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Copyright ©Universalinet.Com, LLC 2009 Internet To connect a subscriber to Cable Services, Internet connectivity serves as the endpoint to the subscriber. {Click, or Press any key to continue} Subscribers Simulation 1: Process for Provisioning a Cable Modem
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Copyright ©Universalinet.Com, LLC 2009 Internet Cable Service Provider Next, the Cable Service Provider defines connectivity between the Internet and the subscribers. CMTS The Cable Service Provider utilizes the Cable Modem Termination System (CMTS) to assign port connectivity to each subscriber. {Click, or Press any key to continue} Subscribers Simulation 1: Process for Provisioning a Cable Modem
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Copyright ©Universalinet.Com, LLC 2009 Internet Cable Service Provider CMTS (Headend) {Click, or Press any key to continue} Subscribers The Cable Modem then connects to the CMTS to provide the subscriber with individual connectivity to the Service Provider via the CMTS. Subscription services may therefore differ among subscribers. Cable Modem Simulation 1: Process for Provisioning a Cable Modem
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Copyright ©Universalinet.Com, LLC 2009 {Click, or Press any key to continue} Step 1: The cable modem must obtain a Data Over Cable Service Interface Specifications (DOCSIS) configuration file, using the CMTS Trivial File Transfer Protocol (TFTP) server. Cable Modem Network Access: ENABLED Class of Service: Class ID: 1 Max DS Rate: 512000 bps Max US Rate: 512000 bp US Channel Priority: 7 (highest) Guaranteed min US rate: 0 (no guaranteed rate) Max US Transmit Burst: 1600 bits Baseline Privacy: DISABLED Concatenation: DISABLED Shared Secret: (is dependent upon CMTS configuration) DOCSIS Configuration File Simulation 1: Process for Provisioning a Cable Modem
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Copyright ©Universalinet.Com, LLC 2009 {Click, or Press any key to continue} In this DOCSIS configuration file, "Network Access: ENABLED" and "Class of Service" are absolutely required to enable the cable modem to send and receive Internet traffic. Cable Modem Network Access: ENABLED Class of Service: Class ID: 1 Max DS Rate: 512000 bps Max US Rate: 512000 bp US Channel Priority: 7 (highest) Guaranteed min US rate: 0 (no guaranteed rate) Max US Transmit Burst: 1600 bits Baseline Privacy: DISABLED Concatenation: DISABLED Shared Secret: (is dependent upon CMTS configuration) DOCSIS Configuration File Simulation 1: Process for Provisioning a Cable Modem
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Copyright ©Universalinet.Com, LLC 2009 {Click, or Press any key to continue} CMTS DHCP Server Step 2: Next, the cable modem obtains its IP network address through the CMTS DHCP server. Cable Modem Cable Service Provider CMTS TFTP Server Simulation 1: Process for Provisioning a Cable Modem
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Copyright ©Universalinet.Com, LLC 2009 Simulation 1: Process for Provisioning a Cable Modem {Click, or Press any key to continue} Step 3: The cable modem operates at Layer 1 (physical) and Layer 2 (media access control [MAC]/logical link control) of the Open System Interconnect (OSI) Reference Model. Therefore, Layer 3 (network) protocols (e.g. IP traffic) can be transmitted over the cable modem to the subscriber. A cable modem has at least two MAC addresses, one for the coax interface (or, HFC MAC) and one for the Ethernet interface (or, CMCI MAC for cable modem to CPE MAC). Cable Modem * Applications * Processes * Memory TCP/IP Stack DOCSIS MAC Address Engine Ethernet MAC/LLC DOCSIS Physical Subscriber Personal Computer (PC) Headend DOCSIS Network CPE Network Layer 1Layer 2 Layer 3
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Copyright ©Universalinet.Com, LLC 2009 Simulation 1: Process for Provisioning a Cable Modem {Click, or Press any key to continue} Step 4: The cable modem next obtains upstream parameters. The CMTS continuously broadcasts three separate messages on every downstream channel that relates to the MAC layer. The messages are: [1] the synchronization message (SYNC), [2] the upstream channel descriptor (UCD), and [3] the bandwidth allocation map (MAP). The cable modem must continuously identify and decode these messages in order to properly transmit data onto the cable upstream path. Cable Modem Subscriber Personal Computer (PC) Upstream Downstream CMTS
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Copyright ©Universalinet.Com, LLC 2009 Simulation 1: Process for Provisioning a Cable Modem {Click, or Press any key to continue} Step 5: The cable modem registers and ensures Quality of Service (QoS) settings with the CMTS. Cisco routers can also use command statements to enforce various QoS profiles on the cable modem. Command statements such as: Router(config)# show cable qos profile and Router(config)# cable qos permission enforce index assign and provision classes of service to the cable modems using QoS profiles. Cable Modem Subscriber Personal Computer (PC) Upstream Downstream CMTS QoS Profiles
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Copyright ©Universalinet.Com, LLC 2009 Simulation 1: Process for Provisioning a Cable Modem {Click, or Press any key to continue} Step 6: The cable modem next must scan and lock on the downstream frequency. The Cisco cable downstream frequency command statement sets the downstream frequency which is recognized by the cable modem, during the initialization process. An example configuration snippet is shown. Cable Modem Subscriber Personal Computer (PC) CMTS !-- for a non-lab environment 64 QAM is suggested cable downstream interleave-depth 32 cable downstream frequency 525000000
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Copyright ©Universalinet.Com, LLC 2009 {Click, or Press any key to continue} CMTS DHCP Server Step 7: The last step is for the cable modem to obtains its IP network address through the CMTS DHCP server. Cable Modem Cable Service Provider CMTS TFTP Server Simulation 1: Process for Provisioning a Cable Modem
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Copyright ©Universalinet.Com, LLC 2009 {Click, or Press any key to continue} Simulation 1: Process for Provisioning a Cable Modem Therefore, the seven (7) steps to provision a cable modem to connect to a headend, as defined by the DOCSIS standard are: 1.Acquire DOCSIS configuration file from TFTP 2.Perform IP network initialization 3.Establish OSI Layer 1 and Layer 2 communications 4.Obtain upstream parameters 5.Register and ensure QoS settings with the CMTS 6.Scan and lock the downstream frequency 7.Acquire IP configuration parameters via DHCP
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Copyright ©Universalinet.Com, LLC 2009 End of Simulation 1
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