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454-319/1: Vo ice over IP. Lecture No. 6 Gateway configuration, FXS, FXO, EM, ISDN PRI and BRI. Miroslav Voz ňák VŠB - Technical University of Ostrava Department of Telecommunications Faculty of Electrical Engineering and Computer Science 17. listopadu 15, 708 33 Ostrava – Poruba
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454-319/1: Voice over IP Lecture No.6 Gateway configuration, FXS, FXO, EM, ISDN PRI and BRI Miroslav Vozňák VŠB - Technical University of Ostrava Department of Telecommunications Faculty of Electrical Engineering and Computer Science 17. listopadu 15, 708 33 Ostrava – Poruba mailto:miroslav.voznak@vsb.cz http://homel.vsb.cz/~voz29 Miroslav Voznak, lecture on H.323
POTS Plain Old Telephone Service – analog tel. network • CO Central Office - public telephone exchange • telco – Telecommunication Company • LEC – Local Exchange Carrier (local teleph. comp.) • IXC – Interexchange Carrier (for long distance) • FXS - Foreign eXchange Subscriber • An FXS interface provides POTS service (BORSCHT) • FXO - Foreign eXchange Office • An FXO receives POTS service, typically from a Central Office • An FXO interface provides on-hook/off-hook indication (loop closure) Miroslav Voznak, lecture on H.323
Subscriber loop • - suitable when conventional phones should be connected directly to VoGWvia an FXS interface • an FXS interface connects directly to a standardtelephone and supplies ring, voltage, and dial tone, but can also be used for PBXinterconnection • a disadvantage is that when calling inward towards the PBX, an extensionnumber can be dialled only as DTMF (Dual-Tone Multi-Frequency) suffix, after a call isestablished and is already accounted for.This type of interface is usually a low-cost solution; • E&M • E&M commonly stands for both Ear and Mouth or recEive and transMit • It allows extension dialling before the conversation begins. • It requires a special interface card forthe PBX, if the PBX is already equipped with this card, this can also be a low-cost solution; Miroslav Voznak, lecture on H.323
ISDN BRI or PRI • ISDN PRI or BRI is the most commonly used interface for interconnection VoIP gateway with PSTN or PBX. • in the case of PBX there is used DSS1 or QSIG, QSIG is a powerful signaling in corporate network • in the case of PSTN interconnecting it’s mostly used DSS1 signaling but for operators peering is required SS7 • Cisco IOS must be higher than 12.1(5) Miroslav Voznak, lecture on H.323
a practical configuration of Cisco Gateway • configure through: • console cable, RS232, terminal: 9600, 8, NO, 1, HW flow control • remote access: telnet (non-secured) or ssh • basic commands: • enable /* switch to enable mode config t /* switch to configuration mode • show run /* show actual configuration wr /* save configuration • CTRL+Z /* cancel shutdown • ? /* list of options , exit /* exit a level , no /* deactivate or remove option • network settings: • # interface FastEthernet0/0 • # ip address 158.196.81.201 255.255.255.0 /* IP address assigning • # ip route 0.0.0.0 0.0.0.0 158.196.81.1 /* default gateway setting Miroslav Voznak, lecture on H.323
How to configure GnuGK with Cisco GW During the registration is sent GRQ a RRQ with name of Gatekeeper as Gatekeeperidentifier (id) and Gateway is registered wit prefixes listed in h323-gateway voiptech-prefixand with its h323-id. # interface FastEthernet0/0 # ip address 158.196.81.200 255.255.255.0 # h323-gateway voip interface # h323-gateway voip id OpenH323GK ipaddr 158.196.81.103 1718 priority 100 # h323-gateway voip h323-id gw1vsb # h323-gateway voip tech-prefix 0 Name of GNU GK submitted in section Main of file /etc/gatekeeper.ini must be thesame as id of Gatekeeper inCiscoGW [Gatekeeper::Main] Name=OpenH323GK Miroslav Voznak, lecture on H.323
check up the state of registration # config terminal # no gateway /* unregister # gateway /* register to GK show gateway # sh gateway /* show status of registration H.323 ITU-T Version: 4.0 H323 Stack Version: 0.1 H.323 service is up Gateway gw1vsb is registered to Gatekeeper OpenH323GK Miroslav Voznak, lecture on H.323
voice settings: # voice rtp send-recv # voice service voip # h323 # h245 caps mode restricted /* prevents DTMF a T.38 indication in H.245 TCS as a optional # h245 tunnel disable /* by default is H.245 tunneling enabled # voice-port 0/0 # compand-type a-law /* default PCM compand type # cptone CZ /* czech control tones # bearer-cap 3100Hz /* default bearer capability Miroslav Voznak, lecture on H.323
ISDN BRI configuration of Cisco GW for Network Side # interface BRI0/0 /*identification of interface in Cisco # no ip address /* because it’s Voice interface # isdn switch-type basic-net3 /* basic-net3 means BRI with DSS1 /* basic-qsig means BRI with QSIG # isdn overlap-receiving /* ability to accept dialing digit by digit # isdn protocol-emulate network /* L3 will operate in network side mode # isdn layer1-emulate network /* L1/L2 will operate in network side mode # isdn incoming-voice modem /* incoming calls are treated as modem calls # isdn send-alerting /* will send ALERTING message # isdn sending-complete /* can include Sending Complete inf. element # isdn static-tei 0 /* TEI=0 is configuration for Point to Point # isdn skipsend-idverify /* do not send TEI verification for User Side # isdn protocol-emulate user /* L3 will operate in user side mode # isdn layer1-emulate user /* L1/L2 will operate in user side mode # as a optinal isdn no skipsend-idverify /* send TEI verification in PMP Miroslav Voznak, lecture on H.323
