1 IMS(IP Multimedia Subsystem)

1.1 IMS µîÀå ¹è°æ

1.2 IMS ÀÇ Á¤ÀÇ

1.3 IMS Architecture

1.4 IMS ±¸¼º ³ëµå ¿ªÇÒ

1.4.1 P-CSCF

1.4.2 S-CSCF

1.4.3 I-CSCF

1.4.4 UE

2 IMS °ü·Ã ÇÁ·ÎÁ§Æ®

2.1 IMS Software

3 IMS °ü·Ã Âü°í ÀÚ·á

4 IMS ¹®¼­

3¼¼´ë À̵¿Åë½Å ±¹Á¦Ç¥ÁØÈ­ ±â±¸ÀÎ 3GPP(3rd Generation Partnership Project)¿Í 3GPP2¿¡¼­´Â W-CDMA¿Í CDMA2000 °¢°¢ÀÇ ¹«¼± ±â¼ú¿¡ ±â¹ÝÀ¸·Î ÇÑ ¼­ºñ½º¸¦ Á¦°øÇϱâ À§ÇÑ °¢°¢ÀÇ »óÀÌÇÑ RAN(Radio Access Network)°ú CN(Core Network) Ç¥ÁØÈ­¸¦ ÁøÇàÇÏ¿© ¿Ô´Ù. ±×·¯³ª, 2002³â¿¡, ¾ç Ç¥ÁØÈ­ ±â±¸¿¡¼­´Â, ±âÁ¸ÀÇ »ç¿ëÀÚÀÎ Legacy MS(Mobile Station)¿¡°Ô ¼­ºñ½º¸¦ Á¦°øÇÏ´Â ±âÁ¸ Network À§¿¡ VoIP(Voice over IP) µîÀÇ ½Ç½Ã°£ ÀÀ¿ë ¼­ºñ½º¸¦ Æ÷ÇÔÇÏ´Â IP Multimedia ¼­ºñ½ºÀÇ Á¦°øÀ» À§ÇØ µ¿ÀÏÇÑ Network Architecture »ç¿ëÀ» °áÁ¤ÇÏ¿´´Ù.

3GPPÀÇ IMS(IP Multimedia Subsystem)¿Í 3GPP2ÀÇ MMD(Multimedia Domain)°¡ ¹Ù·Î ±× °ÍÀÌ´Ù. IMS Ç¥ÁØÈ­´Â 3GPP¿¡¼­ ¸ÕÀú ½ÃÀ۵Ǿî, ÇöÀç Release 7ÀÌ ÁøÇàÁß¿¡ ÀÖ°í, 3GPP2´Â MMD¸¦ ±¸¼ºÇÏ´Â Áß¿ä ¿ä¼Ò·Î¼­ 3GPPÀÇ IMS¸¦ Å« ¼öÁ¤ ¾øÀÌ ±×´ë·Î ¼ö¿ëÇÏ°í ÀÖ´Ù. ÃÖ±Ù¿¡´Â, À¯¼±¸Á¿¡¼­ÀÇ VoIP ¹× ¸ÖƼ¹Ìµð¾î ¼­ºñ½º¸¦ Á¦°øÇÒ ½Ã¿¡ IMSÀÇ ±â´ÉÀ» È°¿ëÇÏ¿© Á¦°øÇÏ°íÀÚÇÏ´Â »ç¾÷ÀÚÀÇ ¿ä±¸»çÇ×ÀÌ ´ëµÎµÇ°í Àִµ¥, ÀÌ´Â ÇâÈÄ FMC(Fixed and Mobile Convergence, À¯¹«¼±ÅëÇÕ) ±¤´ë¿ª ¼­ºñ½º¸¦ Á¦°øÇÏ´Â µ¥ À־, IMS°¡ ½ÇÁ¦ÀûÀÎ À¯¹«¼± °øÅëÀÇ Â÷¼¼´ë ÁÖ¿ä ¸Á ±â¼úÀÇ Ç¥ÁØÀ¸·Î ÀÚ¸®Àâ°í ÀÖÀ½À» ÀǹÌÇÑ´Ù.À¯¼± ¸Á¿¡¼­ IMS¿¡ ´ëÇÑ Ç¥ÁØÈ­ ³íÀÇ´Â IETF¿¡¼­ÀÇ ±âÁ¸ SIP/SDP(Session Initiation Protocol/Session Description Protocol) °ü·Ã WGµé°ú, ITU-TÀÇ NGN, IEEE802.16 ±â¼ú ±â¹ÝÀÇFixed/Mobility ¼­ºñ½º Á¦°øÀ» À§ÇÑ WiMAX Forum µî¿¡¼­ ÁøÇàµÇ°í ÀÖ´Ù.

