I am a network engineer at an ISP. I thought at the very least if I knew nothing else, I understood the concept of autonegotiation and up/up and up/down.
Then I got this job. And it was a paradigm shift, probably because up until this point I didn't have much experience with fiber connections (I figure meh, same concept as copper cables, just a different medium!)
So I'll cut to the chase. How in the flying f*** can you have a fiber connection from one switch to another, in which one switch shows up/up on the port and the other shows up/down, which is caused by an autonegotiation mismatch?
Do I simply not understand autoneg? Autonegotiate (as I understand it) means:
Switch A: "Hey I can do up to 1Gbps and Full, but I'm open to doing whatever you can"
Switch B: "I am open to negotiating too! I can only do 100Mbps but I can do Full"
Both switches: "Ok, it's agreed then that we'll do 100Mbps/Full" LINK UP!
Perhaps even more mindblowing to me is just the general premise that Switch A can be up/up but Switch B can be up/down. Again, I've only ever seen this behavior on a fiber link.
HOW!? Is there some mystical dark magic with fiber that I don't understand? Do not be afraid of insulting my intelligence. I have no shame. I am dying to know what the reason is behind this.
No comments:
Post a Comment