From jeanjour at comcast.net Mon Sep 7 10:38:42 2026 From: jeanjour at comcast.net (John Day) Date: Mon, 7 Sep 2026 13:38:42 -0400 Subject: [ih] History question In-Reply-To: <9be0ef8f-af48-4b83-8e3f-ebfb5cfcf5be@gmail.com> References: <20260725223938.GJ21299@miplet.aaaaa.org> <5DE37783-403E-4000-97BA-8A054BA816DE@isoc.org> <20260729172316.5C551117AF9C0@ary.qy> <3c196157-2320-4b62-aea4-e3c7aa993800@3kitty.org> <88e6fc4b-6ac2-44a3-9626-e076d3a26c15@3kitty.org> <90B7EF0E-BE0A-48F3-B292-6387F03F895C@crankycanuck.ca> <29e3509b-b1e3-4e2b-8805-243222c0f8ec@dcrocker.net> <20260801204426.1DCA01183D4CF@ary.qy> <8a64e2cc-c6db-4a65-8a42-d6ceb75c7d70@channelisles.net> <9be0ef8f-af48-4b83-8e3f-ebfb5cfcf5be@gmail.com> Message-ID: When and who brought the multihoming question to general discussion? When was it first recognized as an issue, even if there was no real discussion about a solution? Take care, John Day From woody at pch.net Mon Sep 7 11:04:27 2026 From: woody at pch.net (Bill Woodcock) Date: Mon, 7 Sep 2026 20:04:27 +0200 Subject: [ih] History question In-Reply-To: References: <20260725223938.GJ21299@miplet.aaaaa.org> <5DE37783-403E-4000-97BA-8A054BA816DE@isoc.org> <20260729172316.5C551117AF9C0@ary.qy> <3c196157-2320-4b62-aea4-e3c7aa993800@3kitty.org> <88e6fc4b-6ac2-44a3-9626-e076d3a26c15@3kitty.org> <90B7EF0E-BE0A-48F3-B292-6387F03F895C@crankycanuck.ca> <29e3509b-b1e3-4e2b-8805-243222c0f8ec@dcrocker.net> <20260801204426.1DCA01183D4CF@ary.qy> <8a64e2cc-c6db-4a65-8a42-d6ceb75c7d70@channelisles.net> <9be0ef8f-af48-4b83-8e3f-ebfb5cfcf5be@gmail.com> Message-ID: <2ad11dd9-f274-41ca-8f1f-0e84ec3044d3@pch.net> On 9/7/26 12:38, John Day via Internet-history wrote: > When and who brought the multihoming question to general discussion? > > When was it first recognized as an issue, even if there was no real discussion about a solution? Assuming you mean the multihoming of using multiple "upward" direction networks to ensure continuous availability of transit, that was already established practice when I built my first one in 1989. So it predated the modern NII / IXP architecture and the transit / peering distinction. So at that time there was no clear direction "up" but more just generally "backboneward" since the backbone didn't have a specific center, and multihoming didn't necessarily mean toward that center because transit cones hadn't yet been defined. BGP was standardized in 1989. EGP as a subset of GGP in 1982. https://www.rfc-editor.org/rfc/rfc823.txt https://www.rfc.fr/rfc/en/rfc0827.pdf https://www.rfc-editor.org/info/rfc1105/ -Bill -------------- next part -------------- A non-text attachment was scrubbed... Name: OpenPGP_signature.asc Type: application/pgp-signature Size: 840 bytes Desc: OpenPGP digital signature URL: From craig at tereschau.net Mon Sep 7 11:26:17 2026 From: craig at tereschau.net (Craig Partridge) Date: Mon, 7 Sep 2026 12:26:17 -0600 Subject: [ih] History question In-Reply-To: References: <20260725223938.GJ21299@miplet.aaaaa.org> <5DE37783-403E-4000-97BA-8A054BA816DE@isoc.org> <20260729172316.5C551117AF9C0@ary.qy> <3c196157-2320-4b62-aea4-e3c7aa993800@3kitty.org> <88e6fc4b-6ac2-44a3-9626-e076d3a26c15@3kitty.org> <90B7EF0E-BE0A-48F3-B292-6387F03F895C@crankycanuck.ca> <29e3509b-b1e3-4e2b-8805-243222c0f8ec@dcrocker.net> <20260801204426.1DCA01183D4CF@ary.qy> <8a64e2cc-c6db-4a65-8a42-d6ceb75c7d70@channelisles.net> <9be0ef8f-af48-4b83-8e3f-ebfb5cfcf5be@gmail.com> Message-ID: Are you talking about