学员提问：
老是跳出这个错误信息，是什么问题？
*Mar 1 00:06:42.407: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthern
et0, changed state to down
*Mar 1 00:07:15.575: %PQUICC_ETHER-1-LOSTCARR: Unit 0, lost carrier. Transceive
r problem?
*Mar 1 00:08:15.575: %PQUICC_ETHER-1-LOSTCARR: Unit 0, lost carrier. Transceive
r problem?
*Mar 1 00:09:15.575: %PQUICC_ETHER-1-LOSTCARR: Unit 0, lost carrier. Transceive
r problem?
*Mar 1 00:10:15.575: %PQUICC_ETHER-1-LOSTCARR: Unit 0, lost carrier. Transceive
r problem?
*Mar 1 00:11:15.575: %PQUICC_ETHER-1-LOSTCARR: Unit 0, lost carrier. Transceive
r problem?
*Mar 1 00:12:15.575: %PQUICC_ETHER-1-LOSTCARR: Unit 0, lost carrier. Transceive
r problem?
*Mar 1 00:13:15.575: %PQUICC_ETHER-1-LOSTCARR: Unit 0, lost carrier. Transceive
r problem?
*Mar 1 00:14:15.575: %PQUICC_ETHER-1-LOSTCARR: Unit 0, lost carrier. Transceive
r problem?
*Mar 1 00:15:15.575: %PQUICC_ETHER-1-LOSTCARR: Unit 0, lost carrier. Transceive
r problem?
捷盈讲师及学员解答：
路由器报告以太网接口没有和线路连通。