1-Tn_ss005_e1_1 Zxwn Msc Server Dimensioning(New Edit)-73

ZXWN MSC Server Dimensioning

Course Objectives

Basic Concept A Interface Iu Interface Mc Interface Nc Interface

Description of Traffic Model

During network planning, the first step is to confirm the traffic model. The traffic model varies with operator, and the planning results from different traffic models are very different.

The traffic model is actually statistics data, so the adopted traffic model during planning is made according to the statistics data of the previous period. However, subscriber actions continuously changes, so the traffic model also continuously changes.


The traffic model usually includes the following parts:

MS-related part: It usually includes the following parameters

Traffic model parameters Reference Values Remarks

Number of calls in busy hours 1.59 Related with subscriber actions, this parameter greatly varies with operator, and with area of the same operator.

Number of video calls for a 3G subscriber in busy hours 0.12 Related with subscriber actions, this parameter is only for

3G subscribers, and greatly varies with operator.

Number of SMSs in busy hours 0.8 Related with subscriber actions, this parameter greatly varies with operator.

Number of LUs in busy hours 2 Related with the network radio planning, this parameter is of little difference between operators.

Number of HOs in busy hours 1 Related with the network radio planning, this parameter is of little difference between operators.

Number of Auths in busy hours 2 Related with the network parameter setting, this parameter is of little difference between operators.

Cross-VLR location update ratio 0.2 Related with the network radio planning, this parameter is

of little difference between operators.

CAMEL subscriber ratio 0.25 This parameter is related with the service development of operators

CRBT subscriber ratio 0.3 This parameter is related with the service development of operators

Mean call duation 60S Related with subscriber actions, this parameter greatly varies with operator.

Mean call duration of video calls fro 3G subscribers 90S Related with subscriber actions, this parameter greatly

varies with operator.



Trunk-related part

Traffic model parameters

Reference Values

Remarks

Erl 0.6It is usually 0.7 or 0.8, having no difference between operators.

Mean call duration 60SRelated with subscriber actions, this parameter greatly varies with operator.


Traffic model parameters Reference Values Remarks

Intra MSC Traffic 0.4 ZTE ASSUMPTION

Inter MSC Transit Traffic 0.15 ZTE ASSUMPTION

MS<->PSTN 0.3 ZTE ASSUMPTION

MS<->Other PLMN 0.3 ZTE ASSUMPTION

CRBT Holding Time (S) 15 ZTE ASSUMPTION

Networking Planning Procedure

Networking Planning Procedure Network planning has two cases. In one case, a new network is built. In the other case, one or more Network Elements

(NEs) are added to an existing network.

Networking Planning Procedure

Networking planning procedure mainly contains the following steps: Plan the network capacity and subscriber distribution,

including the subscriber capacity of each local network. Plan the networking scheme of the network, including

NE distribution and design. Plan the networking scheme of the bearer network, and

the bearer type to be adopted. Plan the networking scheme of the service network. Plan the networking scheme of the operation and

maintenance network (billing, network management and other systems).

Plan the networking scheme of the equipment.

Course Objectives


A Interface

MSCSBSC

VLAN/MACIP

SCTPM3UASCCP

BSSAP

A Interface

Lu FlowNo. Message Name Message Direction Packet Length

(SCCP Layer)

1 CR(InitUE(LU Req)) BSC → MSC 61

2 CC MSC → BSC 9

3 DT1(DT(LU Accept)) MSC → BSC 17

4 DT1(DT(TMSI ReAlloc Compete))

BSC → MSC 12

5 DT1(DT(Clear Command)) MSC → BSC 13

6 DT1(DT(Clear Complete）） BSC → MSC 10

7 RLSD MSC → BSC 9

8 RLC BSC → MSC 7

Total number of BSC → MSC packets

4 90

Total number of MSC → BSC packets

4 48

MONo. Message Name Message

Direction

Packet Length (SCCP Layer)

