Customer Premises Equipment
Customer premises equipment (CPE) usually includes the router, the CSU/DSU, the cabling, and often an analog modem for OOB (out-of-band) access for monitoring and management. ISPs typically offer the customer a choice of buying the CPE and access line, buying just the access line, or just paying a monthly fee with all equipment and access needs taken care of by the ISP. As with most everything, any arrangement is available at the right price. ISPs usually are responsible for maintaining equipment or packages that they provide. ISPs usually have predefined packages that include the CPE and/or access. If the customer does not want to take the package, he would be required to choose equipment that has been preapproved by the ISP. The customer would then be responsible for troubleshooting and maintaining his own equipment. The provider is always available to solve problems, usually for an extra fee. Figures 2-9 through 2-11 illustrate some examples of ISP packages.
In the scenario illustrated in Figure 2-9, the ISP is responsible for the access line and the CSU/DSU all the way up to the CSU's serial connector at the customer location. Restrictions might be imposed on the customer premises router to meet some memory or software revision guidelines.
Figure 2-9. Example: ISP Provides Access and CSU/DSU;
Customer Provides Router
Figure 2-9. Example: ISP Provides Access and CSU/DSU;
Customer Provides Router
In the scenario illustrated in Figure 2-10, the ISP has provided everything, and its responsibility ends at the LAN port on the router at the customer's premises.
Figure 2-10. Example: ISP Provides Access, Router, and
CSU/DSU
Figure 2-10. Example: ISP Provides Access, Router, and
CSU/DSU
In the scenario illustrated in Figure 2-11, the customer provides the CPE and the access line. The provider's responsibility ends at the POP's wiring closet, where the ISP interconnects with the carrier's central office.
Continue reading here: Basic IP Addressing
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