qos issues in gprs/umts networks
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QoS Issues in GPRS/UMTS NetworksShiao-Li Charles Tsao ()
() [email protected]
TEL:886-3-591-4651 FAX:886-3-5820310
• Why QoS ? • End-to-End QoS Architecture • QoS in GPRS Networks • QoS in UMTS Networks • QoS in 3G All IP • End-to-End QoS in Heterogeneous Wireless Network • Conclusions
3
Why Why QoS QoS ??
• What is QoS ? – Quality of Service is a mechanism that provides a level of
assurance that ensures that a service or application can be delivered to the end-user in a satisfactory time frame (QoS forum)
– Depending on different users and different APs – does not create additional bandwidth – manages the existing bandwidth in more efficient way – allows for predictable delays, delay variation (jitter) and
packet loss rates
WhyWhy QoSQoS ? (Cont.)? (Cont.)
• Why we need QoS ? – Consistent and predictable to real-time and non-real-time
service above a minimum level – Unique problems for wireless communication
• bandwidth-limiting (engineering approaches to solve QoS problem over fixed network fail)
• error-prone (retransmission is what we always do over fixed network, but it costs too much over wireless network)
• time-variant
5
WhyWhy QoSQoS ? (Cont.)? (Cont.)
• Do we need application QoS or end-to-end QoS ? – YES. That is why we need QoS
• QoS architecture – ATM QoS – IP QoS architecture
• MPLS, IntServ, DiffServ – QoS for optical networks
6
CN Gateway
UMTS Bearer Service
Backbone Bearer Service
Iu Bearer Service
Radio Bearer Service
• End-to-End bears : architecture migration DiffServ, or
IntServIP IP IP
IP IP IP GTP GTP GTP GTP
IP
L1/L2
• End-to-End bears : architecture migration DiffServ, or
IntServIP IP IP
IP
• End-to-End bears : architecture migration
10
MS
IP
11
• General ideas - Initiate
4 : Send packet 3‘ : IP QoS session mapping & establishment
4‘ : Send packet through real-time MAC/RLC based on QoS profile and radio priority
SGSNMS GGSNBSS
12
• General ideas – Modify and Roaming
2 : PDP Context Modification
1‘ : Re-mapping QoS profile and radio priority to real-time MAC/RLCBSS
BSS SGSN
SGSN GGSNMS
13
• QoS profile configuration
PDP Context #3
PDP Context #2
PDP Context #1
MS HLRSGSN GGSN
•Precedence class : high, normal, low •Delay class : 1-3 (predictive), 4 (best effort) •Reliability class : 1 (highest) – 5 (lowest) •Peak throughput class : 1 (lowest, 8kbps) – 9 (highest, 2048 kbps) •Mean throughput class : 1 (lowest, 0.22kbps) – 18 (highest, 111kbps), 31 (best effort)
14
• Protocol stack
SGSN GGSN HLR
PDP Context #3
PDP Context #2
PDP Context #1
• Subscriber attaches to network
4 Attach Acpt.
• Admission control and QoS session establishment
SGSNMS BSS GGSN Host
GGSN may further restrict the QoS given its
capabilities and load
3 Activate PDP Context Rsp. (QoS Neg.)
4 Activate PDP Context Acpt. (QoS Neg., Radio Priority) through neg. LLC SAP
MS either accepts the QoS or deactivates the PDP
context
1 Activate PDP Context Req. (QoS Req.) through req. LLC SAP
SGSN may restrict the requested QoS given its capabilities, load and the
subscribed QoS
SGSN selects radio priority based on QoS negotiated
* MS has attached to the GPRS network* MS has attached to the GPRS network
17
• QoS modification
SGSNMS BSS GGSN Host 1 Update PDP Context Req. (QoS Neg.)
GGSN may further restrict the QoS given its
capabilities and load
2 Update PDP Context Rsp. (QoS Neg.)
3 Modify PDP Context Req. (QoS Neg., Radio Priority) through neg. LLC SAP
MS either accepts the QoS or deactivates the PDP
context
SGSN selects radio priority based on QoS negotiated
18
• QoS during Handover (Inter-BSS)
SGSNMS New BSS GGSN Host
1 Data Packets Old BSS
Data packet through the specific LLC SAP and to RLC/MAC with QoS profile and radio priority to new BSS
2 Data Packets
Data packet through the specific LLC SAP and to RLC/MAC with QoS profile and radio priority
19
• QoS during Handover (Inter-SGSN)