multihoming a host or a network (host connected to multiple networks, network connected to multiple providers). For hosts, the issue appeared c. 1982/3 when Berkeley connected UCBVAX to multiple Ethernets (I think for reliability reasons). Around the same time they also put IP router capability in the BSD networking code. Berkeley thought deeply about the issues but, for reasons unclear, didn't surface their insights in the community until the late 1980s. I remember Mike Karels at an IETF Host Requirements meeting, going through a late draft of the requirements document. At various points he said "you don't want to say that as it breaks multihoming" and then had to explain to the room what the issue was, because most of us were clueless. For networks, the advent of NSFNET in 1987. Suddenly you could be connected to both ARPANET and NSFNET. Also, because NSFNET was flakey, people leased direct lines to peer institutions. EGP promptly displayed all its limitations -- there's a SIGCOMM '87 paper where Dave Mills and Hans-Werner Braun presented interim solutions. Craig On Mon, Sep 7, 2026 at 11:38?AM John Day via Internet-history < internet-history at elists.isoc.org> wrote: > When and who brought the multihoming question to general discussion? > > When was it first recognized as an issue, even if there was no real > discussion about a solution? > > Take care, > John Day > -- > Internet-history mailing list > Internet-history at elists.isoc.org > https://elists.isoc.org/mailman/listinfo/internet-history > - > Unsubscribe: > https://app.smartsheet.com/b/form/9b6ef0621638436ab0a9b23cb0668b0b?The%20list%20to%20be%20unsubscribed%20from=Internet-history > -- ***** Craig Partridge's email account for professional society activities and mailing lists. From dhc at dcrocker.net Mon Sep 7 11:35:01 2026 From: dhc at dcrocker.net (Dave Crocker) Date: Mon, 7 Sep 2026 18:35:01 +0000 (UTC) Subject: [ih] History question In-Reply-To: References: <20260725223938.GJ21299@miplet.aaaaa.org> <5DE37783-403E-4000-97BA-8A054BA816DE@isoc.org> <20260729172316.5C551117AF9C0@ary.qy> <3c196157-2320-4b62-aea4-e3c7aa993800@3kitty.org> <88e6fc4b-6ac2-44a3-9626-e076d3a26c15@3kitty.org> <90B7EF0E-BE0A-48F3-B292-6387F03F895C@crankycanuck.ca> <29e3509b-b1e3-4e2b-8805-243222c0f8ec@dcrocker.net> <20260801204426.1DCA01183D4CF@ary.qy> <8a64e2cc-c6db-4a65-8a42-d6ceb75c7d70@channelisles.net> <9be0ef8f-af48-4b83-8e3f-ebfb5cfcf5be@gmail.com> Message-ID: <44150783-615c-4d0e-9d41-95ec51b6eb43@dcrocker.net> On 9/7/2026 11:26 AM, Craig Partridge via Internet-history wrote: > For networks, the advent of NSFNET in 1987. Suddenly you could be > connected to both ARPANET and NSFNET. I had heard -- though I have no details -- that there was ad hoc multi-homing of networks prior to that, though NSFNet certainly forced formalization of the capability. d/ -- Dave Crocker dhc at dcrocker.net bluesky: @dcrocker.bsky.social mast: @dcrocker at mastodon.social +1.408.329.0791 Volunteer, Silicon Valley Chapter Northern California Coastal Region Information & Planning Coordinator American Red Cross dave.crocker2 at redcross.org From dhc at dcrocker.net Mon Sep 7 11:37:09 2026 From: dhc at dcrocker.net (Dave Crocker) Date: Mon, 7 Sep 2026 18:37:09 +0000 (UTC) Subject: [ih] History question In-Reply-To: References: <20260725223938.GJ21299@miplet.aaaaa.org> <5DE37783-403E-4000-97BA-8A054BA816DE@isoc.org> <20260729172316.5C551117AF9C0@ary.qy> <3c196157-2320-4b62-aea4-e3c7aa993800@3kitty.org> <88e6fc4b-6ac2-44a3-9626-e076d3a26c15@3kitty.org> <90B7EF0E-BE0A-48F3-B292-6387F03F895C@crankycanuck.ca> <29e3509b-b1e3-4e2b-8805-243222c0f8ec@dcrocker.net> <20260801204426.1DCA01183D4CF@ary.qy> <8a64e2cc-c6db-4a65-8a42-d6ceb75c7d70@channelisles.net> <9be0ef8f-af48-4b83-8e3f-ebfb5cfcf5be@gmail.com> Message-ID: <8faea6d5-4fe4-4aea-b82b-9e5840f9ba4e@dcrocker.net> On 9/7/2026 10:38 AM, John Day via Internet-history wrote: > When and who brought the multihoming question to general discussion? fwiw, email mult-homing was demonstrated in some X.400 business cards, which documented an enterprise email address accessible by a list of independent providers. d/ -- Dave Crocker dhc at dcrocker.net bluesky: @dcrocker.bsky.social mast: @dcrocker at mastodon.social +1.408.329.0791 Volunteer, Silicon Valley Chapter Northern California Coastal Region Information & Planning Coordinator American Red Cross dave.crocker2 at redcross.org From jeanjour at comcast.net Mon Sep 7 11:50:36 2026 From: jeanjour at comcast.net (John Day) Date: Mon, 7 Sep 2026 14:50:36 -0400 Subject: [ih] History question In-Reply-To: References: <20260725223938.GJ21299@miplet.aaaaa.org> <5DE37783-403E-4000-97BA-8A054BA816DE@isoc.org> <20260729172316.5C551117AF9C0@ary.qy> <3c196157-2320-4b62-aea4-e3c7aa993800@3kitty.org> <88e6fc4b-6ac2-44a3-9626-e076d3a26c15@3kitty.org> <90B7EF0E-BE0A-48F3-B292-6387F03F895C@crankycanuck.ca> <29e3509b-b1e3-4e2b-8805-243222c0f8ec@dcrocker.net> <20260801204426.1DCA01183D4CF@ary.qy> <8a64e2cc-c6db-4a65-8a42-d6ceb75c7d70@channelisles.net> <9be0ef8f-af48-4b83-8e3f-ebfb5cfcf5be@gmail.com> Message-ID: <043A37D8-A289-4C14-8A59-AFB11BE2D842@comcast.net> Multihoming a host. > On Sep 7, 2026, at 14:26, Craig Partridge wrote: > > Are you talking about multihoming a host or a network (host connected to multiple networks, network connected to multiple providers). > > For hosts, the issue appeared c. 1982/3 when Berkeley connected UCBVAX to multiple Ethernets (I think for reliability reasons). Around the same time they also put IP router capability in the BSD networking code. Berkeley thought deeply about the issues but, for reasons unclear, didn't surface their insights in the community until the late 1980s. I remember Mike Karels at an IETF Host Requirements meeting, going through a late draft of the requirements document. At various points he said "you don't want to say that as it breaks multihoming" and then had to explain to the room what the issue was, because most of us were clueless. > > For networks, the advent of NSFNET in 1987. Suddenly you could be connected to both ARPANET and NSFNET. Also, because NSFNET was flakey, people leased direct lines to peer institutions. EGP promptly displayed all its limitations -- there's a SIGCOMM '87 paper where Dave Mills and Hans-Werner Braun presented interim solutions. > > Craig > > On Mon, Sep 7, 2026 at 11:38?AM John Day via Internet-history > wrote: >> When and who brought the multihoming question to general discussion? >> >> When was it first recognized as an issue, even if there was no real discussion about a solution? >> >> Take care, >> John Day >> -- >> Internet-history mailing list >> Internet-history at elists.isoc.org >> https://elists.isoc.org/mailman/listinfo/internet-history >> - >> Unsubscribe: https://app.smartsheet.com/b/form/9b6ef0621638436ab0a9b23cb0668b0b?The%20list%20to%20be%20unsubscribed%20from=Internet-history > > > > -- > ***** > Craig