Subject: [Megaco] Which scenario is correct in the hairpin connection?

From: "Noh Jeong Min" <[email-masked]>
Date: Thu, 7 Nov 2002 17:12:41 +0900

Hi, MEGACO list again.

I would like to get some clarification on hairpin connection.
When the two physical terminations are added to context, then how do we set topology or  localcontrol mode ?

There are two kinds of Add scenario. Which scenario is correct in the hairpin connection?

1) When the two physical terminations are added to context, MGC set topology(A,B,isolate). 
   And if callee subscriber hook off, then MGC change topology( A,B,bothway).
2) When the two physical terminations are added to context, MGC set localcontrol mode(Inactive).
   And if callee subscriber hook off, then MGC change localcontrol mode(SendReceive).
3)  1,2 are also incorrect. It needs another scenario.

Wait for your reply.
Thanks and best regards.

CASE 1: Use a topology descriptor.

   Step 1) MGC to MG1: 
   MEGACO/1 [123.123.123.4]:55555 
   Transaction = 10004{ 
        Context = ${ 
            Topology = { LINE/1, LINE/2, isolate },
                Add = LINE/2{ 
                      Media{ Stream = 1{ LocalControl {Mode = SendReceive} }}, 
                        Events=1234{al/of(strict=state)},  
                        Signals{al/ri}   ; start ringing 
                },
                Add = LINE/1{ 
                        Media{ Stream = 1{ LocalControl {Mode = SendReceive} }}, 
                        Signals {cg/rt} ; start ringback
                }
       } 
   } 
   Step 2) reply MG to MGC
   Step 3) MG to MGC, Notify =LINE/2{Events{al/of}}
   Step 4) MGC to MG, Reply

   Step 5) MGC to MG1: 
   MEGACO/1 [123.123.123.4]:55555 
   Transaction = 10006 { 
      Context = 2000 { 
       Topology = { LINE/1, LINE/2, bothway },
         Modify = LINE/1 { 
            Signals { } ; to turn off ringback
         }, 
         Modify = LINE/2 { 
            Events = 1235 {al/on(strict=state)}, 
            Signals { } ; to turn off ringing  
         } 
      } 
   } 

CASE 2 : Use a localcontrol mode.

   Step 1) MGC to MG1: 
   MEGACO/1 [123.123.123.4]:55555 
   Transaction = 10004{ 
        Context = ${ 
                ; default Topology (LINE/1,LINE/2,bothway)
                Add = LINE/2{ 
                      Media{ Stream = 1{ LocalControl {Mode = inactive} }}, 
                        Events=1234{al/of(strict=state)},  
                        Signals{al/ri}  ; start ringing
                },
                Add = LINE/1{ 
                        Media{ Stream = 1{ LocalControl {Mode = inactive} }}, 
                        Signals {cg/rt}  ; start ringback
                }
       } 
   } 
   Step 2) reply MG to MGC
   Step 3) MG to MGC, Notify =LINE/2{Events{al/of}}
   Step 4) MGC to MG, Reply
   Step 5) MGC to MG1: 

   MEGACO/1 [123.123.123.4]:55555 
   Transaction = 10006 { 
      Context = 2000 { 
         Modify = LINE/1 { 
            Media{ Stream = 1{ LocalControl {Mode = SendReceive} }},
            Signals { } ; to turn off ringback
         }, 
         Modify = LINE/2 {
            Media{ Stream = 1{ LocalControl {Mode = SendReceive} }}, 
            Events = 1235 {al/on(strict=state)}, 
            Signals { } ; to turn off ringing  
         } 
      } 
   } 

Noh Jeong Min.
IMT System Development Group.
MERCURY Corporation. Ltd.
Tel : +82 031 310 5714, +82 031 310 5718
Email : [email-masked]