1 RA Update Req.
New SGSN
5 RA Update Acpt./Complete …
MS BSS SGSN GGSN
Radio Priority
PDP Context (QoS Profile)PDP Context (QoS Profile)• QoS control and maintenance
L2 L1
21
Flow control over frame relay
MS BSS SGSN GGSN
Through specific LLC SAPs based
on QoS delay class
• Packet flow
IP QoS based on PDP context (QoS profile)IP QoS based on PDP context (QoS profile)
22
• Difficulties of QoS control in GPRS Networks – TDMA radio
• Best effort traffic • Shared capacity, no fixed reservation • Non-optimized handover for real-time packets
– BSS knows nothing about PDP context (QoS Profile) • Mapping complicated QoS profile into 4 priorities (LLC and
radio priorities) – No QoS mechanisms standardized on core network
• QoS mechanisms can be applied to core network, but the bottleneck is in radio interface
– One QoS profile per PDP address • No per flow QoS
23
• Why QoS in UMTS is important ? – 1G cellular system (AMPS)
• analog voice/circuit switch (radio network) – 2G cellular system (GSM)
• digital voice/circuit switch (radio network) – 2.5G cellular system (GPRS)
• digital data/packet switch (radio network) • Address QoS issues but not required to implement
– 3G cellular system (3GPP R99/R4) • digital voice/data/packet switch (radio network) • WCDMA introduced •• QoS QoS features are design in and ready for providing packet voicefeatures are design in and ready for providing packet voice
– Beyond 3G (3GPP R5/R6) • digital voice/data/packet switch (radio and core network)
24
• General ideas - Initiate
UE
SGSN GGSN
4 : RAB establishment
5 : PDP Modification if required
5‘ : IP QoS re-mapping if required
25
• General ideas – Modify and Roaming
RNC
UE SGSN GGSN
RNC
26
• QoS profile configuration
PDP Context #3
PDP Context #2
PDP Context #1
UE HLRRNC SGSN GGSN
27
• UMTS Bearer Service – Traffic classes
Traffic class Conversational class
Background Background best
effort Fundamental characteristics
- Preserve time relation (variation) between information entities of the stream Conversational pattern (stringent and low delay )
- Preserve time relation (variation) between information entities of the stream
- Request response pattern - Preserve payload content
- Destination is not expecting the data within a certain time - Preserve payload content
Example of the application
28
• QoS Attributes (QoS profile) Traffic class Conversational
class Streaming class Interactive class Background class
Maximum bitrate (kbps) < 2 048 (1) (2) < 2 048 (1) (2) < 2 048 - overhead (2) (3)
< 2 048 - overhead (2) (3)
Delivery order Yes/No Yes/No Yes/No Yes/No Maximum SDU size (octets)
<=1 500 or 1 502 (4) <=1 500 or 1 502 (4) <=1 500 or 1 502 (4) <=1 500 or 1 502 (4)
SDU format information (5) (5) Delivery of erroneous SDUs
Yes/No/- (6) Yes/No/- (6) Yes/No/- (6) Yes/No/- (6)
Residual BER 5*10-2, 10-2, 5*10-3, 10-3, 10-4, 10-6
5*10-2, 10-2, 5*10-3, 10-3, 10-4, 10-5, 10-6
4*10-3, 10-5, 6*10-8 (7) 4*10-3, 10-5, 6*10-8 (7)
SDU error ratio 10-2, 7*10-3, 10-3, 10-4, 10-5
10-1, 10-2, 7*10-3, 10-3, 10-4, 10-5
10-3, 10-4, 10-6 10-3, 10-4, 10-6
Transfer delay (ms) 100 up to FFS (9) 250 up to FFS (9) Guaranteed bit rate (kbps)
< 2 048 (1) (2) < 2 048 (1) (2)
Traffic handling priority 1,2,3 (8) Allocation/Retention priority
1,2,3 (8) 1,2,3 (8) 1,2,3 (8) 1,2,3 (8)
29
• Radio access bearer – Attributes mapping from Radio access bearer attributes
(implementation dependent) • Spreading code format • Turbo encoder format • Interleaver • Open-loop power control threshold • Usage of RLC acknowledge
30
QoSQoS in UMTS Networks (Cont.)in UMTS Networks (Cont.)
• Core Network Bearer Services – Operator’s option to use QoS capabilities in IP or ATM
layer • IP-based backbone
– Interoperation with IP-based backbone is based on DiffServ
– Mapping from UMTS QoS classes to DiffServ codepoint • Operator controls the mapping, depending on bandwidth and
resource provisioning among DiffServ classes • Interoperability between operators based on Service Level
Aggrements
31
SGSN GGSN HLR
PDP Context #3
PDP Context #2
PDP Context #1
• Subscriber attaches to network
4 Attach Acpt.
• PDP context, QoS profile, traffic flow template, and packet filters
SGSNRNC PDP Context Act.
