How a little bit of TCP knowledge is essential
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Re: How a little bit of TCP knowledge is essential
#2This can be generalised. It is also one of my favorite ways of doing developer interviews. Do they have a working/in-depth knowledge of what keeps the inter webs running? So many people have never ventured out of their main competence bubble, and that bubble can be quite small (but focused, I suppose).
For all I know, they believe everything is kept together with the help of magic. I guess I don't trust people who don't have a natural urge to understand at least the most basic things of our foundations.
Re: How a little bit of TCP knowledge is essential
#3Summary: If you know learn a little, you realize that each packet might be separately acknowledged before the next one is sent. In particular, note this quote: Net::HTTP doesn’t set TCP_NODELAY on the TCP socket it opens, so it waits for acknowledgement of the first packet before sending the second.
By setting TCP_NODELAY, they removed a series of 40ms delays, vastly improving performance of their web app.
Re: How a little bit of TCP knowledge is essential
#4This can be generalised. It is also one of my favorite ways of doing developer interviews. Do they have a working/in-depth knowledge of what keeps the inter webs running? So many people have never ventured out of their main competence bubble, and that bubble can be quite small (but focused, I suppose). For all I know, they believe everything is kept together with the help of magic. I guess I don't trust people who do…
I used to thing this way before I realized it's just an arbitrary hoop you make people jump through. To you, people understanding TCP might be what you claim is a basic foundation. However, it's just about as arbitrary as asking people to explain 802.11 RTS/CTS or clos switch fabrics, which are both equally as important to delivering day-to-day network traffic. Additionally, they both can come up as things you need to understand when trying to optimize jitter/latency in sensitive local network traffic applications.
Don't judge people based on which components of networks they happened to take an interest in and dive into.
Re: How a little bit of TCP knowledge is essential
#5John Rauser of pinterest gave a wonderful talk about TCP and the lower bound of Internet latency recently that has a lot in common with what's discussed in the article here. Worth a watch I think if you enjoyed the blog post.
Re: How a little bit of TCP knowledge is essential
#6Can wireshark/riverbed (application perf tests) profiling help to solve these kind of problems?
Re: How a little bit of TCP knowledge is essential
#7This can be generalised. It is also one of my favorite ways of doing developer interviews. Do they have a working/in-depth knowledge of what keeps the inter webs running? So many people have never ventured out of their main competence bubble, and that bubble can be quite small (but focused, I suppose). For all I know, they believe everything is kept together with the help of magic. I guess I don't trust people who do…
I used to thing this way before I realized it's just an arbitrary hoop you make people jump through. To you, people understanding TCP might be what you claim is a basic foundation. However, it's just about as arbitrary as asking people to explain 802.11 RTS/CTS or clos switch fabrics, which are both equally as important to delivering day-to-day network traffic. Additionally, they both can come up as things you need t…
On the other extreme, I've seen people ask why is that IP address divided by 16? (10.0.0.0/16)
Re: How a little bit of TCP knowledge is essential
#8Earlier quoted context omitted.
I used to thing this way before I realized it's just an arbitrary hoop you make people jump through. To you, people understanding TCP might be what you claim is a basic foundation. However, it's just about as arbitrary as asking people to explain 802.11 RTS/CTS or clos switch fabrics, which are both equally as important to delivering day-to-day network traffic. Additionally, they both can come up as things you need t…
On the other extreme, I've seen people ask why is that IP address divided by 16? (10.0.0.0/16)
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Re: How a little bit of TCP knowledge is essential
#9This can be generalised. It is also one of my favorite ways of doing developer interviews. Do they have a working/in-depth knowledge of what keeps the inter webs running? So many people have never ventured out of their main competence bubble, and that bubble can be quite small (but focused, I suppose). For all I know, they believe everything is kept together with the help of magic. I guess I don't trust people who do…
I used to thing this way before I realized it's just an arbitrary hoop you make people jump through. To you, people understanding TCP might be what you claim is a basic foundation. However, it's just about as arbitrary as asking people to explain 802.11 RTS/CTS or clos switch fabrics, which are both equally as important to delivering day-to-day network traffic. Additionally, they both can come up as things you need t…
I learned a lot about TCP (including delayed acks), the basics of 802.11, and the basics of switching fabrics in my undergrad networking class, so I wouldn't say it's totally unrealistic for someone to talk a little about those topics, depending on the role.
Re: How a little bit of TCP knowledge is essential
#10Can wireshark/riverbed (application perf tests) profiling help to solve these kind of problems?
wireshark would totally help!