From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from tuna.sandelman.ca (tuna.sandelman.ca [IPv6:2607:f0b0:f:3:216:3eff:fe7c:d1f3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 280F43B29D for ; Wed, 15 Apr 2020 16:57:47 -0400 (EDT) Received: from sandelman.ca (obiwan.sandelman.ca [209.87.249.21]) by tuna.sandelman.ca (Postfix) with ESMTP id 4FB833897C; Wed, 15 Apr 2020 16:56:01 -0400 (EDT) Received: from localhost (localhost [IPv6:::1]) by sandelman.ca (Postfix) with ESMTP id 03222602; Wed, 15 Apr 2020 16:57:41 -0400 (EDT) From: Michael Richardson To: Mikael Abrahamsson , cerowrt-devel In-Reply-To: References: X-Mailer: MH-E 8.6; nmh 1.7+dev; GNU Emacs 25.1.1 X-Face: $\n1pF)h^`}$H>Hk{L"x@)JS7<%Az}5RyS@k9X%29-lHB$Ti.V>2bi.~ehC0; <'$9xN5Ub# z!G,p`nR&p7Fz@^UXIn156S8.~^@MJ*mMsD7=QFeq%AL4m Subject: Re: [Cerowrt-devel] 800gige X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 15 Apr 2020 20:57:47 -0000 --=-=-= Content-Type: text/plain Mikael Abrahamsson via Cerowrt-devel wrote: > Backbone ISPs today are built with lots of parallel links (20x100GE for > instance) and then we do L4 hashing for flows across these. This means got it. inverse multiplexing of flows across *links* > We're now going for 100 gigabit/s per lane (it's been going up from 4x2.5G > for 10GE to 1x10G, then we went for lane speeds of 10G, 25G, 50G and now > we're at 100G per lane), and it seems the 800GE in your link has 8 lanes of > that. This means a single L4 flow can be 800GE even though it's in reality > 8x100G lanes, as a single packet bits are being sprayed across all the > lanes. Here you talk about *lanes*, and inverse multiplexing of a single frame across *lanes*. Your allusion to PCI-E is well taken, but if I am completing the analogy, and the reference to DWDM, I'm thinking that you are talking about 100 gigabit/s per lambda, with a single frame being inverse multiplexed across lambdas (as lanes). Did I understand this correctly? I understand a bit of "because we can". I also understand that 20 x 800GE parallel links is better than 20 x 100GE parallel links across the same long-haul (dark) fiber. But, what is the reason among ISPs to desire enabling a single L4 flow to use more than 100GE? Given that it seems that being able to L3 switch 800GE is harder than switching 8x flows of already L4 ordered 100GE. (Flowlabel!), why pay the extra price here? While I can see L2VPN use cases, I can also see that L2VPNs could generate multiple flows themselves if they wanted. -- ] Never tell me the odds! | ipv6 mesh networks [ ] Michael Richardson, Sandelman Software Works | IoT architect [ ] mcr@sandelman.ca http://www.sandelman.ca/ | ruby on rails [ --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEbsyLEzg/qUTA43uogItw+93Q3WUFAl6XdUQACgkQgItw+93Q 3WVpvAgAo1//sF112XvKjhtp8gE835+PAKE+rBJMvEhSfLR6ezWn3YVvEydhYi3A ti9wzccYaBzxfivzRhi8g5QytgvZcCtuvPs14+MNlt61y7JfS+oz5HXDNFt3xXeU arWB7o24TCyjDtoZCRC+J8lc0faczmhQaBxyKO03rs84uqKe7X40dosNiBiuJaFo Zn8g1YAq1MeB9QEV4fWEpOgCbTOZJwNKWhz2Sa37zDNNfgBEsWEgN3e2SJjS4s0c fGQ/Y+/SPiGyVaBj4oexn2TjguG7HOVezRmZcJbUSyiWlMfYIqNeanFMSm6axxjk 9Rpe96tgnU0SjwydmqAyzZksQ0I6rg== =UdHf -----END PGP SIGNATURE----- --=-=-=--