protocols ladp
TRANSCRIPT
![Page 1: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/1.jpg)
1GSM Network and Services 2G1723 Johan Montelius
GSM Network and Services
Interfaces and protocols - even more three letter acronyms
![Page 2: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/2.jpg)
2GSM Network and Services 2G1723 Johan Montelius
Interfaces
HLR
VLR
BSC
MSC
AA-bis
Um
B
C
EIR
F
D
G
VLR
E
MSC
![Page 3: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/3.jpg)
3GSM Network and Services 2G1723 Johan Montelius
Signaling protocols BSS
LAPDm LAPDm LAPD
radio radio E1
LAPD
E1
RR BTSM BTSM
RRRR
MM
CM
Um Abis A
![Page 4: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/4.jpg)
4GSM Network and Services 2G1723 Johan Montelius
Signaling protocols BSS
LAPDm LAPDm LAPD
radio radio E1
LAPD
E1
RR BTSM BTSM
RRRR
MM
CM
• LAPD – Link Access Procedure D channel, the link layer defined for ISDN, provides retransmission, error detection ...
• E1 – the physical layer most often used for ISDN, 30 traffic channels and one signaling channel all of 64kbps
![Page 5: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/5.jpg)
5GSM Network and Services 2G1723 Johan Montelius
Signaling protocols BSS
LAPDm LAPDm LAPD
radio radio E1
LAPD
E1
RR BTSM BTSM
RRRR
MM
CM
• RR – radio resource management
– idle mode: monitoring broadcast channels
– dedicated mode: request, measure quality, power control, handover, syncronization of encryption, ...
• BTSM – BTS management, the BSC controls the radio resources of the BTS
BSCBTSMS
![Page 6: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/6.jpg)
6GSM Network and Services 2G1723 Johan Montelius
Signaling protocols – MS/BSC/MSC
MTP2
MTP1
MTP3
SCCP
DTAP
MTP2
MTP1
MTP3
SCCP
DTAP
MM
CM
SS7
BSC MSC
RR
![Page 7: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/7.jpg)
7GSM Network and Services 2G1723 Johan Montelius
SS7 – signaling system number 7
• MTP – message transfer part, defines layer one to three. – MTP1: could be E1
– MTP2: link layer, error detection, retransmission...
– MTP3: addressing in the form of signaling points, one interface has a unique address, limited address range
• SCCP – signaling connection control part– segmentation, global addressing, sub addressing
(similar to UDP ports), each mobile has a MSC unique SCCP address
![Page 8: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/8.jpg)
8GSM Network and Services 2G1723 Johan Montelius
DTAP/MM/CM
• Direct transfer application part – Will enclose a MM message so that it
is transparently shipped over the BSC and BT to the MM layer at the mobile phone
• Mobility management– location area updating, paging,
authentication ...
• Connection Management– Call control, SMS, supplementary
services
MTP2
MTP1
MTP3
SCCP
DTAP
MM
CM
MSC
![Page 9: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/9.jpg)
9GSM Network and Services 2G1723 Johan Montelius
Signaling protocols – BSC/MSC
MTP2
MTP1
MTP3
SCCP
BSSAP
MTP2
MTP1
MTP3
SCCP
BSSAP
BSC MSC
• BSS Application Part – the MSC will direct the BSC, for example when doing handover between two BSCs
![Page 10: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/10.jpg)
10GSM Network and Services 2G1723 Johan Montelius
Signaling protocols – MSC/HLR/VLR/...
MTP2
MTP1
MTP3
SCCP
• TCAP - transaction capabilities application part, defined in the SS7 stack
• MAP – mobile application part, this is the application layer protocol used by the nodes for example register updating and query
TCAP
MAP
![Page 11: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/11.jpg)
11GSM Network and Services 2G1723 Johan Montelius
Which are important
• MAP
• BSSAP / BTSM
• CM
• MM
• RR
• LAPDm
• Radio
• ... and of course the traffic channels
![Page 12: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/12.jpg)
12GSM Network and Services 2G1723 Johan Montelius
Services – what is offered
• Bearer services
– basic bit pipes in various sizes
• Tele services
– Speech, SMS, fax, teletext ...
• Supplementary services
– Controls the tele services
![Page 13: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/13.jpg)
13GSM Network and Services 2G1723 Johan Montelius
Bearer services
• Circuit switched data services
– up to 9.6 kbps
– up to 57.6 kbps using 4x14.4 HSCSD (how)
• Circuit swicthed data comes as:
– tranparent or non-transparent, the network does error detection and retransmission
• GRPS has introduced new bearer services
– data services are migrating to GPRS
![Page 14: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/14.jpg)
14GSM Network and Services 2G1723 Johan Montelius
Teleservices
• Voice, TS11
• Emergency call, TS12
• Fax, TS61
• SMS,
– mobile terminating TS21
– mobile originating TS22
• Message Handling System, TS31
• Teletext TS51 – does anyone use this?
![Page 15: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/15.jpg)
15GSM Network and Services 2G1723 Johan Montelius
Supplementary services
• Call forwading
– always/busy/no reply/not reacable
• Barring
– Outgoing: all or international
– Incoming: all or international when roaming
• Number presentation
• Call waiting
• Multi-party
![Page 16: Protocols LADP](https://reader038.vdocument.in/reader038/viewer/2022100601/55721208497959fc0b8febd8/html5/thumbnails/16.jpg)
16GSM Network and Services 2G1723 Johan Montelius
Transport of voice
Radio
Cipher
Code
GSC
Radio
Cipher
Code
E1 E1E1
GSC A-law
• GSM Speech Code is converted in the TRAU (often in the BSC) to A-law (regular phone voice codec)