Nghien Cuu Hoat Dong Va Cach Trien Khai Tong Dai Ip Pbx Asterisk

7/22/2019 Nghien Cuu Hoat Dong Va Cach Trien Khai Tong Dai Ip Pbx Asterisk

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HC VIN CNG NGHBU CHNH VIN THNGC STHNH PHHCH MINH

------oOo------

KHA LUN TT NGHIP I HCNgnh:in t- Vin thng H:Hon chnh i hc Chnh quy

Nin kha:2006 - 2008

ti:

NGHIN CU HOT NGV TRIN KHAI MNG IP PBX ASTERISK

M s: 08406360117

Gio vin hng dn:Ths. Phm nh NguynSinh vin thc hin:Lp:

Nm 2008

Trn Hong Vinh06VTH1


2/69

LI MU

Trong giai on pht trin hin nay, nhiu doanh nghip thay i v pht trinnhiu chi nhnh vi a bn hot ng rng ln. Cng vi spht trin ca cc gii

php IP, spht trin ca hthng mng truyn dliu c bit l Internet. Tt cto iu kin nhng gii php trn nn IP hnh thnh v pht trin. Mt trong sl gii php IP PBX Asterisk cung cp cho doanh nghip gii php in thoi trn nnVoIP, ph hp vi chi ph v yu cu hot ng ca doanh nghip.

Kho lun tt nghip nghin cu vhot ng v cch trin khai tng i IP PBX

Asterisk. c chi lm 5 chng chnh:

Chng 1: Tng quan vtng i IP PBX Asterisk: trnh by cc khi nim chung

c bn lin quan n tng i IP PBX Asterisk.

Chng 2: Ci t tng i IP PBX Aster isk: hng dn ci t thnh cng mttng i IP PBX Asterisk, cc cng chtrtrong vic cu hnh v vn hnh tng i.

Chng 3: Tm hiu cch cu hnh Asterisk: nghin cu su hn vcch cu hnh

cc chc nng trong tng i IP PBXAsterisk.

Chng 4: Xy dng mt tng i thc t: cc bc xy dng mt tng i IP

PBX Asterisk thc txut pht tyu cu ca mt doanh nghip.

Chng 5: nh gi chung v hng mca ti.

Khi vit cun Kha lun tt nghip ny em ht sc cgng c hon chnh,nhng do kin thc cn hn chtrong mi trng Linux v tng i Asterisk nn chcchn skhng trnh khi thiu st, v vy em rt mong nhn c sgp ca quThy C v cc bn.

Em xin chn thnh cm n cc Thy C gio ca Hc vin Cng nghBu chnh

Vin thng - C sTp. HCh Minh, c bit l khoa Vin thng 2 o to, gio

dc em hc hi c nhiu kin thc quan trng v bch. Em cng xin gi li cmn chn thnh n Thy Phm nh Nguyn, ngi Thy nh hng v gip

em rt nhiu hoa thnh cun kha lun ny.

TPHCM, ngy 30 thng 9 nm 2008Sinh vin thc hin

Trn Hong Vinh


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MC LC

CHNG I: TNG QUAN VTNG I IP PBX ASTERISK...................10

1.1 Gii thiu Asterisk - Asterisk l g?................................................................ 101.1.1 Vai tr ca Digium i vi Asterisk............................................................101.1.2 Dn Zapata v cc mi quan hca n vi Asterisk................................11

1.2 V sao chn Asterisk?....................................................................................... 111.2.1 Gim chi ph mt cch mnh m.................................................................111.2.2 Mi trng pht trin nhanh chng v ddng..........................................121.2.3 Giu tnh nng.............................................................................................121.2.4 Ni dung ng trn in thoi.....................................................................121.2.5 Kiu quay slinh hot v mnh..................................................................121.2.6 M ngun mchy trn nn Linux..............................................................12

1.2.7 Cc gii hn trong kin trc ca Asterisk...................................................121.3 Kin trc ca Asterisk..................................................................................... 12

1.3.1 Cc knh...................................................................................................... 13

1.3.2 Codec v chuyn dch codec........................................................................ 141.3.3 Cc giao thc.............................................................................................. 141.3.4 Cc ng dng.............................................................................................. 14

1.4 M ttng quan tng i IP PBX Asterisk....................................................151.5 So snh gia cc loi tng i..........................................................................16

1.5.1 in thoi sdng m hnh PBX/Softswitch c..........................................161.5.2 in thoi dng hthng Asterisk............................................................... 16

1.6 Xy dng mt hthng kim tra .................................................................... 171.6.1 Mt FXO, mt FXS...................................................................................... 171.6.2 Nh cung cp dch vVoIP, ATA................................................................171.6.3 Board FXO khng t tin, ATA.................................................................. 17

1.7 Mt sng dng ca Asterisk......................................................................... 181.7.1 IP PBX......................................................................................................... 18

1.7.2 Sdng IP trong cc tng i PBX c........................................................191.7.3 Bqua chi ph gi in thoi ng di.....................................................201.7.4 Server ng dng (IVR, in thoi hi ngh, Voicemail)...............................201.7.5 Media Gateway........................................................................................... 21

1.7.6 Trung tm giao tip chm sc khch hng - Contact Center Platform (CallCenter)................................................................................................................. 22

1.8 VoIP vi Asterisk............................................................................................. 221.8.1 Cc u im ca VoIP................................................................................. 22

1.8.1.a Tnh hi t.........................................................................................................221.8.1.b Chi ph c shtng........................................................................................231.8.1.c Tiu chun m...................................................................................................231.8.1.d Stch hp gia my tnh v in thoi...........................................................23

1.8.2 Kin trc VoIP ca Asterisk........................................................................231.8.3 Cc giao thc VoIP v m hnh OSI............................................................ 24

1.8.4 Lm sao chn mt giao thc?................................................................. 251.8.4.a SIP - giao thc thit lp phin..........................................................................251.8.4.b IAX - Inter Asterisk eXchange..........................................................................25


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1.8.4.c Giao thc iu khin cng phng tin MGCP...............................................261.8.4.d H.323................................................................................................................261.8.4.e Bng so sch cc giao thc..............................................................................26

1.8.5 User, Peer v Friend................................................................................... 26

1.8.6 Cc codec v chuyn i codec...................................................................271.8.7 Lm sao chn mt codec ph hp........................................................... 271.8.8 Phn mo u do phn Header ca giao thc............................................271.8.9 Kthut lu lng....................................................................................... 28

1.8.9.a Sn gin ho................................................................................................281.8.9.b Phng php ErlangB.....................................................................................28

1.8.10 Gim bng thng yu cu cho VoIP..........................................................291.8.10.a Nn RTP Header.............................................................................................291.8.10.b IAX2 trunk mode.............................................................................................30

1.8.10.c Gim VoIP ti.................................................................................................30

CHNG 2: CI T TNG I IP PBX ASTERISK.................................31

2.1 Ci t tng phn............................................................................................. 312.1.1 Ci t hiu hnh CentOS......................................................................312.1.2 Ci t cc gi trong tng i Asterisk.......................................................36

2.1.2.a Chun bcc tp tin trc khi ci t..............................................................362.1.2.b Compiling v ci t cc gi............................................................................372.1.2.c Ci t Asterisk-GUI........................................................................................40

2.2 Gii thiu Trixbox cc thnh phn................................................................. 412.2.1 Ci t Trixbox............................................................................................ 41

2.3 Cc htrtrong vn hnh v cu hnh Asterisk...........................................442.3.1 Mt slnh chnh trong CLI ca Asterisk...................................................44

2.3.1.a Cc lnh chung ...............................................................................................442.3.1.b Cc lnh cho SIP .............................................................................................442.3.1.c Qun trServer ...............................................................................................44

2.3.2 Cc cng chtrvn hnh v cu hnh Asterisk......................................452.3.2.a Phn mm Putty................................................................................................452.3.2.b Phn mm WINSCP..........................................................................................46

CHNG 3: TM HIU CCH CU HNH ASTERISK...............................48

3.1 Tm hiu cc tp tin cu hnh trong Asterisk.................................................483.2 Ngphp ca Asterisk..................................................................................... 48

3.2.1 Nhm n.................................................................................................... 49

3.2.2 Cc ty chn i tng kiu ngphp tha k...........................................493.2.3 Dng thc thphc hp.............................................................................. 50

3.3 Tm hiu cu hnh mt giao tip PSTN........................................................... 503.3.1 Ci t X100P............................................................................................. 513.3.2 Ci v cu hnh driver card X100P............................................................. 51

3.4 Tm hiu cu hnh in thoi IP SIP............................................................... 513.4.1 Phn chung [general]................................................................................. 513.4.2 Phn Client.................................................................................................. 52

3.5 Tim hiu s quay s..................................................................................... 533.5.1 Sni b(Extensions)................................................................................. 53

3.5.1.a Mt smu s(pattern)....................................................................................533.5.1.b Cc v dvsni b (extensions)..................................................................54

3.5.2 Su tin (Priorities)..................................................................................54


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3.5.3 ng dng (Applications)............................................................................. 543.5.4 Ngcnh (Contexts).................................................................................... 55

3.6 Tm hiu cch to mt s quay s..............................................................563.6.1 V dc bn................................................................................................ 563.6.2 Mt v dkhc............................................................................................. 563.6.3 Cc knh cu ni sdng ng dng dial()..................................................57

3.7 Tm hiu cch to mt hthng IVR..............................................................583.7.1 ng dng background() ............................................................................ 583.7.2 ng dng record() ...................................................................................... 583.7.3 ng dng playback() ................................................................................ 593.7.4 ng dng read() ......................................................................................... 593.7.5 ng dng gotoif() ...................................................................................... 59

3.8 Xy dng mt hthng IVR............................................................................ 593.8.1 Thu m li cho........................................................................................... 603.8.2 To ra hthng IVR.................................................................................... 60

CHNG 4: XY DNG MT TNG I THC T.................................614.1 M tcc bc thc hin................................................................................. 614.2 M tchc nng v hot ng ca tng i...................................................614.3 Cu hnh phn cng......................................................................................... 614.4 Ci t tng i Asterisk................................................................................. 614.5 Chun bv ci t cc thit bFXS, FXO.....................................................614.6 Cu hnh cc thng strong tng i.............................................................654.7 Thit lp cc Client v kim tra cuc gi........................................................66

CHNG 5: NH GI CHUNG V HNG MCA TI...............67

5.1 nh gi chung................................................................................................. 675.1.1 u im....................................................................................................... 675.1.2 Nhng im hn ch.................................................................................... 67

5.1 Hng mca ti........................................................................................ 68

TI LIU THAM KHO..................................................................................... 69


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MC LC CC HNHHnh 1: Kin trc ca Asterisk........................................................................................4

Hnh 2: Tng quan tng i IP PBXAsterisk.................................................................6

Hnh 3: in thoi sdng m hnh PBX/Softswitch c...............................................7

Hnh 4: in thoi dng hthng Asterisk.....................................................................7Hnh 5: Hthng Asterisk 1x1........................................................................................8

Hnh 6: Tng i IP PBX.................................................................................................9

Hnh 7: Stch hp Asterisk vi hthng tng i PBX c.........................................10

Hnh 8: Bqua chi ph gi in thoi ng di..........................................................11

Hnh 9: Asterisk nh mt server ng dng...................................................................11

Hnh 10: Asterisk nh mt media gateway...................................................................12

Hnh 11: Asterisk hot ng nh mt Trung tm giao tip..........................................13

Hnh 12: Kin trc VoIP ca Asterisk...........................................................................15

Hnh 13: VoIP trong m hnh OSI.................................................................................15

Hnh 14: Ci t CentOS - Khi ng vic ci t.......................................................22

Hnh 15: Ci t CentOS - Giao din bt u ci t CentOS....................................22

Hnh 16: Ci t CentOS - Chn ngn ng..................................................................23

Hnh 17: Ci t CentOS - Chn kiu bn phm...........................................................23

