Wireshark · Wireshark-users: [Wireshark-users] Delay-Calculations with RTCP-Packets

[Eram Khan <eramk2003@xxxxxxxx>]

Hi!! I am Eram Khan from Germany. Studying Computer Enginerring at the Niederrhein University of Applied Sciences and currently busy with my thesis project.

 

I am testing the VoIP connections of a firm here in Germany with wireshark 0.99.5. They have here the Siemens Opticlient Telephone Software. Im using the RTCP- Packets to determine the parameters jitter, packet-loss and delay. I have problems in delay calculations, according to RFC 3550 the formula is : A - LSR - DLSR

where A = the arrival time of the reception report,

LSR = the middle 32 bits out of 64 bits in the NTP time stamp of the most recent sender report and DLSR = the delay expressed in 1/65536 between receiving the last SR packet from a source and sending the reception report block.

I have a confusion regarding the conversion of these values, I hav asked my Prof and his colleagues and the Network Administrator here in the firm, all hav different views. 2 of the views im describing below:

 

View. 1

 

Delay (in ms) = Arrival time - (LSRx1000) - DLSR/(65536x1000)

Arrival time and DLSR are from the same rtcp packet and LSR is also from the same packet.

Arrival time conversion with respect to 01.01.1900.

I get a negative value for delay.

 

View. 2

Delay = Arrival time - LSR - DLSR

Arrival time and DLSR are from the same rtcp packet and LSR is from the next rtcp packet ( which contradicts the definition of LSR)

Arrival time conversion with respect to 01.01.1900.

I get a negative value sometimes and sometimes an extremely high value for delay.

 

I hav read the Wireshark guide too and found this:

The internal format that Wireshark uses to keep a packet time stamp consists of the date (in days since 1.1.1970) and the time of day (in nanoseconds since midnight).

 

But I calculate the Arrival time from 01.01.1900 as it is for NTP-timestamp.

Im also confused with conversions of LSR and which value is correct. Could somebody send an example calculation where i can see step by step how the calculation is done.

Thanks a heap!!!

Attachments: View1-2 Arrival time calculation and View 2 Delay calculation using Frame 1114 in rtcp-test and rtcp-test (consist of rtcp packets only, open it with Notepad)

 

---

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Attachment: View1and2-ArrivalTime.doc
Description: 1484490726-View1and2-ArrivalTime.doc

Attachment: Delay-View2.doc
Description: 1068495821-Delay-View2.doc

No.     Time        Source                Destination           Protocol Info
    135 2.126712    10.132.21.130         10.136.10.249         RTCP     Sender Report   Source description   

Frame 135 (126 bytes on wire, 126 bytes captured)
    Arrival Time: Apr 23, 2007 10:36:06.697480000
    [Time delta from previous packet: 2.126712000 seconds]
    [Time since reference or first frame: 2.126712000 seconds]
    Frame Number: 135
    Packet Length: 126 bytes
    Capture Length: 126 bytes
    [Frame is marked: True]
    [Protocols in frame: eth:ip:udp:rtcp]
    [Coloring Rule Name: UDP]
    [Coloring Rule String: udp]
Ethernet II, Src: Fujitsu_54:20:71 (00:0b:5d:54:20:71), Dst: IETF-VRRP-virtual-router-VRID_15 (00:00:5e:00:01:15)
Internet Protocol, Src: 10.132.21.130 (10.132.21.130), Dst: 10.136.10.249 (10.136.10.249)
User Datagram Protocol, Src Port: 29101 (29101), Dst Port: 29329 (29329)
Real-time Transport Control Protocol (Sender Report)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Sender Report (200)
    Length: 12
    Sender SSRC: 109693800
    Timestamp, MSW: 3386306166 (0xc9d6ee76)
    Timestamp, LSW: 3010772074 (0xb374bc6a)
    [MSW and LSW as NTP timestamp: Apr 23, 2007 08:36:06,7010 UTC]
    RTP timestamp: 10400
    Sender's packet count: 66
    Sender's octet count: 1320
    Source 1
        Identifier: 335286385
        SSRC contents
        Extended highest sequence number received: 20
        Interarrival jitter: 0
        Last SR timestamp: 0 (0x00000000)
        Delay since last SR timestamp: 0
Real-time Transport Control Protocol (Source description)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 7
    Chunk 1, SSRC/CSRC 109693800
[RTCP frame length check: OK - 84 bytes]