ÃÖ±Ù À̵¿Åë½Å°ú ÀÎÅͳÝÀÇ ±Þ°ÝÇÑ ¹ßÀü¿¡ µû¶ó À̵¿°¡ÀÔÀÚ¿¡°Ô °íÇ°ÁúÀÇ ´Ù¾çÇÑ ¸ÖƼ ¹Ìµð¾î ¼­ºñ½º Á¦°øÀÌ ¿ä±¸µÇ°í ÀÖ´Ù. ÀÌ·¯ÇÑ ¸ÖƼ ¹Ìµð¾î ¼­ºñ½ºÀÇ ¹ß´ÞÀº ±âÁ¸ÀÇ CS(Circuit-Switched) µµ¸ÞÀο¡¼­ PS(Packet-Switched) µµ¸ÞÀÎÀ¸·ÎÀÇ º¯È­¸¦ ¿ä±¸ÇÏ¿´°í, ´õ ³ª¾Æ°¡ IP ±â¹Ý ÇüÅÂÀÇ Â÷¼¼´ë ÇٽɸÁÀ¸·ÎÀÇ ÁøÈ­¸¦ ¸ð»öÇÏ°í ÀÖ´Ù.
3GPP¿¡¼­´Â IM(IP-based Multimedia) ¼­ºñ½º¸¦ Á¦°øÇϱâ À§ÇØ ALL IP ±â¹ÝÀÇ ¸Á ÂüÁ¶¸ðµ¨À» Ç¥ÁØÈ­ ÇÏ°í ÀÖ´Ù. IMS ¼­ºñ½º¶õ À̵¿ °¡ÀÔÀÚ¿¡°Ô IP ±â¹Ý ÆÐŶ ¼­ºñ½º¸¦ ¿øÇÒÈ÷ Á¦°øÇÒ ¼ö ÀÖ´Â ±¸Á¶¸¦ ¸»Çϴµ¥, ÀÌ´Â °¡ÀÔÀÚ°¡ ±âÁ¸ÀÇ À½¼º, ¿µ»ó µîÀÇ ½Ç½Ã°£(real-time) ¼­ºñ½º´Â ¹°·Ð ÆÄÀÏÀü¼Û, À̸ÞÀÏ, ´Ü¹® ¸Þ½ÃÁö µîÀÇ ºñ ½Ç½Ã°£(non real-time) ¼­ºñ½º¸¦ µ¿½Ã¿¡ »ç¿ëÇÒ ¼ö ÀÖ°Ô Çϰųª, ÀÌµé ¼­ºñ½º¸¦ ÀÌ¿ëÇÑ »õ·Î¿î ¼­ºñ½º, ¿¹¸¦ µé¸é ºñµð¿ÀÆù, ÀνºÅϽº ¸Þ¼¼Â¡, ÀÀ±Þ ÀüÈ­, Location ¼­ºñ½º, ÇÁ¸®Á¨½º ¼­ºñ½º µîÀ» ÀÌ¿ëÇÒ ¼ö ÀÖ°Ô ÇÏ´Â °ÍÀ» ÀǹÌÇÑ´Ù.