Hnh 18: Ci t CentOS - Cu hnh thit lp cng v phn vng cng...............23

Hnh 19: Ci t CentOS - Phn vng cng cho CentOS.........................................24

Hnh 20: Ci t CentOS - Thit lp a chIP............................................................24

Hnh 21: Ci t CentOS - Ch

n mi gi

.....................................................................25Hnh 22: Ci t CentOS - Nhp password Console cho hthng..............................25

Hnh 23: Ci t CentOS - Chn cch ci t..............................................................25

Hnh 24: Ci t CentOS - Chn cc gi htrcho Asterisk......................................26

Hnh 25: Ci t CentOS - Chn kiu loader khi ng..............................................26

Hnh 26: Ci t CentOS - Chun bci t..............................................................27

Hnh 27: Ci t CentOS - Qu trnh ci t...............................................................27

Hnh 28: Ti cc gi ci t Asterisk.........................................................................28

Hnh 29: Khi chy configure cho compile..................................................................29

Hnh 30: Tuchn menu sau khi to menu bng lnh make menuselect......................29Hnh 31: Sau khi dng lnh make install thnh cng...................................................30

Hnh 32: To cc tp tin cu hnh mu.........................................................................30

Hnh 33: To cc ti liu chng trnh ca Asterisk....................................................30

Hnh 34: Ci t asterisk-addons..............................................................................31

Hnh 35: Giao din bt u ci t Trixbox.................................................................33

Hnh 36: Chn loi bn phm.....................................................................................33

Hnh 37: Chn Vng thi gian cho hthng................................................................33

Hnh 38: Password cu hnh Asterisk......................................................................34

Hnh 39: Tin trnh ci t Trixbox 1...........................................................................34

Hnh 40: Tin trnh ci t Trixbox 2...........................................................................34


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Hnh 41: Giao din cu hnh qua Web ca Trixbox.....................................................34

Hnh 42: Giao din phn mm Putty -ng nhp........................................................36

Hnh 43: Giao din phn mm Putty - Ca slnh......................................................36

Hnh 44: Giao din phn mm WINSCP -ng nhp ................................................37

Hnh 45: Giao din phn mm WINSCP - Sdng......................................................37

Hnh 46: TDM400P card...............................................................................................52

Hnh 47: FXO module (S100M - mu ), FXS Module (X100M - mu xanh)............52

Hnh 48: Thit lp cc thng sX-lite..........................................................................56


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MC LC CC BNGBng 1: Bng so sch cc giao thc.............................................................................17

Bng 2: Cc kiu ngphp trong Asterisk...................................................................39

Bng 3: Danh sch tham kho cc driver ca Digium.................................................53


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TVIT TTACD

CTI

DSPGPL

IVR

LCR

MGCPRTP

TCP

UDP

Automatic call distribution

Computer telephony integration

Digital Signal ProcessorsGeneral Public License

Interactive Voice Response

Least Cost Routing

Media Gateway Control ProtocolReal Time Protocol

Transmission Control Protocol

User Data Protocol

Phn phi cuc gi tngThit bkt hp my tnh in thoi

Bxl tn hiu sBn quyn thuc cng ngp ng tng tc thoinh tuyn chi ph thpGiao thc iu khin cng phng tinGiao thc thi gian thcGiao thc iu khin truyn tiGiao thc gi dliu ngi dng


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CHNG I: TNG QUAN VTNG I IP PBX ASTERISK

CHNG I: TNG QUAN VTNG I IP PBX ASTERISK1.1 Gii thiu Asterisk - Asterisk l g?

Asterisk l mt phn mm m ngun m c ci t mt ln trn mt my tnhPC c cc giao tip tng ng i km vi phn cng, c thc sdng nh l mt

PBX vi y tnh nng cho ngi sdng gia nh, cng ty, cc nh cung cp dchvVoIP v vin thng. Asterisk cn l mt cng ng m ngun mv l mt sn

phm thng mi ca Digium. Sdng minph v thay i tdo ph hp vi ccyu cu ca mnh. Asterisk cho php khnng kt ni thi gian thc gia mng PSTNv cc mng VoIP. V Asterisk c nhiu tnh nng hn mt tng i PBX, ta khng ch

c nhng nng cp cho tng i PBX ang tn ti m cn c thc nhiu thminh:

Kt ni cc nhn vin lm vic tnh n mt vn phng PBX thng quamng Internet.

Kt ni nhiu vn phng nhiu ni khc nhau trn nn mng IP, mngring hay ngay cmng internet.

Cho php cc nhn vin c thtch hp Web v email vi Voicemail.

Xy dng cc ng dng ging nh IVR cho php cc kt ni n hthng

hng i ca bn hay cc ng dng khc.

Cho php cc nhn vin lm vic di ng truy cp vo PBX ca cng ty t

bt kni no vi chmt kt ni bng thng rng hay kt ni VPN.

V nhiu thkhc na

Asterisk bao gm nhiu ti nguyn cao cp chtm thy trong cc hthng cao cp

v dnh:

Nhc chcho cc khch hng khi ang i trong cc hng i cuc

gi, dng htrphng tin v cc file MP3.

Cc hng i cuc gi, ni m mt nhm agent c thtrli cc

cuc in thoi v gim st cc hng i.Tch hp vi vn bn qua ging ni v nhn dng thoi.

Cc dliu chi tit c chuyn i tdng tp tin vn bn v cc c

sdliu SQL.Khnng kt ni PSTN thng qua c2 dng ng dy sv tng

t.

1.1.1 Vai tr ca Digium i vi Aster isk

Digium mt cng ty Huntsville Alabama l ngi to ra v l nh pht trinchnh ca Asterisk. Bn cnh vic trthnh nh ti trchnh ca spht trin caAsterisk. Digium cn sn xut ra cc card giao tip in thoi v nhng phn cngkhc cho cc tng i PBX Asterisk.

Digium a ra Asterisk vi 3 dng bn quyn khc nhau:

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+ Asterisk bn quyn thuc cng ng (General Public License GPL). y l dng

c sdng nhiu nht. N bao gm tt ccc tnh nng, min ph trong sdng vtdo thay i tun theo cc lut bn quyn m GPL a ra.

+ Asterisk phin bn thng mi: l mt phin bn mi gn y. N khng c mtscc tnh nng mrng trong GPL. Phin bn thng mi c sdng trong mt

vi cng ty khng thsdng phin bn GPL, hu ht l v hkhng mun a mngun ca hi km vi Asterisk. Phin bn GPL yu cu bt kspht trin notrong phin bn GPL phi c cng khai m ngun.

+ Asterisk OEM: hu ht c sdng bi cc nh sn xut PBX khi hkhngmun cng ng bit phn mm ca sn phm ca hxut thn tAsterisk.

1.1.2 Dn Zapata vcc mi quan hca n vi Aster isk

Dn Zapata c pht trin bi Jim Dixon ngi cn c trch nhim trong vicpht trin phn cng c sdng trong Asterisk. Ch rng phn cng cng l m

ngun mv v thn c thc sdng bi bt kcng ty no khc. Digium,Sangoma v Varion l mt vi cng ty sn xut card chnh cho tng i Asterisk PBX.C ththam kho dn Zapata ti a ch:http://www.asteriskdocs.org/modules/tinycontent/index.php?id=10

Chc nng chnh ca phn cng Asterisk l sdng bxl CPU ca my tnh xl m thanh, trit nhiu v chuyn i m. Ngc vi hu ht cc card hin ti sdng bxl tn hiu s(DSP - Digital Signal Processors) thc hin nhng cngvic ny. Quyt nh sdng bxl CPU ca my tnh lm gim gi thnh ca mch

mt cch nhanh chng. V thcc bn mch ca Digium rhn nhiu ln so vi cc ccbn mch ang tn ti khc v dnh ca Dialogicm Aculab v nhng cng ty khc, vchng khng cn yu cu cc DSP t tin. Vn ca cc bn mch ny l chng yucu nhiu CPU v mt CPU yu c thlm nh hng n cht lng thoi.

1.2 V sao chn Asterisk?

1.2.1 Gim chi phmt cch mnh m

Nu so snh mt tng i PBX truyn thng vi Asterisk vi cc giao tip svin thoi. Asterisk chrhn mt t so vi cc tng i PBX ny. Tuy nhin, Asterisk

tht skhng cn trtin khi thm vo cc chc nng nh voicemail, ACD, IVR vCTI. Vi nhng tnh nng cao cp ny th Asterisk rhn nhiu ln so vi PBX truynthng. Cn khi em so sch tng i PBX Asterisk vi tng i PBX tng tgi rth khng cng bng bi v n c rt nhiu tnh nng m trong cc hthng PBXtng tkhng c.

im li dthy nht tpha khch hng l tnh c lp ca Asterisk. Mt vi nhsn xut ngy nay khng cn phi gi cho khch hng mt khu hay ti liu cu hnhg c. Vi Asterisk bn c thlm g ty thch, ngi sdng c hon ton tdo vhn na n c thtruy cp vi giao din chun.

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http://www.asteriskdocs.org/modules/tinycontent/index.php?id=10http://www.asteriskdocs.org/modules/tinycontent/index.php?id=10http://www.asteriskdocs.org/modules/tinycontent/index.php?id=10


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CHNG I: TNG QUAN VTNG I IP PBXASTERI SK

1.2.2 Mi trng pht tr in nhanh chng vddng

Asterisk c thc mrng bng cch sdng cc ngn ngkch bn ging nhPHP v Perl vi cc giao din AMI v AGI. Asterisk l m ngun mv m ngunca n c thc chnh sa bi ngi sdng. M ngun c vit hu ht trn

ngn nglp trnh ANSI C.

1.2.3 Giu tnh nng

Asterisk c hng lot cc chc nng m khng thtm thy hoc l ty chn trong cc

tng i PBX truyn thng (v dnh voicemail, CTI, ACD, IVR, nhc chv ghi m).

1.2.4 Ni dung ng trn in thoi

Asterisk c lp trnh trn ngn ngC v cc ngn ngthng thng khc trongmi trng pht trin ngy nay. Khnng cung cp ni dung ng hu nh khng cgii hn.

1.2.5 Kiu quay slinh hot vmnh

Mt im mnh na ca Asterisk nu nh bn so snh vi cc tng i PBX, ngaycnhng thn gin nh LCR (nh tuyn chi ph thp Least Cost Routing) khngc trong PBX hay l ty chn. Th vi Asterisk th vic la chn tuyn tt nht ddng v chnh xc.

1.2.6 M ngun mchy trn nn Linux

Mt trong nhng tnh nng mnh nht ca Asterisk l cng ng ca n. Khi bntruy cp vo wiki (www.voip-info.org), cc danh sch phn phi email v cc dinn. Vic trnh Asterisk thng nhanh chng v bt kli g ca n u tm ra.

Asterisk c thl phn mm in thoi PBX c kim tra nhiu nht trn thgii. Tcc phin bn 1.0 n 1.2 c hn 3000 sthay i v cc li trong m ngun c sacha. Tin trnh ny m bo rng ta c mt m va c tnh n nh va hu nhkhng c li.

1.2.7 Cc gii hn trong kin trc ca Aster isk

Mt vi gii hn trong Asterisk n tvic sdng trong m hnh thit kinthoi Zapata. Trong kiu thit kny, Asterisk sdng CPU ca my tnh xl cc

knh thoi thay v sdng cc card DSP chuyn dng thng thy trong cc hthng

khc. Mc d iu ny cho php n gim nhiu chi ph trong giao din phn cng. Mththng trnn phthuc vo CPU ca my tnh. Asterisk nn chy trn mt mytnh chuyn dng v c cu hnh phn cng ph hp vi xl thoi. Thng nn sdng Asterisk trn mt VLAN c lp trnh broadcast tiu tn nhiu bng thng

ca CPU (bo broadcast tcc vng lp hay ca virus). Mt vi card giao tip mi tnhiu nh cung cp bao gicng bao gm cDSP trit nhiu, codec v m nhim

cc tnh nng khc. N lm cho Asterisk tt hn.

