Feature Overview
Table 3 | Cable Access Router Initialization Sequences and Events (continued) | |
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Sequence | Event | Description |
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4 | Establish IP connectivity. | After the next MAP message broadcast, the router uses a |
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| shared require timeslot to invoke Dynamic Host Configuration |
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| Protocol (DHCP) to establish IP connectivity with the TCP/IP |
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| network at the headend. |
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| The DHCP server sends a response containing the router’s IP |
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| address as well as the IP addresses for the default gateway, |
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| time of day (TOD) server, and Trivial File Transfer Protocol |
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| (TFTP) server, and the DOCSIS configuration file to be |
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| downloaded. Depending on the particular network |
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| configuration, other information could be provided, such as |
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| the IP addresses for a syslog server or security server. |
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| Note The DHCP server is typically a dedicated server at the |
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| headend, but it could also be a CMTS such as a Cisco uBR7200 |
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| series universal broadband router. |
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| The router configures itself for the specified IP address and |
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| gets the current date and time from the specified TOD server. |
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5 | Establish the time of day. | The cable access router accesses the TOD server for the |
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| current date and time, which is used to create time stamps for |
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| logged events (such as those displayed in the MAC log file). |
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6 | Establish security. | Full Security, a planned enhancement to Baseline Privacy, is |
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| not fully defined nor currently supported by the DOCSIS |
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| specification, and is therefore not supported by the |
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| Cisco uBR900 series. |
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7 | Transfer operational parameters. | Using TFTP, the router downloads the specified DOCSIS |
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| configuration file and configures itself for the appropriate |
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| parameters. The DOCSIS configuration file defines the |
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| router’s operating mode such as the provisioned downstream |
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| and upstream service assignments, including assigned |
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| frequencies, data rates, modulation schemes, Class of Service |
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| (CoS), type of services to support, and other parameters. Cisco |
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| provides tools to help automate the creation of configuration |
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| files. |
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| Note The DOCSIS configuration file must be in the exact |
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| format given by the DOCSIS specification. An incorrect |
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| DOCSIS configuration file can cause the Cisco uBR900 series |
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| to constantly cycle offline. Such errors include wrong |
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| downstream frequency, wrong UCD, wrong downstream |
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| Channel ID, invalid CoS, incorrect BPI privacy configurations |
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| or shared secret strings. |
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| The cable access router sends another registration request to |
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| the CMTS containing the CoS parameters given in the |
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| DOCSIS configuration file. |
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| The CMTS verifies that the router is using the appropriate CoS |
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| profile and converts the temporary SID into a data SID with a |
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| service class index that points to the applicable CoS profile. |
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8 | Perform registration. | The router completes its secondary ranging and is then online, |
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| passing data between the HFC network and the PCs and other |
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| CPE devices that are connected to the router. |
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