- NANOG - lists.nanog.org

Latency, TCP ACKs and upload needs
by Jean-Francois Mezei 22 Apr '16

22 Apr '16

As part of the ongoing CRTC hearings, the incumbents' claim that continued implementation of the current 5/1 standard would make Canada a world leader for broadband in the future. A satellite company who currently can't even deliver its advertised 5/1 now brags its next satellite will deliver 25/1. So I have a few questions: Considering a single download TCP connection. I am aware that modern TCP stacks will rationalize ACKs and send 1 ACK for every x packets received, thus reducing upload bandwidth requirements. Is this basically widespread and assumed that everyone has that ? Also, as you split available bandwidth between multiple streams, won't ack upload requirements increase because ACK rationalisation happens far less often sicne each TCP connection has its own context for ACKs? When one considers the added latency of satellite links, does 25/1 make sense ? (I need a sanity check to distinguish between marketing spin presented to the regulator and real life) I noticed that in the USA, EXEDE Satellite advertises 12/3 plans and they are also on a VIA Sat satellite, presumably the same vehicle that Xplornet tries to deliver its measly 5/1 on. Would all beams be identical on a satellite or can they be configured differently with a ISP adjustable rate of upload/download inside the same spectrum ? Also, when you establish a TCP connection, do most stacks have a default window size that gives the sender enough "patience" to wait long enough for the ACK ? If sender sends packet 457, doesn't get ACK in time and resends 457, doesn't that also result in reduction in window size (the very opposite of what would be needed in high latency links) ? And when the first ACK finally arrives, won't the sender assume this ACK was for the resent 457 ? Or is satellite latency low enough that stacks all have enough default "patience" to wait for ACKs and this is a non issue ? (Note Xplornet refused to answer questions on whether they operate special proxies at their gound stations to manage TCP connections to appear "close"). What i am trying to get at here is whether 25/1 on satellite, in real life with a few apps exchanging data, would actually be able to make use of the 25 download speed or whether the limited 1mbps upload would choke the downloads ?

10 12

DOCSIS 3.1 upstream
by Jean-Francois Mezei 21 Apr '16

21 Apr '16

Canadian cable carriers seem to have all told the CRTC they can only carry 42mhz in the upstream because their amplifiers and nodes only amplify that narrow band in the upstream direction. Is/was 42mhz common across north america ? In a typical installation, how much of the 42mhz is actually usable for upstream data ? (aka: how many 6mhz chunks are taken for TV STBs, Telephony and whatever other upstream channels. I think I heard that one 6mhz chunk is used for one the low numbered TV analogue channels. (although cablecos are slowly widthdrawing analogue TV now). Am trying to figure out realistic bandwidth that a cableco with 42mhz limits for upstream will get on 3.1. Also, have cablecos with such limits for upstream begun to upgrade the cable plant to increase the upstream bandwidth ? Canadian cablecos have told the regulator it would be prohibitively expensive to do so, but incumbents tend to exagerate these things when it is convenient. (they can then claim higher costs/congestion/need for node splits which increates regulated wholesale rates). And would it be correct that in RFoG deployment, the 42mhz limit disapears as the customer equipment talks directly tothe CMTS over fibre all the way ?

4 5

CDN, Steam, Origin and NAT.
by Laurent Dumont 21 Apr '16

21 Apr '16

Hi, We are running a small-ish LAN event in Toronto where we have to use a single IP address to NAT between 250-350 players. I have been made aware of possible issues with different services like Steam, Origin and Twitch who can run into issues when a large number of connections seem to originate from a single IP address. I just wanted to poke the list to see if anyone can chime him on their experiences with NATing customers and the impact it might have on public services. I am usually using public IP address space for players when designing most large LAN events. Dealing with NAT for a medium-ish amount of customers is not something I am used to do. It feels silly to worry about that when you assume that WISP sometimes(mostly?) use CGN when providing internet to customers. The same could be said of most large office buildings around the world. I appreciate any input on the matter! Thanks Laurent

6 5

Mobile providers in the US for backup access
by Dovid Bender 20 Apr '16

20 Apr '16

A while ago some people mentioned that some US carriers have basic internet plans for backup access to their equipment. A few questions: 1) Do they give you a public IP per connection or do you tunnel back to a central location and then connect via the tunnel? 2) Which carriers offer this and what kind of devices do you use to connect? Is it simply a GSM card on a "MyFi" like device? We have lots of Pi's out there that we want backup access to. 3) Can you send off list contacts and pricing that you have gotten in the past? TIA. Dovid

7 10

Re: ASR-9K CPU troubleshooting
by Scott Weeks 20 Apr '16

20 Apr '16

--- regezos(a)gmail.com wrote: From: Rukka Pal <regezos(a)gmail.com> How do you guys troubleshoot high CPU utilization on the ASR-9K platform? Detailed guides are available for IOS platforms, but I can't seem to find anything useful for the ASR. The average line-card (0/0/CPU0: A9K-24x10GE-TR) CPU utilization of my routers is about 10%, however recently I have noticed that 3-5 times a day it increases to 40% and stays there for about an hour (20% spp + 10% netio + the rest). I know this is well withing the acceptable range, but I am the kind of person who likes to understand every change in his network and during the investigation I had to realize that I simply don't have the tools to troubleshoot the ASR CPU. ----------------------------------- On cisco: sho proc cpu scott