Same PDP Address Different NSAPI
Different QoS
Different QoSPDP Context
Same PDP Address Different NSAPI
Different QoS
PDP Context
TFT TFT
• PDP context, QoS profile, traffic flow template, and packet filters
SGSNUE GGSNRNC Incoming packet
different QoS
PDP Context
different QoS
• Protocol stack
• Admission control and QoS session establishment
SGSNUE RNC GGSN Host
GGSN may further restrict the QoS given its
capabilities and load
4 RAB Setup (QoS Neg.)
RRM Algorithms 5 RL/RB Establishment
6 RAB Est. Rsp.
1 Activate PDP Context Req. (QoS Req.)
SGSN may restrict the requested QoS given its capabilities, load and the
subscribed QoS
* continue* continue
• Admission control and QoS session establishment (Cont.)
SGSN GGSN Host
MS either accepts the QoS or deactivates the PDP context
7 Update PDP Context Req. (QoS Neg.)
8 Update PDP Context Rsp. Not used in UMTSNot used in UMTS
UE RNC
9 Activate PDP Context Acpt. (Q
In case QoS was downgraded by RNC, SGSN may inform GGSN about the new QoS
37
• Secondary PDP Context Activation
SGSNUE RNC GGSN Host
capabilities and load
4 RAB Setup (QoS Neg.)
RRM Algorithms 5 RL Establishment
6 RAB Est. Rsp.
1 Activate PDP Context Req. (QoS Req., TFTTFT)
SGSN may restrict the requested QoS given its capabilities, load and the
subscribed QoS
* continue* continue
• Secondary PDP Context Activation (Cont.)
SGSN GGSN Host
MS either accepts the QoS or deactivates the PDP context
7 Update PDP Context Req. (QoS Neg.)
8 Update PDP Context Rsp. Not used in UMTSNot used in UMTS
UE RNC
9 Activate PDP Context Acpt. (Q
In case QoS was downgraded by RNC, SGSN may inform GGSN about the new QoS
39
• QoS setup procedures (control plane)
Transl. Transl.
Adm. Contr
RAB Manager
3. RAB4. RB 5. CN Bearer (opt.)
6. Ack. (UMTS Bearer)
• PDP context modification – SGSN-initiated
– PDP context preserved for backgroup/interactive traffic class – PDP context preserved for streaming/conversational traffic class
with max. bit rate = 0 kbps
41
• QoS control during handovers – Inter RNC handovers
• SRNS relocation – Inter SGSN handovers
• Inter SGSN handover
• Serving SRNS Relocation (soft handover)
Old SGSN Source RNC New SGSN
Target RNC GGSN
1 Relocation Required (Source ID, Target ID, SRNCSRNC-->TRNC container>TRNC container) 2 Forward Rel. Req. (PDP context(PDP context)
3 Relocation Req. (SRNC(SRNC-->TRNC container>TRNC container, RABsRABs))
Establishment of RABs/RBs 4 Relocation Req. Ack. (RABs(RABs OK, OK, RABsRABs fail)fail)
5 Forward Rel. Rsp. 6 Relocation Command
7 Relocation commit
• Serving SRNS Relocation (soft handover) (Cont.)
Old SGSNUE Source RNC New SGSN
Target RNC GGSN
9 Relocation Detect 10 Update PDP Context Req. (QoS(QoS Neg.Neg.) 11 Update PDP Context Rsp.
10a UTRAN mobility info
12 Relocation complete
15 Iu release Com/complete
• Inter SGSN RA update
Old SGSNMS RNC GGSN
1 RA Update Req.
New SGSN
5 RA Update Acpt./Complete …
UE RAN SGSN GGSN UE
N or NN or N--11 TFTs
IP xxx IP xxx
NN TCP/UDP Flows
NSAPI-1 NSAPI-1 TFT
RB ID-1 RB ID-1
N N NSAPIs
N N GTP-U 1 1 Iu
1~N1~N PDP Context 11--NN PDP Context
• QoS control (user plane) PDP Context
* We assume there are * We assume there are NN PDP ContextsPDP Contexts M M RBs (SRBs)
46
• QoS control (user plane)
Fast QoS Control
Fast QoS Control
• 3G R5
Gi
Mg
Mc
Gr
Cx
Mm
Gi
Gn
Iu
Gc
Mi
SGSN
Ga
Gi
48
4. 100 Trying
18. GPRS:Activate PDP context accept
19. COMET
25. PRACK 26. PRACK
27. 200 OK (PRACK)
28. 200 OK (PRACK)
32. 200 OK (INVITE)
29. 200 OK (INVITE)
33. ACK 34. ACK
14. COPS: REQ (Activate PDP context)
16. COPS: RPT (Activate PDP context)
15. COPS: DEC (Policy information)
31. COPS: RPT (Report outcome)
30. COPS: DEC (Open "gate")
49
QoSQoS in 3G All IP (Cont.)in 3G All IP (Cont.)
• Framework for QoS mapping between IMS and GPRS
P-CSCF
GGSN
1 : Authorize QoS
QoSQoS in 3G All IP (Cont.)in 3G All IP (Cont.)
• Framework for generating requested QoS parameters in the UE
Application
(SDP)
UE
QoSQoS in 3G All IP (Cont.)in 3G All IP (Cont.)
