Upload
youssouf-doumbia
View
137
Download
7
Embed Size (px)
Citation preview
Objectives
• BICC application in R4 network
• BICC protocol structure and message introduction
• BICC signaling flow
Upon completion of this course,you will be able to:
The Architecture of 3G R4
MGW
Signalling and Data Transfer Interface
Signalling Interface
UTRAN PSTN/ Legacy/External
HLR Applications & Services
MSC server GMSC server
Mc
D C
MGW Nb
Nc
Iu
Iu
CAP CAP
Mc
GERAN
A
A
BICC apply in the Nc interface
Basic concept
Outgoingprocedures
Incomingprocedures
BCF
Call Service Function (CSF)
BIWF
SERVING NODE (SN)
Bearer Control SignallingBearer Control Signalling
Bearer
SCOPE OF THISRECOMMENDATION
Call Control Signalling(BICC protocol or
other signallingsystem)
Call Control Signalling(BICC protocol or
other signallingsystem)
Call Bearer Control (CBC)signalling
Serving node:
Basic concept• SN types
– ISN : provides the interface with non-BICC networks and terminal equipment
– GSN : provides gateway functionality between two network domains
– TSN : provides transit functionality between ISNs and GSNs
Basic concept
Call Service Function (CSF)
Bearer Control Function (BCF)
Serving Node (SN)
Call Control Signaling (BICC protocol)
Call Control Signaling (BICC protocol)
Bearer Control Signaling Bearer Control Signaling
Bearer
Main scope of the BICC specification
Separation between call and bearer
Network model of BICC
ISUP CC
BAT ASE
APM ASE BICC
ASE
BCF
Interface Serving Node (ISN)
CC
BAT ASE
APM ASEBICC
ASE
BCF
Transit Serving Node (TSN)
BAT ASE
APM ASE BICC
ASE
BCF
BICC signaling
Bearer control signaling
Bear Bear Bear
Bearerstreams
BICC protocol Model
• Signalling Transport Layer : MTP3 for TDM NetworkSCTP over IP for IP networkSSLOP for TAM network
• STC : Signalling Transport Converters. Mapping function according to underlying layers
SignallingTransport
Layers
BICC procedures
genericinterface
call controlprotocol
bearerspecificinterface
bearer controlprotocol
BearerControl
MappingFunction
genericinterface
transportspecificinterface
SignallingTransportConverter
Structure of the Protocol Stack
BICC
SCTP
IP
MAC
L1
(G)MSC ServerNc
MSC Server
c) SCTP/IP based
NcMSC Server
d) ATM based
(G)MSC Server
BICCBICC
SCTP
IP
MAC
L1
STC
SAAL
AAL5
MTP3B
ATM
PL
BICC
STC
SAAL
AAL5
MTP3B
ATM
PL
BICC
MTP3
MTP2
MTP1
(G)MSC ServerNc
MSC Server
a) TDM based
(G)MSC ServerNc
MSC Server
b) M3UA based
BICC
L1
BICC
M3UA
IP
MAC
L1
BICC
MTP3
MTP2
MTP1
SCTP
M3UA
IP
MAC
SCTP
BICC
SCTP
IP
MAC
L1
(G)MSC ServerNc
MSC Server
c) SCTP/IP based
NcMSC Server
d) ATM based
(G)MSC Server
BICCBICC
SCTP
IP
MAC
L1
STC
SAAL
AAL5
MTP3B
ATM
PL
BICC
STC
SAAL
AAL5
MTP3B
ATM
PL
BICC
MTP3
MTP2
MTP1
BICC
MTP3
MTP2
MTP1
(G)MSC ServerNc
MSC Server
a) TDM based
(G)MSC ServerNc
MSC Server
b) M3UA based
BICC
L1
BICC
M3UA
IP
MAC
L1
BICC
MTP3
MTP2
MTP1
BICC
MTP3
MTP2
MTP1
SCTP
M3UA
IP
MAC
SCTP
BICC Message StructureCIC
Message type code
Mandatory fixed part
Mandatory variable part
Optional part
Call Instance Code (CIC) is a logic number associated with
the inter-office calling relation
Format of BICC messages• CIC is used to identify signalling relation between peer BICC entities and associate all the PDUs to
that relation.
