1 / 40

RFC-4123 SIP-H.323 Interworking Requirements

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

halden
Download Presentation

RFC-4123 SIP-H.323 Interworking Requirements

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

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

  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. H.323 Zone Terminal Terminal Gatekeeper Terminal Terminal Gateway MCU Gateway Router SIP H.323 PSTN

  4. H.323 Protocol • H.225.0 • 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. H.323 Protocol Stack

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

  8. RAS Signaling - Registration Terminal Gatekeeper RRQ RCF ／／ ／／ URQ UCF RRQ: Registration RequestRCF: Registration ConfirmURQ: Unregistration RequestUCF: Unregistration Confirm

  9. RAS Signaling - Admission Terminal Gatekeeper Terminal ARQ ACF Setup ARQ ACF ／／ ／／ ／／ DRQ DRQ DCF DCF ARQ: Admission RequestACF: Admission ConfirmDRQ: Disengage RequestDCF: Disengage Confirm

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

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

  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. H.245 Procedure Terminal Terminal TCSMSD Both Terminal sendinformation signalling at the same time, they don’t need to wait Ack signalling. TCSMSD TCSAMSDA TCSAMSDA OLC OLC OLCA OLCA OLCC RTPRTCP ESC ESC

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

  15. H.323 detailed header info

  16. H.225 - Q.931 header

  17. H.245 - 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. H.245 - MSD (cont.)

  19. H.245 - OLC, OLCA, OLCR

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

  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. 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. 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. 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. Register(IWF colocated with SIP server) H.323 Terminal Gatekeeper IWF/GW SIP UA RRQ RCF RRQ RCF REGISTER RRQ RCF 200 OK

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

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

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

  30. Call from SIP to H.323 H.323 Terminal IWF/GW SIP UA INVITE Setup Connect (no faststart) TCS (g711Ulaw) TCSAck TCS (g711Alaw & g711Ulaw) TCSAck 200 OK c=IN IP4 1.2.3.4 m=audio 5000 RTP/AVP 0 OLC (g711Ulaw) OLCAck(1.2.3.4:5000) ACK OLC (g711Ulaw) OLCAck(5.6.7.8:9000) RTPRTCP

  31. Call from SIP to H.323 (with faststart) H.323 Terminal IWF/GW SIP UA INVITE To:abc@ncnu.edu c=IN IP4 5.6.7.8 m=audio 9000 RTP/AVP 0 Setup faststart={g711Ulaw,Tx}, {g711Ulaw,Rx,5.6.7.8:9000} 200 OK c=IN IP4 1.2.3.4 m=audio 5000 RTP/AVP 0 Connect faststart= {g711Ulaw,Tx,1.2.3.4:5000} {g711Ulaw,Rx} ACK RTPRTCP

  32. Call from H.323 to SIP H.323 Terminal IWF/GW SIP UA Setup (no faststart) INVITE 180 Ringing 200 OK Connect TCS (g711Alaw) TCSAck TCS (g711Alaw & g711Ulaw) TCSAck ACK with updated SDP c=IN IP4 1.2.3.4 m=audio 5000 RTP/AVP 8 OLC (g711Alaw) OLCAck(1.2.3.4:5000) OLC (g711Alaw) OLCAck(5.6.7.8:9000) RTPRTCP

  33. Call from H.323 to SIP (with faststart) H.323 Terminal IWF/GW SIP UA Setup destination:def@ncnu.edu.tw faststart={g711Ulaw,Tx}, {g711Ulaw,Rx,1.2.3.4:5000} INVITE To:def@ncnu.edu.tw c=IN IP4 1.2.3.4 m=audio 5000 RTP/AVP 0 200 OK c=IN IP4 5.6.7.8 m=audio 9000 RTP/AVP 0 Connect faststart= {g711Ulaw,Tx,5.6.7.8:9000} {g711Ulaw,Rx} ACK RTPRTCP

  34. Mapping Addresses SIP address format SIP-Address = (name-addr j addr-spec) name-addr = [display-name] ”<” addr-spec ”>” 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. Mapping Addresses (cont.) H323 address format { e164 IA5String (SIZE(1..128)) (FROM("0123456789\#*,")), h323-ID BMPString (SIZE (1..256)), ..., url-ID IA5String ( SIZE(1 .. 512)),-- URL Style address transport-ID TransportAddress, -- IPv4, IPv6, IPX etc.,... email-ID IA5String (SIZE(1..512)), partyNumber PartyNumber }

  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) • email-ID • exceeds 512 characters -> 414 (Address Too Long) • transport-ID • If host is indicated as a dotted quad

  37. SIP to H323 - examples • SIP - “sip:j.doe@big.com” is converted to anH.323 - { h323-ID=”sip:j.doe@big.com”, url-ID=”sip:j.doe@big.com”, email-ID=“j.doe@big.com” } • SIP - “sip:+1-212-555-1212:1234@gateway.com; user=phone”H.323 – { e164=”12125551212”, h323-ID=”sip:+1-212-555-1212:1234@gateway.com”, url-ID=”sip:+1-212-555-1212:1234@gateway.com”, email-ID=“+1-212-555-1212:1234@big.com” } • SIP - ”sip:alice@10.1.2.3”H.323 - { h323-ID=”sip:alice@10.1.2.3”, url-ID=”sip:alice@10.1.2.3”, tranport-ID= IPAddress 10.1.2.3:1720, email-ID=“alice@10.1.2.3” } • SIP - “A. Bell <sip:a.g.bell@bell-tel.com>”H.323 - { h323-ID=”A.Bell <sip:a.g.bell@bell-tel.com>”, url-ID=”sip:a.g.bell@bell-tel.com”, email-ID=“A. Bell <a.g.bell@belltel.com>” }

  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 email-ID is present, then it is used in the SIP-URI

  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. Reference • SIP-H.323 Signaling Gateway • http://www1.cs.columbia.edu/~kns10/research/gw/ • Interworking Between SIP/SDP and H.323 • http://www.cs.columbia.edu/~kns10/publication/draft-singh-sip-h323-01.pdf • Mapping of ISUP Overlap Signalling to SIP • http://www.ietf.org/rfc/rfc3578.txt • Carrier Grade Voice Over IP • Chapter 4, 5

More Related