• Authorize QoS resources at originating PCF
UE GGSN P-CSCF PCF
SDP
SDP
SDP
SDP
3. QoS authorisation
QoSQoS in 3G All IP (Cont.)in 3G All IP (Cont.)
• Mobile Originated without End to End RSVP (Activation)
UE P-CSCF PCFSGSN GGSN
2. Activate PDP Req.
3. Create PDP Req.
8. Create PDP Res.
9. Activate PDP Acc.
5. Process resource request
• Seamless Roaming in Heterogeneous Wireless Networks
3G/2.5G/2G Core Network3G/2.5G/2G Core Network
Enterprise IntranetEnterprise Intranet
• QoS Concerns for Roaming in Heterogeneous Networks
3G/2.5G/2G Core Network3G/2.5G/2G Core Network
Enterprise IntranetEnterprise Intranet
• Logical View of End-to-End IP QoS
End to End IP Bearer Radio Access Bearer CN Bearer Backbone Bearer CN Bearer Radio Access Bearer
End to End IP Bearer Radio Access Bearer CN Bearer Backbone Bearer CN Bearer
End to End IP Bearer Radio Access Bearer CN Bearer Radio Access Bearer
…
• Generic End-to-End QoS Architecture
UE:User Equipment RAN:Radio Access Network CN:core network (or intranet) Backbone:Backbone network (or Internet)
L2 QoS Control & Admission Control L3 QoS Control & Admission Control QoS Translator
57
• Generic Handoff Models in Heterogeneous Wireless Networks
InterInter--RAN (L2) HandoffsRAN (L2) Handoffs WLAN AP - WLAN AP, UMTS RAN - UMTS RAN, UTRAN – GERAN, UTRAN - BRAN
CN BackboneUE RAN
IntraIntra--CN HandoffsCN Handoffs UMTS SGSN - UMTS SGSN, Intranet Router – Intranet Router
InterInter--CN HandoffsCN Handoffs UMTS PLMN - UMTS PLMN Router - Router InterInter--system Handoffssystem Handoffs UMTS - WLAN
58
• QoS for Inter Radio Access Network Handoffs
L2 L2 QoSQoS
L3 L3 QoSQoS
L2 L2 QoSQoS
L3 L3 QoSQoS
•Radio resource management (RRM) •Heterogeneous radio resource management (Heterogeneous RRM) •Frame synchronization for soft/hard handoffs •QoS renegotiation
59
• QoS for Intra/Inter Core Network Handoffs
L2 L2 QoSQoS
L3 L3 QoSQoS
L2 L2 QoSQoS
L3 L3 QoSQoS
UE RAN CN Backbone CN RAN UE
UE RAN CN
• QoS for Inter System Handoffs
L2 L2 QoSQoS
L3 L3 QoSQoS
L2 L2 QoSQoS
L3 L3 QoSQoS
UE RAN CN
• Mobile IP for Intersystem Handoffs
InternetInternet
Router Gateway
• Mobile IP Problems+ and Recent Development
InternetInternet
Router Gateway
Latency Latency <ietf<ietf--mipv6mipv6-- hierarchicalhierarchical
MobileMobile--initiated or initiated or networknetwork--initiated initiated
handoffs for handoffs for Seamless roamingSeamless roaming <<ietfietf--fastfast--mipv6>mipv6>
63
• QoS Problems for Intersystem Handoffs
InternetInternet
Router Gateway
MS
MS
HA/FA
HA/FA
Host
QoSQoS profile profile needs to be needs to be transferred transferred
during handoffsduring handoffs
Resource alone the new Resource alone the new routing path should be routing path should be reserved in advanced reserved in advanced
for some for some APsAPs
QoS QoS Profile should be Profile should be renegotiated with new renegotiated with new systems and translated systems and translated to new to new QoS QoS profileprofile
64
ConclusionsConclusions
• GPRS suffers from design defects to support QoS • Maybe it is not required to build in QoS features in GPRS
– Radio interface is the bottleneck – The range of the QoS that radio interface can offer is quite different
from these of the fixed network. It does not make sense to map two scales which have a large gap
•• QoSQoS is required for 3G and is a MUST for B3Gis required for 3G and is a MUST for B3G • QoS features for 3G system such as UMTS has already designed has already designed
inin •• Take Take QoS QoS into consideration for 3G productsinto consideration for 3G products or deployment deployment
of 3G system of 3G system –– will also help you to move to B3G smoothlywill also help you to move to B3G smoothly
QoS Issues in GPRS/UMTS Networks
Outline
QoS in UMTS Networks
QoS in 3G All IP (Cont.)
QoS in 3G All IP (Cont.)
QoS in 3G All IP (Cont.)
QoS in 3G All IP (Cont.)
