A TestKing.com technician is troubleshooting connectivity problems between two r
A TestKing.com technician is troubleshooting connectivity problems between two routers that are directly connected through the serial line. The technician notices that the serial line is up but cannot see any neighbors displayed in the output of the show cdp neighbors command.In which OSI layer is the problem most likely occurring?（）
A. Physical
B. Data link
C. Network layer
D. Transport layer
E. Application layer
正确答案：参考B
词条内容仅供参考，如果您需要解决具体问题
（尤其在法律、医学等领域），建议您咨询相关领域专业人士。