No.     Time        Source                Destination           Protocol Info
    394 5.870414    10.136.10.249         10.132.21.130         RTCP     Sender Report   Source description   

Frame 394 (118 bytes on wire, 118 bytes captured)
    Arrival Time: Apr 23, 2007 10:36:10.441182000
    [Time delta from previous packet: 3.743702000 seconds]
    [Time since reference or first frame: 5.870414000 seconds]
    Frame Number: 394
    Packet Length: 118 bytes
    Capture Length: 118 bytes
    [Frame is marked: True]
    [Protocols in frame: eth:ip:udp:rtcp]
    [Coloring Rule Name: UDP]
    [Coloring Rule String: udp]
Ethernet II, Src: NortelNe_5a:56:14 (00:04:dc:5a:56:14), Dst: Fujitsu_54:20:71 (00:0b:5d:54:20:71)
Internet Protocol, Src: 10.136.10.249 (10.136.10.249), Dst: 10.132.21.130 (10.132.21.130)
User Datagram Protocol, Src Port: 29329 (29329), Dst Port: 29101 (29101)
Real-time Transport Control Protocol (Sender Report)
    [Stream setup by H245 (frame 42)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Sender Report (200)
    Length: 12
    Sender SSRC: 335286385
    Timestamp, MSW: 3386313297 (0xc9d70a51)
    Timestamp, LSW: 2294360354 (0x88c12922)
    [MSW and LSW as NTP timestamp: Apr 23, 2007 10:34:57,5342 UTC]
    RTP timestamp: 39360
    Sender's packet count: 83
    Sender's octet count: 4980
    Source 1
        Identifier: 109693800
        SSRC contents
        Extended highest sequence number received: 25286
        Interarrival jitter: 5
        Last SR timestamp: 4000756596 (0xee76b374)
        Delay since last SR timestamp: 245278
Real-time Transport Control Protocol (Source description)
    [Stream setup by H245 (frame 42)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 5
    Chunk 1, SSRC/CSRC 335286385
[RTCP frame length check: OK - 76 bytes]

No.     Time        Source                Destination           Protocol Info
    452 6.686355    10.132.21.130         10.136.10.249         RTCP     Sender Report   Source description   

Frame 452 (126 bytes on wire, 126 bytes captured)
    Arrival Time: Apr 23, 2007 10:36:11.257123000
    [Time delta from previous packet: 0.815941000 seconds]
    [Time since reference or first frame: 6.686355000 seconds]
    Frame Number: 452
    Packet Length: 126 bytes
    Capture Length: 126 bytes
    [Frame is marked: True]
    [Protocols in frame: eth:ip:udp:rtcp]
    [Coloring Rule Name: UDP]
    [Coloring Rule String: udp]
Ethernet II, Src: Fujitsu_54:20:71 (00:0b:5d:54:20:71), Dst: IETF-VRRP-virtual-router-VRID_15 (00:00:5e:00:01:15)
Internet Protocol, Src: 10.132.21.130 (10.132.21.130), Dst: 10.136.10.249 (10.136.10.249)
User Datagram Protocol, Src Port: 29101 (29101), Dst Port: 29329 (29329)
Real-time Transport Control Protocol (Sender Report)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Sender Report (200)
    Length: 12
    Sender SSRC: 109693800
    Timestamp, MSW: 3386306171 (0xc9d6ee7b)
    Timestamp, LSW: 1099511628 (0x4189374c)
    [MSW and LSW as NTP timestamp: Apr 23, 2007 08:36:11,2560 UTC]
    RTP timestamp: 47360
    Sender's packet count: 297
    Sender's octet count: 5940
    Source 1
        Identifier: 335286385
        SSRC contents
        Extended highest sequence number received: 96
        Interarrival jitter: 0
        Last SR timestamp: 173115585 (0x0a5188c1)
        Delay since last SR timestamp: 51838
Real-time Transport Control Protocol (Source description)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 7
    Chunk 1, SSRC/CSRC 109693800
[RTCP frame length check: OK - 84 bytes]

No.     Time        Source                Destination           Protocol Info
    680 9.806748    10.132.21.130         10.136.10.249         RTCP     Sender Report   Source description   