Partridge's email account for professional society activities and mailing lists. From byeager at fastmail.fm Mon Sep 7 14:01:28 2026 From: byeager at fastmail.fm (william yeager) Date: Mon, 7 Sep 2026 14:01:28 -0700 Subject: [ih] History question In-Reply-To: <043A37D8-A289-4C14-8A59-AFB11BE2D842@comcast.net> References: <20260725223938.GJ21299@miplet.aaaaa.org> <5DE37783-403E-4000-97BA-8A054BA816DE@isoc.org> <20260729172316.5C551117AF9C0@ary.qy> <3c196157-2320-4b62-aea4-e3c7aa993800@3kitty.org> <88e6fc4b-6ac2-44a3-9626-e076d3a26c15@3kitty.org> <90B7EF0E-BE0A-48F3-B292-6387F03F895C@crankycanuck.ca> <29e3509b-b1e3-4e2b-8805-243222c0f8ec@dcrocker.net> <20260801204426.1DCA01183D4CF@ary.qy> <8a64e2cc-c6db-4a65-8a42-d6ceb75c7d70@channelisles.net> <9be0ef8f-af48-4b83-8e3f-ebfb5cfcf5be@gmail.com> <043A37D8-A289-4C14-8A59-AFB11BE2D842@comcast.net> Message-ID: In 1982/83 at Stanford we had a VAX750 with both 10mbps and 3mbps ethernet interfaces. I think it ran BSD 4.1 Unix. The latter was built and distributed by the Computer Science department. > On Sep 7, 2026, at 11:50 AM, John Day via Internet-history wrote: > > Multihoming a host. > >> On Sep 7, 2026, at 14:26, Craig Partridge wrote: >> >> Are you talking about multihoming a host or a network (host connected to multiple networks, network connected to multiple providers). >> >> For hosts, the issue appeared c. 1982/3 when Berkeley connected UCBVAX to multiple Ethernets (I think for reliability reasons). Around the same time they also put IP router capability in the BSD networking code. Berkeley thought deeply about the issues but, for reasons unclear, didn't surface their insights in the community until the late 1980s. I remember Mike Karels at an IETF Host Requirements meeting, going through a late draft of the requirements document. At various points he said "you don't want to say that as it breaks multihoming" and then had to explain to the room what the issue was, because most of us were clueless. >> >> For networks, the advent of NSFNET in 1987. Suddenly you could be connected to both ARPANET and NSFNET. Also, because NSFNET was flakey, people leased direct lines to peer institutions. EGP promptly displayed all its limitations -- there's a SIGCOMM '87 paper where Dave Mills and Hans-Werner Braun presented interim solutions. >> >> Craig >> >> On Mon, Sep 7, 2026 at 11:38?AM John Day via Internet-history > wrote: >>> When and who brought the multihoming question to general discussion? >>> >>> When was it first recognized as an issue, even if there was no real discussion about a solution? >>> >>> Take care, >>> John Day >>> -- >>> Internet-history mailing list >>> Internet-history at elists.isoc.org >>> https://elists.isoc.org/mailman/listinfo/internet-history >>> - >>> Unsubscribe: https://app.smartsheet.com/b/form/9b6ef0621638436ab0a9b23cb0668b0b?The%20list%20to%20be%20unsubscribed%20from=Internet-history >> >> >> >> -- >> ***** >> Craig Partridge's email account for professional society activities and mailing lists. > > -- > Internet-history mailing list > Internet-history at elists.isoc.org > https://elists.isoc.org/mailman/listinfo/internet-history > - > Unsubscribe: https://app.smartsheet.com/b/form/9b6ef0621638436ab0a9b23cb0668b0b?The%20list%20to%20be%20unsubscribed%20from=Internet-history ?????????? ????? ???? ????????? From brian.e.carpenter at gmail.com Mon Sep 7 14:03:06 2026 From: brian.e.carpenter at gmail.com (Brian E Carpenter) Date: Tue, 8 Sep 