3GPP¿¡¼­´Â ALL IP ¸Á ÂüÁ¶ ¸ðµ¨À» Ç¥ÁØÈ­ Çϸ鼭 IMS ¼­ºñ½º¸¦ Á¦°øÇϱâ À§ÇØ CSCF¿Í HSSÀÇ ±â´É¿ä¼Ò¸¦ Æ÷ÇÔÇÏ´Â IMSÀ» Á¤ÀÇÇÏ°í ÀÖÀ¸¸ç À̵é°ú °ü·ÃµÈ ¿©·¯ ±â´É ¿ä¼Òµé°úÀÇ ÀÎÅÍÆäÀ̽º¸¦ Ç¥ÁØÈ­ ÇÏ°í ÀÖ´Ù. ¶ÇÇÑ IMSÀ» Ç¥ÁØÈ­ ÇÔ¿¡ ÀÖ¾î ÀÎÅÍ³Ý Ç¥ÁØ ±×·ì(Internet Standardization Group)ÀÎ IETF¿Í ¸¹Àº ºÎºÐ¿¡ À־ »óÈ£ Çù·ÂÇÏ°í ÀÖ´Ù. ÀÌ´Â IMS ¼­ºñ½º°¡ ¼¼¼Ç ¼³Á¤À» ±âº»À¸·Î ÇÑ ÆÐŶ ¼­ºñ½º µµ¸ÞÀÎÀ» ±â¹ÝÀ¸·Î ÇÏ°í Àֱ⠶§¹®ÀÌ´Ù.

IMSÀÇ ±¸¼º¿ä¼Ò¿Í ÀÎÅÍÆäÀ̽º´Â ±×¸² 1°ú °°´Ù. 3GPP IM CN ¼­ºê½Ã½ºÅÛÀº ¸ÖƼ¹Ìµð¾î signaling°ú barer trafficÀ» Àü¼ÛÇϱâ À§ÇØ UMTS ±â¹ÝÀÇ PS µµ¸ÞÀθ¦ »ç¿ëÇÏ°í, ¶ÇÇÑ À¯¼± ÀÎÅÍ³Ý Å͹̳ΰúÀÇ ½É¸®½ºÇÑ ¿¬°áÀ» À¯ÁöÇÏ°í ¾×¼¼½º ¸ÅüÀÇ µ¶¸³ÀûÀÎ ¸Á ¿¬µ¿À» À§Çؼ­ °¡´ÉÇÑ ÇÑ IETF Ç¥ÁØ ±Ô°ÝÀ» ¸¹ÀÌ ¼ö¿ëÇÏ°í ÀÖ´Ù.

±×¸² 1 IP Multimedia Subsystem Architecture

CSCF(Call Session Control Function)´Â °¡ÀÔÀÚ°¡ À§Ä¡ÇÏ°í ÀÖ´Â ¸Á¿¡ µû¶ó ±â´ÉÀÌ ´Ù¸£´Ù. µû¶ó¼­ ±× À§Ä¡¿Í ¿ªÇÒÀ» ±âÁØÀ¸·Î Proxy-CSCF(P-CSCF), Interrogating CSCF(I-CSCF), Serving CSCF(S-CSCF)·Î ³í¸®ÀûÀ¸·Î ±¸ºÐÇÒ ¼ö ÀÖ´Ù.

P-CSCF´Â UE°¡ IMS¿¡ Á¢¼ÓÇϴ ù Æ÷ÀÎÆ® ÁöÁ¡À¸·Î GGSN°ú °°Àº µµ¸ÞÀο¡ Á¸Àç ÇÑ´Ù. P-CSCFÀÇ ÁÖ¼Ò´Â ¡°Local CSCF Discovery¡± ¸ÞÄ¿´ÏÁòÀ» »ç¿ëÇÏ¿© PDP Context¿¡ ÀÇÇØ UE¿¡°Ô Àü´ÞµÈ´Ù. P-CSCF´Â RFC 3261¿¡ Á¤ÀÇÇÑ ÇÁ·Ï½Ã³ª UAó·³ µ¿ÀÛÇÑ´Ù. ÇÁ·Ï½Ã·Î µ¿ÀÛÇÒ ¶§ P-CSCF´Â SIP INVITE ¸Þ¼¼ÁöÀÇ Request-URI¸¦ ¼öÁ¤ÇÒ ¼ö ¾øÁö¸¸ ºñÁ¤»óÀûÀÎ »óȲ¿¡ ÀÇÇؼ­ ¼¼¼ÇÀÌ Á¾·áµÇ´Â ½ÃÁ¡¿¡´Â UA·Î µ¿ÀÛÇÏ¿© Request-URIÀ» ¼öÁ¤ÇÒ ¼ö ÀÖ´Ù. ¾Æ·¡´Â ´ëÇ¥ÀûÀÎ P-CSCFÀÇ ±â´ÉÀÌ´Ù.