Frame 680 (126 bytes on wire, 126 bytes captured)
    Arrival Time: Apr 23, 2007 10:36:14.377516999
    [Time delta from previous packet: 3.120393999 seconds]
    [Time since reference or first frame: 9.806748999 seconds]
    Frame Number: 680
    Packet Length: 126 bytes
    Capture Length: 126 bytes
    [Frame is marked: True]
    [Protocols in frame: eth:ip:udp:rtcp]
    [Coloring Rule Name: UDP]
    [Coloring Rule String: udp]
Ethernet II, Src: Fujitsu_54:20:71 (00:0b:5d:54:20:71), Dst: IETF-VRRP-virtual-router-VRID_15 (00:00:5e:00:01:15)
Internet Protocol, Src: 10.132.21.130 (10.132.21.130), Dst: 10.136.10.249 (10.136.10.249)
User Datagram Protocol, Src Port: 29101 (29101), Dst Port: 29329 (29329)
Real-time Transport Control Protocol (Sender Report)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Sender Report (200)
    Length: 12
    Sender SSRC: 109693800
    Timestamp, MSW: 3386306174 (0xc9d6ee7e)
    Timestamp, LSW: 1632087572 (0x6147ae14)
    [MSW and LSW as NTP timestamp: Apr 23, 2007 08:36:14,3800 UTC]
    RTP timestamp: 72640
    Sender's packet count: 455
    Sender's octet count: 9100
    Source 1
        Identifier: 335286385
        SSRC contents
        Extended highest sequence number received: 148
        Interarrival jitter: 1
        Last SR timestamp: 173115585 (0x0a5188c1)
        Delay since last SR timestamp: 256573
Real-time Transport Control Protocol (Source description)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 7
    Chunk 1, SSRC/CSRC 109693800
[RTCP frame length check: OK - 84 bytes]

No.     Time        Source                Destination           Protocol Info
    763 10.870432   10.136.10.249         10.132.21.130         RTCP     Sender Report   Source description   

Frame 763 (118 bytes on wire, 118 bytes captured)
    Arrival Time: Apr 23, 2007 10:36:15.441200999
    [Time delta from previous packet: 1.063684000 seconds]
    [Time since reference or first frame: 10.870432999 seconds]
    Frame Number: 763
    Packet Length: 118 bytes
    Capture Length: 118 bytes
    [Frame is marked: True]
    [Protocols in frame: eth:ip:udp:rtcp]
    [Coloring Rule Name: UDP]
    [Coloring Rule String: udp]
Ethernet II, Src: NortelNe_5a:56:14 (00:04:dc:5a:56:14), Dst: Fujitsu_54:20:71 (00:0b:5d:54:20:71)
Internet Protocol, Src: 10.136.10.249 (10.136.10.249), Dst: 10.132.21.130 (10.132.21.130)
User Datagram Protocol, Src Port: 29329 (29329), Dst Port: 29101 (29101)
Real-time Transport Control Protocol (Sender Report)
    [Stream setup by H245 (frame 42)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Sender Report (200)
    Length: 12
    Sender SSRC: 335286385
    Timestamp, MSW: 3386313302 (0xc9d70a56)
    Timestamp, LSW: 2292457358 (0x88a41f8e)
    [MSW and LSW as NTP timestamp: Apr 23, 2007 10:35:02,5338 UTC]
    RTP timestamp: 79680
    Sender's packet count: 167
    Sender's octet count: 10020
    Source 1
        Identifier: 109693800
        SSRC contents
        Extended highest sequence number received: 25539
        Interarrival jitter: 1
        Last SR timestamp: 4001259847 (0xee7e6147)
        Delay since last SR timestamp: 69659
Real-time Transport Control Protocol (Source description)
    [Stream setup by H245 (frame 42)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 5
    Chunk 1, SSRC/CSRC 335286385
[RTCP frame length check: OK - 76 bytes]

No.     Time        Source                Destination           Protocol Info
    996 14.196318   10.132.21.130         10.136.10.249         RTCP     Sender Report   Source description   