1 CR(InitUE(CM service request)) BSC → MSC 55

2 CC MSC → BSC 9

3 DT1(DT(CM service accept)) MSC → BSC 12

4 DT1(DT(Setup)) BSC → MSC 29

5 DT1(DT(Call proceeding)) MSC → BSC 12

6 DT1(DT(Assignment Request)) MSC → BSC 28

7 DT1(DT(Assignment Complete)) BSC → MSC 13

8 DT1(DT(Alerting)) MSC → BSC 16

9 DT1(DT(Connect)) MSC → BSC 20

10 DT1(DT(Connect acknowledge)) BSC → MSC 12

11 DT1(DT(Disconnect)) MSC → BSC 15

12 DT1(DT(Release)) BSC → MSC 12

13 DT1(DT(Release complete)) MSC → BSC 12


15 DT1(DT(Clear Complete ）） BSC → MSC 10


17 RLC BSC → MSC 7

Total number of BSC → MSC packets 7 138

Total number of MSC → BSC packets 10 146

MT

No. Message Name Message Direction


1 UDT(Page) MSC → BSC 49

2 CR(InitUE(Page response)) BSC → MSC 54

3 CC MSC → BSC 9

4 DT1(DT(Setup)) MSC → BSC 31

5 DT1(DT(Call confirm)) BSC → MSC 12

6 DT1(DT(Assignment Request)) MSC → BSC 33

7 DT1(DT(Assignment Complete)) BSC → MSC 13

8 DT1(DT(Alerting)) BSC → MSC 12

9 DT1(DT(Connect)) BSC → MSC 12

10 DT1(DT(Connect acknowledge)) MSC → BSC 12

11 DT1(DT(Release)) MSC → BSC 12

12 DT1(DT(Release complete)) BSC → MSC 12







Authentication

No. Message Name Message Direction Packet Length

(SCCP Layer)

1 DT1(DT(AUTH REQ)) MSC → BSC 29

2 DT1(DT(AUTH RESP)) BSC → MSC 16

3 DT1(DT(SECURITY CMD)) MSC → BSC 21

4 DT1(DT(SECURITY CMP ）） BSC → MSC 10

Total number of BSC → MSC packets

2 26

Total number of MSC → BSC packets

2 50

SMS MO

No. Message Name Message Direction Packet Length (SCCP Layer)

1 CR(InitUE(CM service request)) BSC → MSC 55

2 CC MSC → BSC 9

3 DT1(DT(CM service accept)) MSC → BSC 12

4 DT1(DT(CP-DATA)) BSC → MSC 153

5 DT1(DT(CP-ACK)) MSC → BSC 12

6 DT1(DT(CP-DATA)) MSC → BSC 15

7 DT1(DT(CP-ACK))) BSC → MSC 12







SMS MTNo. Message Name

Message Direction


1 UDT(Page) MSC → BSC 49

2 CR(InitUE(Page response)) BSC → MSC 54

3 CC MSC → BSC 9

4 DT1(DT(CP-DATA)) MSC → BSC 152

5 DT1(DT(CP-ACK)) BSC → MSC 12

6 DT1(DT(CP-DATA)) BSC → MSC 15

7 DT1(DT(CP-ACK)) MSC → BSC 12





Total number of BSC → MSC

packets 5 98

Total number of MSC → BSC

packets 6 244

Hand Over Outgoing

No. Message NameMessage Direction


1 DT1(DT(Handover Required)) BSC → MSC 32

2 DT1(DT(Handover Command)) MSC → BSC 23




6 RLC BSC → MSC 7

Total number of BSC → MSC

packets 3 49

Total number of MSC → BSC

packets 3 45

Hand Over Incoming



1 DT1(DT(HandoverRequest))MSC →

BSC72

2DT1(DT(HandoverRequestAcknowled

ge))BSC →

MSC16

3 DT1(DT(Handover Detect))BSC →

MSC13

4 DT1(DT(Handove Complete）） BSC → MSC

13



A Interface

Summary: BSC － MGW signaling traffic

Service Flow

Message Direction Number of Packets Packet Length (SCCP Layer)