End-to-End QoS in Heterogeneous Wireless Network
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
Conclusions
() [email protected]
TEL:886-3-591-4651 FAX:886-3-5820310
• Why QoS ? • End-to-End QoS Architecture • QoS in GPRS Networks • QoS in UMTS Networks • QoS in 3G All IP • End-to-End QoS in Heterogeneous Wireless Network • Conclusions
3
Why Why QoS QoS ??
• What is QoS ? – Quality of Service is a mechanism that provides a level of
assurance that ensures that a service or application can be delivered to the end-user in a satisfactory time frame (QoS forum)
– Depending on different users and different APs – does not create additional bandwidth – manages the existing bandwidth in more efficient way – allows for predictable delays, delay variation (jitter) and
packet loss rates
WhyWhy QoSQoS ? (Cont.)? (Cont.)
• Why we need QoS ? – Consistent and predictable to real-time and non-real-time
service above a minimum level – Unique problems for wireless communication
• bandwidth-limiting (engineering approaches to solve QoS problem over fixed network fail)
• error-prone (retransmission is what we always do over fixed network, but it costs too much over wireless network)
• time-variant
5
WhyWhy QoSQoS ? (Cont.)? (Cont.)
• Do we need application QoS or end-to-end QoS ? – YES. That is why we need QoS
• QoS architecture – ATM QoS – IP QoS architecture
• MPLS, IntServ, DiffServ – QoS for optical networks
6
CN Gateway
UMTS Bearer Service
Backbone Bearer Service
Iu Bearer Service
Radio Bearer Service
• End-to-End bears : architecture migration DiffServ, or
IntServIP IP IP
IP IP IP GTP GTP GTP GTP
IP
L1/L2
• End-to-End bears : architecture migration DiffServ, or
IntServIP IP IP
IP
• End-to-End bears : architecture migration
10
MS
IP
11
• General ideas - Initiate
4 : Send packet 3‘ : IP QoS session mapping & establishment
4‘ : Send packet through real-time MAC/RLC based on QoS profile and radio priority
SGSNMS GGSNBSS
12
• General ideas – Modify and Roaming
2 : PDP Context Modification
1‘ : Re-mapping QoS profile and radio priority to real-time MAC/RLCBSS
BSS SGSN
SGSN GGSNMS
13
• QoS profile configuration
PDP Context #3
PDP Context #2
PDP Context #1
MS HLRSGSN GGSN
•Precedence class : high, normal, low •Delay class : 1-3 (predictive), 4 (best effort) •Reliability class : 1 (highest) – 5 (lowest) •Peak throughput class : 1 (lowest, 8kbps) – 9 (highest, 2048 kbps) •Mean throughput class : 1 (lowest, 0.22kbps) – 18 (highest, 111kbps), 31 (best effort)
14
• Protocol stack
SGSN GGSN HLR
PDP Context #3
PDP Context #2
PDP Context #1
• Subscriber attaches to network
4 Attach Acpt.
• Admission control and QoS session establishment
SGSNMS BSS GGSN Host
GGSN may further restrict the QoS given its
capabilities and load
3 Activate PDP Context Rsp. (QoS Neg.)
4 Activate PDP Context Acpt. (QoS Neg., Radio Priority) through neg. LLC SAP
MS either accepts the QoS or deactivates the PDP
context
1 Activate PDP Context Req. (QoS Req.) through req. LLC SAP
SGSN may restrict the requested QoS given its capabilities, load and the
subscribed QoS
SGSN selects radio priority based on QoS negotiated
* MS has attached to the GPRS network* MS has attached to the GPRS network
17
• QoS modification
SGSNMS BSS GGSN Host 1 Update PDP Context Req. (QoS Neg.)
GGSN may further restrict the QoS given its
capabilities and load
2 Update PDP Context Rsp. (QoS Neg.)
3 Modify PDP Context Req. (QoS Neg., Radio Priority) through neg. LLC SAP
MS either accepts the QoS or deactivates the PDP
context
SGSN selects radio priority based on QoS negotiated
18
• QoS during Handover (Inter-BSS)
SGSNMS New BSS GGSN Host
1 Data Packets Old BSS
Data packet through the specific LLC SAP and to RLC/MAC with QoS profile and radio priority to new BSS
2 Data Packets
Data packet through the specific LLC SAP and to RLC/MAC with QoS profile and radio priority
19
• QoS during Handover (Inter-SGSN)
