Refer to the exhibit.
A network administrator is troubleshooting a connectivity problem on the serial interfaces. The
output from the show interfaces command on both routers shows that the serial interface is up,
line protocol is down. Given the partial output for the show running-config in the exhibit, what is the
most likely cause of this problem?
A.
The serial cable is bad.
B.
The MTU is incorrectly configured.
C.
The Layer 2 framing is misconfigured.
D.
The IP addresses are not in the same subnet.
From the output we see the Serial0/0 of RouterA is in “status up/protocol down” state which indicates a Layer 2 problem so the problem can be:
+ Keepalives mismatch
+ Encapsulation mismatch
+ Clocking problem
A frame is a digital data transmission unit in computer networking and telecommunication. A frame typically includes frame synchronization features consisting of a sequence of bits or symbols that indicate to the receiver the beginning and end of the payload data within the stream of symbols or bits it receives. If a receiver is connected to the system in the middle of a frame transmission, it ignores the data until it detects a new frame synchronization sequence.
In the OSI model of computer networking, a frame is the protocol data unit at the data link layer. Frames are the result of the final layer of encapsulation before the data is transmitted over the physical layer.[1] A frame is “the unit of transmission in a link layer protocol, and consists of a link layer header followed by a packet.”
Each frame is separated from the next by an interframe gap. A frame is a series of bits generally composed of framing bits, the packet payload, and a frame check sequence. Examples are Ethernet frames, Point-to-Point Protocol (PPP) frames, Fibre Channel frames, and V.42 modem frames.
In telecommunications, specifically in time-division multiplex (TDM) and time-division multiple access (TDMA) variants, a frame is a cyclically repeated data block that consists of a fixed number of time slots, one for each logical TDM channel or TDMA transmitter. In this context, a frame is typically an entity at the physical layer. TDM application examples are SONET/SDH and the ISDN circuit switched B-channel, while TDMA examples are the 2G and 3G circuit-switched cellular voice services. The frame is also an entity for time-division duplex, where the mobile terminal may transmit during some timeslots and receive during others.
Often frames of several different sizes are nested inside each other. For example, when people use Point-to-Point Protocol over asynchronous serial communication, the 8 bits of each individual byte are framed by start and stop bits,[3][4] the payload data bytes in a network packet are framed by the header and footer, and several packets can be framed with frame boundary octets.
Protocol Status refers generally two the layer to status. It is always down if the Line status is down. if the Line status is up,a protocol status of down usually is caused by mismatched data link layer configuration