• message type code
• the mandatory fixed part
• the mandatory variable part
• the optional part, which may contain fixed length and variable length parameter fields
Blocking and Unblocking of CIC
• All outgoing non test calls are blocked using those CIC values
• Incoming non test call with those CIC leads to error case
• Incoming Test calls with those CIC values are permitted to be carried out
• Outgoing test calls using those CIC values are also permitted
Main message of BICC protocol
IAM : Initial address messageAPM : Application transport messageACM : Address complete messageANM : Answer message REL : ReleaseRLC : Release complete
Chap3 signaling flow
3.1 BICC bearer establish mode3.1 BICC bearer establish mode
3.2 forward bearer establish
3.3 backward bearer establish
3.4 tunnel
3.5 CODEC negotiation
3.6 call release
Basic Call Setup• Forward Bearer Setup
No Tunnel caseFast Tunnel
Delayed Forward Tunnel
• Backward Bearer Setup No Tunnel CaseDelayed Backward Tunnel
Forward Bearer Setup• Bearer setup is initiated in the forward direction of the call
• CSF decides whether bearer setup will be in forward direction or in backward direction
• CSF decides if tunnelling is supported. BCF decides if tunnelling is used
• Tunnelling is carrying Bearer Control Info embedded in BICC messages
Chap3 signaling flow
3.1 BICC bearer establish mode
3.2 forward bearer establish3.2 forward bearer establish
3.3 backward bearer establish
3.4 tunnel
3.5 CODEC negotiation
3.6 call release
Forward Establish Flow
CSF
BCF-N
CSF
IAM (Action = Connect Forward), (BNC characteristics)
Bearer Set-up req. (BNC-ID=y1), (BIWF-Addr=y)
Bearer-Setup-Connect
IAM
ACM
ACM ANM
ANM
CSF-N
BCF-N
ISN-B
IAM (COT on previous), (Action = Connect Forward) , (BNC characteristics)
Bearer Set-up req. (BNC-ID=z1), (BIWF-Addr=z)
Bearer-Setup-Connect
ACM
ANM
“BBB”
COT
APM (Action = Connect Forward, no notification) (BNC-ID=y1), (BIWF Addr=y)
APM (Action = Connect Forward, no notification) (BNC-ID=z1), (BIWF Addr=z)
BICC BICC
BCF-N (z) (y)
“AAA”
ISUP ISUP
ACM
ANM
(x)
Chap3 signaling flow
3.1 BICC bearer establish mode
3.2 forward bearer establish
3.3 backward bearer establish3.3 backward bearer establish
3.4 tunnel
3.5 CODEC negotiation
3.6 call release
Backward Establish Flow
CSF-N
BCF-N (x)
CSF-T
IAM (Action = Connect backward), (BNC-ID=x1), (BIWF-Addr=x) , (BNC
characteristics)
Bearer Set-up req. (BNC-ID=x1), (BIWF-Addr=x)
Bearer-Setup-Connect
IAM
ACM
ACM
ANM
ANM
CSF-N
BCF-N
IAM (Action = Connect backward), (COT on previous), (BNC-ID=y1), (BIWF-
Addr=y) , (BNC characteristics)
Bearer Set-up req. (BNC-ID of BIWF y), (BIWF-Addr=y)
Bearer-Setup-Connect
ACM
ANM
“BBB”
COT
BICC BICC
BCF-N (y)
“AAA”
ISUP ISUP
ACM
ANM
(z)
Chap3 signaling flow
3.1 BICC bearer establish mode
3.2 forward bearer establish
3.3 backward bearer establish
3.4 tunnel3.4 tunnel
3.5 CODEC negotiation
3.6 call release
Tunnel• Bearer Setup Messages (IPBCP) are sent embedded in BICC messages
• Fast Tunnel : Tunnel data transferred in first IAM message
1: Tunnel Info
5: APM (tunnel data)
2: IAM (tunnel data)
4: Tunnel Info 6: Tunnel Info 3: Tunnel Info
CSF
BCF
CSF
BCF
Tunnel Contd…• Forward Delayed Tunnel : Tunnel data not transferred in first IAM message or in
first backward APM message , Starts from first forward direction APM message
3: Tunnel Info
2: APM (tunnel data)
1: IAM (tunnel data)
6: Tunnel Info 8: Tunnel Info 5: Tunnel Info
CSF
BCF
CSF
BCF
4: APM (tunnel data)
7: APM (tunnel data)
Tunnel contd…• Backward Delayed Tunnel : Tunnel data not transferred in first IAM message , but
starts from first APM message in backward direction
6: Tunnel Info
4: APM (tunnel data)
1: IAM (tunnel data)
2: Tunnel Info 5: Tunnel Info 3: Tunnel Info
CSF
BCF
CSF
BCF
Chap3 signaling flow
3.1 BICC bearer establish mode
3.2 forward bearer establish
3.3 backward bearer establish
3.4 tunnel
3.5 CODEC negotiation3.5 CODEC negotiation
3.6 call release
Codec Negotiation• The Supported Codec List is constructed and contains all the codecs, in priority order, that are
offered for use in the call from the SN initiating codec negotiation.
• Intermediate SN will delete the codecs from the received Supported Codec List which it cannot support and is passed to next SN
• Terminating SN selects the codec with highest priority in the received Supported Codec List that can be supported by it. This is selected codec. This is passed to previous SN.