1.3 Kin trc ca Asterisk

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GSM,ALaw,Ulaw,G.723

G.729,ADPCM,MP3,

Speex,LPC10

GSM,WAV,G723af,

MP3

nhdngfileAPI

DchCodecA

PI

phn lin quan n kin trc nh cc knh, codec mha gii m v cc ng dng.

1:SIPcaModemTip theo


Voicemail, T HiNgh, ThGi, Danh

B, Tnh Cc

Cc ng dng Asterisk API

Dch Codec

Qun l I/O,

Chy ng dng

Chuyn mchPBX li

Lp Lch

BnpModule ng

Cc knh Asterisk API

ADTRAN VOFRHnhISDNKin trcH323Asterisk

Hnh trn m tkin trc cAsterisk.Thoi, Thitchng ta sgii thch cc thnh

bkhch hng,

1.3.1 Cc knh

Mt knh tng ng vi 1 line thoi, nhng trong nh dng sn thng baogm bi mt hthng bo hiu tng thoc shay skt hp ca codec v cc giaothc bo hiu (v dnh SIP-GSM, IAX - quy lut ). Ban u tt ccc kt ni inthoi l tng tv c nhiu ting di v nhiu. Sau , hu ht cc hthng uchuyn i qua cc hthng s, vi m thoi tng tc chuyn i thnh dng s

bi PCM trong hu ht cc trng hp. Kiu ny cho php vic truyn dn vi tc

64kbps khng cn nn.Phn cng TDM htr:Card Zaptel (thng do Digium sn xut)

+ Wildcard T410P - 4 giao tip E1/T1 (chsdng PCI 3.3 V)+ Wildcard T405P - 4 giao tip E1/T1 (chsdng PCI 5.0 V)+ TE110P - 1 cng giao tip E1/T1+ TDM400P - 4 giao tip analog FXO or FXS

+ TDM2400 - 24 cng FXS or FXOCc board trn sdng cc driver knh chan_zap

+ Card Linux

+ Quicknet Phonejack v linejack c thc sdng

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+ Card ISDN v cc driver

+ ISDN4Linux - driver c, khng khuyn khch sdng+ ISDN CAPI

+ Voicetronix: 4,8 v 16 cng analog. By gihcn sn xut cc card E1/T1.Nhng card ny cng sdng cc driver knh chan_zap

1.3.2 Codec vchuyn dch codec

Chng ta thng cgng c nhiu kt ni c thtrn mt mng dliu. Codeccho php cc tnh nng mi trong thoi s. Bnn tnh hiu l mt phn quan trngnht, V n cho php tlnn 8-1. Nhng tnh nng khc bao gm bpht hin thoi,

bgiu mt gi mt v bto cn bng nhiu. Nhng codec trn u c bn trongAsterisk v nhng codec ny c thc chuyn i tdng ny sang dng khc. Bntrong Asterisk sdng mt slinear nh nh dng dng khi n cn chuyn i tmtcodec ny n mt codec khc. Mt vi codec trong Asterisk c htrchcho kiu

pass-through v nhng kiu codec ny khng thdch c.Htrcc codec sau:+ G.711 ulaw (USA) - (64 Kbps)

+ G.711 alaw (Europe) - (64 Kbps)

+ G.723.1 - chcho kiu pass-through+ G.726 - (16/24/32/40kbps)+ G.729 - cn bn quyn (8Kbps)+ GSM - (12-13 Kbps)

+ iLBC - (15 Kbps)+ LPC10 - (2.5 Kbps)

+ Speex - (2.15-44.2 Kbps)

1.3.3 Cc giao thc

Gn y giao thc bo hiu SIP thng c sdng. H.323 c sdng trongcc hthng VoIP c v hu ht cc hthng c dng giao thc ny. IAX l mt chnla khc ang trnn phbin v chng lm vic tt vi NAT Tranversal v c thtitkim c bng thng.

Asterisk htrcc giao thc:+ SIP+ H323

+ IAXv1 e v2

+ MGCP

+ SCCP (Cisco Skinny)

+ Nortel unistim

1.3.4 Cc ng dng

lm cu ni tmt in thoi ny n mt in thoi khc th mt ng dng gil bquay s c sdng. Hu ht cc tnh nng trong Asterisk ging nhvoicemail v cuc gi hi nghc thc hin nh l cc ng dng. Ta c ththy cc

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ng dng Asterisk bng cch sdng lnh show applications trong console, c th

thm cc ng dng tcc phn Asterisk-addons tnh cung cp thba hoc ngay cmt vi ng dng cng lm c.

1.4 M ttng quan tng i IP PBX Asterisk

IP Phones

Telcos, PBX

Analog Phones

ServerAsterisk

SoftswitchMedia Gateway

VoicemailT Hi Ngh

Nhc Ch

Hnh 2: Tng quan tng i IP PBX AsteriskAsterisk l mt m ngun PBX mhot ng ging nh mt PBX lai, cc cng

nghtch hp nh TDM1 v in thoi IP. Asterisk sn sng cho p ng tng tcthoi IVR (Interactive Voice Response) v phn phi cuc gi tng ACD (Automaticcall distribution) n pht trin mcc ng dng mi. Trong hnh bn trn, ta c ththyrng cc kt ni Asterisk n telcos v cc tng i PBX ang tn ti sdng cc giaotip tng tv sv cng htrin thoi tng tv IP. N c thhot ng nh lmt softswitch, media gateway, voicemail, thoi hi nghv nhc ch.

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1.5 So snh gia cc loi tng i

1.5.1 in thoi sdng m hnh PBX/Softswitch c

Hnh 3: in thoi sdng m hnh PBX/Softswitch cTrong m hnh softswitch c, tt ccc thnh phn u c bn c lp (Music

on hold, Vocemail, giao tip vi IP phone, cc tnh nng cao cp nh IVR, ACD).V vy bn phi mua mi thnh phn v sau tch hp chng vo tng i PBX hay

mi trng softswitch. Chi ph v nguy c cao v hu nh cc thit bl ring.1.5.2 in thoi dng hthng Aster isk

IP Phone

UnifiedMessaging

PSTNGateway

Softswitch POTSTelephonyGateway

Telco

PBX

Hnh 4: in thoi dng hthng Aster isk

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Trong hthng Asterisk cc chc nng mi u c tch hp trong hthng Asterisk

v khng cn phi u t thm nhiu sdng v vn hnh nhng tnh nng ny.

1.6 Xy dng mt hthng kim tra

Internet

IP Phone Nh CC Dch VVoIP Analog Phone

Server Linux

AsteriskAnalog Telephony

Adapter

Telco, PBX

Analog Phone

Hnh 5: Hthng Asterisk 1x1Khi thc hin mt gii php Asterisk, bc u tin ca chng ta l to ra mt h

thng kim tra. Hthng kim tra n gin nht l PBX 1x1 vi chmt ng inthoi v mt line. C rt nhiu cch to. Chng ta hy thmt vi trong s:

1.6.1 Mt FXO, mt FXS

Cch u tin v n gin nht xy dng mt hthng kim tra l mua mtboard mch TDM400 ca Digium vi mt cng FXO v mt cng FXS. Kt ni cngFXO vo ng line ang tn ti v FXS vo mt in thoi tng t. y chng tac kiu tng i PBX 1x1.

1.6.2 Nhcung cp dch vVoIP, ATA

y l mt tuchn. Trong trng hp ny chng ta sng k vi nh cung cpthoi c c trung kSIP v sphi mua mt btng thch in thoi tng tdng SIP. Bn sc thchi t hn 100$ nu bn c my tnh ri.

1.6.3 Board FXO khng t tin, ATA

y l cch bt u. C mt vi loi V.90 fax/modem lm vic c viAsterisk v nh l mt FXO board. Mt vi board ca Digium u tin c to ra sdng nhng loi ny (X100P v X101P). Nhng board ny l nhng V.90 fax/modemc chipset ca Mororola v Intel (chipsets (Motorola 68202-51, Intel 537PU, Intel

537PG, Intel Ambient MD3200). Chng khng dtm ra v chng khng cn c snxut na; tuy nhin, mt vi ci c bn nh mt dng X100P. c c FXS

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bn c thsdng mt bthch ng in thoi tng t. Mt ln na bn c thtn t

hn 100$ bt u nu nh bn c sn my tnh.

1.7 Mt sng dng ca Asterisk

C nhiu vin cnh khc nhau cho cc ng dng ca Asterisk. Chng ta slit kdanh sch mt vi trong s v gii thch nhng u im v cc gii hn tn titrong tng ng dng.

1.7.1 IP PBX

Mt v dthng dng nht l vic ci t mt tng i mi hay thay thtng iPBX d c sn. Nu bn so snh Asterisk vi mt vi thkhc c ththay thc

bn sthy rng n rhn v c nhiu tnh nng hn nhng tng i PBX ang ctrn thtrng. Nhiu cng ty by giang btin ra c c nhng tnh nng caAsterisk bao gm cnhng tng i PBX.

Hnh 6: Tng i IP PBX

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1.7.2 Sdng I P trong cc tng i PBX c

Hnh 7: Stch hp Aster isk vi hthng tng i PBX cHnh bn trn m tcch thng dng nht c sdng trong vic thit lp.

Nhng cng ty ln thng khng mun nhiu nguy c khi phi u t vo nhng cng

nghmi v cng thi im li mun khng phi u t vo nhng thit bc. Cho

php IP chy trn cc tng i PBXc c thtn rt nhiu chi ph v v vy, vic ktni mt tng i Asterisk PBX sdng T1/E1 c thl mt la chn tt. Mt im likhc l khnng kt ni n cc nh cung cp dch vVoIP.

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1.7.3 Bqua chi phgi in thoi ng di

Hnh 8: Bqua ch i ph gi in thoi ng diMt ng dng rt hu ch cho VoIP l tnh kt ni cc chi nhnh vi nhau thng

qua Internet hay mt mng WAN. Vic sdng mt kt ni dliu c sn cho phpbn bqua (bypass) chi ph in thoi ng di trong cc kt ni vin thng gianhng vn phng chnh v cc chi nhnh.

1.7.4 Server ng dng (IVR, in thoi hi ngh, Voicemail )

Telco

T1/Analog

T1/AnalogAsterisk PBX

IVR ServerConference Server

VoicemailUnified Messaging

Hnh 9: Asterisk nh mt server ng dngAsterisk cn c thc sdng nh mt server ng dng cho tng i PBX ang

sdng hay c thc kt ni trc tip n PSTN. Asterisk c thlm c cc dchvnh voicemail, nhn fax, thu m cuc gi, IVR c kt ni n mt c sdliu.

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Vic sdng Asterisk nh mt server ng dng lm gim chi ph mt cch ng k

nu em so snh vi nhng gii php khc.

1.7.5 Media Gateway

Nh Cung CpVoIP

H.323/T1/Analog SIP

Nh Cung CpVoIP

EthernetSIP

Proxy

Khch Hng

Hnh 10: Asterisk nh mt media gatewayHu ht cc nh cung cp VoIP sdng SIP chuyn n my chtt cnhng

ng k, thng tin khu vc v sxc thc ca ngi dng SIP. D sao chng na hphi gi cuc gi n PSTN mt cch trc tip hay nh tuyn n thng qua mt cucgi xc nh nh cung cp sdng kt ni VoIP SIP hay H.323. Asterisk c thlm

vic nhmt B2BUA (back to back user agent) hay Media Gateway thay thchonhng softwitch hay media gateway t tin. So snh gi ca mt gateway 4 E1/T1 t

thtrng nh sn xut vi Asterisk. Gii php Asterisk c thgim chi ph nhiu lnhn l cc gii php khc v n c khnng chuyn dch cc giao thc bo hiu(H.323, SIP, IAX) v cc codec (G.711, G.729).

