oting From: <sip:9735551212@sbc.sip-provider.com>;tag=383B4-0 To: <sip:9735551212@sbc.sip-provider.com> Date: Thu,03 Feb 2011 01:17:07 GMT Call-ID: 26F3EF99-2E6A11E0-800D80A2-733EA81A@192.168.0.3 CSeq: 102 CANCEL Max-Forwards: 70 Timestamp: 1296695831 Reason: Q.850;cause=16 Content-Length: 0 *Feb 3 01:17:11.112: //-1/xxxxxxxxxxxx/SIP/Msg/ccsipDisplayMsg: Received: SIP/2.0 200 OK Via: SIP/2.0/UDP 192.168.0.3:5060;branch=z9hG4bKB1761 From: <sip:9735551212@sbc.sip-provider.com>;tag=383B4-0 To: ip:9735551212@sbc.sip-provider.com>;tag=aprq1smnhpo-146jaq00000c Call-ID: 26F3EF99-2E6A11E0-800D80A2-733EA81A@192.168.0.3 CSeq: 102 CANCEL Timestamp: 1296695831 *Feb 3 01:17:11.136: //-1/xxxxxxxxxxxx/SIP/Msg/ccsipDisplayMsg: Received: SIP/2.0 487 Request Terminated Via: SIP/2.0/UDP 192.168.0.3:5060;branch=z9hG4bKB1761 From: <sip:9735551212@sbc.sip-provider.com>;tag=383B4-0 To: <sip:9735551212@sbc.sip-provider.com>;tag=131481110 Call-ID: 26F3EF99-2E6A11E0-800D80A2-733EA81A@192.168.0.3 CSeq: 102 INVITE Timestamp: 1296695827 Contact: <sip:9735551212@208.73.146.95:5060;transport=udp> Content-Length: 0 User-Agent: Cisco-SIPGateway/I0S-12.x *Feb 3 01:17:11.144: //-1/xxxxxxxxxxxx/SIP/Msg/ccsipDisplayMsg: Sent: ACK sip:9735551212@sbc.sip-provider.com:5060SIP/2.0 Via: SIP/2.0/UDP 192.168.0.3:5060;branch=z9hG4bKB176: From: <sip:9735551212@sbc.sip-provider.com>;tag=383B4-0 To: sip:9735551212@sbc.sip-provider.com>;tag=131481110 Date: Thu,03Feb 2011 01:17:07 GMT Call-ID: 26F3EF99-2E6A11E0-800D80A2-733EA81A@192.168.0.3 Max-Forwards: 70 CSeq: 102 ACK Allow-Events: telephone-event Content-Length: 0 Chapter 30: VolP CHAPTER 31 Introduction to QoS Quality of service (QoS) is deployed to prevent data from saturating a link to the point that other data cannot gain access to it. Remember, WAN links are serial links, which means that bits go in one end and come out the other end in the same order. Regardless of whether the link is a 1.5 Mbps T1 or a 155 Mbps OC3, the bits go in one at a time, and they come out one at a time. QoS allows certain type