1 RA Update Req.
New SGSN
5 RA Update Acpt./Complete …
MS BSS SGSN GGSN
Radio Priority
PDP Context (QoS Profile)PDP Context (QoS Profile)• QoS control and maintenance
L2 L1
21
Flow control over frame relay
MS BSS SGSN GGSN
Through specific LLC SAPs based
on QoS delay class
• Packet flow
IP QoS based on PDP context (QoS profile)IP QoS based on PDP context (QoS profile)
22
• Difficulties of QoS control in GPRS Networks – TDMA radio
• Best effort traffic • Shared capacity, no fixed reservation • Non-optimized handover for real-time packets
– BSS knows nothing about PDP context (QoS Profile) • Mapping complicated QoS profile into 4 priorities (LLC and
radio priorities) – No QoS mechanisms standardized on core network
• QoS mechanisms can be applied to core network, but the bottleneck is in radio interface
– One QoS profile per PDP address • No per flow QoS
23
• Why QoS in UMTS is important ? – 1G cellular system (AMPS)
• analog voice/circuit switch (radio network) – 2G cellular system (GSM)
• digital voice/circuit switch (radio network) – 2.5G cellular system (GPRS)
• digital data/packet switch (radio network) • Address QoS issues but not required to implement
– 3G cellular system (3GPP R99/R4) • digital voice/data/packet switch (radio network) • WCDMA introduced •• QoS QoS features are design in and ready for providing packet voicefeatures are design in and ready for providing packet voice
– Beyond 3G (3GPP R5/R6) • digital voice/data/packet switch (radio and core network)
24
• General ideas - Initiate
UE
SGSN GGSN
4 : RAB establishment
5 : PDP Modification if required
5‘ : IP QoS re-mapping if required
25
• General ideas – Modify and Roaming
RNC
UE SGSN GGSN
RNC
26
• QoS profile configuration
PDP Context #3
PDP Context #2
PDP Context #1
UE HLRRNC SGSN GGSN
27
• UMTS Bearer Service – Traffic classes
Traffic class Conversational class
Background Background best
effort Fundamental characteristics
- Preserve time relation (variation) between information entities of the stream Conversational pattern (stringent and low delay )
- Preserve time relation (variation) between information entities of the stream
- Request response pattern - Preserve payload content
- Destination is not expecting the data within a certain time - Preserve payload content
Example of the application
28
• QoS Attributes (QoS profile) Traffic class Conversational
class Streaming class Interactive class Background class
Maximum bitrate (kbps) < 2 048 (1) (2) < 2 048 (1) (2) < 2 048 - overhead (2) (3)
< 2 048 - overhead (2) (3)
Delivery order Yes/No Yes/No Yes/No Yes/No Maximum SDU size (octets)
<=1 500 or 1 502 (4) <=1 500 or 1 502 (4) <=1 500 or 1 502 (4) <=1 500 or 1 502 (4)
SDU format information (5) (5) Delivery of erroneous SDUs
Yes/No/- (6) Yes/No/- (6) Yes/No/- (6) Yes/No/- (6)
Residual BER 5*10-2, 10-2, 5*10-3, 10-3, 10-4, 10-6
5*10-2, 10-2, 5*10-3, 10-3, 10-4, 10-5, 10-6
4*10-3, 10-5, 6*10-8 (7) 4*10-3, 10-5, 6*10-8 (7)
SDU error ratio 10-2, 7*10-3, 10-3, 10-4, 10-5
10-1, 10-2, 7*10-3, 10-3, 10-4, 10-5
10-3, 10-4, 10-6 10-3, 10-4, 10-6
Transfer delay (ms) 100 up to FFS (9) 250 up to FFS (9) Guaranteed bit rate (kbps)
< 2 048 (1) (2) < 2 048 (1) (2)
Traffic handling priority 1,2,3 (8) Allocation/Retention priority
1,2,3 (8) 1,2,3 (8) 1,2,3 (8) 1,2,3 (8)
29
• Radio access bearer – Attributes mapping from Radio access bearer attributes
(implementation dependent) • Spreading code format • Turbo encoder format • Interleaver • Open-loop power control threshold • Usage of RLC acknowledge
30
QoSQoS in UMTS Networks (Cont.)in UMTS Networks (Cont.)
• Core Network Bearer Services – Operator’s option to use QoS capabilities in IP or ATM
layer • IP-based backbone
– Interoperation with IP-based backbone is based on DiffServ
– Mapping from UMTS QoS classes to DiffServ codepoint • Operator controls the mapping, depending on bandwidth and
resource provisioning among DiffServ classes • Interoperability between operators based on Service Level
Aggrements
31
SGSN GGSN HLR
PDP Context #3
PDP Context #2
PDP Context #1
• Subscriber attaches to network
4 Attach Acpt.
• PDP context, QoS profile, traffic flow template, and packet filters
SGSNRNC PDP Context Act.
Same PDP Address Different NSAPI
Different QoS
Different QoSPDP Context
Same PDP Address Different NSAPI
Different QoS
PDP Context
TFT TFT
• PDP context, QoS profile, traffic flow template, and packet filters
SGSNUE GGSNRNC Incoming packet
different QoS
PDP Context
different QoS
• Protocol stack
• Admission control and QoS session establishment
SGSNUE RNC GGSN Host
GGSN may further restrict the QoS given its
capabilities and load
4 RAB Setup (QoS Neg.)
RRM Algorithms 5 RL/RB Establishment
6 RAB Est. Rsp.
1 Activate PDP Context Req. (QoS Req.)
SGSN may restrict the requested QoS given its capabilities, load and the
subscribed QoS
* continue* continue
• Admission control and QoS session establishment (Cont.)
