Comcast: Simulating shitty network connections so you can build better systems

[lostdog]

The greatest part of this project is that if you ever get sued for trademark infringement, you can force their lawyers to have to explain why anyone could possibly confuse the product of Comcast Corp. with making your internet as flakey and slow as possible.

[unsignedint]

To be honest, when I looked at this title, I thought Comcast made a tool and publicized the tool to simulate suboptimal network...

[kodah]

There's an old paper on that networking, by design, is not reliable or efficient - which is more cogent than ever in large scale distributed systems. What Comcast would cite would likely be that, so I doubt it would reveal the quiet part said out loud about the reliability of Comcast's services.

A couple citations I liked:

https://queue.acm.org/detail.cfm?id=2655736

https://blog.acolyer.org/2014/12/18/the-network-is-reliable/

[versale]

On the other hand projects named this way are not easily googleable.

[the_biot]

Not really, they just need to point at the trademark registration. There is nothing to explain or be embarrassed about.

[encryptluks2]

Simple, they already know Comcast is synonymous with flakey slow Internet and shitty customer service. But they already paid off congress and know there is nothing you can do about it.

[karmakaze]

Well Canadian Tire Corp tried to claim ownership of the domain crappytire.com and lost. Looks like the domain was eventually bought out.

[DonHopkins]

If only Comcast customers had a way of simulating non-shitty network connections...

[whateveracct]

You could also rebrand this program to comcast-simulator lmao

[daviddever23box]

Grinning from ear to ear on that point...!

[heavyset_go]

Sounds expensive.

[TaylorAlexander]

Tangent but I was always annoyed at how poorly google products work offline. One time I was using google maps to navigate to a remote address. Once I got close to the address google maps crashed and I re-opened the app. I had no cellular service. The app remembered the actual map data but did not remember the address I had just typed in to the program 15 minutes earlier. I had to guess what street address I was heading to! Why they designed the app to store all search history exclusively in the cloud and not keep a local copy is beyond me, but I presume when working at google they always have an excellent connection and hadn’t thought of what would happen if a user lost service. Being able to at least see the search history would have saved me some grief!

[mh-]

I've experienced that same behavior too. But I also happen to know that, at least in the earlier days of android, they had sophisticated labs available for emulating poor network conditions and software for spoofing GPS on-device in the lab.

Which just makes it more frustrating.

[coryrc]

> Why they designed the app to store all search history exclusively in the cloud and not keep a local copy is beyond me

It used to. It was intentionally removed. I say this as a customer who read the update notes, not as an employee of Google.

I'll let you guess why they did. I have my opinion why and it is not flattering to the company, to say the least.

[lostgame]

For all the hate it gets, I can confirm that Apple Maps does not exhibit this behaviour, and I also believe Waze doesn’t, as well; though my memory is hazy on that one.

Driving around in Northern Canada, as I am often wont to do with my partner; you’re without cell service at least half the time; and even when you do have cell service - data is very uncommon.

My girlfriend and I ran into this issue twice with Google Maps, tested if Apple Maps exhibited the same behaviour, and since it hadn’t - neither of us have actually used Google Maps since.

This is - of course - iOS-specific advice.

[salawat]

Making a tool that retains it's use in isolation from Google and the cloud is antithetical to the SaaS philosophy.

[pehtis]

If you are on macOS you can use the "Network Link Conditioner" System Preferences pane that is included with Xcode for the same effect.

You can find that in the Additional Tools for Xcode download, in the Hardware folder.

[fredley]

I used to work with someone who would frequently explode on group video calls, usually with the anger directed at a single victim.

I worked out that if it happened to me, I could use the OSX link conditioner (built in to XCode) to degrade the connection realistically. Coming back after he'd finished his tirade with a 'sorry, my internet capped out, could you repeat that' took a lot of the heat out of the situation.

[distances]

Sidenote, but I have never ever witnessed someone getting angry at another person in a meeting, remote or in person. I don't even know how I'd react except being flabbergasted at the unprofessionalism.

[bertil]

I wish more companies cared about making their product accessible with poor connection, but also no connection at all.

Google Maps is probably the most egregious example of that: you are likely to need it outside of your usual Wifi, and possibly where cellular coverage is poor. Why not offer reasonable off-line support? The Apple TV app is confusing too: they offer the option to download shows (like Netflix does) but the feature is essentially unusable.

[LAC-Tech]

It's a hard problem.

Offline means you're dealing with conflict detection, resolution, and caching strategies. Do you do multi-master? Have a single remote master but cache commands as a fallback? How do you test your solution?

And if you're dealing with the web, then you have to deal with IndexedDB which can sometimes be nuked by the browser, or have show stopping bugs (looking at you safari). There's also limited capacity compared to severside. Even if you use a library, under the hood they all use IndexedDB - there is no getting away from its limitations.

If anyone's interested in this stuff, I'd love to chat. I'm between contracts and trying to make an old app of mine work offline, lots of fun but also challenging.

[dmd]

I’m real confused about you calling out Google Maps when it has fantastic offline support (which I use all the time).

[roflc0ptic]

Maps does let you download areas for offline use. I'd agree that it's non-ideal for long trips, though in practice this has never been a huge problem for me.