1. UEÀÇ REGISTER ¸Þ½ÃÁö¸¦ UEÀÇ Request-URI¸¦ ÂüÁ¶ÇÏ¿© I-CSCF·Î Àü´ÞÇÑ´Ù.
   
2. UE·ÎºÎÅÍ ¼ö½ÅÇÑ SIP ¸Þ½ÃÁö¸¦ S-CSCF·Î Àü´ÞÇÑ´Ù.
   
3. SIP Proxy ±â´ÉÀ» ¼öÇàÇÑ´Ù.
   
4. ´Ü´ë´Ü ¼¼¼Ç ¼³Á¤ ¼öÇàÁß Charge Data Record(CDR)¸¦ ¹ß»ýÇÑ´Ù.
   
5. UE¿Í Security AssociationÀ» À¯ÁöÇÑ´Ù.
   
6. PDF¸¦ ÅëÇÑ GGSNÀÇ ÀÚ¿ø°ËÁõ°ú QoS °ü¸®¸¦ ÇÑ´Ù.
   
   

S-CSCF´Â ¼­ºñ½º ºê·ÎÄ¿ ¿ªÇÒÀ» ¼öÇàÇÑ´Ù. ÀÌ´Â ¿©·¯ ¼­ºñ½º¸¦ Áö¿øÇϱâ À§ÇØ »ç¾÷ÀÚ°¡ ÇÊ¿ä¿¡ µû¶ó ¼¼¼Ç »óŸ¦ À¯ÁöÇÏ°í, ÇØÁ¦ÇÏ´Â ±â´ÉÀ» ¼öÇàÇÑ´Ù. ¶ÇÇÑ SIP Registrar ¹× Location Service±â´ÉÀ» °®´Â´Ù. ¾Æ·¡´Â S-CSCFÀÇ ´ëÇ¥ÀûÀÎ ±â´ÉµéÀÌ´Ù.

1. ÀÚ½ÅÀÌ S-CSCFÀÓÀ» HSS¿¡ µî·ÏÇÏ°í ÀÌÈÄ UEÀÇ °¡ÀÔÀÚ Á¤º¸¸¦ ¹Þ¾Æ ÀúÀåÇÑ´Ù.
   
2. ½ÇÁ¦ µî·ÏµÈ UEÀÇ ¼¼¼Ç »óÅ°ü¸®¸¦ Çϸ鼭 ¼­ºñ½º Á¦¾î¸¦ ¼öÇàÇÑ´Ù.
   
3. UE¿¡°Ô ¼­ºñ½º ÀÚ¿ø°ú °ü·ÃµÈ Á¤º¸¸¦ Á¦°øÇÑ´Ù.
   
4. PSTN ¶Ç´Â CS µµ¸ÞÀÎÀ¸·Î Àü´ÞµÇ´Â ¼¼¼Ç ¿äû ¸Þ½ÃÁö´Â BGCF (Breakout Gateway Control Function)·Î Àü´ÞÇÑ´Ù.
   
5. Multi-Party call µîÀÇ ¼­ºñ½º Áö¿øÀ» À§ÇØ MRF¿Í Åë½ÅÇÑ´Ù.
   
6. UE µî·Ï ½Ã HSS·ÎºÎÅÍ ¼ö½ÅÇÑ ÀÎÁõÁ¤º¸¸¦ ÅëÇØ ÀÎÁõÀ» ¼öÇàÇÑ´Ù.
   
   

I-CSCF´Â Network ProviderÀÇ Home Network¸¦ º¸È£ÇÏ´Â ÀÏÁ¾ÀÇ ¹æÈ­º® ¿ªÇÒÀ» ¼öÇàÇÑ´Ù. ÀÌ¿Ü¿¡ I-CSCF´Â HSSÀÇ »ç¿ëÀÚ Á¤º¸¸¦ °Ë»öÇÏ¿© ÀûÀýÇÑ S-CSCF¸¦ ¼±ÅÃÇÏ´Â ±â´É ¶ÇÇÑ Æ÷ÇÔÇÏ°í ÀÖ´Ù.

