前天就来日立了,只不过是给分了个工位,适应了一下工作环境。由于昨天的微软二面很失败,于是乎,决定今天开始到日立正式上班了……
      工作环境还好吧,最让我感到亲切的是这边有十几个师兄,而且有个师兄和我同组,都是IP网络系统研究室的。
      上午把开发环境搭了起来,没什么好写的。
      收获最大的莫过于午餐时师兄的一席话了,充分感受到了软院大家庭的温暖。
      刘师兄在日立干了三个月了,老板让三个月干完的活,他1个半月就搞定了,为此对日立的人浮于事还大发牢骚:本来很快就可以做完的东西,非要拖延,日立的研发部门和政府机关没什么太大区别!也许这就是家族企业的劣势?不过,话说回来了,研发部门又不是工程部门,很少有赶工期的,因此,很多研发部门的主管看重的是质量而不是速度,很简单的道理,大Boss说你这个部门好,要方方面面好,一旦有一点做的不足,大Boss就开始批评这个部门了~~
      其实师兄都蛮真诚的,说了很多告诫我的话,感受最深的是研一要多写些代码,读代码当然更是必须的,面试时看的是你有没有项目经验,这里所说的项目,至少要保证4、5千行的代码量吧。
      刘师兄不太想在日立工作,虽然薪酬还可以,据说正式员工、硕士第一年就月入1万。主要原因还是在这边没什么激情。
      下午看了a document,which describes the Lawful Intercept Procedure using Session  Initiation Protocol (SIP) used by the Open Mobile Alliance (OMA) for Push to talk over Cellular (PoC) along with their applicability, which is limited to the OMA PoC application.
      那么,什么是PoC呢?
      PoC Push to talk over Cellular)「隨按即說」是一種建立在蜂巢式行動電話架構下的新興服務。使用者在設定完群組名單之後,只需要在支援PoC服務的手機上按下PoC按鈕,即可快速地與其他PoC使用者進行一對一或者一對多的語音通話,省去一一通知群組內每位成員的麻煩。
      Talk Burst: A Talk Burst is the flow of media from a PoC User while that has the permission to send media.
       FBI Agent:Not that Federal Bureau of Investigation:),is a PoC Client/User who has special access to tap any other PoC user supported by the PoC server.
       Mode-of-Tapping: The tapping shall be done in split or combined mode. 
 
Lawful Interception Operation in PoC

       The Lawful Interception request information contains a series of information lines.  Each line contains some part of the operation information and follows text based encoding rules and procedures that could be carried in the SIP signaling message.

   
   Procedure at the PoC User to perform Legal Interception:
       The FBI Agent, who has the special privileges to listen to any PoC User, is himself a PoC User. The FBI Agent (PoC User) 
       1. SHALL Set the Request-URI of the SIP INVITE request to the  Conference-factory-URI for the PoC service in the Home PoC Network.
       2. SHALL add the Lawful Intercept Message body which carries the information regarding

       a. PoC User to be tapped.
      
       b. The mode in which the tapping should be done.(Split or Combined mode)
         
       c. The direction in which the tapping should be done.(Only in case of split mode.(send or receive))
         
           i. If "direction=send", the FBI agent (PoC User) requests for tapping only the media streams sent out by the PoC User who is to be tapped.
             
           ii.If "direction=receive", the FBI agent (PoC User) requests for tapping only the media streams that is received the PoC  User who is to be tapped.

        
        3. SHALL generate an initial SIP INVITE request according to the rules and procedures of [RFC3261] and the general procedure as in section  6.1.3.1 with the media stream direction as "sendonly" in the  session description parameter
   Procedures at the PoC Server performing the Lawful Intercept function:
        PoC Control Plane Procedure:
        PoC User Plane Procedure
   Procedure at the PoC User to stop Legal Interception:
   Procedure at the PoC Server to stop Legal Interception:
  
Lawful Intercept Request Protocol Syntax
        The media type follows the conventions of the SIP (RFC 3261 [1]) for Lawful intercept request header information formatting. The Lawful intercept request header information contains a series of information headers with each of the information header lines terminated by a CRLF.
     Lawful-intercept request-info  =  *info-header
     info-header = "header-name" HCOLON header-value *(COMMA header value) 
    CRLF
     Header Fields
         It is required that the Mode-of-Tapping header field be present as the first header field. 
         Mode-of-Tapping
            