[tgsovlerkhgsel]

Offline support on Android is excellent. I'd guess most people don't use it offline on a laptop.

[seper8]

Google Maps is literally free and here you are complaining it won't work when you don't have internet... But it will: https://support.google.com/maps/answer/6291838?hl=en&co=GENI...

[ChrisMarshallNY]

The best way to do this, is minimize the amount of data, going back and forth.

In today's age, with multi-megabyte 4K background videos, and enormous dependency chains, that's a hard sell.

I dealt with it, by writing my own backend, with a fairly optimized API, and consulting it in JIT "bursts."

That’s considered “square,” these days.

[adrianople378]

I use Organic Maps exactly for this reason. Google Maps is too unreliable when cycling and I need an offline solution (also OpenStreetMaps have better coverage of cycling routes than Google does).

https://organicmaps.app/

[secondcoming]

HERE maps are downloadable.

[samatman]

Love the project, likely to use it, and I wish more developers were compelled to use Southeast-Asian-island levels of latency, jitter, and bandwidth, at least once a week while writing websites.

The name is choice, I almost hope you get a nasty letter so you can share it with the rest of us. Hard to search for though...

Might I offer.... Concast?

[chillax]

There's also toxiproxy - https://github.com/Shopify/toxiproxy

[LgWoodenBadger]

About 15 years or so ago, we looked at buying a hardware appliance that would let you build and simulate virtual networks with all sorts of different characteristics. Packet loss, latency, etc.

We developed software for retail point of sale systems, and some of the stores we had to support had all sorts of awful infrastructure, both inside the store and between the store and the “rest of the world.”

I can’t remember the name, but I believe it was an Israeli company, and the device was programmed/configured through Visio (iirc).

[luma]

The 2.6 Linux kernel includes the ability to create this sort of havoc on your network interfaces via netem[1]. Using the `tc` tool you can add latency, jitter, packet loss, packet reordering, corruption, duplication, or rate limiting. You can apply this to an entire interface or have it only apply to single IPs or ranges of IPs as it works through the existing QOS framework in Linux. Combined with a routing interface and you can leverage this to create a wan emulator for external hosts without much trouble.

This is incredibly useful when smoke testing large scale distributed systems or for test/development of protocols intended to be used over dicey connections.

[1] https://www.linux.org/docs/man8/tc-netem.html

[dchest]

> Here's a list of network conditions with values that you can plug into Comcast

Here's an idea: take this list and embed it into the program so that you can execute it like this:

  comcast -use gprs

[hackernj]

I don't need this software, because Comcast is my ISP.

[mynegation]

I remember there is some kind of provision in the copyright law for satire in the performance art. There was a cafe set up once for few days called “Dumb Starbucks” and that was not deemed copyright infringement. Not a lawyer, this is not a legal advice.

[PaulHoule]

Comcast is pretty good compared to Frontier. People with DSL don’t want to hear you bitch about your cable provider, particularly one that (relative to others) charges a premium price for a premium product.

[iameli]

Generally when a product doesn't work for half an hour every day, with no acknowledgement from support or fix, I would hesitate to use the word "premium." I've also lived with 12 Mbps DSL; at least it was rock solid 24/7.

[DangitBobby]

I bought a wireless home internet subscription and a router with WAN failover capabilities because I was tired of 10 minute outages 3 times a week. Great for you if Comcast provides you with premium product. They simply do not here.

I'm not completely unsympathetic to people stuck with DSL since I grew up with dial-up and that's still all my parents can get (apart from wireless), but I'm absolutely entitled to and will continue to bitch about Comcast's service when relevant.

[k_sze]

There’s another tool called “clumsy” that I used some years ago.

[game-of-throws]

Comcast rebranded themselves as Xfinity to try to shake their reputation. Maybe this project should be renamed too.

[kjs3]

They only rebranded the consumer side, and that was as I recall coincident with their move from being a 'cable company' to pushing bundled IP services. The business side is still branded Comcast. I don't think they much care about their reputation, at least not enough on it's own to rebrand. In many of their markets there isn't much in the way of an alternative other than the at-least-as-shitty AT&T.

[oceliker]

Would it be possible to use this to target specific domains rather than IP blocks? I have been looking for a way to break my instant gratification browsing habits (twitter, reddit etc.) by introducing random delays into those websites, essentially making them barely usable, which works a lot better than blocking them outright. There are some existing browser extensions with a similar idea, but they usually only delay the initial load, so once you get through that barrier you are allowed to browse freely.

I could manually do a DNS lookup and plug the IP address in, but I don't know enough about internet protocols to know whether that would work with Cloudflare etc.

[anikdas]

Another tool that is built into linux is tc[1]

[1]https://man7.org/linux/man-pages/man8/tc.8.html

[goodpoint]

This is unnecessary. You can use tc qdisc as written on the readme.

[jlund-molfese]

This tool provides a common interface for multiple OSes, which might be useful for someone who frequently switches between Linux and OS X or does development on a Mac but uses Linux in their pipelines.

[the_biot]

Not sure why you're getting downvoted, because you're right. This tool is literally a wrapper around that.

[butlerm]

This reminds me of an Amiga utility someone made called 'viacom' that when run would create a nice semi-transparent pattern of static interference all over the screen.