LUBSC － MGW 4 90

MGW － BSC 4 48

CALLBSC － MGW 8 159.5

MGW － BSC 8.5 132.5

SMSBSC － MGW 5 167.5

MGW － BSC 6 157

HOBSC － MGW 3 45.5

MGW － BSC 2 58.5

AUTHBSC － MGW 2 26

MGW － BSC 2 50

A Interface

Signaling Traffic Dimensioning---MSCS –BSC BWms-a-bsc-mgw ＝（ Ncall × BWcall-bsc-mscs ＋

Nlu × BWlu-bsc-mscs ＋ Nsms × BWsms-bsc-mscs ＋ Nauth × BWauth-bsc-mscs ＋ Nho × BWho-bsc-mscs ） × 8 / 3600 (bps)

BWx ＝ Message length ＋ Number of messages × Protocol header overhead

BWa-bsc-mscs ＝ Nuser ×BWms-a-bsc-mscs

A Interface

Traffic Model

Since the BSCMSC signaling traffic in most of the flows is heavy, only the BSCMSC signaling traffic is calculated.

Traffic model parameters Values

Ncall 1.69

Nlu 2

Nsms 0.8

Nauth 2

Nho 1

Nuser 1400000*0.6 (stage1)

Protocol Header Overhead

ProtocolsHeader Overhead

（ BYTE） Remarks

MAC8 ＋ 14 ＋ 4 ＋ 8 ＝34

8 bytes are for the lead code, 14 bytes are for the header overhead, 4 bytes are for the tail overhead, and 8 bytes are for the interval between framesA

MAC/VLAN8 ＋ 18 ＋ 4 ＋ 8 ＝38

VLAN header is added

IP 20

SCTP 28

M3UA 40 Adding all the optional items

Bearer Type Possible Combination Header Overhead

IP M3UA/SCTP/IP/VLAN/MAC 126

A Interface

A Interface

For Example BWcall-bsc-mscs =159.5+8*126 ＝ 1167.5 BWlu-bsc-mscs =90+4*126=594 BWsms-bsc-mscs =167.5+5*126=797.5 BWauth-bsc-mscs =26+2*126=278 BWho-bsc-mscs =45.5+3*126=423.5 BWms-a-bsc-mscs ＝（ 1.69 × 1167.5 ＋ 2 × 594 ＋

0.8× 797.5 ＋ 2 × 278 ＋ 1× 423.5 ） × 8 / 3600 =10.62bps

BWa-bsc-mscs =840000*10.62=8.92Mbps

Course Objectives


Iu Interface

RNC

VLAN/MACIP

SCTPM3UASCCP

RANAP

MSCS



AAL5 bandwidth(number)

1 CR （ InitUE （ LU Req）） RNC － > MSCS

99 3

2 CCMSCS － >

RNC8 1

3 DT1 （ DT （ LU Accept）） MSCS － > RNC

45 2

4DT1 （ DT （ TMSI ReAlloc Compete））

RNC － > MSCS

21 1

5 DT1 （ DT （ IuReleaseCmd）） MSCS － > RNC

19 1

6 DT1 （ DT （ IuReleaseComplete）） RNC － > MSCS

14 1

7 RLSDMSCS － >

RNC8 1

8 RLCRNC － >

MSCS7 1

Total number of RNC → MSC packets 4 141 6

Total number of MSC →RNC packets 4 80 5

Iu Interface—LU

Iu Interface—MO call




1 CR （ InitUE （ CM service request））

RNC － > MSCS

91 3

2 CC MSCS － > RNC

8 1

3 DT1 （ DT （ CM service accept）） MSCS － > RNC

19 1

4 DT1 （ DT （ Setup）） RNC － > MSCS

39 2

5 DT1 （ DT （ Call proceeding）） MSCS － > RNC

34 2

6 DT1 （ RAB ASSIGNMENT REQUEST）

MSCS － > RNC

175 5

7 DT1 （ RAB ASSIGNMENT RESPONSE）

RNC － > MSCS

27 2

8 DT1 （ DT （ Alerting）） MSCS － > RNC

21 1

9 DT1 （ DT （ Connect）） MSCS － > RNC

21 1

No. Message NameMessage

Direction Packet Length (SCCP Layer)