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1.7.6 Trung tm giao tip chmsc khch hng - Contact Center Platform (Call Center)

Hng i Cuc Gi

1-800

ACDRingall, RoundRobin, Mrmemory

LeastRecent, Priority

Agent 1 Agent 2 Agent N

Hnh 11: Aster isk hot ng nh mt Trung tm giao tipMt trung tm giao tip chm sc khc hng l mt gii pht rt phc tp. N kt

hp nhiu cng nghnh tng phn phi cuc gi ACD (Automatic calldistribution), tng tc p ng thoi IVR (Interactive voice response), gim st cuc

gi v nhiu thkhc na. Vc bn, c 3 kiu trung tm giao tip chm sc khchhng: bn trong (inbound), bn ngoi (outbound) v hn hp (blended).

Trung tm giao tip inbound rt phc tp, thng yu cu ACD, IVR, CTI, thu m,gim st v cc bo co. Asterisk c mt hng i cuc gi ACD c xy dng sn.IVR c thc thc hin thng qua AGI (Asterisk gateway interface) hay cc c ch

bn trong nh ng dng nn. Thit bkt hp my tnh in thoi CTI (Computertelephony integration) c thc hin thng qua vic sdng AMI (Asterisk Manager

interface), thu m v bo co c xy dng trong Asterisk.Cho mt trung tm giao tip outbound, mt btuyn on hay bquay stt l

thnh phn chnh. Mc d nhiu bquay sang c sn tm ngun mAsterisk

nhng n khng kh nu ta txy dng.Mt trung tm giao tip hn hp cho php cc hot ng inbound v outbound

ng thi, thit kim tin bng cch sdng tt hn thi gian ca cc agent. N chophp sdng Asterisk v c chACD ca n thc hin gii php hn hp.

1.8VoIP vi Asterisk

1.8.1 Cc u im ca VoI P

1.8.1.a Tnh hi t

u im chnh ca VoIP l tnh kt hp dliu v thoi trong mng gim chi ph

(tnh hi t). Tuy nhin, nu sphn tch chl vic gim chi ph cho thoi khng th c

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thkhng thc hin VoIP. Vic gim chi ph c a ra bi cc cng ty vin

thng kh nhanh trnn rhn v quan trng l n din ra trc khi trnh VoIP.

1.8.1.b Chi ph c shtng

Mt khc, vic sdng mt kin trc htng mng n lm gim chi ph c kt

hp vi nhng phn thm vo, bra v thay i. Vic IP phdng mang n cho cngnghVoIP nhiu thit bmi nh l cell phone, PDA c nhng trong hthng vmy tnh xch tay (laptop).

1.8.1.c Tiu chun m

Cui cng, cc chun mbn trn VoIP c xy dng l cu ni cho stdotrong vic chn la nh phn phi v u im l lm cho khch hng trthnh vuathay v l phn phtrong cc nh sn xut vin thng v PBX.

1.8.1.d Stch hp gia my tnh v in thoi

in thoi th ra i sm hn my tnh nhiu. in thoi PBX l chuyn mchknh. i khi mt my tnh gim st chuyn mch. Vi VoIP, in thoi pht trin tvic c to ra da vo cc chun ca my tnh. iu ny lm cho vic sdng ccng dng in thoi my tnh rhn rt nhiu v ddng hn nhng mu c. Bn cthnhanh chng to ra mt danh sch di cc ng dng in thoi da trn Asterisk.Bn c thpht trin IVR, ACD, CTI, sngi gi, mn hnh popup v nhiu ngdng khc.

1.8.2 Kin trc VoIP ca Aster isk

Kin trc Asterisk c chra bn di. Asterisk sdng tt ccc giao thc VoIPtrong cc knh. Ta c thsdng bt kcodec no hay giao thc no. Khi nim quantrng nht l cu ni Asterisk ni knh ny n knh khc. Sau ta c thdch ccgiao thc bo hiu nh H.323, SIP v IAX vi nhau v ngay ccc bcodec khcnhau. V dnh bn c thdch mt cuc gi tmt in thoi theo giao thc SIPtrong mng LAN sdng chun m ho G.711 sang mt kt ni H.323 n nh cungcp dch vVoIP sdng chun m ho G.729.

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GSM,ALaw,Ulaw,G.723

G.729,ADPCM,MP3,

Speex,LPC10

GSM,WAV,G723af,

MP3

nhdngfileA

PI

DchCodecA

PI

Asterisk, nhng n lun sn sng nh mt phn thm vo (add-on).

KinSIP VoIP c

chi tit kin trc ca


Voicemail, T HiNgh, ThGi, Danh

B, Tnh Cc

Cc ng dng Asterisk API

Dch Codec

Qun l I/O,

Chy ng dng

Chuyn mchPBX li

Lp Lch

BnpModule ng

Cc knh Asterisk API

ADTRAN VOFRHnh 12:ISDNtrc H323a Aster isk

Tip theo chng ta sm tModem Thoi, ThitSIP v IAX. H.323 khng thuc

bkhch hng,

1.8.3 Cc giao thc VoI P vm hnh OSI

Hnh 13: VoIP trong m hnh OSI

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VoIP tng ng vi mt tp cc giao thc khc nhau lm vic chung vi nhau. Cc

lp khc nhau trong m hnh OSI c gii thiu trong giao tip VoIP. Hnh bn trn sgip ta c thhiu c vai tr ca mi giao thc v mi quan hgia chng vi nhau.

L lp u tin trong 4 lp chl mt mng dliu ging nh mng Internet trongkinh doanh v gia nh. Bn c thsdng mt vi giao thc QoS ging nh l

diffserv hay cbwfq u tin ho cc gi thoi v nng cao cht lng thoi, huht cc giao thc VoIP sdng giao thc RTP giao thc thi gian thc nh l giaothc truyn ti chn la.

Trong lp phin (session), cc giao thc c nhim vthit lp v gii tocc cucgi. H.323 l mt trong nhng giao thc c nht v hon thin trong nhim vny.SIP by gic sdng rng ri trong thtrng nh cung cp dch vVoIP, bncnh H.323. Cc giao thc bo hiu sdng TCP hay UDP truyn ti cc gi.

Trong lp trnh din (presentation), chng ta c cc bm ho gii m chuyn i

dng thc dng a phng tin tmt kiu nh dng sang mt kiu khc vi cc ctnh khc.

V d: SIP sdng port 5060 UDP hay TCP truyn ti tn hiu bo hiu. Giaothc thi gian thc RTP truyn ti dng m thanh sdng port 1000 n 2000 trongAsterisk (nh c nh ngha trong rtp.conf). Mt cuc gi c thc m ho trongchun G.711. Mt softphone trong lp ng dng ssdng nhng lp thp hn giao tip.

H.323 sdng TCP port 1720 v port 1719 truyn ti tn hiu bo hiu. RTP

truyn ti m thanh thng sdng UDP port t16383 n 32768. Mt cuc gi cthc m ho trong G.729.

1.8.4 Lm sao chn mt giao thc?

1.8.4.a SIP - giao thc thit lp phin

SIP l mt chun IETF m, c nh ngha r rng trong RFC 3261. Hu ht ccnh cung cp dch vVoIP hin ti sdng SIP v n trthnh mt chun VoIP phdng nht. Sc mnh ca SIP l trthnh mt chun da vo IETF. SIP th nhgnnu em so snh vi giao thc H.323. im yu chnh ca SIP l NAT tranversal, mt

kh khn cho hu ht cc nh cung cp dch vVoIP.1.8.4.b IAX - I nter Aster isk eXchange

IAX l mt giao thc mc nh ngha bi Digium v n hin ti l mt bnnhp. Bn c thdownload n twww.ietf.org/internet-drafts/drafts-guy-iax00.txt.IAX l mt giao thc tt ctrong mt v n truyn ti bo hiu v a phng tinthng qua mt cng UDP 4569. Mark Spencer pht trin IAX nh mt giao thcnhphn lm gim bng thng. Sc mnh chnh ca IAX l lm gim bng thngsdng (n khng sdng RTP) trong khi cng thi im rt ddng sdng cho

NAT v firewall tranversal v n chsdng port UDP 4569. Trong mt vi tnh

hung IAX dng trung kc thlm gim bng thng thoi sdng i 1/3.

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1.8.4.c Giao thc iu khin cng phng tin MGCP

MGCP l mt giao thc c sdng chung vi H.323, SIP v IAX. N c u

im ln l tnh mm do. N c cu hnh trong cuc gi tc nhn thay v ccgateway. iu ny lm n gin tin trnh cu hnh v cho php qun l tp trung.Tnh thc thi ca Asterisk th khng ton din v n dng nh khng c nhiu ngi

dng n.

1.8.4.d H.323

H.323 c sdng nhiu trong VoIP. N l mt trong nhng giao thc VoIP utin v c bn cho vic thit lp kt ni cho nhng hthng htng VoIP c da trncc gateway. H.323 vn chun trong thtrng gateway, mc d thtrng ang

chuyn dch chm qua SIP. Sc mnh ca H.323 bao gm schp thun ln ca thtrng v tnh tnhin. Cc im yu ca H.323 lin quan n sphc tp trong victhc hin v cc chi ph kt hp chun.

1.8.4.e Bng so sch cc giao thc

Giao thc

IAX2

SIP

MGCP

H.323

SCCP

Chun

IETF nhp

IETF chun

IETF/ITUchun

ITU chun

Thuc Cisco

c sdng

Cc trung kAsterisk.in thoi IAX2.Kt ni gia IAX vi nh cung cp dch v.

in thoi SIP.Kt ni gia SIP vi nh cung cp dch v.

in thoi MGCP.Hin ti khng c htrtrong kt ni gia MGCPvi nh cung cp dch v.

in thoi H.323.H.323 gateway.

Hin ti khng c htrtrthnh mtgatekeeper nhng c thkt ni n 1 gatekeeper bn

ngoi.

in thoi ca Cisco.

Bng 1: Bng so sch cc giao thc

1.8.5 User , Peer vFriend

C 3 loi client ca SIP v IAX: User, Peer v FriendUser chto c kt ni n server Asterisk.Peer chnhn c cuc gi tserver Asterisk.

Friend lm c chai. Thng thng mt server hay mt thit bsyu cu chai khi nim ny cng mt lc. Mt friend l mt shortcut n mt user + peer.Mt in thoi sc thri vo loi ny, v n cn to v nhn cc cuc gi.

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1.8.6 Cc codec vchuyn i codec

Ta ssdng mt codec chuyn i tn hiu thoi tdng tng tsang dngs. Cc bcodec th khc nhau tuthuc vo cht lng thoi, tlnn, bng thngv cc yu cu tnh ton. Cc dch v, phone v cc gateway thng htrnhiu loi,

codec G.729 l mt codec rt thng dng v yu cu bn quyn.

Asterisk htrcc loi codec sau: GSM: 13 Kbps

iLBC: 13.3 Kbps

ITU G.711: 64 Kbps

ITU G.723.1: 5.3/6.3 Kbps

ITU G.726: 16/24/32/40 Kbps

ITU G.729: 8 Kbps

Speex - 2.15 to 44.2 Kbps

LPC10 - 2.5 KbpsAsterisk cho php chuyn dch gia cc codec. Nhiu trng hp khng th

chuyn i nhtrng hp G.723 chc htrtrong dng pass-through. Chuyn tmt kiu codec ny sang mt kiu khc lm tiu tn nhiu ti nguyn tCPU. V vynn trnh vic chuyn i ny nu c th.

1.8.7 Lm sao chn mt codec ph hp

Vic chn la loi codec ty thuc vo nhiu kha cnh khc nhau:+ Cht lng thoi.

+ Chi ph nghe.+ Mc tiu tn xl ca CPU.+ Bng thng yu cu.+ Khnng khc phc mt gi.

+ Tnh sn sng cho Asterisk v thit bin thoi.

