SIP/2.0 200 OK
Via: SIP/2.0/UDP nm;rport=26810;received=224.165.192.68;branch=foo
Call-ID: 50000
From: <sip:nm@nm>;tag=root
To: <sip:nm2@nm2>;tag=foo
CSeq: 42 OPTIONS
Allow: PRACK, INVITE, ACK, BYE, CANCEL, UPDATE, SUBSCRIBE, NOTIFY, REFER, OPTIONS
Accept: application/sdp, application/pidf+xml, application/xpidf+xml, message/sipfrag;version=2.0, application/simple-message-summary
Supported: replaces, 100rel, norefersub
Allow-Events: presence, refer, message-summary
User-Agent: Eltek R7121
Content-Length:  0