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

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

#51

Post by api »

wallflower wrote: post #47
Spooky23 wrote: post #24

Earlier quoted context omitted.

My favorite enterprise network pathologies: - Randomly block specific ports "because security" - Limit RPC port ranges to some random small number. - Strange network optimizations. Example: Optimize TCP Window Size to support NT4 clients on 56k frame relay circuits. - Very Slow DNS response - Optimize core switching rules to fully utilize switch CPU. Avoid configurations that take place in an asic. - Long DHCP Leases…

It makes me wonder at how Skype manages to tunnel though almost anything.

Primer I wrote a while back: https://www.zerotier.com/blog/?p=226

Skype has abandoned P2P, though I'm not sure why. One possibility is that MS now has middle boxes deployed at so many interchange and peering points that there's no benefit in maintaining the added complexity. Another is that it was to comply with surveillance/tapping requirements.

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

#53

Post by ot »

api wrote: post #51
wallflower wrote: post #47

Earlier quoted context omitted.

It makes me wonder at how Skype manages to tunnel though almost anything.

Primer I wrote a while back: https://www.zerotier.com/blog/?p=226 Skype has abandoned P2P, though I'm not sure why. One possibility is that MS now has middle boxes deployed at so many interchange and peering points that there's no benefit in maintaining the added complexity. Another is that it was to comply with surveillance/tapping requirements.

IIRC they said that it's because of the shift to mobile. You can't really do P2P when the majority of your clients sit on phones.

EDIT: [I can't reply to the comment below, so I'll add here] It's most likely not a technological problem, but rather than data usage is limited on mobile and you don't want your user to pay for traffic they didn't use.

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

#54

Post by j_s »

wallflower wrote: post #47
Spooky23 wrote: post #24

Earlier quoted context omitted.

My favorite enterprise network pathologies: - Randomly block specific ports "because security" - Limit RPC port ranges to some random small number. - Strange network optimizations. Example: Optimize TCP Window Size to support NT4 clients on 56k frame relay circuits. - Very Slow DNS response - Optimize core switching rules to fully utilize switch CPU. Avoid configurations that take place in an asic. - Long DHCP Leases…

It makes me wonder at how Skype manages to tunnel though almost anything.

Alex Pankratov, the developer of Hamachi, discusses his approach here: https://swapped.cc/#!/hamachi

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

#55

Post by api »

ot wrote: post #53
api wrote: post #51

Earlier quoted context omitted.

Primer I wrote a while back: https://www.zerotier.com/blog/?p=226 Skype has abandoned P2P, though I'm not sure why. One possibility is that MS now has middle boxes deployed at so many interchange and peering points that there's no benefit in maintaining the added complexity. Another is that it was to comply with surveillance/tapping requirements.

IIRC they said that it's because of the shift to mobile. You can't really do P2P when the majority of your clients sit on phones. EDIT: [I can't reply to the comment below, so I'll add here] It's most likely not a technological problem, but rather than data usage is limited on mobile and you don't want your user to pay for traffic they didn't use.

I keep hearing a categorical "you can't do P2P on mobile." I intend to fling myself at this problem like a drunk seagull soon, so I'll blog on it. I think it's possible, but with a number of special considerations around wakeup-quantization and general power management, some protocol augmentation, and a high tolerance for nodes appearing and disappearing.

Primer concept: http://en.wikipedia.org/wiki/Interrupt_coalescing

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

#56

Post by Florin_Andrei »

bobmagoo wrote: post #7
cordite wrote: post #5

Would something like this be DMCA'd or taken down because of the name? (Not that it is violating copyright by its contents)

I had that thought as well. From poking around various IP law sites, DMCA is purely for copyright infringement, and can possibly open you up to more liability if you try to use it for trademark claims (what this would be), see http://www.lexology.com/library/detail.aspx?g=13f9814f-b56e-... for an example. If Comcast wanted to take this down, it would be through a trademark infringement claim. (IANAL, etc, etc)

So... the project is infringing on Comcast's ownership of shitty networks?

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

#57

Post by jvehent »

I don't need this, I have comcast.

    $ sudo ping -i 0.02 8.8.8.8
    [...]
    64 bytes from 8.8.8.8: icmp_seq=578 ttl=53 time=15.5 ms
    ^C
    --- 8.8.8.8 ping statistics ---
    579 packets transmitted, 364 received, 37% packet loss, time 13854ms
    rtt min/avg/max/mdev = 15.009/19.308/50.884/6.152 ms, pipe 2

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

#58

Post by phil21 »

e40 wrote: post #40
shanemhansen wrote: post #34

Earlier quoted context omitted.

I hate comcast customer service with a passion, and their pricing models are super hostile to existing customers. But their internet service has been very reliable and very fast for several years for me. I rarely have internet outages.

Just yesterday I noticed my bill had gone up to $147. I called and did the yearly "I'll cancel if you don't give me a discount" nonsense. An hour out of my day. Btw, they had raised the price of my 5 static IPs to $24.95 (from $9.95). I have to lease their modem ($12.95) because of the static IPs. I did research and found out that my registrar (namecheap.com) has free dynamic dns, so I'm going to switch to that and g…

> I have to lease their modem ($12.95) because of the static IPs.

This isn't actually true, assuming you are on the consumer side of the fence. No experience on a business line though.

Source: Has extra IPs on his owned modem, after fighting with them for a couple weeks.

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

#59

Post by [deleted] »

api wrote: post #16

Nice. It'd be neat to include options to simulate other pathological conditions often encountered in the field like: - Multiple layers of NAT - overlapping un-synchronized timeouts are one thing ... but the REAL fun comes in when intermediate layers have the same IP ranges as IPs you are trying to reach on the "outside" of the NAT sandwich. All kinds of "interesting" things can happen, like the "software laser": http…

[deleted]

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

#60

Post by athenot »

ejdyksen wrote: post #4

If you're on Mac OS, you can also install the Network Link Conditioner from the Apple dev tools, which is a prefpane that serves the same purpose: http://nshipster.com/network-link-conditioner/

And on the command line, you can use the dummynet(4) command (can be useful to automate testing under various network conditions).
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