1.8.8 Phn mo u do phn Header ca giao thc

Mc d cc codec sdng t bng thng nhng chng ta phi phi bn lun vmo

u (overhead) do phn header ca giao thc to ra ging nh Ethernet, IP, UDP v

RTP. Quan st iu ny chng ta c thni rng bng thng phthuc vo phnheader sdng. Nu chng ta l mt mng Ethernet, bng thng yu cu l cao hnkhi sdng mt mng PPP v PPP header ngn hn trong mng Ethernet. Chng tahy xem qua mt vi v d:

Codec g.711 (64 Kbps) Ethernet (Ethernet+IP+UDP+RTP+G.711) = 95.2 Kbps

PPP (PPP+IP+UDP+RTP+G.711) = 82.4 Kbps Frame-Relay (FR+IP+UDP+RTP+G.711) = 82.8 Kbps

Codec G.729 (8 Kbps)

Ethernet (Ethernet+IP+UDP+RTP+G.729) = 31.2 Kbps PPP (PPP+IP+UDP+RTP+G.729) = 26.4 Kbps

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Frame-Relay (FR+IP+UDP+RTP+G.729) = 26.8 Kbps

1.8.9 Kthut lu lng

Vn chnh trong thit kcc mng VoIP l kch thc sng line v bngthng c yu cu cho tng kch thc cthnh vn phng txa hay mt nh cungcp dch v, scuc gi ng thi trong Asterisk cng quan trng (thng schnhquyt nh kch thuc ca Asterisk).

1.8.9.a Sn gin ho

iu u tin v c sdng rng ri l tnh n gin ho gim scuc gibi kiu user. V d:

Cc tng i PBX thng mi (mt cuc gi ng thi cho mi 5 extension)Ngi sdng gia nh (mt cuc gi ng thi cho 16 user)V d: Cng ty c mt vn phng chnh vi 120 extension v 2 chi nhnh, chi

nhnh u tin c 30 extension v chi nhnh th2 vi 15 extension. Mc tiu cachng ti l nh kch thc sng trung kE1 trong vn phng chnh v bngthng c yu cu cho mng Fram-Relay:

1.a Sng T1Tng sextension sdng ng T1: 120+30+15=165 linesVic sdng 1 ng trung kcho mi 5 extension cho thng mi sdng

tng sng line = 33 v xp x2xT1 lines1.b Bng thng yu cuChng ta chn G.729 codec v bng thng yu cu, cht lng thoi v mi

trng tiu tn CPU.Vi mt ng trung kcho mi 5 extension:

Bng thng yu cu cho chi nhnh s1 (Frame-relay): 26.8*6=160.8 KbpsBng thng yu cu cho chi nhnh s2 (Frame-relay): 26.8*3= 80.4 Kbps

1.8.9.b Phng php Erlang B

1.a Scuc gi ng thi trong VoIPi khi, tnh n gin khng phi l phong php tt nht. Khi bn c dliu pha

trc, bn c thyu cu ln nhiu c tnh khc. Agner Karup Erlang (cng ty in

thoi Copenhagen, 1909) pht trin mt cng thc tnh ton sng line trongmt nhm trung kgia hai thnh ph. Chng ta ssdng cng thc ny. Erlang lmt n vo c lu lng thng c sdng trong vin thng, n c sdngmiu tln ca lu lng trong mt gi.

V d: 20 cuc gi trong mt givi 5 pht trung bnh cho mi cuc gi.Bn tnh serlang nh sau:Lu lng tnh theo pht trong mt gil: 20x5=100 phtGilu lng trong mt gi: 100/60=1,66 Erlangs

Bn c thtnh c con sny tmt cuc gi c ghi nht k vo hthngv sdng n thit kra mng ca bn tnh ton sng line yu cu. Ming line c bit n c thtnh cho bng thng yu cu.

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Erlang B l phng php c sdng nhiu nht tnh sng line trong mt

nhm trung k. N giscc cuc gi n mt cch ngu nhin (dng phn bPoisson) v cc cuc gi bkho ngay lp tc c gii to. Phng php ny yu cu

bn phi bit vlu lng gicao im Busy Hour Traffic (BHT). Bn c thc cBHT ny tnht k cuc gi hay mt cch n gin l BHT =17% scuc gi pht

trong mt ngy.Mt bin squan trng khc l cp dch vGoS (Grade of Service). GoS nh

ngha scuc gi c thbkho trong nhm ng line. Bn c thiu chnh thng sny. N thng nm 0.05 (5% cc cuc gi bmt) hay 0.01 (1% cuc gi bmt).

V d: Sdng cng v dtrn chng ta cho mt vi dliu trong thnh phn lulng. Tnht k cuc gi hthng chng ta khm ph ra dliu ny.

Dliu tcuc gi ghi nht k (pht cuc gi v BHT)Chi nhnh chnh n chi nhnh con 1 = 2000 pht, BHT= 300 pht

Chi nhnh chnh n chi nhnh con 2 = 1000 pht, BHT = 170 phtChi nhnh 1 n chi nhnh 2 = 0, BHT = 0, GoS=0.01Chi nhnh chnh n chi nhnh con 1 - BHT = 300pht/60 = 5 Erlangs

Chi nhnh chnh n chi nhnh con 2 - BHT = 170pht/60 = 2.83 ErlangsSdng bng tnh Erlang ti www.erlang.com1.b Bng thng yu cuChng ta sdng mt mng WAN ni m gi mt him khi xy ra. Chng ta s

chn G.729 codec v cht lng thoi tt ca n v dliu c nn (8Kbps).

Chn codec: G.729Lp Datalink: Frame-relayc lng bng thng cho chi nhnh 1: 28.8x11 = 294.8 Kbpsc lng bng thng cho chi nhnh 2: 26.8x8 = 214.40 Kbps

1.8.10 Gim bng thng yu cu cho VoIP

C 3 phng php lm gim bng thng c yu cu cho cc cuc gi VoIP:

+ Nn RTP header

+ IAX trunked

+ VoIP ti (payload)

1.8.10.a Nn RTP H eader

Trong mng Frame-relay v PPP, ta c thsdng nn RTP header, nn RTP

header c nh ngha trong RFC 2508. N l mt chun IETF cho nhiu router. Tuynhin ch rng mt vi loi router yu cu mt tp c tnh khc cho ti nguyn nyc sn sng.

Snh hng ca vic sdng nn RTP header ny l khng c c s. N gimbng thng c yu cu trong v dca chng ta t26.8 Kbps cho mi cuc mthoi xung 11.2 Kbps, gim c 58.2%.

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1.8.10.b I AX2 trunk mode

Nu ang kt ni 2 server Asterisk, ta c thsdng giao thc IAX2 trong dng

trunk mode. Cng nghtin phong ny khng yu cu bt kmt router cthno vn c thp dng cho bt kloi datalink no. IAX2 trunk mode sdng li cng

phn header tcc cuc gi th2 v cc cuc gi sau . Sdng G.729 v mt

ng PPP link, cuc gi u tin tn 30 Kbps bng thng, nhng cuc gi thhai sdng cng phn header nh cuc gi thnht nn gim mc bng thng cn thitcho cuc gi ny xung 9.6 Kbps.

1.8.10.c Gim VoIP ti

Tht khng may phng php ny khng c trongAsterisk. N thng sdnglc trong cc gateway trn Internet. Vic sdng phn ti (payload) ln lm tngtrca hthng.

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CHNG 2: CI T TNG I IP PBX ASTERISK

Hnh 16: Ci t CentOS - Chn ngn ng

Hnh 17: Ci t CentOS - Chn kiu bn phm

Hnh 18: Ci t CentOS - Cu hnh thit lp cng vphn vng cng

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Hnh 19: Ci t CentOS - Phn vng cng cho CentOS

Trong kthut phn vng trong Linux hay CentOS th ngi ta thng chia ra lm4 phn chnh:

Phn vng/boot: khong 100MB dng lu dliu khi ng hthng.Phn vngswap: tt nht l dung lng gp 2 ln RAM, i vi hthng >4GB

RAM th ta chn bng vi dung lng RAM. Phn vng swap sl mt phn vng

gip cho hiu hnh hot ng nhanh hn, tng tnh vng nhVirtual Memorytrong Windows.

Phn vng/home: dung lng khong mt na dung lng cn li cha dliu cho user.

Phn vng/: y l phn vng root chim phn dung lng cn li.

Hnh 20: Ci t CentOS - Th it lp a chIPPhn thit lp a chIP: ta c thsdng Dynamic cp a chIP tng hoc t

thit lp a chIP bng tay. Phn thit lp a chIPv6 c thbqua v khng sdng.

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Hnh 21: Ci t CentOS - Chn mi gi

Hnh 22: Ci t CentOS - Nhp password Console cho hthng

Hnh 23: Ci t CentOS - Chn cch ci t

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Phn thit lp cch ci t: n gin ta chcn ci theo kiu server. Khng cn

ci nhng kiu c giao din nh Gnome hay KDE v sau ny ta scu hnh trc tipqua Console hoc bng phn mm Putty.

Chn Customize now ci t thm cc gi htrcho Asterisk.

Hnh 24: Ci t CentOS - Chn cc gi htrcho Aster iskPhn chn cc gi htrcho Asterisk: ta cn chnDevelopment Tools, chi tit cc

gi trong ny ta c thbm nt Optional packages tm hiu chi tit hn. Cc giny shtrcc chng trnh v th vin ta ci t v vn hnh thnh cngAsterisk sau ny.

Hnh 25: Ci t CentOS - Chn kiu loader khi ng

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Hnh 26: Ci t CentOS - Chun bci t

Hnh 27: Ci t CentOS - Qu trnh ci tQu trnh ci t CentOS din ra khong 20 pht sau ta khi ng li hthng

v tin trnh ci t CentOS thnh cng, tip theo l ci t cc gi thc hin chcnng tng i IP PBX Asterisk.

2.1.2 Ci t cc gi tr ong tng i Asterisk

2.1.2.a Chun bcc tp tin trc khi ci t

+ To th mc lu trcc tp tin ci t Asterisk# cd /usr/src

# mkdir asterisk

# cd asterisk

+ Dng lnh wget ti cc gi ci t Asterisk. Cc gi ny c ly ttrangweb chnh ca Asterisk http://www.asterisk.org/downloads bng cc click chut phi

vo dng download ca cc gi ci t v chn Copy Link Location.+ Ta ln lt download cc gi tin vth mc/usr/src/asteriskgm:

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Asterisk-1.4.21.2

Zaptel-1.4.21.1

Libpri-1.4.7

Addons-1.4.7

+ Ta sdng cc lnh sau:# wgethttp://downloads.digium.com/pub/asterisk/releases/asterisk-1.4.21.2.tar.gz

# wgethttp://downloads.digium.com/pub/zaptel/releases/zaptel-1.4.12.1.tar.gz

# wgethttp://downloads.digium.com/pub/libpri/releases/libpri-1.4.7.tar.gz

# wgethttp://downloads.digium.com/pub/asterisk/releases/asterisk-addons-1.4.7.tar.gz

Hnh 28: Ti cc gi ci t Aster isk+ V cc gi tin download vdi dng tp tin nn nn ta phi gii nn trc khi

compile vo trong hthng. Ta sdng cc cu lnh sau gii nn cc gi ci t:# tar -xzvf asterisk-1.4.21.2.tar.gz

