REGISTER sip:cs.columbia.edu SIP/2.0
Via: SIP/2.0/UDP 128.59.19.251:13170
From:
<sip:xiaotaow@cs.columbia.edu>;tag=e74959cf-fd33-49d6-b6d8-4a0ba844c8bd
To: <sip:xiaotaow@cs.columbia.edu>
Call-ID: 2196e87c-e89a-4239-945b-dc52d1e70a35@128.59.19.251
CSeq: 1 REGISTER
Contact: <sip:128.59.19.251:13170>;methods="INVITE, MESSAGE, INFO,
SUBSCRIBE, OPTIONS, BYE, CANCEL, NOTIFY, ACK"
User-Agent: Windows RTC/1.0
Expires: 1200
Event: registration
Allow-Events: presence
Content-Length: 0


SUBSCRIBE sip:william@cs.columbia.edu SIP/2.0
Via: SIP/2.0/UDP 128.59.19.251:13170
From: "xiaotaow"
<sip:xiaotaow@cs.columbia.edu>;tag=cc9aa6a9-bab4-4c91-92e9-d2a4bba691d5
To: <sip:william@cs.columbia.edu>
Call-ID: fe2f2185-879e-410d-8434-bd7bf85acf9c@128.59.19.251
CSeq: 1 SUBSCRIBE
Contact: <sip:128.59.19.251:13170>
User-Agent: Windows RTC/1.0
Expires: 1800
Content-Length: 0



NOTIFY sip:xiaotaow@128.59.19.27:5060 SIP/2.0
Via: SIP/2.0/UDP 128.59.19.251:13170
From: sip:william@conductor.cs.columbia.edu;tag=d2dd3c15-b762-486b-8911-25ed3a3bd975
To: sip:xiaotaow@cs.columbia.edu
Call-ID: 330938581@128.59.19.27
CSeq: 1 NOTIFY
Contact: <sip:128.59.19.251:13170>
User-Agent: Windows RTC/1.0
Content-Type: application/xpidf+xml
Content-Length: 353

<?xml version="1.0"?>
<!DOCTYPE presence
PUBLIC "-//IETF//DTD RFCxxxx XPIDF 1.0//EN" "xpidf.dtd">
<presence>
<presentity uri="sip:xiaotaow@cs.columbia.edu;method=SUBSCRIBE" />
<atom id="1003">
<address uri="sip:128.59.19.251:13170;user=ip" priority="0.800000">
<status status="open" />
<msnsubstatus substatus="online" />
</address>
</atom>
</presence>


MESSAGE sip:william@cs.columbia.edu SIP/2.0
Via: SIP/2.0/UDP 128.59.19.251:13170
From: "xiaotaow"
<sip:xiaotaow@cs.columbia.edu>;tag=b74bd706-1728-4fa8-ae71-ee8e561dd790
To: <sip:william@cs.columbia.edu>
Call-ID: 57004e35-976d-458d-abfc-f7a8bf59c243@128.59.19.251
CSeq: 1 MESSAGE
Contact: <sip:128.59.19.251:13170>
User-Agent: Windows RTC/1.0
Content-Type: text/plain;
  charset=UTF-8;msgr=WAAtAE0ATQBTAC0ASQBNAC0ARgBvAHIAbQBhAHQAOgAgAEYATgA9AE0AaQBjAHIAbwBzAG8AZgB0ACUAMgAwAFMAYQBuAHMAJQAyADAAUwBlAHIAaQBmADsAIABFAEYAPQA7ACAAQwBPAD0AMAA7ACAAQwBTAD0AOAA2ADsAIABQAEYAPQAyADIADQAKAA0ACgA
Content-Length: 7

test it