【正文】 in shared Request slots Use Temp SID (Service ID) (Needed for every use of US) DHCP Acknowledgement Contains IP Addr, Default GW, ToD Server, TFTP Server Addr and TFTP Boot Config File Name. MAP Broadcast Contains US time sharing information (One per 4 ms per US Channel) Grant Returned when successful ToD Request In Allocated slots TOD Complete ToD Response Contains Time of Day per RFC 868 (Not NTP) DOCSIS Protocol and Signal Sequence DHCP Discover Now in Allocated Slots DHCP Reply DHCP offers an IP address IP Address Assigned (CMAC_LOG_DHCP_Complete) 49 Cisco Systems Confidential Cable Modem Setup (Cont.) Head End Interface Cable Modem TFTP Boot File Transfer Contains QoS Parameters Specifies Privacy, new software download, etc. TFTP Boot Request Send TFTP Boot File name Now in allocated slots Cable Modem Online Maintain Station Link using periodic Keep Alives May need to Hop upstream frequency due to Noise (means Link Reset) Registration Request Send QoS Parameters in Allocated Slots Registration Response Contains Assigned SID Modem registered Fail if QoS not available Or Authentication failed DOCSIS Protocol and Signal Sequence 50 Cisco Systems Confidential Baseline Privacy Head End Interface Generate Private KEK Key Encryption Key Encrypt KEK by Public Key Cable Modem Decrypt KEK using Public Key KEK Life is 7 days (Configurable 1 to 70 days) Request TEK Send Public Key Request KEK Encrypted Data Flow Enabled Only Data inside IEEE frame is encrypted using TEK 40/56 bit DES encryption supported Must reestablish keys within configured Grace Period before Life expiry Generate Private TEK Traffic Encryption Key Encrypt TEK by KEK Decrypt TEK using KEK TEK Life is 12 hours (Configurable 30 min to 7 days) DOCSIS Protocol and Signal Sequence 51 Cisco Systems Confidential Modem Initialization Sequence Power ON Scan for Downstream Channel Dwonstream Sync Established Establish Security Obtain Upstream Parameters Upstream Parameters Acquired Start Ranging Complete Ranging and Auto Adjustments Establish IP Connectivity IP Complete Establish TOD TOD Established Initialize Baseline Privacy Security Established Transfer Operational Parameters Transfer Complete Register withuBR7246 Registration Complete Baseline Privacy Initialized Operational 52 Presentation_ID 169。 1999, Cisco Systems, Inc. DOCSIS Protocol and Signaling Sequence Demonstration 53 Cisco Systems Confidential offline modem considered offline init(r1) modem sent initial ranging init(r2) modem is ranging init(rc) ranging plete init(d) dhcp request received init(i) dhcp reply received。 IP address assigned init(t) TOD request received. init(o) TFTP request was received. online modem registered, enabled for data online(d) modem registered, but work access for the CM is disabled online(pk) modem registered, BPI enabled and KEK assigned online(pt) modem registered, BPI enabled and TEK assigned reject(m) modem did attempt to register。 registration was refused due to bad mic reject(c) modem did attempt to register。 registration was refused due to bad COS reject(pk) KEK modem key assignment rejected reject(pt) TEK modem key assignment rejected “ Show Cable Modem” State mand Defined DOCSIS Protocol and Signal Sequence 54 Cisco Systems Confidential DOCSIS Protocol and Signal Sequence “ T” Timers Defined T1 A CM timing parameter referenced as “Wait for UCD timeout” and having a duration of five UCD maximum time intervals (approximately 10 seconds). T2 A CM timing parameter referenced as “Wait for broadcast ranging timeout” and having a duration of five ranging intervals (approximately 10 seconds). T3 A CM timing parameter referenced as “Wait for ranging response” and having a duration of between 50 and 200 msec (default 200 msec). T4 A CM timing parameter referenced as “Wait for unicast ranging opportunity” If the pendingtillplete field was used earlier by this modem, then the value of the field must be added to this interval. The maximum value is 30 seconds. T5 A CMTS timing parameter referenced as “Wait for upstream channel change response” and having a maximum interval of 2 seconds. T6 A CM timing parameter referenced as “Wait for registration response” and having maximum interval of 2 seconds. 55 Cisco Systems Confidential Flap List Explained MAC addr Identifies subscriber Cable IF Physical port identifier Ins of times in 180 seconds that the modem restarts initial ranging. Hit of times CMTS sent a station maintenance message and received a response. Miss of times CMTS sent a station maintenance message and didn’t receive a response. CRC of CRC errors from that modem. P Adj of times CMTS told CM to adjust TX power more than 3dB Flap Algorithm based on P Adj and Ins Time Most recent time that the modem dropped off the system Universal Broadband Router Overvie