Frame 996 (126 bytes on wire, 126 bytes captured)
    Arrival Time: Apr 23, 2007 10:36:18.767086000
    [Time delta from previous packet: 3.325885001 seconds]
    [Time since reference or first frame: 14.196318000 seconds]
    Frame Number: 996
    Packet Length: 126 bytes
    Capture Length: 126 bytes
    [Frame is marked: True]
    [Protocols in frame: eth:ip:udp:rtcp]
    [Coloring Rule Name: UDP]
    [Coloring Rule String: udp]
Ethernet II, Src: Fujitsu_54:20:71 (00:0b:5d:54:20:71), Dst: IETF-VRRP-virtual-router-VRID_15 (00:00:5e:00:01:15)
Internet Protocol, Src: 10.132.21.130 (10.132.21.130), Dst: 10.136.10.249 (10.136.10.249)
User Datagram Protocol, Src Port: 29101 (29101), Dst Port: 29329 (29329)
Real-time Transport Control Protocol (Sender Report)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Sender Report (200)
    Length: 12
    Sender SSRC: 109693800
    Timestamp, MSW: 3386306178 (0xc9d6ee82)
    Timestamp, LSW: 3285649981 (0xc3d70a3d)
    [MSW and LSW as NTP timestamp: Apr 23, 2007 08:36:18,7650 UTC]
    RTP timestamp: 108160
    Sender's packet count: 677
    Sender's octet count: 13540
    Source 1
        Identifier: 335286385
        SSRC contents
        Extended highest sequence number received: 221
        Interarrival jitter: 4
        Last SR timestamp: 173443236 (0x0a5688a4)
        Delay since last SR timestamp: 213909
Real-time Transport Control Protocol (Source description)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 7
    Chunk 1, SSRC/CSRC 109693800
[RTCP frame length check: OK - 84 bytes]

No.     Time        Source                Destination           Protocol Info
   1114 15.869765   10.136.10.249         10.132.21.130         RTCP     Sender Report   Source description   

Frame 1114 (118 bytes on wire, 118 bytes captured)
    Arrival Time: Apr 23, 2007 10:36:20.440533999
    [Time delta from previous packet: 1.673447999 seconds]
    [Time since reference or first frame: 15.869765999 seconds]
    Frame Number: 1114
    Packet Length: 118 bytes
    Capture Length: 118 bytes
    [Frame is marked: True]
    [Protocols in frame: eth:ip:udp:rtcp]
    [Coloring Rule Name: UDP]
    [Coloring Rule String: udp]
Ethernet II, Src: NortelNe_5a:56:14 (00:04:dc:5a:56:14), Dst: Fujitsu_54:20:71 (00:0b:5d:54:20:71)
Internet Protocol, Src: 10.136.10.249 (10.136.10.249), Dst: 10.132.21.130 (10.132.21.130)
User Datagram Protocol, Src Port: 29329 (29329), Dst Port: 29101 (29101)
Real-time Transport Control Protocol (Sender Report)
    [Stream setup by H245 (frame 42)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Sender Report (200)
    Length: 12
    Sender SSRC: 335286385
    Timestamp, MSW: 3386313307 (0xc9d70a5b)
    Timestamp, LSW: 2287469932 (0x8858056c)
    [MSW and LSW as NTP timestamp: Apr 23, 2007 10:35:07,5326 UTC]
    RTP timestamp: 119520
    Sender's packet count: 250
    Sender's octet count: 15000
    Source 1
        Identifier: 109693800
        SSRC contents
        Extended highest sequence number received: 25792
        Interarrival jitter: 0
        Last SR timestamp: 4001547223 (0xee82c3d7)
        Delay since last SR timestamp: 109616
Real-time Transport Control Protocol (Source description)
    [Stream setup by H245 (frame 42)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 5
    Chunk 1, SSRC/CSRC 335286385
[RTCP frame length check: OK - 76 bytes]

No.     Time        Source                Destination           Protocol Info
   1351 19.286186   10.132.21.130         10.136.10.249         RTCP     Sender Report   Source description   

Frame 1351 (126 bytes on wire, 126 bytes captured)
    Arrival Time: Apr 23, 2007 10:36:23.856954000
    [Time delta from previous packet: 3.416420001 seconds]
    [Time since reference or first frame: 19.286186000 seconds]
    Frame Number: 1351
    Packet Length: 126 bytes
    Capture Length: 126 bytes
    [Frame is marked: True]
    [Protocols in frame: eth:ip:udp:rtcp]
    [Coloring Rule Name: UDP]
    [Coloring Rule String: udp]
Ethernet II, Src: Fujitsu_54:20:71 (00:0b:5d:54:20:71), Dst: IETF-VRRP-virtual-router-VRID_15 (00:00:5e:00:01:15)
Internet Protocol, Src: 10.132.21.130 (10.132.21.130), Dst: 10.136.10.249 (10.136.10.249)
User Datagram Protocol, Src Port: 29101 (29101), Dst Port: 29329 (29329)
Real-time Transport Control Protocol (Sender Report)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Sender Report (200)
    Length: 12
    Sender SSRC: 109693800
    Timestamp, MSW: 3386306183 (0xc9d6ee87)
    Timestamp, LSW: 3655017169 (0xd9db22d1)
    [MSW and LSW as NTP timestamp: Apr 23, 2007 08:36:23,8510 UTC]
    RTP timestamp: 149440
    Sender's packet count: 935
    Sender's octet count: 18700
    Source 1
        Identifier: 335286385
        SSRC contents
        Extended highest sequence number received: 306
        Interarrival jitter: 0
        Last SR timestamp: 173770840 (0x0a5b8858)
        Delay since last SR timestamp: 221118
Real-time Transport Control Protocol (Source description)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 7
    Chunk 1, SSRC/CSRC 109693800
[RTCP frame length check: OK - 84 bytes]