IMS¿¡ ¼ÓÇÑ »ç¿ëÀÚ¸¦ ĪÇÑ´Ù. UE´Â SIP¸¦ ÅëÇÑ ¼¼¼Ç ¼³Á¤, ¿ä±¸ ¸Þ½ÃÁö¸¦ Àü¼ÛÇÒ ¼ö ÀÖÀ¸¸ç, PDP Context¸¦ ÅëÇÑ QoS Profile Á¤º¸¸¦ ¿äû, ÀÀ´ä¹ÞÀ» ¼ö ÀÖ´Ù.

IMS¿¡ ´ëÇÑ ´õ ÀÚ¼¼ÇÑ »çÇ×Àº ¾Æ·¡ ¸µÅ©¸¦ ÂüÁ¶¹Ù¶ø´Ï´Ù.

• review_IMS.pps : IMS Review ÀÚ·áÀÔ´Ï´Ù.
  
  

IMS´Â 3GPP¿¡¼­ Ç¥ÁØÈ­ ÁøÇàÁßÀÌ´Ù. ÇöÀç Release 7ÀÌ ÁøÇàÁßÀ̸ç Release 99 ºÎÅÍ Release 6±îÁö ÁøÇàÇÏ¿© IMSÀÇ Àüü Architecture ¹× ±âº» ¼­ºñ½ºµéÀº Ç¥ÁØÈ­°¡ ³¡³­»óÅÂÀÌ´Ù. ¾Æ·¡ÀÇ ¹®¼­µéÀº IMS¸¦ ¿¬±¸Çϱâ À§Çؼ­ ÇÊ¿äÇÑ ¹®¼­µéÀÌ´Ù.
ÀÌÁß TS 23.228Àº IMSÀÇ °¡Àå Áß¿ä ¹®¼­·Î½á ¹Ýµå½Ã ¼÷ÁöÇؾ߸¸ ÇÑ´Ù.

• 3GPP TS 23.002 V6.10.0(2005-12) (Release 6) Network Architecture
  
• 3GPP TS 23.228 V6.14.0(2006-06) (Release 6) IP Multimedia Subsystem(IMS) Stage2
  
• 3GPP TS 24.228 V5.14.0(2005-12) (Release 5) Signalling flows for the IP multimedia call control based on SIP and SDP stage3
  
• 3GPP TS 23.218 V6.4.0 (2006-06) (Release 6) IP Multimedia (IM) session handling; IM call model Stage2
  
• 3GPP TS 24.229 V6.11.0(2006-06) (Release 6) IP Multimedia Call Control Protocol based on SIP and SDP Stage3
  
• 3GPP TS 22.228 V6.11.0(2006-03) (Release 6) Service requirements for the IP multimedia core network subsystem Stage1
  
• 3GPP TS 22.141 V6.5.0 (2005-12) (Release 6) Presence Service Stage1
  
• 3GPP TS 23.141 V6.9.0 (2005-12) (Release 6) Presence Service; Architecture and functional description
  
• 3GPP TS 24.141 V6.6.0 (2006-03) (Release 6) Presence Service using the IP Multimedia (IM) Core Network (CN) subsystem Stage3
  
• 3GPP TS 29.208 V6.6.1 (2006-03) (Release 6) End-to-end Quality of Service (QoS) signaling flows
  
• 3GPP TS 23.107 V6.4.0 (2006-03) (Release 6) Quality of Service (QoS) concept and architecture
  
  

¡Ø º» ÀÚ·áÀÇ ÀúÀÛ±ÇÀº ¸ðµÎ ¼þ½Ç´ëÇб³ ³×Æ®¿öÅ©¿¬±¸½Ç(DCN)¿¡ ÀÖ½À´Ï´Ù.