ISDN PRI configuration of Cisco GW for Network Side #controller E1 1/0 # clock source line primary /* layer L1 clock derived from the line - preferred or # clock source internal /* or clock running internal # pri-group timeslots 1-31 #interface Serial1/0:15 # no ip address /* because it’s Voice interface # isdn switch-type primary-net5 /* primary-net5 means PRI with DSS1 # isdn overlap-receiving /* ability to accept dialing digit by digit # isdn not-end-to-end 64 /* overriding the speed that the network reports # isdn protocol-emulate network /* interface operates in network side mode # isdn incoming-voice modem /* incoming calls are treated as modem calls # isdn send-alerting /* will send ALERTING message # isdn sending-complete /* can include Sending Complete inf. element for User side # isdn protocol-emulate user /* interface operates in user side mode Miroslav Voznak, lecture on H.323
the timers on ISDN interface # isdn overlap-receiving T302 /* T302 timer (in miliseconds) waits before expiring # isdn overlap-receiving terminating-char # /* a terminating character in CPN # isdn t306 /* a timer to disconnect a call after the router sends a disconnect message # isdn timer t309 /* a timer to clear to clear network connection and to release B-channel and Call Reference when data-link disconnection has occured, L2 recovery = SATUS ENQUIRY before T309 expires or RESTART after # isdn t310 /* a timer for Call Proceeding Messages, the router waits before disconnecting a call after receiving Call Proceeding Miroslav Voznak, lecture on H.323
Inbound Dial Peer - configuration Inbound peers are associated to incoming Call legs from Voice network (VoIP) on the voice gateway - POTS /* assume the router in this example receives a call setup with dial-string 59699XXXX from the network where XXXX is an extension and 59699 is a prefix # dial-peer voice 1 pots # destination-pattern 59699.... /* this rule accepts 59699xxxx where xxxx are 4 digits # direct-inward-dial # port 0/0 /* T terminator can be used to suspend this digit-by-digit matching, T refers to the T302 interdigit timer # destination-pattern 59699T Miroslav Voznak, lecture on H.323
Outbound Dial Peer - configuration Outbound dial peers are associated to outgoing Call legs toVoice network (VoIP) on the voice gateway, session target is then used to forward the call /* assume the dial-string is 603121212, after GW receives digit 3, the gateway matches dial peer 20, routes the call to session target and forwards the complete dial-string # dial-peer voice 20voip # destination-pattern 59699.... # codec g711alaw /* use this codec type # session target ras /* if GW is registered with Gatekeeper we can use RAS signaling then or # session target ipv4:195.113.222.2 /* a target is a IP address, i.e. Gateway Miroslav Voznak, lecture on H.323
The Digit Translation Rules The digit translation rules can be used for incoming or outgoing numbers. We achieve a rewriting of CPN (Called number) or CLI (calling number). A Received number 59699xxxx will be translated to 42059699xxxx and begining 0 to 420, any TON (Type of Number) will be translated to UNKNOWN # translation-rule 1 # Rule 0 ^59699.... 42059699 ANY unknown # Rule 1 ^0 420 ANY unknown # dial-peer voice 20 voip /* the rule 1 placed into dial-peer # translate-outgoing called 1 /* rewriting CPN or # translate-outgoing calling 1 /* rewriting CLI # voice-port 1/0:15 /* the rule placed as a global into voice-port # translate calling 2 # translate called 4 Miroslav Voznak, lecture on H.323
The Voice Class Codec We create the class for codec selection preference and assign an identification tag then we apply the voice class codec to a dial-peer. # voice class codec 99 # codec preference 1 g711alaw # codec preference 2 g711ulaw # codec preference 3 g729r8 # dial-peer voice 20 voip /* outbound peer # voice-class codec 99 /* a class codec in inbound peer # dial-peer voice 999 voip /* The voice-class codec can’t be placed into POTS, # voice-class codec 99 /* so the incoming direction is solved a little bit # incoming called-number ..T /* illogicaly Miroslav Voznak, lecture on H.323
Progress Tones Progress tones are transmitted in-band, such as ringback, busy tones and announcements. The indication of in-band tones is controlled by PI (Progress Indicator). PI is an information element included in SETUP, ALERTING, CONNECT, PROGRESS or DISCONNECT. If PI=1 or PI=8 then In-band information is available. When a Setup arrives at the originating gateway with a PI=3, it means that in-band messages are expected. If user doesn’t hear ringback tone we use these solutions: # voice call send-alert /* global configuration # voice dial-peer 1 pots /* but ringback must come ! # progress_ind alert enable 8 # progress_ind progress enable 8 # progress_ind connect enable 8 # progress_ind setup enable 3 # voice dial-peer 20 voip /* it forces to generate in-band ringback # progress_ind setup enable 3 or tone ringback alert-no-pi Miroslav Voznak, lecture on H.323
Thank you for your attentionmiroslav.voznak@vsb.cz Miroslav Voznak, lecture on H.323