SGSN GGSN Host
MS either accepts the QoS or deactivates the PDP context
7 Update PDP Context Req. (QoS Neg.)
8 Update PDP Context Rsp. Not used in UMTSNot used in UMTS
UE RNC
9 Activate PDP Context Acpt. (Q
In case QoS was downgraded by RNC, SGSN may inform GGSN about the new QoS
37
• Secondary PDP Context Activation
SGSNUE RNC GGSN Host
capabilities and load
4 RAB Setup (QoS Neg.)
RRM Algorithms 5 RL Establishment
6 RAB Est. Rsp.
1 Activate PDP Context Req. (QoS Req., TFTTFT)
SGSN may restrict the requested QoS given its capabilities, load and the
subscribed QoS
* continue* continue
• Secondary PDP Context Activation (Cont.)
SGSN GGSN Host
MS either accepts the QoS or deactivates the PDP context
7 Update PDP Context Req. (QoS Neg.)
8 Update PDP Context Rsp. Not used in UMTSNot used in UMTS
UE RNC
9 Activate PDP Context Acpt. (Q
In case QoS was downgraded by RNC, SGSN may inform GGSN about the new QoS
39
• QoS setup procedures (control plane)
Transl. Transl.
Adm. Contr
RAB Manager
3. RAB4. RB 5. CN Bearer (opt.)
6. Ack. (UMTS Bearer)
• PDP context modification – SGSN-initiated
– PDP context preserved for backgroup/interactive traffic class – PDP context preserved for streaming/conversational traffic class
with max. bit rate = 0 kbps
41
• QoS control during handovers – Inter RNC handovers
• SRNS relocation – Inter SGSN handovers
• Inter SGSN handover
• Serving SRNS Relocation (soft handover)
Old SGSN Source RNC New SGSN
Target RNC GGSN
1 Relocation Required (Source ID, Target ID, SRNCSRNC-->TRNC container>TRNC container) 2 Forward Rel. Req. (PDP context(PDP context)
3 Relocation Req. (SRNC(SRNC-->TRNC container>TRNC container, RABsRABs))
Establishment of RABs/RBs 4 Relocation Req. Ack. (RABs(RABs OK, OK, RABsRABs fail)fail)
5 Forward Rel. Rsp. 6 Relocation Command
7 Relocation commit
• Serving SRNS Relocation (soft handover) (Cont.)
Old SGSNUE Source RNC New SGSN
Target RNC GGSN
9 Relocation Detect 10 Update PDP Context Req. (QoS(QoS Neg.Neg.) 11 Update PDP Context Rsp.
10a UTRAN mobility info
12 Relocation complete
15 Iu release Com/complete
• Inter SGSN RA update
Old SGSNMS RNC GGSN
1 RA Update Req.
New SGSN
5 RA Update Acpt./Complete …
UE RAN SGSN GGSN UE
N or NN or N--11 TFTs
IP xxx IP xxx
NN TCP/UDP Flows
NSAPI-1 NSAPI-1 TFT
RB ID-1 RB ID-1
N N NSAPIs
N N GTP-U 1 1 Iu
1~N1~N PDP Context 11--NN PDP Context
• QoS control (user plane) PDP Context
* We assume there are * We assume there are NN PDP ContextsPDP Contexts M M RBs (SRBs)
46
• QoS control (user plane)
Fast QoS Control
Fast QoS Control
• 3G R5
Gi
Mg
Mc
Gr
Cx
Mm
Gi
Gn
Iu
Gc
Mi
SGSN
Ga
Gi
48
4. 100 Trying
18. GPRS:Activate PDP context accept
19. COMET
25. PRACK 26. PRACK
27. 200 OK (PRACK)
28. 200 OK (PRACK)
32. 200 OK (INVITE)
29. 200 OK (INVITE)
33. ACK 34. ACK
14. COPS: REQ (Activate PDP context)
16. COPS: RPT (Activate PDP context)
15. COPS: DEC (Policy information)
31. COPS: RPT (Report outcome)
30. COPS: DEC (Open "gate")
49
QoSQoS in 3G All IP (Cont.)in 3G All IP (Cont.)
• Framework for QoS mapping between IMS and GPRS
P-CSCF
GGSN
1 : Authorize QoS
QoSQoS in 3G All IP (Cont.)in 3G All IP (Cont.)
• Framework for generating requested QoS parameters in the UE
Application
(SDP)
UE
QoSQoS in 3G All IP (Cont.)in 3G All IP (Cont.)
