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Study Question 4
- Thread starter SnowNinja
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To have some idea what this is all about. I found some info on the website of cisco:
Duplex Mismatch: If the switch port receives a lot of late collisions, this usually indicates a duplex mismatch problem. There are other causes for late collisions: a bad NIC, cable segments that are too long, but the most common reason today is a duplex mismatch. The full duplex side thinks it can send whenever it wants to. The half duplex side is only expecting packets at certain times - not at "any" time.
Duplex Mismatch: If the switch port receives a lot of late collisions, this usually indicates a duplex mismatch problem. There are other causes for late collisions: a bad NIC, cable segments that are too long, but the most common reason today is a duplex mismatch. The full duplex side thinks it can send whenever it wants to. The half duplex side is only expecting packets at certain times - not at "any" time.
I do find this an interesting item. So I search on the cisco documentation and found this:
source:
Late Collisions
To allow collision detection to work properly, the period in which collisions are detected is restricted (512 bit-times). For Ethernet, this is 51.2us (microseconds), and for Fast Ethernet, 5.12us. For Ethernet stations, collisions can be detected up to 51.2 microseconds after transmission begins, or in other words up to the 512th bit of the frame.
When a collision is detected by a station after it has sent the 512th bit of its frame, it is counted as a late collision.
If I understand it correct than I would say that a local collision is a collision in it's own segment (collision domain) and a late collision is a specific kind of collision. It's a collision detected after the 512th bit of its frame.
source:
Late Collisions
To allow collision detection to work properly, the period in which collisions are detected is restricted (512 bit-times). For Ethernet, this is 51.2us (microseconds), and for Fast Ethernet, 5.12us. For Ethernet stations, collisions can be detected up to 51.2 microseconds after transmission begins, or in other words up to the 512th bit of the frame.
When a collision is detected by a station after it has sent the 512th bit of its frame, it is counted as a late collision.
If I understand it correct than I would say that a local collision is a collision in it's own segment (collision domain) and a late collision is a specific kind of collision. It's a collision detected after the 512th bit of its frame.
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