PDF user manual for CopperEdge 150

RRSEDFNVThe CE150 can be configured for a number of loopback testsuseful not only in isolating failures but also in evaluating lineperformance over various segments of the end-to-end circuit. Inthe current CE150 product release, loopbacks are available fortest and evaluation of the following: SDSL ports; DS3 ATM andFrame Relay ports; and DS1 ports.Three DSL loopbacks (between the CE150 main processor andthe subscriber CPE) are controlled through the cmLoop group.All of the loopback tests are packet-oriented, except the SCM-CPE BER loopback, which is a bit-error rate test. The cmLoopHistorygroup provides information on the ten most recenttests run through the cmLoop group. For information on configuringcmLoop and cmLoopHistory, see the CopperEdge 150CopperCraft Reference and MIB Definitions manual. The followingdiagram illustrates the DSL loopback tests supported onthe CE150.SCM-CPE BERLoopback*SCM-DSL ModulePortPacket LoopbackCopperEdgeDSLAMCPESCM-CR-EthernetPacket LoopbackDSLMod.TestApp.SystemControlModuleOrigin* BER is Bit Error Rate for SDSL,and Block Error Rate for IDSL.DSL Subscriber-Side Loopbacks(2&/RRSEDFNVThe EOC Loopback is used for troubleshooting IDSL links. Usinga small portion of the ISDN band called the Embedded OperationsChannel (EOC) is helpful in isolating IDSL lineproblems by allowing you to test the various segments betweenthe CE150 and the CPE that comprise an IDSL loop. Using theEOC, each network element (that is, each segment or hop) reportsits presence and is counted by the CE150. With the numberof elements (number of hops) between the CE150 and theCPE known, specific network elements can then be placed intoloopback mode by addressing the test command to the devicethat is one, two, three (or more) elements downstream from theCE150. The following diagram illustrates the concept. Note thatthe endpoint CPE is always referred to as Hop 0 or Element 0,regardless of how many intervening elements may be present.&KDSWHU7URXEOHVKRRWLQJ