Chapter 7 - Configuring and Verifying Switch Interfaces Flashcards
What does the Description command allow you to do?
Write a text description about a particular interface (e.g. What its purpose is).
What does it mean when an interface speed has ‘a-‘ before it?
The speed auto negotiation process has already completed and the speed that was negotiated will follow.
What is the difference between down and administratively down?
Administratively down means that a user entered the ‘shutdown’ command on the interface. Down just means that there is something physically incorrect about the port (e.g. it has nothing plugged into it).
How does autonegotiation work where only one devices uses autonegotiation by the IEEEs standards?
If autonegotiation fails:
Speed - Use your slowest supported speed of that interface (on 10/100/1000 that would be 10mbps)
Duplex - If your speed is 10mbps or 100mbps use half duplex. Otherwise use full duplex.
How does Cisco augment the standard autonegotiation process?
If autonegotiation fails:
Speed - Attempt to sense the speed without autonegotation (e.g. it may be configured manually), if that fails then use IEEE standard of that interfaces slowest speed.
Duplex - Use IEEE standard. If your speed is 10mbps or 100mbps use half duplex. Otherwise use full duplex.
What is ‘line status’ and ‘protocol status’ on an interface?
Line status refers to Layer 1 status and protocol status refers to layer 2 status.
What is macro-bending?
When you bend a fibre cable too much to the point it can no longer transmit or receive data.
List all line status, protocol status, and interface status combinations.
Line status = administratively down Protocol status = down Interface status = disabled Potential root cause = Shutdown has been issued on
the interface
Line status = down Protocol status = down Interface status = notconnect Potential root cause = Layer 1 fault (e.g. faulty cable)
or the connected device is
shutdown/turned off.
Line status = up Protocol status = down Interface status = notconnect Potential root cause = Not expected on LAN switch
physical interfaces.
Line status = down Protocol status = down Interface status = err-disabled Potential root cause = Port security has disabled the
(err-disabled) interface.
Line status = up Protocol status = up Interface status = connected Potential root cause = The interface is working.
Error Types: CRC
Cyclic Redundancy Check Errors occur when a frame is discarded by FCS for having a transmission error and did not pass the FCS math. Can be caused by collisions.
Error Types: Runts
- Frames that did not meet the minimum frame size requirement (64 bytes).
- Can be caused by collisions.
Error Types: Giants
Frames that exceeded the maximum frame size requirement (1518 bytes).
Error Types: Input errors
A total of many counters (e.g. Giants, Runts, CRC, frame, no buffer, ignored counts, overrun).
Error Types: Frame
Received frames that have an illegal format (e.g. Ending with a partial byte) can be caused by collisions.
Error Types: Packets Output
Total number of packets (encapsulated in frames) forwarded out of an interface.
Error Types: Output Errors
Total number of packets (encapsulated in frames) that a switch port tried to transmit but for which a problem occurred.
