|
Fysiska Indikatorer
Error Typer
|
Short/Runt (R)
Flag
|
CRC(C)
Flag
|
Collision (X)
Flag
|
Frame Length
(Bytes)
|
Collision Data
(AA/55)
|
AA/55 Length
(Bytes)
|
Streaming Data
(FF/00)
|
FF/00 Length (Bytes)
|
Comments
|
|
Electrical Noise
|
No
|
Yes
|
No
|
>=64
|
No
|
------
|
No
|
------
|
Random data change. Caused by
EMI, RFI or mismatched cabling.
|
|
Collision! (Propogation Delay)
|
Yes
|
Yes
|
Yes/No
|
<64
|
Yes/No
|
<=8B
|
No
|
------
|
Normal due to network contention.
Sniffer analyzer needs to see at least 2 bytes of DA to display, else just
increment collision counter.
|
|
Late Collision!
|
No
|
Yes
|
Yes/No
|
>=64
|
Yes/No
|
<8B
|
No
|
------
|
Collision may not propogate back
to source while it's still transmitting. This causes slow response times
as responsibility for retransmission is passed up to the protocol stack.
|
|
Signal Reflection
|
Yes
|
Yes
|
Yes/No
|
<32B
|
Yes/No
|
<8B
|
No
|
------
|
Poor signal termination causes
data to travel back to source, damaging frame in progress. Frame from a
particular node is always damaged in the same place, dependent upon its
position on the network.
|
|
Hub Jam (Fragment Extension)
|
Yes
|
Yes
|
No
|
<16B
|
Yes
|
<16B
|
No
|
------
|
Normal.Repeater/hub extends collision
(<96bits) on one side of repeater to make other side busy during collision.
|
|
Mild Jabber
|
Yes/No
|
Yes
|
Yes/No
|
Any
|
Yes/No
|
>8B
|
Yes/No
|
>8B
|
.Collision data is slightly longer
than expected: monitor carefully.
|
|
Jabber!
(Hardware Failure)
|
No
|
Yes
|
Yes/No
|
>64
|
Yes/No
|
>>8B
|
Yes/No
|
>>8B
|
Collision data is excessive; NIC
or transceiver is falling
|
|
Giant
|
No
|
Yes
|
Yes/No
|
>1518
|
Yes/No
|
>>8B
|
Yes/No
|
>>8B
|
Node has failed and is streaming
data. Managed hubs may partition node; unmanaged hubs may not.
|