10 DT1 （ DT （ Connect acknowledge）） RNC － > MSCS 26 2

11 DT1 （ DT （ Disconnect）） MSCS － > RNC 24 1

12 DT1 （ DT （ Release）） MSCS － > RNC 26 2

13 DT1 （ DT （ Release complete）） RNC － > MSCS 21 1

14 DT1 （ DT （ IU RELEASE COMMAND））

MSCS － > RNC 19 1

15 DT1 （ DT （ IU RELEASE COMPLETE））

RNC － > MSCS 14 1

16 RLSD MSCS － > RNC 8 1

17 RLC RNC － > MSCS 7 1



Iu Interface

No. Message Name Message Direction Packet Length (SCCP Layer)

AAL5 (number)

1 UDT （ Page） MSCS － > RNC 67 2

2 CR （ InitUE （ Page response）） RNC － > MSCS 91 3

3 CC MSCS － > RNC 8 1

4 DT1 （ DT （ Setup）） MSCS － > RNC 51 2

5 DT1 （ DT （ Call confirm）） RNC － > MSCS 30 2

6 DT1 （ RAB ASSIGNMENT REQUEST） MSCS － > RNC 175 5

7 DT1 （ RAB ASSIGNMENT RESPONSE） RNC － > MSCS 27 2

8 DT1 （ DT （ Alerting）） RNC － > MSCS 21 1

9 DT1 （ DT （ Connect）） RNC － > MSCS 40 2

10 DT1 （ DT （ Connect acknowledge）） MSCS － > RNC 21 1

11 DT1 （ DT （ Release）） MSCS － > RNC 26 2

12 DT1 （ DT （ Release complete）） RNC － > MSCS 21 1


MSCS － > RNC 19 1


RNC － > MSCS 14 1





Iu Interface--MT




1 CR （ InitUE （ CM service request）） RNC － > MSCS 92 3

2 CC MSCS － > RNC 8 1

3 DT1 （ DT （ CM service accept）） MSCS － > RNC 39 2

4 DT1 （ DT （ CP-DATA）） RNC － > MSCS 153 4

5 DT1 （ DT （ CP-ACK）） MSCS － > RNC 26 2

6 DT1 （ DT （ IuReleaseCmd）） MSCS － > RNC 19 1

7 DT1 （ DT （ IuReleaseComplete）） RNC － > MSCS 14 1





Iu Interface—SMS originating

Iu Interface—SM terminate

No. Message NameMessage

Direction Packet Length (SCCP Layer)


