Question for Network types - capacity calculations

[Hawkwind]

Question for you Network infrastructure types

For a large office type network of say 400-600 users how would you go about calculating internet usage and capacity of the pipe required from the ISP?

Are there any standard industry formulas for this type of calculation?

Note: found a white paper on the net regards using Erlang's telephony formula which seems rather abstract for quick calculations - is this used in the industry?
https://www-roc.inria.fr/twiki/pub/RAP/JamesRobertsPublications/BR12.pdf

 

[Gahn]

oO good luck
There are no comprehensive out of the box tools that i know of (you need to take in account kb requirement differences from service to service on a per user basis).
Having said that i wouldn't miss the opportunity to configure QoS for such an installation.

 

[DaGaffer]

I'd be surprised if there's a standard answer as it depends on a. type of organisation (creatives move image and video around a lot), comms strategy (VOIP? lots of video conferencing? Multi-site comms?), acceptable use policy (users can access YouTube, iPlayer etc.), and of course all the XML, FTP and other regular application messaging going on; back up and archiving policy, and resilience plan. What I do know is that if you add all that bandwidth up, but Deebs works for you, you double the figure for porn.

 

[Killswitch]

I wish I worked somewhere that thought about this stuff.

To support VOIP, email and basic web browsing I've found you can easily get away with 100Kb/s per user. Now if your users have specific requirements like the need to upload massive files (creative), use streaming video (remote support) or spent a lot of time on the phone (call centre) then you might need to bump this up. I reckon an office of 500 "normal" users could survive on a 20Mb/s symmetric connection but 50Mb/s would be better.

The firm I do IT for has about 600 users total, but across like 7 offices. We generally stick to the above kind of numbers or greater, depending on how much connectivity costs. For example the office I work out of has 1Gb/s for 8 users!

As Gahn says if you want to use VOIP then some kind of QoS is a good idea to make sure you're not saturating your upstream with lolcats and killing the quality of your important phone calls.

 

[Hawkwind]

oO good luck
There are no comprehensive out of the box tools that i know of (you need to take in account kb requirement differences from service to service on a per user basis).
Having said that i wouldn't miss the opportunity to configure QoS for such an installation.

It gets more complicated for us as we are doing this at > 20000 ft in the air Using Ku band satellites we obviously we suffer from a high latency typically 750 mS. We are aiming to establish a minimum spec of 64kbps per user with a burst rate of 100kbps.

There does not appear to be a proper modelling tool available for standard office networks let alone what we are doing with multiple satellites and multiple transponders on those satellites.

 

[Hawkwind]

I'd be surprised if there's a standard answer as it depends on a. type of organisation (creatives move image and video around a lot), comms strategy (VOIP? lots of video conferencing? Multi-site comms?), acceptable use policy (users can access YouTube, iPlayer etc.), and of course all the XML, FTP and other regular application messaging going on; back up and archiving policy, and resilience plan. What I do know is that if you add all that bandwidth up, but Deebs works for you, you double the figure for porn.

Yes to most of that with some exceptions on the VOIP. Backup/Archiving is not an issue. This is an internet service on aircraft.

 

[Hawkwind]

I wish I worked somewhere that thought about this stuff.

To support VOIP, email and basic web browsing I've found you can easily get away with 100Kb/s per user. Now if your users have specific requirements like the need to upload massive files (creative), use streaming video (remote support) or spent a lot of time on the phone (call centre) then you might need to bump this up. I reckon an office of 500 "normal" users could survive on a 20Mb/s symmetric connection but 50Mb/s would be better.

Typical satellite transponders can provide up to 72 MHz (saturated transponder) at roughly 1.3 bits per Hz with modulation and compression that's around 93 Mbps. Typical uptake of 8-12% of passengers use the service and globally we have over 2000 aircraft signed up. The modelling starts to get a bit complicated

Just to give you an idea on a flight from Istanbul to New York we see an aircraft use anything up to 15 Gb of total data usage. We are trying to discourage airlines offering VOIP but some want it. Personally I think its a gimick and won't be used much. packet data would have to be prioritised to keep the link up and we would limit amount of passengers that could use it simultaneously.

Phone service for GSM, SMS and GPRS data run through the same pipe but usage is small.

