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.
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.
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 220.127.116.11 with the media stream direction as "sendonly" in the session description parameter
info-header = "header-name" HCOLON header-value *(COMMA header value)
Mode-of-Tapping = " Mode-of-Tapping" HCOLON Modes-of-Tapping
Modes-of-Tapping = "split" | "combined"
Example: Mode-of-Tapping: split
Direction = "Direction" HCOLON Directions
Directions = "send" | "receive"
Example: Direction: send
SIP-URI = "sip:" [ userinfo ] hostport uri-parameters [ headers ]
Example: PoC-User-to-be-Tapped: sip:email@example.com
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>
User-Agent: PoC-User/OMA1.0 Acme-Talk5000/v1.01
Authorization: Digest username=" FBI_Agent-private@networkA.net",
Contact: <sip: FBI_Agent @conference-factoryURInet >
Allow: INVITE,ACK,CANCEL,BYE,REFER,MESSAGE,SUBSCRIBE, NOTIFY,PUBLISH
Content-Type: multipart/mixed; boundary=unique-boundary-1
o=ezimmerer 2890844526 2890842807 IN IP4 18.104.22.168
c=IN IP4 motds.mot.com
m=audio 3456 RTP/AVP 97
m=application 2000 udp TBCP
a=fmtp:TBCP queuing=1; tb_priority=2; timestamp=1
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 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 .
The grammar for this mime-type is mostly derived out of the SIP specification (RFC 3261). The following definitions are derived from the SIP specification (RFC 3261) 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" |
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.