# tar -xzvf zaptel-1.4.12.1.tar.gz

# tar -xzvf libpri-1.4.7.tar.gz

# tar -xzvf asterisk-addons-1.4.7.tar.gzKhi gii nn xong trong th mc/usr/src/asteriskta c 4 th mc con:

asterisk-1.4.21.2

zaptel-1.4.12.1

libpri-1.4.7

asterisk-addons-1.4.7

2.1.2.b Compiling v ci t cc gi

+ Ci t Zaptel

Gi Zaptel nn ci t trc tin. Ta dng ln lt cc lnh sau ci t:# cd zaptel-1.4.12.1

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http://downloads.digium.com/pub/asterisk/releases/asterisk-1.4.21.2.tar.gzhttp://downloads.digium.com/pub/asterisk/releases/asterisk-1.4.21.2.tar.gzhttp://downloads.digium.com/pub/asterisk/releases/asterisk-1.4.21.2.tar.gzhttp://downloads.digium.com/pub/zaptel/releases/zaptel-1.4.12.1.tar.gzhttp://downloads.digium.com/pub/zaptel/releases/zaptel-1.4.12.1.tar.gzhttp://downloads.digium.com/pub/zaptel/releases/zaptel-1.4.12.1.tar.gzhttp://downloads.digium.com/pub/libpri/releases/libpri-1.4.7.tar.gzhttp://downloads.digium.com/pub/libpri/releases/libpri-1.4.7.tar.gzhttp://downloads.digium.com/pub/libpri/releases/libpri-1.4.7.tar.gzhttp://downloads.digium.com/pub/asterisk/releases/asterisk-addons-1.4.7.tar.gzhttp://downloads.digium.com/pub/asterisk/releases/asterisk-addons-1.4.7.tar.gzhttp://downloads.digium.com/pub/asterisk/releases/asterisk-addons-1.4.7.tar.gzhttp://downloads.digium.com/pub/asterisk/releases/asterisk-addons-1.4.7.tar.gzhttp://downloads.digium.com/pub/libpri/releases/libpri-1.4.7.tar.gzhttp://downloads.digium.com/pub/zaptel/releases/zaptel-1.4.12.1.tar.gzhttp://downloads.digium.com/pub/asterisk/releases/asterisk-1.4.21.2.tar.gz


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# ./configure

# make

# make install

+ Ci t libpri# cd ../ libpri-1.4.7

# make

# make install

+ Ci t Asterisk# cd ../asterisk-1.4.21.2

# ./configure

Hnh 29: Khi chy conf igure cho compile# make menuselect

Hnh 30: Tuchn menu sau khi to menu bng lnh make menuselect# make

# make install

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Hnh 31: Sau khi dng lnh make instal l thnh cngTo cc tp tin cu hnh mu

# make samples

Hnh 32: To cc tp tin cu hnh muTo cc ti liu chng trnh ca Asterisk# make progdocs

Hnh 33: To cc ti l iu chng trnh ca Aster isk

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+ Ci t asterisk-addons

# asterisk-addons-1.4.7

# ./configure

# make

Hnh 34: Ci t asteri sk-addons# make install

Qu trnh ci t Asterisk thnh cng.Ch sau khi ci t thnh cng Asterisk ta c cc th mc quan trng sau:

/etc/asterisk/: cha cc file configuration dng *.conf, bn c ththay i trc tipcc file config bng mt editor (vi) v reload asterisk thay i c hiu lc.

/var/lib/asterisk/ : Cha cc file library, sound ..etc ca Asterisk.

2.1.2.c Ci t Asteri sk-GUI

+ Ta dng lnh svn ti Asterisk-GUI vv tin hnh ci t. Ta ln lt sdngcc lnh sau:

# svn co http://svn.digium.com/svn/asterisk-gui/branches/2.0 asterisk-gui

# cd asterisk-gui

# ./configure

# make

# make install

+ Sau khi ci t xong ta cn cu hnh 2 file sau:- Sa tp tinmanager.conftrong th mc/etc/asterisk/# vi /etc/asterisk/manager.conf

Sa tp tinmanager.confthnh:[general]

enabled=yes

webenabled=yes

port=5038

bindaddr=0.0.0.0

[vinh]

; cho php truy cp qua web

; lng nghe trn tt ccc port; to mt user admin login qua web cu hnh

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Cc bc ci t chnh:

Hnh 35: Giao din bt u ci t Tr ixbox

Hnh 36: Chn loi bn phm

Hnh 37: Chn Vng thi gian cho hthng

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Hnh 38: Password cu hnh Asteri sk

Hnh 39: Tin trnh ci t Tr ixbox 1

Hnh 40: Tin trnh ci t Tr ixbox 2

Hnh 41: Giao din cu hnh qua Web ca Tr ixbox

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2.3 Cc htrtrong vn hnh v cu hnh Asterisk2.3.1 Mt slnh chnh trong CL I ca Asterisk

vo CLI ca Asterisk ta dng lnh# asterisk -r

2.3.1.a Cc lnh chung

abort haltadd extension

debug channel

no debug channel

help

show agents

show applications

show application

show channel

show channels

show codecs

show conferences

show dialplan

show locals

show queues

show voicemail users

2.3.1.b Cc lnh cho SIP

sip debug

sip no debug

sip reload

sip show channels

sip show channel

sip show peers

2.3.1.c Qun trServer

restart now

: hucc tin trnh ang btreo: thm 1 sni bvo trong ng

: d li trn mt knh no : hy d li trn mt knh no : hin thdanh sch htr: hin thtrng thi ca cc agent: hin thdanh sch cc ng dng Asterisk htr: m tchi tit mt ng dng: hin ththng tin mt knh: hin ththng tin nhiu knh: hin ththng tin cc codec

: hin thtrng thi ca cc phng hi ngh: hin ths quay s: hin thtrng ca cc knh ni b: hin thtrng thi cc hng i: hin thcc hp th thoi ca ngi dng ng k

: d li SIP: hy d li SIP: reload sip.conf

: hin thcc knh SIP ang hot ng: hin ththng tin knh SIP chi tit: hin thdanh sch cc sSIP trong tng i

: khi ng li Asterisk lp tcrestart when convenient: khi ng Asterisk khi khng c cuc gi noreload

stop now

stop when convenient

show version

: reload cu hnh: tt Asterisk lp tc: tt Asterisk khi khng c cuc gi no: hin thphin bn Asterisk

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2.3.2 Cc cng chtrvn hnh vcu hnh Asterisk

2.3.2.a Phn mm Putty

Phn mm Putty htrta trong vic cu hnh trc tip ln hiu hnh Linux txa dng SSH. y l mt cng crt thng dng cu hnh Linux dng Consolelnh.

Ta c thti phn mm t:http://the.earth.li/~sgtatham/putty/0.60/x86/putty.exeSau y l mt shnh nh ca chng trnh Putty

Hnh 42: Giao din phn mm Putty -ng nhp

Hnh 43: Giao din phn mm Putty - Ca slnh

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http://the.earth.li/~sgtatham/putty/0.60/x86/putty.exehttp://the.earth.li/~sgtatham/putty/0.60/x86/putty.exehttp://the.earth.li/~sgtatham/putty/0.60/x86/putty.exehttp://the.earth.li/~sgtatham/putty/0.60/x86/putty.exe


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2.3.2.b Phn mm WINSCP

Phn mm WINSCP gip ta thao tc trn cc tp tin v phn vng cng trongmi trng Linux ging nh chng trnh Windows Commander trong Windows, hay

NC dng trong DOS.WINSCP gip ta tit kim rt nhiu thi gian trong vic cp nht v qun l cc tp

tin trong Linux, bng cc thao tc rt n gin.Ta c thti phn mm t:http://winscp.net/eng/index.phpSau y l mt shnh nh ca chng trnh WINSCP

Hnh 44: Giao din phn mm WINSCP -ng nhp

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Hnh 45: Giao din phn mm WINSCP - Sdng

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CHNG 3: TM HIU CCH CU HNH ASTERI SK

CHNG 3: TM HIU CCH CU HNH ASTERISK3.1 Tm hiu cc tp tin cu hnh trong Asterisk

Ta c thcu hnh Asterisk trong console mode, hoc c mt cch tin li hn lbin tp trc tip cc tp tin cu hnh trong/etc/asterisk. Mi ng dng ring ca

Asterisk nh voicemail, zaptel, music-on-hold, meetme, conference, iax u c tptin cu hnh ring ca mnh, tuy nhin c 2 tp tin cu hnh quan trng nht lsip.conf

vextension.conf:

-sip.conf: tp tin cu hnh vcc thng tin ca cc sni bclient nh username,password, IP, type, security, codec l thnh phn cn bn nht lu githng tin trong

Asterisk.-extension.conf: tp tin cu hnh vcc lut nh tuyn cuc gi, lut quay s(s

quay s), cc extension trong ngoi v nhng tnh nng c bit khc.extensions.confl tp tin quan trng nht trong bt kcu hnh Asterisk no.

Cc tp tin cu hnh khc:-voicemail.conf: tp tin cu hnh cho hthng hp th thoi (voice-mail) ca

Asterisk. Asterisk c thdng lnh Sendmail trn CentOS gi mail n cho cc achc lu trong tp tin cu hnh ny.

-zaptel.conf: tp tin ny nm ngoi/etc, l tp tin cha thng sindex, driver dnh

cho Linux khi kch hot cc thit bin thoi cm trc tip vo Asterisk thng quacng PCI.

-zapata.conf: cng thuc module zaptel, nhng l tp tin kt ni cc thit bin

thoi c khai bo vo hthng chnh ca Asterisk.-iax(2).conf: cc thng svIAX (inter-asterisk protocol) dng khi kt ni 2

Asterisk box vi nhau.-meetme.conf: mt chc nng to room conference cn bn.

3.2 Ngphp ca Asterisk

Asterisk c iu khin bng cc tp tin cu hnh dng vn bn (text) c lutrong th mc/etc/asterisk. Kiu nh dng tp tin ny tng tnh tp tin .initrong Windows. Dy chm phy ; c sdng ghi ch, du = v => tng

ng nhau v du khong trng c bqua.[Session]

Key = value ; Khi to bin[Session 2]

Key => value ; Khai bo i tngAsterisk bin dch = v => cng mt cch thc. iu khc bit l c php c

sdng y khc nhau cho i tng v bin. C php l ging nhau gia tt ccctp tin v c 3 loi ngphp c chra bn di:

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Loi ngphp

Nhm n

Tuchn ktha

i tng cto ra

Tt ctrn cngmt dng

Tuchn cto trc, itng kthacc tuchn

Tp tin cuhnh

extensions.conf

zapata.conf

V d

exten=>4000,1,Dial(SIP/4000)

[channels]context=default

signalling=fxs_ks

group=1channel => 1

[cisco]type=friend

secret=mysecret

Dng thc thphc hp

Mi thc thnhn mt ngcnh

sip.confiax.conf

host=10.1.30.50

context=trusted

[xlite]

type=friend

secret=xlite

host=dynamic

Bng 2: Cc kiu ngphp trong Asterisk3.2.1 Nhm n

Kiu nh dng nhm n c sdng trong cc tp tinextensions.conf,meetme.confvvoicemail.confl ngphp c bn nht. Mi i tng c khai bo

vi cc ty chn trong cng mt hng.V d:[Session]

Object 1 => op1,op2,op3

Object 2=> op1b,op2b,op3b

Trong v dny, Object 1 c to ra vi cc ty chn op1, op2, op3 trong khiobject 2 c to ra vi cc ty chn op1b, op2b, op3b.

3.2.2 Cc ty chn i tng kiu ngphp tha k

Kiu nh dng ny c sdng bizapata.confvagents.confni c nhiu tychn sn sng, hu ht cc giao tip, cc i tng chia sv khai bo cc knh. Cc

ty chn cho i tng c khai bo pha trn i tng v c thc thay itrong i tng khc. Mc d khi nim ny hi kh hiu nhng n rt dsdng.

V d:[Session]

op1 = bas

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op2 = adv

object=>1

op1 = int

object => 2

Hai dng cu hnh u tin gi trca ty chn op1 v op2 l bas v adv. Khi

i tng 1 c to ra n c to ra sdng option 1 nh l bas voption 2 nhl adv. Sau khi nh ngh i tng 1 chng ta thay i option 1 sang int. Sau chng ta to ra i tng 2 vi option 1 l int v option 2 l adv.

3.2.3 Dng thc thphc hp

Kiu nh dng ny c sdng trongiax.conf,sip.confv trong nhng tp tincu hnh ni m c nhiu thc thvi nhiu ty chn. C bn, kiu nh dng nykhng chia smt lung ln cc cu hnh chung. Mi mt thc thnhn mt ngcnh. i khi ngcnh c dnh ring ging nh [general] cho cu hnh ton cc.