• Authorize QoS resources at originating PCF
UE GGSN P-CSCF PCF
SDP
SDP
SDP
SDP
3. QoS authorisation
QoSQoS in 3G All IP (Cont.)in 3G All IP (Cont.)
• Mobile Originated without End to End RSVP (Activation)
UE P-CSCF PCFSGSN GGSN
2. Activate PDP Req.
3. Create PDP Req.
8. Create PDP Res.
9. Activate PDP Acc.
5. Process resource request
• Seamless Roaming in Heterogeneous Wireless Networks
3G/2.5G/2G Core Network3G/2.5G/2G Core Network
Enterprise IntranetEnterprise Intranet
• QoS Concerns for Roaming in Heterogeneous Networks
3G/2.5G/2G Core Network3G/2.5G/2G Core Network
Enterprise IntranetEnterprise Intranet
• Logical View of End-to-End IP QoS
End to End IP Bearer Radio Access Bearer CN Bearer Backbone Bearer CN Bearer Radio Access Bearer
End to End IP Bearer Radio Access Bearer CN Bearer Backbone Bearer CN Bearer
End to End IP Bearer Radio Access Bearer CN Bearer Radio Access Bearer
…
• Generic End-to-End QoS Architecture
UE:User Equipment RAN:Radio Access Network CN:core network (or intranet) Backbone:Backbone network (or Internet)
L2 QoS Control & Admission Control L3 QoS Control & Admission Control QoS Translator
57
• Generic Handoff Models in Heterogeneous Wireless Networks
InterInter--RAN (L2) HandoffsRAN (L2) Handoffs WLAN AP - WLAN AP, UMTS RAN - UMTS RAN, UTRAN – GERAN, UTRAN - BRAN
CN BackboneUE RAN
IntraIntra--CN HandoffsCN Handoffs UMTS SGSN - UMTS SGSN, Intranet Router – Intranet Router
InterInter--CN HandoffsCN Handoffs UMTS PLMN - UMTS PLMN Router - Router InterInter--system Handoffssystem Handoffs UMTS - WLAN
58
• QoS for Inter Radio Access Network Handoffs
L2 L2 QoSQoS
L3 L3 QoSQoS
L2 L2 QoSQoS
L3 L3 QoSQoS
•Radio resource management (RRM) •Heterogeneous radio resource management (Heterogeneous RRM) •Frame synchronization for soft/hard handoffs •QoS renegotiation
59
• QoS for Intra/Inter Core Network Handoffs
L2 L2 QoSQoS
L3 L3 QoSQoS
L2 L2 QoSQoS
L3 L3 QoSQoS
UE RAN CN Backbone CN RAN UE
UE RAN CN
• QoS for Inter System Handoffs
L2 L2 QoSQoS
L3 L3 QoSQoS
L2 L2 QoSQoS
L3 L3 QoSQoS
UE RAN CN
• Mobile IP for Intersystem Handoffs
InternetInternet
Router Gateway
• Mobile IP Problems+ and Recent Development
InternetInternet
Router Gateway
Latency Latency <ietf<ietf--mipv6mipv6-- hierarchicalhierarchical
MobileMobile--initiated or initiated or networknetwork--initiated initiated
handoffs for handoffs for Seamless roamingSeamless roaming <<ietfietf--fastfast--mipv6>mipv6>
63
• QoS Problems for Intersystem Handoffs
InternetInternet
Router Gateway
MS
MS
HA/FA
HA/FA
Host
QoSQoS profile profile needs to be needs to be transferred transferred
during handoffsduring handoffs
Resource alone the new Resource alone the new routing path should be routing path should be reserved in advanced reserved in advanced
for some for some APsAPs
QoS QoS Profile should be Profile should be renegotiated with new renegotiated with new systems and translated systems and translated to new to new QoS QoS profileprofile
64
ConclusionsConclusions
• GPRS suffers from design defects to support QoS • Maybe it is not required to build in QoS features in GPRS
– Radio interface is the bottleneck – The range of the QoS that radio interface can offer is quite different
from these of the fixed network. It does not make sense to map two scales which have a large gap
•• QoSQoS is required for 3G and is a MUST for B3Gis required for 3G and is a MUST for B3G • QoS features for 3G system such as UMTS has already designed has already designed
inin •• Take Take QoS QoS into consideration for 3G productsinto consideration for 3G products or deployment deployment
of 3G system of 3G system –– will also help you to move to B3G smoothlywill also help you to move to B3G smoothly
QoS Issues in GPRS/UMTS Networks
Outline
QoS in UMTS Networks
QoS in 3G All IP (Cont.)
QoS in 3G All IP (Cont.)
QoS in 3G All IP (Cont.)
QoS in 3G All IP (Cont.)
End-to-End QoS in Heterogeneous Wireless Network
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
End-to-End QoS in Heterogeneous Wireless Network (Cont.)
Conclusions