No.     Time        Source                Destination           Protocol Info
   1462 20.870310   10.136.10.249         10.132.21.130         RTCP     Sender Report   Source description   

Frame 1462 (118 bytes on wire, 118 bytes captured)
    Arrival Time: Apr 23, 2007 10:36:25.441078000
    [Time delta from previous packet: 1.584124000 seconds]
    [Time since reference or first frame: 20.870310000 seconds]
    Frame Number: 1462
    Packet Length: 118 bytes
    Capture Length: 118 bytes
    [Frame is marked: True]
    [Protocols in frame: eth:ip:udp:rtcp]
    [Coloring Rule Name: UDP]
    [Coloring Rule String: udp]
Ethernet II, Src: NortelNe_5a:56:14 (00:04:dc:5a:56:14), Dst: Fujitsu_54:20:71 (00:0b:5d:54:20:71)
Internet Protocol, Src: 10.136.10.249 (10.136.10.249), Dst: 10.132.21.130 (10.132.21.130)
User Datagram Protocol, Src Port: 29329 (29329), Dst Port: 29101 (29101)
Real-time Transport Control Protocol (Sender Report)
    [Stream setup by H245 (frame 42)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Sender Report (200)
    Length: 12
    Sender SSRC: 335286385
    Timestamp, MSW: 3386313312 (0xc9d70a60)
    Timestamp, LSW: 2287738451 (0x885c1e53)
    [MSW and LSW as NTP timestamp: Apr 23, 2007 10:35:12,5327 UTC]
    RTP timestamp: 159360
    Sender's packet count: 333
    Sender's octet count: 19980
    Source 1
        Identifier: 109693800
        SSRC contents
        Extended highest sequence number received: 26045
        Interarrival jitter: 5
        Last SR timestamp: 4001880539 (0xee87d9db)
        Delay since last SR timestamp: 103764
Real-time Transport Control Protocol (Source description)
    [Stream setup by H245 (frame 42)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 5
    Chunk 1, SSRC/CSRC 335286385
[RTCP frame length check: OK - 76 bytes]

No.     Time        Source                Destination           Protocol Info
   1642 23.436174   10.132.21.130         10.136.10.249         RTCP     Sender Report   Source description   

Frame 1642 (126 bytes on wire, 126 bytes captured)
    Arrival Time: Apr 23, 2007 10:36:28.006942999
    [Time delta from previous packet: 2.565864999 seconds]
    [Time since reference or first frame: 23.436174999 seconds]
    Frame Number: 1642
    Packet Length: 126 bytes
    Capture Length: 126 bytes
    [Frame is marked: True]
    [Protocols in frame: eth:ip:udp:rtcp]
    [Coloring Rule Name: UDP]
    [Coloring Rule String: udp]
Ethernet II, Src: Fujitsu_54:20:71 (00:0b:5d:54:20:71), Dst: IETF-VRRP-virtual-router-VRID_15 (00:00:5e:00:01:15)
Internet Protocol, Src: 10.132.21.130 (10.132.21.130), Dst: 10.136.10.249 (10.136.10.249)
User Datagram Protocol, Src Port: 29101 (29101), Dst Port: 29329 (29329)
Real-time Transport Control Protocol (Sender Report)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Sender Report (200)
    Length: 12
    Sender SSRC: 109693800
    Timestamp, MSW: 3386306188 (0xc9d6ee8c)
    Timestamp, LSW: 25769804 (0x0189374c)
    [MSW and LSW as NTP timestamp: Apr 23, 2007 08:36:28,0060 UTC]
    RTP timestamp: 183040
    Sender's packet count: 1145
    Sender's octet count: 22900
    Source 1
        Identifier: 335286385
        SSRC contents
        Extended highest sequence number received: 375
        Interarrival jitter: 1
        Last SR timestamp: 174098524 (0x0a60885c)
        Delay since last SR timestamp: 166658
Real-time Transport Control Protocol (Source description)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 7
    Chunk 1, SSRC/CSRC 109693800
[RTCP frame length check: OK - 84 bytes]