2026 09:03:06 +1200 Subject: [ih] History question In-Reply-To: References: <20260725223938.GJ21299@miplet.aaaaa.org> <5DE37783-403E-4000-97BA-8A054BA816DE@isoc.org> <20260729172316.5C551117AF9C0@ary.qy> <3c196157-2320-4b62-aea4-e3c7aa993800@3kitty.org> <88e6fc4b-6ac2-44a3-9626-e076d3a26c15@3kitty.org> <90B7EF0E-BE0A-48F3-B292-6387F03F895C@crankycanuck.ca> <29e3509b-b1e3-4e2b-8805-243222c0f8ec@dcrocker.net> <20260801204426.1DCA01183D4CF@ary.qy> <8a64e2cc-c6db-4a65-8a42-d6ceb75c7d70@channelisles.net> <9be0ef8f-af48-4b83-8e3f-ebfb5cfcf5be@gmail.com> Message-ID: <059e8ba4-b7e5-4290-9898-7881f8e20fd1@gmail.com> RFC 791, page 7 (September 1981): "Care must be taken in mapping internet addresses to local net addresses; a single physical host must be able to act as if it were several distinct hosts to the extent of using several distinct internet addresses. Some hosts will also have several physical interfaces (multi-homing)." That text was also in RFC 760, a.k.a. IEN 128, and in IEN 111 (August 1979). It was completely absent in IEN 28 (February 1978). So I guess the answer to John is "between February 1978 and August 1979." Regards/Ng? mihi Brian Carpenter On 08-Sep-26 05:38, John Day via Internet-history wrote: > When and who brought the multihoming question to general discussion? > > When was it first recognized as an issue, even if there was no real discussion about a solution? > > Take care, > John Day From jeanjour at comcast.net Mon Sep 7 15:03:11 2026 From: jeanjour at comcast.net (John Day) Date: Mon, 7 Sep 2026 18:03:11 -0400 Subject: [ih] History question In-Reply-To: <059e8ba4-b7e5-4290-9898-7881f8e20fd1@gmail.com> References: <20260725223938.GJ21299@miplet.aaaaa.org> <5DE37783-403E-4000-97BA-8A054BA816DE@isoc.org> <20260729172316.5C551117AF9C0@ary.qy> <3c196157-2320-4b62-aea4-e3c7aa993800@3kitty.org> <88e6fc4b-6ac2-44a3-9626-e076d3a26c15@3kitty.org> <90B7EF0E-BE0A-48F3-B292-6387F03F895C@crankycanuck.ca> <29e3509b-b1e3-4e2b-8805-243222c0f8ec@dcrocker.net> <20260801204426.1DCA01183D4CF@ary.qy> <8a64e2cc-c6db-4a65-8a42-d6ceb75c7d70@channelisles.net> <9be0ef8f-af48-4b83-8e3f-ebfb5cfcf5be@gmail.com> <059e8ba4-b7e5-4290-9898-7881f8e20fd1@gmail.com> Message-ID: Was there any discussion multihoming as a general problem before 81-82? > On Sep 7, 2026, at 17:03, Brian E Carpenter via Internet-history wrote: > > RFC 791, page 7 (September 1981): > > "Care must be taken in mapping internet addresses to local net > addresses; a single physical host must be able to act as if it were > several distinct hosts to the extent of using several distinct > internet addresses. Some hosts will also have several physical > interfaces (multi-homing)." > > That text was also in RFC 760, a.k.a. IEN 128, and in IEN 111 (August 1979). It was completely absent in IEN 28 (February 1978). So I guess the answer to John is "between February 1978 and August 1979." > > Regards/Ng? mihi > Brian Carpenter > > On 08-Sep-26 05:38, John Day via Internet-history wrote: >> When and who brought the multihoming question to general discussion? >> When was it first recognized as an issue, even if there was no real discussion about a solution? >> Take care, >> John Day > -- > Internet-history mailing list > Internet-history at elists.isoc.org > https://elists.isoc.org/mailman/listinfo/internet-history > - > Unsubscribe: https://app.smartsheet.com/b/form/9b6ef0621638436ab0a9b23cb0668b0b?The%20list%20to%20be%20unsubscribed%20from=Internet-history