5 4

Software for circuit documentation
by Manuel Marín 19 Apr '16

19 Apr '16

Dear Nanog community We are looking for a network inventory software to document logical circuits and fibers. We have been using Racktables for cross connects and racks documentation and works great, but we did find a way to document MPLS, Eline/ELAN, OTN, SONET, IP circuits, external plant (fibers), etc. I would appreciate if you can share what you use for documentation. Thank you and have a great day Regards

7 6

New Switches with Broadcom StrataDNX
by Colton Conor 19 Apr '16

19 Apr '16

Does anyone know when the switching and router vendors will release their new models with the Broadcom BCM88370 and BCM88670 chips? It looks like these chips could be used as a carrier grade router and/or metro E device. More information here: http://www.broadcom.com/press/release.php?id=s902223 and here: http://www.nextplatform.com/2015/03/19/new-dune-chips-enable-heftier-switch…

9 17

Traffic forecasts
by Tum Eh 18 Apr '16

18 Apr '16

Dear All, Do you use any source other than Telegeography in order to get country's Internet bandwidth infos, or continent to continent capacities etc. BR, Tum

2 2

ARIN 37 Opens Today!
by John Curran 18 Apr '16

18 Apr '16

NANOGers - ARIN 37 opens today. I would highly encourage folks to remotely participate if interested (particularly in any number policy discussions that you feel may be of importance...) Details (including a pointer to remote participation instructions) are attached. Thanks! /John John Curran President and CEO American Registry for Internet Numbers (ARIN) Begin forwarded message: From: ARIN <info(a)arin.net<mailto:info@arin.net>> Subject: [arin-announce] ARIN 37 Opens Today! Date: April 18, 2016 at 7:33:26 AM EST To: <arin-announce(a)arin.net<mailto:arin-announce@arin.net>> The ARIN 37 Public Policy and Members Meeting begins today in Montego Bay, Jamaica. We hope you can join us from 9:00 AM – 4:00 PM EST on Monday and Tuesday to discuss five draft policies, policy simplification, registry data accuracy, ARIN software developments, and the latest news on the IANA Stewardship Transition. We will also feature an IPv6 panel discussion titled “Operational Success Stories,” which will feature case studies and guidance from organizations that have successfully deployed IPv6. We will reconvene on Wednesday from 9:00 AM – 12:00 PM EST for the Members Meeting to hear department updates, as well as reports from the Board, AC, and NRO NC. AGENDA & PRESENTATIONS Preview the agenda and check for updates at: https://www.arin.net/ARIN37_agenda As we receive presentations throughout the week, we will be posting them to: https://www.arin.net/ARIN37_materials FOR REMOTE PARTICIPANTS If you cannot join us in Montego Bay, you can still participate online via webcast, transcript, and YouTube stream. Please register to join the meeting chat room, vote in straw polls, and submit questions or comments. Remote participation info at: https://www.arin.net/ARIN37_remote MEETING RECAP A meeting recap will be posted at the close of today’s session at: http://www.teamarin.net SOCIAL MEDIA On Twitter? Use the hashtag #ARIN37 for all your tweets about the meeting. Join in the conversation at: https://twitter.com/hashtag/ARIN37 Happy Meeting! Regards, Communications and Member Services American Registry for Internet Numbers (ARIN) _______________________________________________ ARIN-Announce You are receiving this message because you are subscribed to the ARIN Announce Mailing List (ARIN-announce(a)arin.net) Unsubscribe or manage your mailing list subscription at: http://lists.arin.net/mailman/listinfo/arin-announce Please contact info(a)arin.net if you experience any issues.

1 0

10G-capable customer router recommendations?
by David Sotnick 18 Apr '16

18 Apr '16

Hello masters of the Internet, I was recently asked to set up networking at a VIP's home where he has Comcast "Gigabit Pro" service, which is delivered on a 10G-SR MM port on a Comcast-supplied Juniper ACX-2100 router. Which customer router would you suggest for such a setup? It needs to do IPv4 NAT, DHCP, IPv4+IPv6 routing and have a decent L4 firewall (that also supports IPv6). The customer pays for "2Gb" service (Comcast caps this at 2G+10% = 2.2Gbps) and would like to get what he pays for (*cough*) by having the ability to stream two 1Gbps streams (or at least achieve > 1.0Gbps). I'm tempted to get another ACX-2100 and do a 4x1Gb LACP port-channel to the customer switch, or replace the AV-integrator-installed Cisco SG300-52P (Cisco switch with e.g. an EX-3300 with 10Gb uplinks). Thanks in advance for your suggestions. -Dave

18 35