[ih] Internet-history Digest, Vol 57, Issue 4

[Karl Auerbach]

I was at the ACM Sigcomm event in Mexico City when Y. Dalal mentioned 
48-bit addresses.  I remember the murmur of surprise that swept over the 
audience.

	--karl--

On 8/22/24 12:10 PM, John Shoch via Internet-history wrote:
> John Levine wrote:
> 
> "It's quite impressive that forty years later Ethernet has the same
> logical formats as the Ethernet that ran on thick yellow coax, even
> though at the hardware level practically nothing is the same."
> 
> In retrospect, the most important and enduring aspect of the DIX Ethernet
> spec (now evolved through multiple generations of design over multiple
> decades) was the packet format.
> 
> At Xerox we learned a lot from the1st generation implementation and
> operation of the Experimental Ethernet (2.94 Mbps) and the Pup internet
> architecture -- a combination which had well-matched but small address
> fields.
> 
> James Carville advised Bill Clinton that, "It's the economy, stupid!"
> I often observe, "it's the addressing, dummy!"
> 
> While the first generation worked well, with thousands of machines and
> dozens of networks, it became clear it would not continue to scale.  It
> required a much broader view of addressing, which led to the audacious idea
> of 48-bit absolute addresses --- that's what allowed the 2nd generation DIX
> Etherent and XNS internet to scale together.
> 
> The person we should thank for that is Yogen Dalal:
> http://www.bitsavers.org/pdf/xerox/parc/techReports/OPD-T8101_48-Bit_Absolute_Internet_and_Ethernet_Host_Numbers.pdf
> https://dl.acm.org/doi/10.1145/800081.802680
> 
> John Shoch
> 
> PS:  If you read the paper, you will see that the 48-bit absolute addresses
> were intended for and implemented on both  the DIX Ethernet and as part of
> XNS internet architecture -- a well crafted "impedance match."  (Other
> people will have a much more informed view on the later, continuing
> migration from IPv4 to IPv6.....)
> 
>>
>> Message: 4
>> Date: 21 Aug 2024 18:06:47 -0400
>> From: "John Levine" <johnl at iecc.com>
>> To: internet-history at elists.isoc.org
>> Subject: Re: [ih] "This is the History of Ethernet."
>> Message-ID: <20240821220647.6AD3392357F0 at ary.lan>
>> Content-Type: text/plain; charset=utf-8
>>
>> It appears that Brian E Carpenter via Internet-history <
>> brian.e.carpenter at gmail.com> said:
>>> BTW, it's worth noting that the *current* IETF STD 37 for ARP (a.k.a. RFC
>> 826) says:
>>>
>>> "This protocol was originally designed for the DEC/Intel/Xerox
>>> 10Mbit Ethernet.  It has been generalized to allow it to be used
>>> for other types of networks.  Much of the discussion will be
>>> directed toward the 10Mbit Ethernet."
>>
>> It's quite impressive that forty years later Ethernet has the same
>> logical formats as the Ethernet that ran on thick yellow coax, even
>> though at the hardware level practically nothing is the same.
>>
>> The Ethernets in my house are all gigabit twisted pair, and if I upgrade
>> it'll likely be to 10G fiber.  But ARP still works.
>>
>> R's,
>> John
>>
>>