RTCP SDP attribute pass from ingress call leg to egress call leg unmodified

[Ogre-74]

Test scheme:
ua1 ([email protected]) -> b2bua (192.168.0.101) -> ua2 ([email protected])
Media is passed through an rtpproxy (192.168.0.101).

As shown below, RTCP SDP attribute pass from ingress call leg to egress call leg unmodified,
although media is passed through an rtpproxy.
I think, that the RTCP SDP attribute should be removed from egress call leg.

Ingress INVITE:

Request-Line: INVITE sip:[email protected]:5062 SIP/2.0
Message Header
    Via: SIP/2.0/UDP 192.168.0.134:1534;rport;branch=z9hG4bKPj735a2264cba84c36bd9657602265d463
    Max-Forwards: 70
    From: <sip:[email protected]>;tag=7da4ba7ff67a422bb089465bbcd2bf65
    To: <sip:[email protected]>
    Contact: <sip:[email protected]:1534;ob>
    Call-ID: 68504c1dfbeb42dca549be075abaa71a
    CSeq: 19945 INVITE
    Allow: PRACK, INVITE, ACK, BYE, CANCEL, UPDATE, INFO, SUBSCRIBE, NOTIFY, REFER, MESSAGE, OPTIONS
    Supported: replaces, 100rel, timer, norefersub
    Session-Expires: 1800
    Min-SE: 90
    User-Agent: MicroSIP/3.18.3
    Content-Type: application/sdp
    Content-Length:   319
Message Body
    Session Description Protocol
        Session Description Protocol Version (v): 0
        Owner/Creator, Session Id (o): - 3731448157 3731448157 IN IP4 192.168.0.134
        Session Name (s): pjmedia
        Bandwidth Information (b): AS:84
        Time Description, active time (t): 0 0
        Session Attribute (a): X-nat:0
        Media Description, name and address (m): audio 4004 RTP/AVP 8 101
        Connection Information (c): IN IP4 192.168.0.134
        Bandwidth Information (b): TIAS:64000
        Media Attribute (a): rtcp:4005 IN IP4 192.168.0.134
        Media Attribute (a): sendrecv
        Media Attribute (a): rtpmap:8 PCMA/8000
        Media Attribute (a): rtpmap:101 telephone-event/8000
        Media Attribute (a): fmtp:101 0-16
        Media Attribute (a): ssrc:2129558419 cname:63600a3a52cb6dee

Egress INVITE:

Request-Line: INVITE sip:[email protected]:58604 SIP/2.0
Message Header
    Via: SIP/2.0/UDP 192.168.0.101:5062;branch=z9hG4bKa83470d3fd30bffb418e9933f7bab4c7;rport
    Max-Forwards: 69
    From: <sip:[email protected]>;tag=8636a93c89e788e511537c4aea1c458f
    To: <sip:[email protected]>
    Call-ID: 68504c1dfbeb42dca549be075abaa71a-b2b_1
    CSeq: 200 INVITE
    Contact: <sip:[email protected]:5062>
    Expires: 300
    User-Agent: Sippy B2BUA (RADIUS)
    cisco-GUID: 3401962361-1366442318-3627064869-582878196
    h323-conf-id: 3401962361-1366442318-3627064869-582878196
    Content-Type: application/sdp
    Content-Length: 344
Message Body
    Session Description Protocol
        Session Description Protocol Version (v): 0
        Owner/Creator, Session Id (o): - 1035059087891 1035059087891 IN IP4 192.168.0.101
        Session Name (s): pjmedia
        Connection Information (c): IN IP4 192.168.0.101
        Bandwidth Information (b): AS:84
        Time Description, active time (t): 0 0
        Session Attribute (a): X-nat:0
        Media Description, name and address (m): audio 41808 RTP/AVP 8 101
        Bandwidth Information (b): TIAS:64000
        Media Attribute (a): rtcp:4005 IN IP4 192.168.0.134
        Media Attribute (a): sendrecv
        Media Attribute (a): rtpmap:8 PCMA/8000
        Media Attribute (a): rtpmap:101 telephone-event/8000
        Media Attribute (a): fmtp:101 0-16
        Media Attribute (a): ssrc:2129558419 cname:63600a3a52cb6dee
        Media Attribute (a): nortpproxy:yes