Codec Negotiation contd.
CSF-N
BCF-N (x)
ISN-A
CSF-T
TSN
IAM (Action = Connect backward), (Codec list) (BNC-ID=x1), (BIWF-Addr=x) , (BNC
characteristics)
Bearer Set-up req. (BNC-ID=x1), (BIWF-Addr=x)
Bearer-Setup-Connect
IAM
ACM
ACM
ANM
ANM
CSF-N
BCF-N
ISN-B
IAM (Action = Connect backward), (Codec list) (COT on previous), (BNC-ID=y1), (BIWF-
Addr=y) , (BNC characteristics)
Bearer Set-up req. (BNC-ID=y1), (BIWF-Addr=y)
Bearer-Setup-Connect ACM
ANM
BICC BICC
BCF-N (y)
“AAA”
ISUP ISUP
ACM
ANM
(z)
APM (Action = Selected codec), (Selected codec), (Available codec list)
APM (Action = Selected codec), (Selected codec), (Available codec list)
Chap3 signaling flow
3.1 BICC bearer establish mode
3.2 forward bearer establish
3.3 backward bearer establish
3.4 tunnel
3.5 CODEC negotiation
3.6 call release3.6 call release
Release• CSF receiving REL, initiates bearer release towards the sender of REL if
this CSF initiated bearer setup before and then sends back RLC
• CSF sending REL to the other CSF, waits until it gets RLC and then initiates bearer release towards the sender of RLC, if this CSF initiated bearer setup before
Release while forward bearer establishment
CSF-N
ISN-A
CSF-T
TSN
CSF-N
ISN-B BICC BICC
REL
REL REL
REL
BCF-N
RLC
RLC
RLC RLC
Bearer release req.
Bearer release Ack.
BCF-N BCF-N
Bearer release Ack.
Bearer release Req.
ISUP ISUP
Release while Backward bearer establishment
CSF-N
ISN-A
CSF-T
TSN
CSF-N
ISN-B BICC BICC
REL
REL REL
REL
BCF-N
RLC
RLC
RLC
RLC Bearer release req.
Bearer release Ack.
BCF-N BCF-N
Bearer release req.
Bearer release Ack.
ISUP ISUP
Example of call setup in caller MSC Server, Forward no tunnel case
666 CC BICC MGRM STC
Setup (Forward, no tunnel, no MGW ID, Initiator)
IAM (connect forward, no tunneling control info IE is present, COT to be expected)
Setup Ack APM(Connect forward, plus notification, BNC id, BIWF address,succeeding MGW-ID)
Bearer Establish (MGW-ID2,no tunneling supported, send/receive, BNC id, BIWF addr)
Info (context id/context id2, termination id)
Bearer Establish Ack ( no tunneling, context id, termination id)
Info (MGW_ID1, MGW ID2)
Info (APM Ind, BIWF address succeeding MGW-ID)
Bearer Established
Bearer Prepare ( MGW-ID2, context id) (when MGW-ID1
<>MGW-ID2,execute internal connection)
Bearer Prepare Ack (context id, termination id, MGW-ID2 address)
Bearer Establish (MGW-ID1,MGW-ID2 address)
Bearer Esstablish (context id2 termination id, MGW-ID2 address)
Example of call setup in MSC Server contd.
666 CC BICC MGW_RM STC
Continuity
COT
ACM Alerting
Answer
Connect Ack
ANM
APM (Connected) << is sent only plus notification>>
Few CBC Methods used for Codec negotiation and codec modification
• Reserve Char to reserve the necessary resources for all specified bearer service characteristics or codecs.
• Confirm Charto confirm one particular codec or one bearer service characteristics to be used and others resources if allocated previously to be released
• Modify Charto change a codec or a bearer service characterstics
Backward bearer setup with Codec Negotiation in caller MSC
CC BICC MGW_RM STC
Setup (MGW-ID1,MGW-ID2, backward, no tunnel,codec list, init iator
IAM (connect forward, BIWFaddress, BNC id, no tunnelingindication)
Info (context id,termination id1 )
Bearer Prepare ( no tunnelsupport, codec list , send/receive,context id)
Bearer Prepare Ack(no tunnel,termination id2, BNC id, BIWF addr)
ACM
Alerting
AnswerANM
Setup Ack
Info (context id,termination id2
APM (connect backward selectedcodec, available codec list)
Confirm Char(selected codec)
Confirm Char AckInfo (selected codec,available codec list)
Continuity
COT
Release of Call• Outgoing side while bearer setup was forward • Incoming side while bearer setup was in
the forward direction
CC BICC STC
Release
Release bearer
Release bearer Ack
Release Complete
MGW_RM
REL
RLC
CCBICCSTC
Release
MGW_RM
REL
Release CompleteRLC
Termination ReleaseAck
Termination Release
Bearer Released