- NANOG - lists.nanog.org

IERS ponders reverse leapsecond...
by Jay Ashworth 12 Aug '22

12 Aug '22

General press loses its *mind*: https://www.cbsnews.com/news/earth-spinning-faster-than-usual-shortest-day-… Have you tested leap second handling, especially in reverse? How do you simulate it? Are there existing test harnesses for simulating it? Cheers, -- jra -- Sent from my Android device with K-9 Mail. Please excuse my brevity.

14 18

400G forwarding - how does it work?
by James Bensley 12 Aug '22

12 Aug '22

Hi All, I've been trying to understand how forwarding at 400G is possible, specifically in this example, in relation to the Broadcom J2 chips, but I don't the mystery is anything specific to them... According to the Broadcom Jericho2 BCM88690 data sheet it provides 4.8Tbps of traffic processing and supports packet forwarding at 2Bpps. According to my maths that means it requires packet sizes of 300Bs to reach line rate across all ports. The data sheet says packet sizes above 284B, so I guess this is excluding some headers like the inter-frame gap and CRC (nothing after the PHY/MAC needs to know about them if the CRC is valid)? As I interpret the data sheet, J2 should supports chassis with 12x 400Gbps ports at line rate with 284B packets then. Jericho2 can be linked to a BCM16K for expanded packet forwarding tables and lookup processing (i.e. to hold the full global routing table, in such a case, forwarding lookups are offloaded to the BCM16K). The BCM16K documentation suggests that it uses TCAM for exact matching (e.g.,for ACLs) in something called the "Database Array" (with 2M 40b entries?), and SRAM for LPM (e.g., IP lookups) in something called the "User Data Array" (with 16M 32b entries?). A BCM16K supports 16 parallel searches, which means that each of the 12x 400G ports on a Jericho2 could perform an forwarding lookup at same time. This means that the BCM16K "only" needs to perform forwarding look-ups at a linear rate of 1x 400Gbps, not 4.8Tbps, and "only" for packets larger than 284 bytes, because that is the Jericho2 line-rate Pps rate. This means that each of the 16 parallel searches in the BCM16K, they need to support a rate of 164Mpps (164,473,684) to reach 400Gbps. This is much more in the realm of feasible, but still pretty extreme... 1 second / 164473684 packets = 1 packet every 6.08 nanoseconds, which is within the access time of TCAM and SRAM but this needs to include some computing time too e.g. generating a key for a lookup and passing the results along the pipeline etc. The BCM16K has a clock speed of 1Ghz (1,000,000,000, cycles per second, or cycle every 1 nano second) and supports an SRAM memory access in a single clock cycle (according to the data sheet). If one cycle is required for an SRAM lookup, the BCM16K only has 5 cycles to perform other computation tasks, and the J2 chip needs to do the various header re-writes and various counter updates etc., so how is magic this happening?!? The obvious answer is that it's not magic and my understanding is fundamentally flawed, so please enlighten me. Cheers, James.

18 64

Facebook down?
by Michael Thomas 11 Aug '22

11 Aug '22

They haven't been serving up images for like an hour or so and now it's showing their fail whale. Not sure if it's a (internal) network problem or not. I'm in California fwiw. Mike

3 5

Getting Fiber to My Town by Jared Mauch
by Jared Brown 11 Aug '22

11 Aug '22

I believe this belongs here: Getting Fiber to My Town by Jared Mauch https://www.youtube.com/watch?v=ASXJgvy3mEg (YouTube video of NLnog presentation) https://nlnog.net/static/live/nlnog_live_sep_2020_jared.pdf (slides for presentation) https://news.ycombinator.com/item?id=24424910#24430901 (discussion on Hacker News with Jared participating) https://washftth.com/ (project homepage) I find this an interesting description of how to apply skills that we normally only use at work to solve connectivity issues at home. Quite timely too, as home connectivity is needed more than ever. Highlights: - location: just outside of Ann Arbor - no fixed broadband since 2002 -> build own network - pre-wire neighbors with fiber drops and feed them off WISP first - lots of work to sign up customers, having to resort to snailmail to reach all - 70% of homes passed signed up - Have ASN, get IPv6 and IPv4 allocation, multihome and connect to local IXP - purchase equipment: fusion splicer, OTDR, materials, directional drill(!) - hire contractors, deal with all manner of problems, theft, stop work orders, unbudgeted costs, unmarked/badly marked utilities, hitting (own) utilities - build own fiber blower(!) for blowing in fiber in ducts - splice, OTDR, resplice, schedule installs ... which don't always go to plan - Upstream very helpful, offered a Cisco 6500 as CPE, however respectfuly declined and went with Arista - Link up! Network is now live with 17 subscribers hooked up. More waiting to be connected - Mixed Active Ethernet and GPON - latency drops from 30 ms to 8 ms, bandwidth from 20-30M to 730M, total commit 1.5G on 10G port, plans from 50M to 500M - SPAM! IPv4 brokers and the usual unsolicited contacts from bottom of the baller IP transit providers - Costs: $126k in 2020, $95k contractors, $32k materials and equipment. Total outlay ~$150k + years of sweat equity. Important to spread out costs over longer period of time to be able to afford. Offset costs by using pre-pay model (Can pay $5,000 up-front and receive $50 credit for 100 months) All in all it was an excellent presentation. I only wish Jared had spent some more time on how he had to become a telco and how this got him better access to the public right of way. Of course, some more details on his directional boring and some nice video of him running the drill would have been a cherry on top :) I'd like to congratulate Jared on lighting up his network and wish him success in running it. I did a similar build almost twenty years ago and regret I didn't have the forethought to document the effort better then. Not that there was a YouTube to put it all on then :) You can find the other presentations from NLnog live September 2020 at https://www.youtube.com/channel/UCVz78FbsOJ6v6xb6S2GpvWQ Jared, not the Mauch one