No.     Time        Source                Destination           Protocol Info
   1814 25.870303   10.136.10.249         10.132.21.130         RTCP     Sender Report   Source description   

Frame 1814 (118 bytes on wire, 118 bytes captured)
    Arrival Time: Apr 23, 2007 10:36:30.441071999
    [Time delta from previous packet: 2.434129000 seconds]
    [Time since reference or first frame: 25.870303999 seconds]
    Frame Number: 1814
    Packet Length: 118 bytes
    Capture Length: 118 bytes
    [Frame is marked: True]
    [Protocols in frame: eth:ip:udp:rtcp]
    [Coloring Rule Name: UDP]
    [Coloring Rule String: udp]
Ethernet II, Src: NortelNe_5a:56:14 (00:04:dc:5a:56:14), Dst: Fujitsu_54:20:71 (00:0b:5d:54:20:71)
Internet Protocol, Src: 10.136.10.249 (10.136.10.249), Dst: 10.132.21.130 (10.132.21.130)
User Datagram Protocol, Src Port: 29329 (29329), Dst Port: 29101 (29101)
Real-time Transport Control Protocol (Sender Report)
    [Stream setup by H245 (frame 42)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Sender Report (200)
    Length: 12
    Sender SSRC: 335286385
    Timestamp, MSW: 3386313317 (0xc9d70a65)
    Timestamp, LSW: 2285682993 (0x883cc131)
    [MSW and LSW as NTP timestamp: Apr 23, 2007 10:35:17,5322 UTC]
    RTP timestamp: 199680
    Sender's packet count: 417
    Sender's octet count: 25020
    Source 1
        Identifier: 109693800
        SSRC contents
        Extended highest sequence number received: 26298
        Interarrival jitter: 2
        Last SR timestamp: 4002152841 (0xee8c0189)
        Delay since last SR timestamp: 159465
Real-time Transport Control Protocol (Source description)
    [Stream setup by H245 (frame 42)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 5
    Chunk 1, SSRC/CSRC 335286385
[RTCP frame length check: OK - 76 bytes]

No.     Time        Source                Destination           Protocol Info
   2006 28.656545   10.132.21.130         10.136.10.249         RTCP     Sender Report   Source description   

Frame 2006 (126 bytes on wire, 126 bytes captured)
    Arrival Time: Apr 23, 2007 10:36:33.227313999
    [Time delta from previous packet: 2.786242000 seconds]
    [Time since reference or first frame: 28.656545999 seconds]
    Frame Number: 2006
    Packet Length: 126 bytes
    Capture Length: 126 bytes
    [Frame is marked: True]
    [Protocols in frame: eth:ip:udp:rtcp]
    [Coloring Rule Name: UDP]
    [Coloring Rule String: udp]
Ethernet II, Src: Fujitsu_54:20:71 (00:0b:5d:54:20:71), Dst: IETF-VRRP-virtual-router-VRID_15 (00:00:5e:00:01:15)
Internet Protocol, Src: 10.132.21.130 (10.132.21.130), Dst: 10.136.10.249 (10.136.10.249)
User Datagram Protocol, Src Port: 29101 (29101), Dst Port: 29329 (29329)
Real-time Transport Control Protocol (Sender Report)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Sender Report (200)
    Length: 12
    Sender SSRC: 109693800
    Timestamp, MSW: 3386306193 (0xc9d6ee91)
    Timestamp, LSW: 953482740 (0x38d4fdf4)
    [MSW and LSW as NTP timestamp: Apr 23, 2007 08:36:33,2220 UTC]
    RTP timestamp: 225280
    Sender's packet count: 1409
    Sender's octet count: 28180
    Source 1
        Identifier: 335286385
        SSRC contents
        Extended highest sequence number received: 462
        Interarrival jitter: 2
        Last SR timestamp: 174426172 (0x0a65883c)
        Delay since last SR timestamp: 178520
Real-time Transport Control Protocol (Source description)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 7
    Chunk 1, SSRC/CSRC 109693800
[RTCP frame length check: OK - 84 bytes]