Cc ty chn c khai bo trong ni dung khai bo.V d:[entity1]

op1=value1

op2=value2

[entity2]

op1=value3

op2=value4

Thc th[entity1] c cc gi trvalue1 v value2 cho cc ty chn op1 v op2.Thc th[entity2] c cc gi trvalue3 v value4 cho cc ty chn op1 v op2.

3.3 Tm hiu cu hnh mt giao tip PSTN

kt ni n mt PSTN ta sphi cn c mt card giao tip FXO v mt ngdy in thoi. Ta c thsdng mt sPBX c sn. Ta c thlm c bng mtcard giao tip in thoi vi vi mt giao tip FXO tnhiu nh cung cp khc nhau.Trong v dny chng ta tm hiu cch ci t mt mch Zaptel:

Ghi ch: c nhiu card FXO khc. Card X100P c thtm thy trn thtrng vi

gi kh r. Nhng mch ny da trn nn fax/modem 56K ca Motorola v Intelchipset. Nhng chipset ny l:

- Motorola 68202-51

- Intel 537PU

- Intel 537 PG

- Intel Ambient MD3200

Khng c m bo mch ny slm vic c. Vic sdng l ty, mt vi vnvting di v m lng thp. Nu ta mun cht lung tt, m bo tin cy thnn dng board ca Digium.

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3.3.1 Ci t X100P

Trc khi ci t mt card X100P vo trong my tnh, ta phi disable tt cccphn cng khng cn dng n hay khng sdng tmch chnh. iu ny sgipcho chng ta trnh c cc vn vchia scc ngt (interrupt). ci t ng

X100P, ta sphi gn card vo trong mt khe PCI v iu chnh 2 tp tin cu hnh:

zaptel.conf: tp tin ny nm ngoi/etc, l tp tin cha thng sindex, driverdnh cho Linux khi kch hot cc thit bin thoi cm trc tip vo Asterisk thngqua cng PCI.

zapata.conf: cng thuc module zaptel, nhng l tp tin kt ni cc thit binthoi c khai bo vo hthng chnh ca Asterisk.

- zaptel.conf

fxsks=1

loadzone = br

defaultzone=brchannels=1

- zapata.conf

[channels]

context=default

signalling=fxs_ks

group=1

channel => 1

3.3.2 Ci vcu hnh driver card X100PSau khi hon tt vic chnh sa cc tp tin trn ta tin hnh load cc biu khin

zaptel v ci t bng cc lnh:# modprobe zaptel

# modprobe wcfxo

# ztcfg -v

# asterisk -g

3.4 Tm hiu cu hnh in thoi IP SIP

Chng ta hy cu hnh cc in thoi SIP. tng l cu hnh mt tng i PBX.SIP c cu hnh trong th mc/etc/asterisk/sip.confv c tt ccc thng slin hti in thoi SIP v nh cung cp dch vVoIP. Cc SIP client phi c cu hnhtrc khi ta nhn hay thc hin cuc gi.

3.4.1 Phn chung [general ]

SIP tp tin c c ttrn xung di. Phn u cha cc thng ston cc[general]. Cc ty chn chnh gm:

allow/disallow: nh ngha codecs no c thc sdng.

bindaddr: a chm Asterisk SIP dng lng nghe (listener). Nu ta thit lpn thnh 0.0.0.0 (mc nh) n slng nghe tt ccc giao tip.

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context: Thit lp ngcnh mc nh cho tt ccc client ngoi trcc client

c thay i.bindport: port SIP UDP dng lng nghe.

maxexpirey: Thi gian ti a cho vic ng k (tnh bng giy).defaultexpirey: Thi gian mc nh cho vic ng k (tnh bng giy).

register: ng k Asterisk ti mt host khc..V d:[general]

bindport = 5060

bindaddr = 10.1.30.45

context = default

disallow = all

allow = ulaw

allow = alawmaxexpirey = 120

defaultexpirey = 80

3.4.2 Phn Client

Sau khi hon thnh cc phn chung [general], tip theo sthit lp cc SIP client.[name]: Khi mt thit bSIP kt ni n Asterisk, n sdng phn username

ca SIP URI tm ra peer/user.type: Cu hnh lp kt ni. Cc tuchn l peer, user v friend.

peer: Asterisk gi cc cuc gi n peer.user: Asterisk nhn cc cuc gi tmt user.friend: Chai cng thi im.host: a chIP hay tn ca host. Tuchn thng thng l dynamic, c s

dng khi host ng k n Asterisk.secret: Mt khu xc thc peer v user.

V d:[cisco]

type=friend

secret=mysecret

host=10.1.30.50

context=trusted

[xlite]

type=friend

secret=xlite

host=dynamic

defaultip=10.1.30.17

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3.5 Tim hiu s quay s

S quay sl tri tim ca Asterisk, n nh ngha cch m Asterisk iu khin,nh tuyn mi cuc gi v bt kcuc gi n PBX. N cha cc s, danh sch lnh

cho Asterisk tun theo. Cc lnh c gn vo cc snhn c tknh hay ngdng. cu hnh Asterisk thnh cng, vic hiu s quay sl rt quan trng.

Hu ht s quay su c cha trong tp tinextensions.confti th mc/etc/asterisk. Tp tin ny sdng ngphp nhm n v c 4 thnh phn chnh sau:

Sni b(Extensions). Su tin (Priorities). ng dng (Applications). Ngcnh (Contexts).

3.5.1 Sni b(Extensions)

S quay sl mt tp hp cc sc nh ngha trc. Mt sl mt chui s

trigger mt skin khi mt cuc gi c thc hin. Cc sc thhoc bng chhoc bng mu s(pattern).

3.5.1.a Mt smu s(pattern)

_ : chvic bt u 1 pattern. X : i din cho bt ksno t0 n 9. N : i din cho bt ksno t2 n 9. Z : i din cho bt ksno trs0.

[dy bt k] : khp vi chmt trong cc k tnm trong du ngoc vung [].

V d: [02-68*#] skhp vi cc k t0, t2 n 6, 8, * hoc #. . : l mt wildcard, khp vi bt kk tno nm pha sau du chm .. | : chvic sdng phm spha trc | gi ra ngoi (thng l s0 hay s

9). Sny c loi bkhng a ra ngoi.Mt sv dca mu s(pattern):9|NXXXXXXXX : bm s9 ra ngoi, dy sgi ra ngoi gm 9 phm sbt

u ts2 n 9 v 8 scn li l bt k. Vy tng cng ngi sdng gi 10 snhng s9 u bloi bv chgi 9 ssau ra ngoi trung k.

_4XXX : chnhng sgi ni bc 4 sbt u ts4._90[2-8]. : dng cho trng hp sgi ra ngoi (bm s9 ra ngoi) ssau l dysng di. Dng trong cc ngcnh cp quyn gi ng di.

_909XXXXXXXX : dng cho trng hp sgi ra ngoi (bm s9 ra ngoi) ssau l dy sdi ng. Dng trong cc ngcnh cp quyn gi di ng.

_91900. : dng cho trng hp sgi ra ngoi (bm s9 ra ngoi) ssau l dy sdch v1900. Dng trong cc ngcnh cp quyn gi dch v1900.

Nh ta thy bn trn, vic hiu v sdng cc mu s(pattern) ny mang li tnhlinh hot v s quay srt mnh cho cu hnh nh tuyn Asterisk.

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3.5.1.b Cc vdvsni b(extensions)

+ V d1:exten=>8580,1,dial(SIP/8580,20)

exten=>8580,2,hangup()

Lnh exten m tbc tip theo ca cuc gi n s8580 l mt tp hp ca cc

snhn c (sc gi). S1 v 2 l u tin nh ngha thtxl. Quays8580 sgi SIP IP Phone c ng k nh 8580. Nu cuc gi khng cngui trli sau 20 giy n sgii tocuc gi.

+ C php Extensionexten=> number (name), {priority|label{+|-}offset}[(alias)],application

Lnh extension exten= theo sau bi mt sni bhoc tn, mt du phy, mtsu tin, mt du phy na v cui cng l ng dng. sni bgn vi a chcacuc gi (sin thoi). Su tin c sdng chthtcc bc thc thi tng

ng vi su tin. ng dng l hnh ng (quay s, gi li, gc my ). Mi mthnh ng l mt ng dng khc nhau.

+ V d2:exten=>_90[2-8].,1,dial(ZAP/g1/${EXTEN:1},20,tT)

exten=>_90[2-8].,n,hangup()

Trn l mt v din hnh cho vic gi ng di ca mt sni b:-_90[2-8].: chra bt u mt pattern, gi ra ngoi dng s9 u v gi i lin

tnh (bt du s0 v sau l s2 n s8 gi m lin tnh). Du chm . chbt kdy sno pha sau u chp nhn.

-ZAP/g1: chng ra l mt trong cc ng trung kri gn vo card FXO.Nu ZAP/1 tc l ng s1, Zap/2 tc l ng s2 v ZAP/g1 l bt kng nori trong dy trung k.

-${EXTEN:1): y l bin ly snhp vo l phn sau ca dy s nhp, tri 1su, tc s9 sbbqua.

3.5.2 Su tin (Priorities)

Su tin nh scc bc thc hin trong mi sc quay. Mi su tin gimt ng dng xc nh. Thng thng sny bt u ts1 v tng tng bc 1

bc trong phn nh ngha sni b. Hin ti cc phin bn Asterisk mi htrvic

sdng thut ngn i din cho su tin tip theo thay v phi gn stip theo.

3.5.3 ng dng (Applications)

Cc ng dng ng mt vai tr quan trng trong Asterisk. Chng iu khin cc

knh thoi, m hiu, chp nhn cc con sc gi tPBX v gii tocuc gi. Ccng dng c thc gi vi cc tuchn chcch hnh x. Ta c thsdng lnh

show applications trong giao din lnh ca Asterisk chra cc ng dng c sn.CLI>show applications

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3.5.4 Ngcnh (Contexts)

Ngcnh ng mt vai tr quan trng trong vic cu hnh s quay scaAsterisk v bo mt. Ngcnh nh ngha mt vng (scope) cho php phn chia s quay sthnh nhiu phn khc nhau. Vic hiu ngcnh c gn kt vi cc knh l

rt quan trng. Khi tng i Asterisk nhn mt cuc gi, cuc gi c xl trong

phn ngcnh gi n (incoming). Ngcnh (context) gi n lun lun c nhngha bi tp tin cu hnh knh (iax.conf, sip.conf, zap.conf).

Gisrng chng ta c 2 lp ngi sdng managers v guests. Gisrngchng ta mun c 2 thng ip cho guests v managers khi hquay s9000. Tac thlm c vic ny bng cc nh ngha ngcnh gi n trong tp tin cu hnhknh (sip.conf, iax.conf, zap.conf).

Trong v dbn di, khi nhanvienA quay s9000, nhanvienA nhn c thngip youareaguest. Khi nhanvienB quay cng sny nhanvienB nhn c thng

ip khc youaremanager.sip.conf

[nhanvienB]

context=managers

host=dynamic

[nhanvienA]context=guests

host=dynamic

extensions.conf

[nhanvienB]

exten=>9000,1,Playback(youareamanager)

[nhanvienA]

exten=>9000,1,Playback(youareaguest)

Khi hiu khi nim ny ta c thto ra nhiu chc nng khc nhau trong Asterisk.Cc ngcnh khc nhau c thc sdng phc vcho nhiu cng ty khc nhau

v nhiu lp ngi dng khc nhau trong cng cu hnh Asterisk. Ngcnh c thc xc nh l ai c thgi c cuc gi ng di v ai khng c.

Ngcnh nhn mt tn bn trong du []. Tt ccc lnh nh ngha sau lmt phn ca ngcnh. bt u mt ngcnh, n gin l chn vo phn ngcnhmi. Mt ngcnh kt thc khi mt ngcnh khc bt u.