 

[Hawkwind]

I got the Service Limits wrong on the minimum. Its 64 Kbit/s minimum, 100 Kbit/s average rate and 256 Kbit/s burst bit rate. Just looking at the contracts

 

[DaGaffer]

I think on an aircraft you'd decide on a contention ratio (how many simultaneous users you'd expect), "normal" browsing behaviour; and scale up from that with an excess on top. I haven't seen full internet access on a plane yet, although I seem to remember reading someone is doing it or about to, but maybe look at similar models from the maritime industry or trains? Wouldn't INMARSAT would be the obvious start point to give you a bandwidth calculation?

 

[Killswitch]

Sounds like a fun project. Must be interesting latency and jitter issues with data from a moving plane. What kind of modulation/compression are you using? I used to work in the US satellite TV industry (sort of). I'd also be interested how you're handling satellite and/or transponder handover. Presumably you won't be able to use the same transponder for a whole transatlantic flight?

 

[Hawkwind]

Sounds like a fun project. Must be interesting latency and jitter issues with data from a moving plane. What kind of modulation/compression are you using? I used to work in the US satellite TV industry (sort of). I'd also be interested how you're handling satellite and/or transponder handover. Presumably you won't be able to use the same transponder for a whole transatlantic flight?

I think on an aircraft you'd decide on a contention ratio (how many simultaneous users you'd expect), "normal" browsing behaviour; and scale up from that with an excess on top. I haven't seen full internet access on a plane yet, although I seem to remember reading someone is doing it or about to, but maybe look at similar models from the maritime industry or trains? Wouldn't INMARSAT would be the obvious start point to give you a bandwidth calculation?

Inmarsat (SBB) is a competitor and too slow for a broadband type experience. OK for basic Web and email but that's about it. It is a 3 satellite solution covering the world. Airbus do a solution called ALNA that operates over SBB (Inmarsat Swift Broadband). Current speed of that service is around 488 Kbps max per aircraft through a single antenna. Our Ku antenna system has a max throughput of 50 Mbps. The Antenna is stearable and we have capacity contracts for 15 different satellites globally with more than transponder in some footprints. The Modem we use is outside of the antenna array (inside the aircraft) and is a standard iDirect Ku modem. Modulation is usually between MODCOD 1 to 5. Switching time between beams is currently around 2-3 mins for stearing, beam lock and handover. We are working to reduce that. On an Eu to US flight you would typically switch twice after the initial login (satellites W2A, T11N, G17 ).

About 1.44 into this vid you can see our antenna in a test chamber going through the rotation etc.


View: http://www.youtube.com/watch?v=lDStQBE_pnw&feature=youtube_gdata

 

[Hawkwind]

Meant to mention we are piping IPTV to the aircraft as well using DVB-S format. 8 channels by end of 2013. These include an IMG sports channel showing F1, Premiership, World Cup, Golf, Tennis.... It will be the same feed globally through all our network. Also working on electronic programming guides and a DVR function for the aircraft side. Prett cool shiz tbh.

Lots of jobs going as well but all in Lake Forest, California.
http://www.panasonic.aero/ on the careers tab

 

[DaGaffer]

Pardon me for saying this, but why on Earth are you asking on here about network capacity when you're working there? I'd kind of assume you have enough Braniacs in-house to answer your question. NB. The corporate office analogy is the wrong starting point anyway.Trains etc. is definitely a better analogy and the usage profile will be nothing like an office.

The live sports thing is pretty interesting (I would imagine the rights negotiations for that lot was fun; which jurisdiction are you in at any one time? If its airline country of origin that creates a few interesting precedents...) For instance on Stena Line you can't pick up BBC iPlayer even in UK waters because the host is in Norway...

 

[Hawkwind]

Pardon me for saying this, but why on Earth are you asking on here about network capacity when you're working there? I'd kind of assume you have enough Braniacs in-house to answer your question. NB. The corporate office analogy is the wrong starting point anyway.Trains etc. is definitely a better analogy and the usage profile will be nothing like an office.