Mode-of-Tapping = " Mode-of-Tapping" HCOLON Modes-of-Tapping 
             Modes-of-Tapping = "split" | "combined" 
             Example: Mode-of-Tapping: split
        Direction
             The Direction header field defines the direction in which the split mode of tapping is done. 
             Direction = "Direction" HCOLON Directions
             Directions = "send" | "receive"
  
             Example: Direction: send
        PoC-User-to-be-Tapped
             PoC-User-to-be-Tapped = "PoC-User-to-be-Tapped" HCOLON SIP-URI or TEL-URI
             SIP-URI = "sip:" [ userinfo ] hostport uri-parameters [ headers ]
  
             Example: PoC-User-to-be-Tapped: sip:sriram@motorola.com
Illustrative Examples

         The Lawful Intercept request information is sent in the INVITE method by the FBI Agent who wants to tap a PoC User listed in his request information.
  
   INVITE sip:FBI_Agent@conference-factoryURI.net SIP/2.0
   P-Preferred-Identity: "FBI_Agent" <sip: FBI_Agent @networkA.net>
   Accept-Contact:*;+g.poc.talkburst; require;explicit 
   User-Agent: PoC-User/OMA1.0 Acme-Talk5000/v1.01
   Authorization: Digest username=" FBI_Agent-private@networkA.net",
   realm="registrar.networkA.net", nonce="",
   uri="sip:registrar.networkA.net", response=""
   Privacy: Id
   Contact: <sip: FBI_Agent @conference-factoryURInet >
   Supported: Timer
   Session-Expires: 1800;refresher=uac
   Allow: INVITE,ACK,CANCEL,BYE,REFER,MESSAGE,SUBSCRIBE, NOTIFY,PUBLISH
   Content-Type: multipart/mixed; boundary=unique-boundary-1
   Content-Length: 407

   –unique-boundary-1
   Content-Type: application/SDP
  
   v=0
   o=ezimmerer 2890844526 2890842807 IN IP4 126.16.64.4
   c=IN IP4 motds.mot.com
   m=audio 3456 RTP/AVP 97
   a=Rtpmap:97 AMR
   a=rtcp:5560
   m=application 2000 udp TBCP
   a=recvonly
   a=fmtp:TBCP queuing=1; tb_priority=2; timestamp=1
  
   –unique-boundary-1
   Content-Type: application/lir
  
   Mode-of-Tapping: split
   Direction: send
   PoC-User-to-be-Tapped: sip:sriram@motorola.com
   –unique-boundary-1–

IANA considerations 
    
   The "application/lir" mime type
      
   This draft registers the "application/lir" MIME media type.
      
   The Lawful intercept request (lir) information is text-based. It follows the recommendations of RFC 2045[10] for the usage of text-based data for MIME.

   This media type is defined by the following information:
 
   Media type name: application
   Media subtype name: lir
   Required Parameters: None
   Encoding scheme: ASCII
   Security considerations: See section 10

9 Formal Syntax
      
   The following syntax specification uses the augmented Backus-Naur Form (BNF) as described in RFC-2234 [3].

   The grammar for this mime-type is mostly derived out of the SIP specification (RFC 3261[1]).  The following definitions are derived from the SIP specification (RFC 3261[1]) token DIGIT HCOLON quoted-string

   Lawful-Intercept-Request-Info = *(Information-Header)
      
   Information-Header  =   (Advice-State  /  Mode-of-Tapping /
                           Direction /  PoC-User-to-be-Tapped)

   Mode-of-Tapping =  " Mode-of-Tapping" HCOLON Modes-of-Tapping Modes-
   of- Tapping = "split" | "combined"
  
   Direction = "Direction" HCOLON Directions Directions = "send" |
    "receive"
   
   PoC-User-to-be-Tapped = "PoC-User-to-be-Tapped" HCOLON SIP-URI or TEL-
   URI SIP-URI = "sip:" [ userinfo ] hostport 
                        uri-parameters [ headers ]

10 Security Considerations
      
   The Lawful Intercept request message body contains sensitive information that requires the use of encryption. Lawful Intercept request information should not be trusted until it is ensured that it is received through reliable sources.

  
   

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