1 UDT （ Page） MSCS － > RNC

64 2

2 CR （ InitUE （ Page response）） RNC － > MSCS

64 2

3 CCMSCS － > RNC

8 1

4 DT1 （ DT （ CP-DATA）） MSCS － > RNC

152 4

5 DT1 （ DT （ CP-ACK）） RNC － > MSCS

26 2

6DT1 （ DT （ IU RELEASE COMMAND））

MSCS － > RNC

19 1

7DT1 （ DT （ IU RELEASE COMPLETE））

RNC － > MSCS

14 1

8 RLSDMSCS － > RNC

8 1

9 RLCRNC － > MSCS

7 1



Iu Interface--AUTH




1DT1 （ DT （ AUTH REQ））

MSCS － > RNC

61 2

2DT1 （ DT （ AUTH RESP））

RNC － > MSCS

31 2

3DT1 （ DT （ SECURITY CMD））

MSCS － > RNC

65 2

4DT1 （ DT （ SECURITY CMP））

RNC － > MSCS

24 1

Total number of RNC → MSC packets

2 55 3

Total number of MSC →RNC packets

2 126 4

Iu Interface--Relocation




1 DT1 （ DT （ RelocationRequire））

RNC － > MSCS

262 7

2 DT1 （ DT （ RelocationCommand））

MSCS － > RNC

213 6


MSCS － > RNC

19 1


RNC － > MSCS

14 1

5 RLSD MSCS － > RNC

8 1

6 RLC RNC － > MSCS

7 1


3 283 9


3 240 8

Iu Interface




1DT1 （ DT （ RelocationRequest））

MSCS － > RNC

262 7

2DT1 （ DT （ RelocationRequestAck）

RNC － > MSCS

226 6

3DT1 （ DT （ RelocationDetect）

RNC － > MSCS

14 1

4DT1 （ DT （ RelocationComplete）

RNC － > MSCS

14 1


3 254 8


1 262 7

Iu Interface

Summary:RNC － MSCS signaling bandwidth

Service Flow Message Direction Number of

Packets Packet Length

LURNCMGW 4 141

MGWRNC 4 80

CALLRNCMGW 7.5 238

MGWRNC 9 365

SMSRNCMGW 4 188.5

MGWRNC 5 175.5

HORNCMGW 3 537

MGWRNC 2 502

AUTHRNCMGW 2 55

MGWRNC 2 126

Iu Interface

Signaling Traffic Dimensioning---MSCS –RNC BWms-iu-rnc-mscs ＝（ Ncall × BWcall-rnc-mscs ＋

Nlu × BWlu-rnc-mscs ＋ Nsms × BWsms-rnc-mscs ＋ Nauth × BWauth-rnc-mscs ＋ Nho × BWho-rnc-mscs ） × 8 / 3600 (bps)

BWx ＝ Message length ＋ Number of messages × Protocol header overhead

BWiu-rnc-mscs ＝ Nuser ×BWms-iu-rnc-mscs

Traffic Model Values

Ncall 1.69

Nlu 2

Nsms 0.8

Nauth 2

Nho 1

Nuser 1400000*0.4 (stage1)

Traffic Model

Iu Interface

Since the MSCSRNC signaling traffic in most of the flows is heavy, only theMSCSRNC signaling traffic is calculated.

Iu Interface

Protocol Header Overhead

ProtocolsHeader Overhead

（ BYTE） Remarks

MAC8 ＋ 14 ＋ 4 ＋ 8 ＝34

8 bytes are for the lead code, 14 bytes are for the header overhead, 4 bytes are for the tail overhead, and 8 bytes are for the interval between framesA

MAC/VLAN8 ＋ 18 ＋ 4 ＋ 8 ＝38

VLAN header is added

IP 20

SCTP 28

M3UA 40 Adding all the optional items

Bearer Type Possible Combination Header Overhead

IP M3UA/SCTP/IP/VLAN/MAC 126

Iu Interface

For Example BWcall-rnc-mscs =365+9*126 ＝ 1499 BWlu-rnc-mscs =80+4*126=584 BWsms-rnc-mscs =175.5+5*126=805.5 BWauth-rnc-mscs =126+2*126=378 BWho-rnc-mscs =502+4*126=1006 BWms-a-rnc-mscs ＝（ 1.69 × 1499 ＋ 2 × 584 ＋

0.8 × 805.5 ＋ 2 × 378 ＋ 1× 1006 ） × 8 / 3600 =13.57bps

BWa-rnc-mscs =560000*13.57=7.6Mbps

Course Objectives


Mc Interface

MGW

MSCS

VLAN/MACIP

SCTPM3UA

H.248/ISUP

Terminal Role Message Direction Message Length Number

Iu interface MO

MSCS->MGW 724 4MGW->MSCS 746 4

Iu interface MT


Iu interface Handoff

MSCS->MGW 970 5

MGW->MSCS 831 5

IP originating side


IP terminating side


A interface MO


A interface MT


A interface Handoff


Ai interface MSCS->MGW 272 2MGW->MSCS 216 2

Playingannouncement


Mc Interface

1. Analyzing Header Overhead of Protocol Stacks

Protocol Stack Type Protocol Stack Type Remarks

H.248/M3UA/SCTP/IP/VLAN/MAC 126

H.248/SCTP/IP/VLAN/MAC 86

H.248/M3UA/SCTP/IP/MPLS/PPP 102

H.248/SCTP/IP/MPLS/PPP 62

Mc Interface

2. Calculation Method BWmc ＝ Na-term × BWa-term ＋ Niu-term × BWiu-

term ＋ Nnb-ai-tdm-term × BWnb-ai-tdm-term ＋ Nnb-ip-term × BWnb-ip-term

Since the MSCS MGW traffic is most of the flows is greater than the MGW MSCS, only the MSCS MGW traffic is calculated.