LOL - I work in Dubai and all the boffins are busy switching our ground network over from MTN control to in-house. I have a meeting with an airline in a few days and wanted to show them some basics on network capacity and how it is calculated. I assumed there would be some basic tools for office type capacity just to give them a grasp on how it is worked out. Basically they are asking stupid questions and their spec requirements like insisting they have 20Mbps down and 5Mbps up per aircraft. Which kinda shows they have very little idea of the technology, the costs or basic network usage.

The live sports thing is pretty interesting (I would imagine the rights negotiations for that lot was fun; which jurisdiction are you in at any one time? If its airline country of origin that creates a few interesting precedents...) For instance on Stena Line you can't pick up BBC iPlayer even in UK waters because the host is in Norway...

The media rights is quite interesting as many channels have regional contracts. The channels we show have we have secured global rights for. In the case of IMG Sports 24 we have basically secured the rights for airspace usage. IMG had those rights seperated from general regional sports contracts. Others channels like Disney did not seperate internet or aircraft usage so we cannot sign such channels. Currently we have BBC World, Euronews, Bloomberg or CNBC, Al Jazeerah, NHK then premium sports channels One Sport and IMG Sports 24.

 

[DaGaffer]

The media rights is quite interesting as many channels have regional contracts. The channels we show have we have secured global rights for. In the case of IMG Sports 24 we have basically secured the rights for airspace usage. IMG had those rights seperated from general regional sports contracts. Others channels like Disney did not seperate internet or aircraft usage so we cannot sign such channels. Currently we have BBC World, Euronews, Bloomberg or CNBC, Al Jazeerah, NHK then premium sports channels One Sport and IMG Sports 24.

TBH Sports and news are the only live categories worth having; stuff like kids and entertainment content you may as well do locally as they don't require immediacy. I'm actually surprised you managed to pick up any worthwhile sports rights tbh, they're usually ridiculously territory/platform specific. News on the other hand; every bugger wants distribution because there's so much over-supply.

 

[Deebs]

As others have said you cannot use a a generic calculation to work it out. For instance, you may have 20 users that use FTP and having that capped globally at 2mbit is ample for them. ie, you need to understand the traffic profile, work out what is acceptable performance and concurrency per traffic type etc.

Also, are you going to use a proxy to cache static assets? So many questions to ask before you can come up with a close answer.

 

[Killswitch]

Also, are you going to use a proxy to cache static assets? So many questions to ask before you can come up with a close answer.

This. Also having a local (ie on the aircraft) caching-proxy would be the place to put any kind of parental controls or content-blocking software as well as any firewalling. Blocking things like BitTorrent, access to porn sites and suchlike would probably lower traffic levels significantly!

Obviously the firewalling and content-blocking could be done on the ground (the request is small, it's the response that's big) but it would all help. I'd also be worried about things like machines with viruses (block traffic between users with dynamic VLANs perhaps?) and machines trying to send spam out and stuff like that. You might need some pretty heavy-duty traffic shaping to make everything play nicely. By having a box on the aircraft doing all this stuff (proxy-cache, firewall, shaping, content-blocking, parental controls) you'd save some bandwidth and probably get much better performance.

As to how much bandwidth you need, it's like Deebs says, it depends massively on the usage. By limiting the usage to (for example) only HTTP and HTTPS then you can have better estimates, but I imagine people will want things like email and VPNs to work as well. The general rule is probably that however much bandwidth you can get to a plane, your users will manage to use it all *somehow*.

I wonder if you could put an Akamai node on the aircraft and update it via Wi-Fi (or a cable) at each airport. That would be, like, cool and stuff.

 

[Hawkwind]

Our ground based NOC firewall and blacklist sorts out most apps but we have seen some torrent usage via VPN's. That is being worked. We do have a server with 1.2 Tb of SSDD available so that is probably a good idea although we are dealing with multiple ISP's depending on airline choice. SAS went with a local ISP. DLH use T-Mobile. Right now the server is mainly used for IPTV streaming into the wireless cabin for PEDs, wired seat equipment, caching and content storage. Also, for the Captcha prior to entering the internet service, lawful requirement in US and Singapore.

We are discussing Wireless transistions from the airport lounge areas to the aircraft. Even streaming movies. So you could start to watch a movie before entering the aircraft then carry on watching it in the cabin. Full VOD control.