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RFC-4123 SIP-H.323 Interworking Requirements Speaker: Yan-Shiang Wang Adviser: Quincy Wu Date: 2005/12/22.

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Presentation on theme: "RFC-4123 SIP-H.323 Interworking Requirements Speaker: Yan-Shiang Wang Adviser: Quincy Wu Date: 2005/12/22."— Presentation transcript:

1 RFC-4123 SIP-H.323 Interworking Requirements Speaker: Yan-Shiang Wang Adviser: Quincy Wu Date: 2005/12/22

2 2 H.323 Introduction Terminal  Endpoint that offers real-time communications with other h.323 endpoint Gateway  Translation services between the h.323 and others Gatekeeper  Controller MCU (Multipoint Control Unit)  Endpoint that manages multipoint conferences

3 3 H.323 Zone Terminal Gateway Gatekeeper GatewayMCU SIP PSTN Router H.323

4 4 H.323 Protocol H  RAS: Registration, Admission, Status Between endpoints and gatekeepers  Q.931: ISDN Layer 3 signaling protocol Between endpoints H.245  Establish and control media streams Between two or more endpoints

5 5 H.323 Protocol Stack Audio/Video Application Terminal/Application Control Audio/Video Codecs RTCP H RAS Signaling H Call (Q.931) Signaling H.245 Control Signaling RTP UDPTCP Network Layer Data Link Layer Physical Layer

6 6 H.323 Protocol (cont.) Gatekeeper  Discovery: udp port 1718  RAS: udp port 1719 Q.931  udp or tcp port 1720 Audio codec  G.711, G.722, G.723, G.728, G.729 Video codec  H.261, H.263

7 7 RAS Signaling - Discovery GatekeeperTerminalGatekeeper GRQ GRJ GCF GRQ: Gatekeeper Request GRJ: Gatekeeper Reject GCF: Gatekeeper Confirm GK discovery multicast address GRQ Terminal sends just one GRQ to the Gatekeeper discovery multicast address. Therefore, the Terminal will now proceed to register with which Gatekeeper.

8 8 RAS Signaling - Registration GatekeeperTerminal RRQ RCF URQ UCF RRQ: Registration Request RCF: Registration Confirm URQ: Unregistration Request UCF: Unregistration Confirm //

9 9 RAS Signaling - Admission GatekeeperTerminal ARQ ACF Setup ACF ARQ: Admission Request ACF: Admission Confirm DRQ: Disengage Request DCF: Disengage Confirm // Terminal // ARQ DRQ DCF DRQ

10 10 Q.931 Signaling Terminal Setup Call Proceeding Connect Release Complete Terminal Alerting H.245 Session Establishment H.245 Session Release Media Exchange

11 11 Direct Endpoint Call Terminal Setup Call Proceeding Connect Release Complete Terminal Alerting H.245 Session Establishment H.245 Session Release Media Exchange Gatekeeper ACF ARQ DCF DRQ ACF ARQ DCF DRQ

12 12 H.245 Signaling TCS: Terminal Capability Set MSD: Master Salve Determination TCSA: TCS Ack MSDA: MSD Ack OLC: Open Logical Channel OLCA: OLC Ack OLCC: OLC Confirm ESC: End Session Command

13 13 H.245 Procedure Terminal TCS MSD OLCA Terminal TCSA MSDA OLC OLCA OLC TCSA MSDA OLCC ESC RTP RTCP Both Terminal send information signalling at the same time, they don’t need to wait Ack signalling.

14 14 H.245 Procedure - Fast Connect Terminal Setup (faststart [logical channel info]) Call Proceeding Connect (faststart [logical channel info]) Release Complete Terminal Alerting Media Exchange

15 15 H.323 detailed header info

16 16 H Q.931 header

17 17 H Master Slave Determination Terminal Type Value  General terminal = 50  Gateway = 60  MCU = 190  MCU (currently managing a conference) = 240 Status Determination Number  Random Largest one is master

18 18 H MSD (cont.)

19 19 H OLC, OLCA, OLCR

20 20 SIP-H.323 Interworking IWF (Interworking Function)  interworking between H.323 and SIP MSF (Media-Switching Fabric)  optional entity within the IWF  switches media such as voice, video, or fax from one network association to another

21 21 SIP-H.323 IWF H.323 Endpoint H.323 Gatekeeper SIP User Agent SIP Server H.323 MCU SIP-H.323 IWF MCF SIP User Agent H.323 Terminal

22 22 SIP-H.323 IWF (cont.) May be integrated into an H.323 GK or SIP server Simply forwards media packets without modification  Should not process media MSF - Convert media from one encoding or format to another  Out of scope for SIP-H.323 protocol translation

23 23 General Interworking Requirements Opening of logical channels  Should support the seamless exchange  Should support open media channels The channel can be opened at the MSF of the IWF When endpoints can’t open media channels themself IWF H.323 features  Should support fast connect  Should support pre-granted ARQ (IWF in GK) Overlapped sending  Follow RFC3578 (from H.323)  Q.931 (from SIP)

24 24 Overlap Signalling Modern switches use en-bloc signalling  Some parts of the PSTN still use overlap signalling Sending only some digits of the callee's number in the first signalling message Further digits are sent in subsequent signalling messages