Mc Interface

Na-term: Number of terminals at the A interface Niu-term: Number of terminals at the IU interface Nnb-ip-term: Number of RTP channels when the Nb

interface adopts IP Nnb-ai-tdm-term: Number of channels when the Nb

interface adopts TDM + Number of TDM channels of the Ai interface

Mc Interface

BWmc: Total traffic over the Mc interface BWa-term: Taffic of each A interface over the Mc interface BWiu-term: Traffic of each Iu interface over the Mc interface BWnb-ip-term: Traffic of IP terminals of each Nb interface

over the Mc interface BWnb-ai-tdm-term: Traffic of TDM terminals of each Nb

interface over the Mc interface (as same as the traffic of TDM terminals of the Ai interface over the Mc interface)

Mc Interface BWa-term ＝（ Etrunk × 3600 / Dcall ） × (( BWcall-a-

term ＋ Nmess-call×Lpro) ＋ Pho × （ BWho-a-term ＋Nmess-ho×Lpro) ＋ Pcall-fail × （ BWann ＋ Nmess-ann×Lpro)×8 / 3600 (bps)

BWiu-term ＝（ Etrunk × 3600 / Dcall ） × (( BWcall-iu-term ＋ Nmess-call×Lpro) ＋ Pho × （ BWho-iu-term ＋Nmess-ho×Lpro) ＋ Pcall-fail × （ BWann ＋ Nmess-ann×Lpro)×8 / 3600 (bps)

BWnb-ip-term ＝（ Etrunk × 3600 / Dcall ） × ( BWcall-nb-ip-term ＋ Nmess-call×Lpro)×8 / 3600 (bps)

BWnb-ai-tdm-term ＝（ Etrunk × 3600 / Dcall ） × ( BWcall-nb-ip-term ＋ Nmess-call×Lpro)×8 / 3600 (bps)

Mc Interface Etrunk: Trunk circuit Erl Dcall: Mean call duration Nmess-call: Number of call flow messages Nmess-ho: Number of handoff flow messages Nmess-ann: Number of messages during the flow of

playing recorded announcement Lpro: Header overhead for transferring protocols Pho: Handoff ratio Pcall-fail: Call failure ratio BWcall-a-term: Mean length of the A interface terminal

messages in each call flow BWcall-iu-term: Mean length of the Iu interface terminal

messages in each call flow

Mc Interface

BWho-a-term: Mean length of the A interface terminal messages in each handoff flow

BWho-iu-term: Mean length of the Iu interface terminal messages in each handoff flow

BWcall-nb-ip-term: Mean length of the Nb interface IP terminal messages in each call flow

BWcall-nb-tdm-term: Mean length of the Nb interface TDM terminal messages in each call flow

Bwann: Mean length of messages in each flow of playing recorded announcement

Pho=Times of handoffs/calls in busy hours Pcall-fail=1 – Call completion ratio

Mc Interface

3.Suppose the traffic model is as follows.

Traffic Model Parameters Supposed Values

Each interface Erl 0 ． 6

Mean call duration 60S

Handoff probability 0 ． 4

Call failure ratio 0 ． 4

Mc Interface

Required bandwidths of each terminal are as follows.

Terminal Type

Protocol Stack

BWa-term

BWiu-term

Nnb-ip-term

Nnb-ai-tdm-term

H.248/M3UA/SCTP/IP/VLAN/MAC 175 bps 239 bps 173 bps 50 bps

H.248/SCTP/IP/VLAN/MAC 139 bps 189 bps 150 bps 42 bps

H.248/M3UA/SCTP/IP/MPLS/PPP 149 bps 201 bps 159 bps 44 bps

H.248/SCTP/IP/MPLS/PPP 125 bps 172 bps 137 bps 37 bps

Mc Interface

A: Suppose there are 15000 A interface channels, and 500 Nb TDM interface E1s in the system, adopting the H.248/M3UA/SCTP/IP/VLAN/MAC protocol stacks. The traffic over the Mc interface is as follows.