No.     Time        Source                Destination           Protocol Info
   2161 30.869681   10.136.10.249         10.132.21.130         RTCP     Sender Report   Source description   

Frame 2161 (118 bytes on wire, 118 bytes captured)
    Arrival Time: Apr 23, 2007 10:36:35.440449000
    [Time delta from previous packet: 2.213135001 seconds]
    [Time since reference or first frame: 30.869681000 seconds]
    Frame Number: 2161
    Packet Length: 118 bytes
    Capture Length: 118 bytes
    [Frame is marked: True]
    [Protocols in frame: eth:ip:udp:rtcp]
    [Coloring Rule Name: UDP]
    [Coloring Rule String: udp]
Ethernet II, Src: NortelNe_5a:56:14 (00:04:dc:5a:56:14), Dst: Fujitsu_54:20:71 (00:0b:5d:54:20:71)
Internet Protocol, Src: 10.136.10.249 (10.136.10.249), Dst: 10.132.21.130 (10.132.21.130)
User Datagram Protocol, Src Port: 29329 (29329), Dst Port: 29101 (29101)
Real-time Transport Control Protocol (Sender Report)
    [Stream setup by H245 (frame 42)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Sender Report (200)
    Length: 12
    Sender SSRC: 335286385
    Timestamp, MSW: 3386313322 (0xc9d70a6a)
    Timestamp, LSW: 2280913230 (0x87f3f94e)
    [MSW and LSW as NTP timestamp: Apr 23, 2007 10:35:22,5311 UTC]
    RTP timestamp: 239520
    Sender's packet count: 500
    Sender's octet count: 30000
    Source 1
        Identifier: 109693800
        SSRC contents
        Extended highest sequence number received: 26551
        Interarrival jitter: 1
        Last SR timestamp: 4002494676 (0xee9138d4)
        Delay since last SR timestamp: 144983
Real-time Transport Control Protocol (Source description)
    [Stream setup by H245 (frame 42)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 5
    Chunk 1, SSRC/CSRC 335286385
[RTCP frame length check: OK - 76 bytes]

No.     Time        Source                Destination           Protocol Info
   2358 33.549805   10.132.21.130         10.136.10.249         RTCP     Sender Report   Source description   

Frame 2358 (126 bytes on wire, 126 bytes captured)
    Arrival Time: Apr 23, 2007 10:36:38.120573000
    [Time delta from previous packet: 2.680124000 seconds]
    [Time since reference or first frame: 33.549805000 seconds]
    Frame Number: 2358
    Packet Length: 126 bytes
    Capture Length: 126 bytes
    [Frame is marked: True]
    [Protocols in frame: eth:ip:udp:rtcp]
    [Coloring Rule Name: UDP]
    [Coloring Rule String: udp]
Ethernet II, Src: Fujitsu_54:20:71 (00:0b:5d:54:20:71), Dst: IETF-VRRP-virtual-router-VRID_15 (00:00:5e:00:01:15)
Internet Protocol, Src: 10.132.21.130 (10.132.21.130), Dst: 10.136.10.249 (10.136.10.249)
User Datagram Protocol, Src Port: 29101 (29101), Dst Port: 29329 (29329)
Real-time Transport Control Protocol (Sender Report)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Reception report count: 1
    Packet type: Sender Report (200)
    Length: 12
    Sender SSRC: 109693800
    Timestamp, MSW: 3386306198 (0xc9d6ee96)
    Timestamp, LSW: 502511174 (0x1df3b646)
    [MSW and LSW as NTP timestamp: Apr 23, 2007 08:36:38,1170 UTC]
    RTP timestamp: 44639624
    Sender's packet count: 1646
    Sender's octet count: 32920
    Source 1
        Identifier: 335286385
        SSRC contents
        Extended highest sequence number received: 544
        Interarrival jitter: 1
        Last SR timestamp: 174753779 (0x0a6a87f3)
        Delay since last SR timestamp: 173211
Real-time Transport Control Protocol (Source description)
    [Stream setup by H245 (frame 27)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 0001 = Source count: 1
    Packet type: Source description (202)
    Length: 7
    Chunk 1, SSRC/CSRC 109693800
[RTCP frame length check: OK - 84 bytes]