10 13

Peering with Google and Microsoft
by Oskar Borgqvist 11 Aug '22

11 Aug '22

Hi Nanog We have tried to get peering with Google but only get answers that they are making their peering system better. I have received this answer for over 1 year. The reason why we needed peering to Google is that they do not send out exact prefixes over IXP RS, which means that our traffic from Sweden down to Germany and up again to Sweden again. This has created a bit of a problem for us. If anyone could help us with this it would be appreciated. Or can give an explanation. Since then, we have also tried to get peering with Microsoft without success. We have tried to contact them via their peering email without success. Would appreciate help here as well. Sincerely, Oskar Borgqvist -- Oskar Borgqvist CEO/Owner/Network Engineer Mail: oskar(a)karabro.se Tele: +46 406 68 80 96 Vi bygger broar mellan internet och människor

5 5

RE: IPv6 internet broken, cogent/telia/hurricane not peering
by VOLKAN KIRIK 11 Aug '22

11 Aug '22

hello nobody has to peer with some operator for free. they are simply trading internet services. they do not have to believe in FREE (as in price) internet connectivity.. if they peered you, you would decrease the price of the products even more and more... ask cogentco (as174) for paid peering. they will give you nice paid peering or ip transit offer that you can use for both ipv4 and ipv6. for example i would assume they would be OK charging he.net (as6939) 5 usd cent per megabit. you need to understand that you are never going to become tier1 without support from as174. they are currently cheapest and they are okay with dual homing too. think like united nations security council. you must think twice; are you gaining any profit by segmenting world-wide internet? or are you loosing prospective single-homing customers because you lack connectivity to as174 clients? we must think big. asking for a money is OKay while begging for FREE service is not... operating NOC and backbone has some expenses that henet wouldnt understand with their rented links. cogentco bear much more expenses than henet i am not here to insult henet but i honestly think that they are contemptible... just like google's peering decision makers. sir! if you have become big content/eyeball operator, doesnt mean that every operator in the industry have to respect your tier-1 policy and give you their services for free. thats the thing henet and google couldnt understand. think like UNSC and you will understand even USA can not do anything they want in the world, as RU has voting right, too. TL;DR; instead of crying here and begging for free service. send real representatives that could negotiate the money you would pay. bye

6 6

IoT - The end of the internet
by Christopher Wolff 11 Aug '22

11 Aug '22

Hi folks, Has anyone proposed that the adoption of billions of IoT devices will ultimately ‘break’ the Internet? It’s not a rhetorical question I promise, just looking for a journal or other scholarly article that implies that the Internet is doomed.

17 28

Sflow/netflow/ipfix open source security projects
by Drew Weaver 10 Aug '22

10 Aug '22

Hello, I am interested in getting involved with an open source project in my spare time. I thought that it may be useful to contribute to an open source project that uses flow data to check for lateral movement inside of networks and also to check for known bads in remote connections. This seems like really low hanging fruit from a defense scenario. I've tried googling around for something like this and I have come up short. Is anyone aware of any such projects? Thanks, -Drew

3 2

Telia->ATT at 350 Cermak
by Rafael Possamai 10 Aug '22

10 Aug '22

After some time monitoring/troubleshooting, we are seeing what looks like congestion between AS1299 and AS7018 at 350 Cermak during typical peak hours. Could someone please reach out off-list if possible? Much appreciated. Thanks, Rafael

1 0

Frontier Dark Fiber
by Mike Hammett 10 Aug '22

10 Aug '22

I'm looking for a contact at Frontier that can discuss dark fiber. My current account exec says they don't offer it, yet prior conversations with him and a previous SE revealed that they very much did (just didn't have availability on the paths I wanted at the time). Their web site highlights it fairly proudly. I'm aware that availability varies. I'm aware that they likely don't want to sell it. ----- Mike Hammett Intelligent Computing Solutions Midwest Internet Exchange The Brothers WISP

8 12