Date: Tue, 20 Oct 2020 14:35:25 +0200 From: "Patrick M. Hausen" <hausen@punkt.de> To: D'Arcy Cain <darcy@druid.net> Cc: freebsd-virtualization@freebsd.org Subject: Re: When is a switch not a switch? Message-ID: <ADC8160C-CA22-4785-9DD3-E477EDF62BBC@punkt.de> In-Reply-To: <309e9df2-51e0-ff71-15ef-e42d0418f193@druid.net> References: <57c32e6d-5572-3d3b-1a57-f3064bee7dc2@druid.net> <20201020065630.GE8272@funkthat.com> <CF189122-7D85-4BF1-9172-75D3EE0E77FB@punkt.de> <3ed627e2-d99a-107e-4135-8aef1ad4ec71@druid.net> <30A67F82-312E-4651-A5E7-2E2AD926FF24@punkt.de> <973b1b56-817f-6976-e5d3-34cfbc373b13@druid.net> <A075C069-1F89-428C-BDB7-7A9F44A4E283@punkt.de> <309e9df2-51e0-ff71-15ef-e42d0418f193@druid.net>
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[-- Attachment #1 --] Hi! > Am 20.10.2020 um 14:10 schrieb D'Arcy Cain <darcy@druid.net>: > > On 10/20/20 7:39 AM, Patrick M. Hausen wrote: >>> When I started I thought of a switch as analogous to a physical switch. If I am in an office with one ethernet jack but I have multiple devices I might connect a switch (or hub) to the jack and plug my devices into the switch. I don't need to create a separate network for my office. All of my devices are on the company network. >> OK, the "switch" interface in FreeBSD is bridge(4). > > Understood. > >> Or to cite Radia Perlman: >> A bridge is a network device making forwarding decisions based on layer 2 addresses. >> A router is a network device making forwarding decisions based on layer 3 addresses. >> "Switch" is a marketing term meaning "faster or cheaper than the competition". > > I always thought that a switch was a hub with packet switching to avoid collisions. That is a bridge. A switch simply is a multiport bridge. And a layer 3 switch is a router. > Or else rename the bridges to "public" and "private". Yep, probably. >> ifconfig_inet0="addm igb0 up" > ifconfig_public="addm bge0 up" > ifconfig_private="addm bge1 up" > >> ifconfig_inet0_alias0="inet 1.2.3.4/24" > ifconfig_public_alias0="inet 1.2.3.4/24" > ifconfig_private_alias0="192.168.151.4/14" > > So why alias? Wouldn't "ifconfig_public=" work? We already have ifconfig_public="addm bge0 up" Adding ifconfig_public="inet 1.2.3.4/24" on another line would overwrite the first one. These are just variable assignments not executable code. You cannot have more than one ifconfig_public line. If you need more than one they have to be named ifconfig_public ifconfig_public_alias0 ifconfig_public_alias1 ... Execution stops at the first undefined one, so no gaps, either. > Not sure I need this as long as arp works as it should. Do I really care what the MAC is? Well, the ARP timeouts specifically of Cisco gear can be enervatingly long so hosts are not reachable after reboot for minutes ... these settings fix that. HTH, Patrick -- punkt.de GmbH Patrick M. Hausen .infrastructure Kaiserallee 13a 76133 Karlsruhe Tel. +49 721 9109500 https://infrastructure.punkt.de info@punkt.de AG Mannheim 108285 Geschäftsführer: Jürgen Egeling, Daniel Lienert, Fabian Stein [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEgzqrjO/mj9CSsTg2kG8u4u3aiVwFAl+O2Y0ACgkQkG8u4u3a iVxAawf6Avy0WuiR8v3nSAk/5/9/8RE1aaFG5yKyoZe9402/fu0+77c8kdbR5zOy yIcHJxX1hLy+YCo484WSOC9ac3upkZyySBFFhzLjvUGObAzVRtNpKwfE3UO85Yst om2fS3NRDJIYWx5Z3HzGsxbtDyFVYXA1uodq8dwq1rCnVaZtE9gTuU5XpPSt/mdB /OQsFfvmQVfbTLFOrCqqZ8ExR5Zi/sU7KQuMum825K5u9H8TjiPmeg5o9uk+YJyZ blQNdwRiSAaqgEVE5EgR/kPq7jIjCUDc2nef5BkpXwJ1+KORdHAOj7jLnOOkYhOI uJebS8wgkDZZtfr5XFbqh0BMiW+cfQ== =3P8P -----END PGP SIGNATURE-----
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