25 25 Interworking Analysis simple call setup mapping addresses finding a subset of capabilities described by H.245 and SDP conferencing and call services security and authentication

26 26 Register (IWF colocated with SIP server) RRQ RCF H.323 Terminal GatekeeperIWF/GWSIP UA RRQ RCF RRQ RCF REGISTER 200 OK

27 27 RRQ (IWF colocated with H.323 GK) RRQ RCF H.323 Terminal SIP ServerIWF/GWSIP UA REGISTER 200 OK REGISTER 200 OK

28 28 Invite (IWF colocated with SIP server) Setup Call Proceeding H.323 Terminal GatekeeperIWF/GWSIP UA ARQ ACF INVITE 100 Trying ARQ ACF Alerting 180 Ringing Connect 200 OK ACK H.245 Signaling RTP RTCP

29 29 Setup (IWF colocated with H.323 GK) Setup Call Proceeding H.323 Terminal SIP ServerIWF/GWSIP UA ARQ ACF Alerting 180 Ringing Connect ACK H.245 Signaling RTP RTCP INVITE 180 Ringing 200 OK ACK 100 Trying negotiate between 200 OK and ACK

30 30 Call from SIP to H.323 Setup H.323 Terminal IWF/GWSIP UA INVITE Connect (no faststart) 200 OK c=IN IP m=audio 5000 RTP/AVP 0 ACK RTP RTCP TCS (g711Ulaw) TCS (g711Alaw & g711Ulaw) TCSAck OLC (g711Ulaw) OLCAck( :5000) OLC (g711Ulaw) OLCAck( :9000)

31 31 Call from SIP to H.323 (with faststart) Setup faststart={g711Ulaw,Tx}, {g711Ulaw,Rx, :9000} H.323 Terminal IWF/GWSIP UA INVITE c=IN IP m=audio 9000 RTP/AVP 0 Connect faststart= {g711Ulaw,Tx, :5000} {g711Ulaw,Rx} 200 OK c=IN IP m=audio 5000 RTP/AVP 0 ACK RTP RTCP

32 32 Call from H.323 to SIP Setup (no faststart) H.323 Terminal IWF/GWSIP UA INVITE 180 Ringing Connect ACK with updated SDP c=IN IP m=audio 5000 RTP/AVP 8 RTP RTCP TCS (g711Alaw) TCS (g711Alaw & g711Ulaw) TCSAck OLC (g711Alaw) OLCAck( :5000) OLC (g711Alaw) OLCAck( :9000) 200 OK

33 33 Call from H.323 to SIP (with faststart) Setup faststart={g711Ulaw,Tx}, {g711Ulaw,Rx, :5000} H.323 Terminal IWF/GWSIP UA INVITE c=IN IP m=audio 5000 RTP/AVP 0 Connect faststart= {g711Ulaw,Tx, :9000} {g711Ulaw,Rx} 200 OK c=IN IP m=audio 9000 RTP/AVP 0 ACK RTP RTCP

34 34 Mapping Addresses SIP address format SIP-Address= (name-addr j addr-spec) name-addr= [display-name] ” ” addr-spec= SIP-URL SIP-URL= ”sip:” [ userinfo ] hostport url-parameters [headers] userinfo= user [ ”:” password ] hostport= host [ ”:” port ] host= hostname j IPv4address url-parameters= *(”;” url-parameter) url-parameter= user-param j...

35 35 Mapping Addresses (cont.) H323 address format { e164IA5String (SIZE(1..128)) (FROM(" \#*,")), h323-IDBMPString (SIZE (1..256)),..., url-IDIA5String ( SIZE( )),-- URL Style address transport-IDTransportAddress, -- IPv4, IPv6, IPX etc.,... -IDIA5String (SIZE(1..512)), partyNumberPartyNumber }

36 36 SIP to H323 h323-ID  SIP-Address -> addr-spec  exceeds 256 characters -> 414 (Address Too Long) e164  “+”, “-” are removed  “p” -> “,” url-ID  exceeds 512 characters -> 414 (Address Too Long) -ID  exceeds 512 characters -> 414 (Address Too Long) transport-ID  If host is indicated as a dotted quad

37 37 SIP to H323 - examples SIP - is converted to an H { } SIP - user=phone” H.323 – { e164=” ”, } SIP - H { tranport-ID= IPAddress :1720, } SIP - “A. Bell ” H { h323-ID=”A.Bell ”, url- -ID=“A. Bell ” }

38 38 Mapping Addresses - H323 to SIP If a url-ID is present and it is a SIP-URL If an h323-ID is present and it can be parsed as a valid SIP-Address, it is used If the transport-ID is present and it does not identify the IWF, then it forms the hostport portion of the SIP URL and the user portion is constructed using h323-ID or e164 If the -ID is present, then it is used in the SIP- URI

39 39 Security Considerations Signaling security for H.323 is described in H.235 The IWF terminates not only the signaling protocols but also the security in each domain  Users at endpoints have to trust the IWF The IWF must not indicate the identity of a user on one side without first performing authentication

40 40 Reference SIP-H.323 Signaling Gateway  Interworking Between SIP/SDP and H.323  singh-sip-h pdf singh-sip-h pdf Mapping of ISUP Overlap Signalling to SIP  Carrier Grade Voice Over IP  Chapter 4, 5


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