it provides security as well • Creation, deletion and modification of tunnels in case of GTP-C
  • 7. GTP Interfaces in LTE • In LTE, version 2 is used for GTP-C and version 1 is used for GTP-U • In simple LTE network implementation, GTP-v2 is used on S5 and S11 interfaces and GTPv1 is used on S1- U, S5, X2-U interfaces (as shown below). In inter-RAT and inter PLMN connectivity, S3, S4, S8, S10, S12 and S16 interfaces also utilize GTP protocols version 1 GTP-U version 2 GTP-C
  • 8. How GTP-U Works ? • GTP-U encapsulation of UE user plane traffic can be easily understood by taking any simple example. Lets see what happens when IP packet generated by UE reaches to eNodeB and is then forwarded to SGW. • Consider any application on UE creates an IP/TCP packet. This packet consist of actual data by application, TCP or UDP header and then IP field information which has source address of UE and destination address of application server (e.g. Facebook) • When the eNodeB receives this packet over air interface, it will put the IP packet inside GTP header which has information related to tunnel IDs. Then further, it is encapsulated inside UDP and IP header and forwarded as ethernet frame towards SGW. Here the IP header contains eNodeB IP as a source address and SGW IP as a destination address
  • 9. GTP-C signalling messages As GTP-Cv2 in LTE is used for tunnel management, some of the signalling messages are listed below which use GTP-Cv2 protocol
  • 10. What is Bearer..?? • Bearer is just a virtual concept. • It defines how the UE data is treated when it travels across the network. • Network might treat some data in a special way and treat others normally. • Some flow of data might be provided guaranteed bit rate while other may face low transfer. • In short, bearer is a set of network parameter that defines data specific treatment • e.g. Person A will always get at least 256 Kbps download speed on his LTE phone while for person B there is no guaranteed bit rate and might face extremely bad download speed at times
  • 11. Default Bearer • When LTE UE attaches to the network for the first time, it will be assigned default bearer which remains as long as UE is attached. • Default bearer is best effort service. • Each default bearer comes with an IP address. • UE can have additional default bearers as well. • Each default bearer will have a separate IP address. • QCI 5 to 9 (Non- GBR) can be assigned to default bearer. • Default bearer is one of the main bearer which is created at the time of initial attach procedure or at the time of new PDN connection. Default bearer represents a PDN connection and exists until UE gets detached from network or UE initiated PDN dis-connectivity explicitly or network force fully trigger release for the default bearer due to policy control. Default bearer is a non-GBR bearer and provide always on IP connectivity.
  • 12. Dedicated Bearer • To put it simple, dedicated bearers provides dedicated tunnel to one or more specific traffic (i.e. VoIP, video etc). • Dedicated bearer acts as an additional bearer on top of default bearer. • It does not require separate IP address due to the fact that only additional default bearer needs an IP address and therefore dedicated bearer is always linked to one of the default bearer established previously. • Dedicated bearer can be GBR or non-GBR (whereas default bearer can only be non-GBR). • For services like VoLTE we need to provide better user experience and this is where Dedicated bearer would come handy. • Dedicated bearer uses “Traffic flow templates (TFT)” to give special treatment to specific services • Dedicated bearer is created when the requested service can't be fulfilled through default bearer. Some services required a high level of QoS like voice call. so network create a dedicated bearer with required QoS . Dedicated bearer may be Non-GBR or GBR depend of qci(QoS class identifier) value. dedicated bearer can be created/release based on requirement but default bearer is created only all on IP connectivity and released only at the time of detach/PDN disconnection.
  • 13. Two default and One dedicated bearer • Usually LTE networks with VoLTE implementations has two default and one dedicated bearer • Default bearer 1: Used for signaling messages (sip signaling) related to IMS network. It uses qci 5 • Dedicated bearer: Used for VoLTE VoIP traffic. It uses qci 1 and is linked to default bearer 1 • Default bearer 2: Used for all other smartphone traffic (video, chat, email, browser etc)
  • 14. Why dont we use dedicated bearer for ims signaling as well ? • IMS network is separate network from normal internet. • And it comes with its own APN. • Therefore we need separate default bearer for IMS network. • This also helps in separating IMS traffic from normal internet traffic as well
  • 15. How it is decided to send voip traffic on dedicated bearer? • Both UE and eNB has TFT which has rules for certain services. For example, incase of VoLTE voip traffic, the rule are defined on the basis of protocol number , destination network ip network etc • TFT----Traffic flow Template
  • 16. How is dedicated bearer linked to default bearer? • The value of "Linked EPS bearer identity" defined in setup info of dedicated bearer is used to link dedicated bearer to default bearer
  • 17. FAQ • What are the information that Default EPS has but Dedicated EPS bearer does not ? • The answer is "APN Name" and "PDN type/PDN Address". • Then What kind of PDN address does Dedicated EPS Bearer will use ? • The answer is "Dedicated EPS Bearer uses the PDN address of Default EPS Bearer it is linked to". • Then how a Dedicated EPS Bearer knows which Default EPS Bearer it is linked to ? • The answer is that it is via a information element called "Linked EPS Bearer Identity" (See the arrow shown in the picture above) • What are the information that both Default EPS Bearer and Dedicated EPS Bearer has ? • The answer is "QCI". • Can Default EPS Bearer and Dedicated EPS Bearer can have the same QCI value ? • The answer is "No, they must have different QCI value". • What is the relation between Default EPS Bearer and an APN ? • The answer is "there is one-to-one relationship between them. One Default EPS Bearer is alllocated for one APN.