C 2 ngcnh quan trng trong tp cu hnhextensions.conf. Ngcnh [globals]c sdng nh ngha cc bin trong khi ngcnh [general] c sdng nh ngha cc tuchn chung.

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3.6 Tm hiu cch to mt s quay s

By gichng ta bt u vi vic to ra s quay su tin. Chng ta ssdng cc v dm ts quay s. Hy i tng bc:

3.6.1 Vdc bn

Trong v dny, Asterisk snhn mt cuc gi, pht ra mt m thanh v gii tocuc gi.

iu chnh tp tinextensions.confbao gm:[incoming]

exten=>s,1,answer()

exten=>s,2,playback(goodbye)

exten=>s,3,hangup()

u tin 1 gi ng dnganswer()trli. Asterisk iu khin ng dy v thitlp cc cuc gi. Sau khi trli n squa u tin tip theo.

u tin 2 gi ng dngplayback()pht ra mt m thanh ttp tingoodbye.gsm.

Cui cng u tin 3 gi ng dnghangup()kt thc cuc gi.M tv d:Mt cuc gi c nhn bi mt giao tip FXO c gi n ngcnh incoming,

c nh ngha trong tp tin cu hnh knh (zapata.conf). Khi mt cuc gi n nc xl trong ss ca ngcnh incoming. Chng ta c 3 tuchn mi tuchngi mt ng dng.

Sc bit s c sdng bt u xl cuc gi n khi sc gi ntng i khng xc nh (v dcuc gi n bi 1 ng line analog).

Nu chng ta trli mt cuc gi, tt hn l chng ta bit ng dng no sthchin. ng dnganswer()c sdng trli mt knh trong trng thi rungchung. Mt vi ng dng yu cu ng dnganswer()trc khi xl cuc gi.

ng dngplayback()c sdng pht ra mt bn tin tmt tp tin m thanhc thu trc. Khi ng dngplayback()c thc thi, bt kphm bm vo a vou c bqua. C php lnhplayback(filename). N spht tp tin vi ui .gsm tth mc m thanh mc nh.

ng dnghangup()lm nhim vging nh tn gi ca n. N gii toknh angkch hot.

3.6.2 Mt vdkhc

Chng ta hy pht trin v du ca chng ta bng cc a ra thm 2 ng dngna:background()vgoto(). iu chnh yu cho cc hthng tng tc trn Asterisk

l ng dngbackground(). N cho php ta pht mt tp tin m thanh trong khi vnang chnhn cc phm sa vo. Khi iu ny xut hin, m thanh ang pht sngng li v thc thi tip theo stuthuc vo cc sc bm.

C php cu lnh ng dngbackground()exten=>extension, priority, background(filename)

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Mt ng dng hu ch khc lgoto(). Nh tn ca n, n nhy tngcnh hin ti

qua mt sni b, mt su tin n mt ni dung xc nh, sni bv mt sutin khc.

C php ng dnggoto():exten=>extension, priority,goto(context,extension, priority)

C php hp lcagoto():Goto(context,extension,priority)

Goto(extension,priority)

Goto(priority)

y l mt v dca mt cng ty nhvi 3 phng ban: kthut htr, kinh doanhv hun luyn. Chng ta hy to ra mt hthng tng tc cho php cc ngi dngc thchn phng ban c gi. u tin, chng ta spht mt on cho hi giithiu ging nh bm phm 1 htrkthut, phm 2 hun luyn, v phm 3

gp phng kinh doanh. Trong v dny chng ta khng xl nhng trng hp gssai. Sau khi ta chn mt phng ban, hthng spht mt bn tin ging nh Bnang kt ni n phng ban v chuyn vic xl n mt ngcnh tng ng.

[incoming]

exten=>s,1,Answer()

exten=>s,2,Background(greeting)

exten=>s,3,hangup()

exten=>1,1,playback(support)

exten=>1,2,goto(support,s,1)exten=>2,1,playback(training)

exten=>2,2,goto(training,s,1)

exten=>3,1,playback(sales)

exten=>3,2,goto(sales,s,1)

Din gii tng bc:Khi mt ngi no thc hin cuc gi in thoi n hthng Asterisk thng

qua card giao tip FXO ( c cu hnh [incoming] trongzapata.conf), ss trong[incoming] c trigger. Ss trli cuc gi sdng ng ng background v

pht mt thng ip cho, chnhn s. Nu ngi sdng bm s1 th hthng schuyn sang s1 v pht mt bn tin tng ng Bn c chuyn n phng htrkthut. Tip theo, s2 gi n [support] xl tip

3.6.3 Cc knh cu ni sdng ng dng dial()

Ta c thnng cp v dca mnh bng cch thm vo lnhdial(). Thay v gi nxl mt ngcnh khc, chng ta schuyn cuc gi n mt sni bmt cchtrc tip dng ng dngdial().

[incoming]

exten=>s,1,Answer()

exten=>s,2,Background(greeting)

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exten=>s,3,hangup()

exten=>1,1,playback(support)

exten=>1,2,Dial(SIP/8000)

exten=>2,1,playback(training)

exten=>2,2,Dial(ZAP/1)

exten=>3,1,playback(sales)

exten=>3,2,Dial(IAX2/8002)

So snh vi v du tin, chng ta va to ra mt ng tt. Thay v gi cuc gin mt ngcnh khc, chng ta by gichuyn cuc gi n knh cui cng. Chosupport, chng ta strc tip gi n SIP phone vi s8000. Cho training chngta schuyn cuc gi trc tip n TDM (analog hoc digital) n knh s1 . Cuicng cho sales chng ta sgi cuc gi n IAX2 phone vi s8002.

3.7 Tm hiu cch to mt hthng IVR

Trc khi thc hin mt hthng IVR ta i tm hiu cc ng dng c bn to rahthng IVR, sau ta i tm hiu cc bc xy dng mt hthng IVR.

3.7.1 ng dng background()

Pht mt tp tin m thanh trong khi vn chnhn cc svo.C php:

background(filename1[filename2][options[langoverride][context]]) ng dng ny spht mt danh sch tp tin c a vo trong khi vn ch

nhn mt sc gi n bi mt knh gi n. tip tc chnhn cc ssau khi

ng dng ny kt thc vic pht cc tp tin m thanh th ng dngWaitExtencsdng. tuchn langoverride chngn ngc sdng nhn cc tp tin mthanh pht ra (tc cc tp tin m thanh c to ra thnh cc btheo tng ngn ng).

Nu mt ngcnh (context) c sdng th n l mt ngcnh ca s quay sm ng dng ny ssdng khi hon tt mt s c gi n. Nu mt trong cctp tin trong danh sch cc tp tin c pht ra khng tn ti th tin trnh pht sbhy b.

3.7.2 ng dng r ecord()

ng dng ny dng thu m tmt knh v to ra mt tp tin nh sn, nu tptin ny tn ti th n sghi ln.

C php:

record(filename.format silence[maxduration][option])

format : l kiu nh dng ca tp tin c thlu c (nh: wav, gsm). silence : l sgiy im lng cho php trc khi bt u thu m. maxduration : l sgiy ghi m ti a nu khng c thng sny hoc thng

sny bng 0 th khng c gii hn vthi gian ghi m.

options : tuchn gm bt kcc k tsau:o 'a' : thm vo mt tp tin m thanh tn ti thay v ghi .o 'n' : khng trli nhng li ghi m bt kng dy c trli hay khng.

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o 'q' : im lng, khng pht ra ting beep bo bt u ghi m.

o 's' : vn givic ghi m cho d ng dy khng trli.o 't' : dng thay vic kt thc ghi m dng du sao * thay v du thng #.

o 'x' : bqua phm bo hiu kt thc ghi m v gin khi no gc my.Nu tn tp tin c cha %d n sthay thcho mt stng dn mi khi mt tp

tin c ghi m.Dng lnh# show file formatsxem cc kiu nh dng m hthng htr.

Ngi sdng bm phm # kt thc vic ghi m, nu ngi sdng gc mygia chng th qu trnh ghi m sbhubv khng lu li tp tin ghi m ny.

3.7.3 ng dng playback()

Pht mt tp tin m thanh (khng cn a vo phn ui)C php:

playback([filename1[& filename2][option])

3.7.4 ng dng read()

ng dng ny dng xc nh trc scon shay mt khong thi gian quy nhtrc (bin s) khi ngi dng nhp vo hthng.

C php:Read(variable[filename][maxdigits][option][attempts][timeout]

filename : tp tin m thanh pht ra truc khi c cc con s. maxdigits : scc con snhp vo ti a. attempts : nu ln hn 1 tc sthnhiu ln nu khng c dliu a vo.

3.7.5 ng dng gotoif()

C php:

Gotoif(condition?[labeliftrue]:[labeliffalse])

ng dng ny sgip cho cuc gi c thnhy n mt vng xc nh trong s quay sda vo gi trtrong phn iu kin (condition). Cuc gi stip tc nlabeliftrue nu thoiu kin v lableiffalse nu khng tho. label c cu trctng tnh cu trc sdng trong ng dng goto().

3.8 Xy dng mt hthng IVR

Yu cu: Khi nhn sIVR spht mt tp tin m thanh vi ni dung Cho mngbn n vi cng ty XYZ, bm phm 1 vo phng kinh doanh, phm 2 vo phnghtrkthut, bm s3 vo phng hun luyn, hoc xin qu khch chtrong giylt gp tng i vin ca chng ti. Khi s1 c bm, cuc gi scchuyn n phng kinh doanh (SIP/4001); nu bm phm s2, cuc gi scchuyn n phng htrkthut (SIP/4002); nu bm phm s3, cuc gi scchuyn n phng hun luyn (SIP/4003). Nu khng c phm no c bm thchuyn cuc gi n tng i vin (SIP/4000).

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Ta thc hin hthng IVR qua 2 bc:

3.8.1 Thu m li cho

Chng ta to ra mt li cho bng cch ghi m mt li cho vi tn c nhp vosau khi quay s9001, sau khi nghe ting bp ta bt u thu m v khi kt thc ta bmnt thng # lu li tp tin ny v pht li tp tin kim tra:

Ta to ra cc lnh sau trong tp tinextensions.conf:exten=_9001.,1,answer()

exten=_9001.,n,record(${EXTEN:4} t)

exten=_9001.,n,playback(${EXTEN:4})

exten=_9001,n,handup()

3.8.2 To ra hthng IVR

OPERATOR=>SIP/4000

[menu]

exten=>s,1,background(mainmenu)

exten=>1,1,goto(sales,s,1)

exten=>2,1,goto(techsupport,s,1)

exten=>3,1,goto(training,s,1)

; Nu bm sai sth chuyn qua sca tng i vinexten=>i,1,dial(${OPERATOR})

; Nu ht thi gian th chuyn qua sca tng i vinexten=>t,1, dial(${OPERATOR})

[sales]exten=s,1,dial(SIP/4001,20,tT)

[techsupport]

exten=s,1,dial(SIP/4002,20,tT)

[training]

exten=s,1,dial(SIP/4003,20,tT)

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CHNG 4: XY DNG MT TNG I THC T

CHNG 4: XY DNG MT TNG I THC T4.1 M tcc bc thc hin

1. M tchc nng v hot ng ca tng i.2. Cu hnh phn cng.

3. Ci t tng i Asterisk.4. Chun bv ci t cc thit bFXS, FXO.

5. Cu hnh cc thng strong tng i.6. Thit lp cc Client v kim tra cuc gi.

4.2 M tchc nng v hot ng ca tng i

M tnhu cu cng ty:+ Khong 50 sni b, m bo khnng xl cuc gi tt trong ni b.+ Bn ngoi gi vo sni bca cng ty phi qua tng i vin, c thgi trc

tip n mt ssc bit.+ Dng hthng IVR giao tip v

Documents

Nghien Cuu Hoat Dong Va Cach Trien Khai Tong Dai Ip Pbx Asterisk