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The history of twisted-pair Ethernet [video]

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Re: The history of twisted-pair Ethernet [video]

#5

Post by Aloha »

I found the reddit thread referenced in the video and left comments -

On the original ethernet being a mistake -

"I have another perspective on this - the bus concept at its roots dates to 1974/75 - a machine that could function as a hub in 1975 or even in 1979 would have potentially been as large and costly as the mini-computers Ethernet was intended to interconnect. A switch at that time would have been extraordinary costly.

Bus was the right technology for the time (as in the right one to go to market), it was right because it was an easy low cost means to get the LAN concept into more peoples hands so they could see the utility of it.

What I did find surprising was Metcalfe's resistance to UTP based standards with a hub in the middle once the technology did catch up - my gut from here 40 years on - makes me think that he was concerned about protecting his investments in 10base5 and 10base2, and making sure his installed base didnt feel like they had an obsolete product - as well as protecting 3Com's position as a 'Market Leader' in the space.

As an aside, I remember working on 10Base2 networks well into the late 90's and early 2000's - it was widely used in certain situations - like computer labs - where the bus topology made installation significantly easier than home runs would have been."

On 8P8C being picked as the connector -

"Also as someone who has spent a portion of my career doing cabling, thank you for picking the 8P8C modular system, its significantly better - both in cost and ease of assembly than anything I'm aware of existing at that time.

While there are some electrical issues with the 8P8C, the connector has been flexible enough that with minor design changes to keep up as line speeds have increased.

As a note, there are several vendors that make push-thru modular connectors (as in the wire extends beyond the front of the connector shell and the crimper trims it, much like how the cut blade on a punch tool works), which completely eliminate the need to accurately trim and face the wire ends - a huge time/frustration savings."

Re: The history of twisted-pair Ethernet [video]

#6

Post by 486sx33 »

Aloha wrote: post #5

I found the reddit thread referenced in the video and left comments - On the original ethernet being a mistake - "I have another perspective on this - the bus concept at its roots dates to 1974/75 - a machine that could function as a hub in 1975 or even in 1979 would have potentially been as large and costly as the mini-computers Ethernet was intended to interconnect. A switch at that time would have been extraordina…

I worked on 10Base2 as well in the mid to late 90s and it was a pain. The terminators, the length restrictions, the repeaters… no hubs but it was hell, one section damaged the whole thing goes down. 10mbit limit to the entire combined throughput. Need more? Add another card to the server… want to talk from one loop to another? Watch server cpu

Re: The history of twisted-pair Ethernet [video]

#7

Post by Aloha »

486sx33 wrote: post #6
Aloha wrote: post #5

I found the reddit thread referenced in the video and left comments - On the original ethernet being a mistake - "I have another perspective on this - the bus concept at its roots dates to 1974/75 - a machine that could function as a hub in 1975 or even in 1979 would have potentially been as large and costly as the mini-computers Ethernet was intended to interconnect. A switch at that time would have been extraordina…

I worked on 10Base2 as well in the mid to late 90s and it was a pain. The terminators, the length restrictions, the repeaters… no hubs but it was hell, one section damaged the whole thing goes down. 10mbit limit to the entire combined throughput. Need more? Add another card to the server… want to talk from one loop to another? Watch server cpu

It did work really well for a ton of computers in the same room in a line however.

Re: The history of twisted-pair Ethernet [video]

#8

Post by timewizard »

Aloha wrote: post #5

I found the reddit thread referenced in the video and left comments - On the original ethernet being a mistake - "I have another perspective on this - the bus concept at its roots dates to 1974/75 - a machine that could function as a hub in 1975 or even in 1979 would have potentially been as large and costly as the mini-computers Ethernet was intended to interconnect. A switch at that time would have been extraordina…

> push-thru modular connectors

Yep. Very fond of the "EZ RJ 45" line in particular. The strain relief that's built into them does not interfere with loading the cable and actually gets a good bite into the jacket once crimped.

The other advantage I've found is that it's harder to accidentally make defective cable ends. Trying to trim and face yourself you run the risk of one of the lines being too short or pulled back during the crimp and not mating well with the lug. The EZ RJ 45 effectively eliminates this as there is always wire under the lug during the crimp.

Re: The history of twisted-pair Ethernet [video]

#9

Post by Kelvin506 »

486sx33 wrote: post #6
Aloha wrote: post #5

I found the reddit thread referenced in the video and left comments - On the original ethernet being a mistake - "I have another perspective on this - the bus concept at its roots dates to 1974/75 - a machine that could function as a hub in 1975 or even in 1979 would have potentially been as large and costly as the mini-computers Ethernet was intended to interconnect. A switch at that time would have been extraordina…

I worked on 10Base2 as well in the mid to late 90s and it was a pain. The terminators, the length restrictions, the repeaters… no hubs but it was hell, one section damaged the whole thing goes down. 10mbit limit to the entire combined throughput. Need more? Add another card to the server… want to talk from one loop to another? Watch server cpu

I made a good living in the 90s going to orgs with "network problems" and fixing things. One of the most common problems was a coax ethernet network that had outgrown itself.

The fix was installing a 10bT/100bTX switch, installing 100bTX NICs in the servers, and breaking up their 10b2/10b5 networks into smaller segments each with media converter connecting it to the switch. An unmanaged 16/24-port 10/100 switch was "only" a couple hundred bucks back then.

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