Total traffic over Mc interface ＝ 15000×163 ＋ 500×30×50 ＝3195000bps ＝ 3.195Mbps

3.2 Mbps traffic is reserved in engineering.

Mc Interface

B: Suppose there are 15000 Iu interface channels, and 15000 Nb IP interface RTP channels in the system, adopting the H.248/M3UA/SCTP/IP/VLAN/MAC protocol stacks. The traffic over the Mc interface is as follows.

Total traffic over the Mc interface ＝ 15000×218 ＋ 15000×173 ＝5865000bps ＝ 5.865Mbps

6 Mbps traffic is reserved in engineering.

In CSL case,the BW of H.248

AErl =0.4 , IuErl =0.6, AiErl=0.6, NbErl=0.3

For a single MGW Erlang=40250

As a result, total H.248 message in Mc interface is:

(AErl* BWA-Term + IuErl * BW-Iu-term+ AiErl* BW-Ai-TDM-term+ NbErl* BW-Nb-ip-term)/0.6=40250*(0.4*175+0.6*239+0.6*50+0.3*173)/0.6=19.8 Mbps

Mc interface (ISUP over IP)

Each ISUP bidirectional calling has 354 Bytes For a single MGW Erlang=40250 Number of inter-offic BHCA=Number of CIC to

PSTN&PLMN*Possible Call Attempts on a CIC Number of CIC to PSTN&PLMN=Traffic to PSTN&PLMN/

Average Trunk Load=40250*60%/0.6=40250 Possible Call Attempts on a CIC= Average Trunk

Load/(60/3600)=0.6*3600/60=36 The total possible call attempts on Ai interface is:

40250*0.6/0.6*(0.6*3600/60)* 354*8/3600=1.14 Mbps

Total signaling message between MGW and MSC Sever includes H.248 massage, and ISUP message.

The total message flow between MGW and MSC Sever is:

(MessageH.248 +MessageISUP)= 19.8 Mbps+1.14 Mbps=20.94 Mbps

Course Objectives


Nc Interface

1. Nc Protocol Stack

MSCS1

VLAN/MACI PSCTP

BI CC

MSCS2

MPLS/ PPP

M3UA

Nc Interface

1.TrFO- dalay forward bearer mode.

No. Message Name Direction Length (BICC Layer)

1 IAM Forward 68

2 APM Backward 41

3 APM Forward 184

4 APM Backward 184

5 COT Forward 7

6 ACM Backward 8

7 ANM Backward 21

8 REL Forwardor Backward 12

9 RLC The reverse of the REL 6

The number of messages 9

The Length of messages 531

Nc Interface 3. The lengths of signaling flow with different

protocol stacks

4. traffic model

Protocol Stack Signaling Flow Length

(Single Direction)

BICC/M3UA/SCTP/IP/VLAN/MAC 833

BICC/M3UA/SCTP/IP/MPLS/POS 725

BICC/SCTP/IP/VLAN/MAC 653

BICC/SCTP/IP/MPLS/POS 545

Traffic Model Parameters Parameter Value

Etrunk 0.6

Dcall 60s

Nc Interface

2.Calculation Formula BWnc ＝ Ncic×BWcic (bps) BWnc: Required bandwidth of the Nc interface BWcic: Required bandwidth of each CIC trunk Ncic: Number of the CIC trunks BWcic ＝ (Ecic × 3600 / Dcall)×BWcall×8/3600 (bps) Ecic: CIC trunk Erl Dcall: Mean call duration BWcall: Required bandwidth of each call

Ncic(inter office IP trunk)=total Erlang* Inter MSC ratio/Average Trunk Load=40250*0.15/0.6=10062.5

BWcic ＝ (Ecic × 3600 / Dcall)×BWcall×8/3600 (bps)

=(0.6 × 3600 /60) ×833×8/3600

=66.64 bps

So : BWnc ＝ Ncic×BWcic (bps)

= 10062.5×66.64=670565 bps=671Kbps

Documents

1-Tn_ss005_e1_1 Zxwn Msc Server Dimensioning(New Edit)-73