TCP Flags Continued: CWR + ECE

Today we venture forth looking at a couple of additional flags found in the TCP header: CWR and ECE. These TCP flags are used together with two flags in the IP header (ECT and CE) to warn senders of congestion in the network thereby avoiding packet drops and retransmissions. Background…

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Packet Congestion Ahead

Why the 200ms delay? Over the course of our work, we have the fortune of diving into numerous network issues. One particularly interesting one involves a curious ~200ms delay in the acknowledgement of the response packet for small HTTP responses. This doesn’t sound all that terrible unless you have a…

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Dissecting DNS Communications

In our previous articles on DNS we gave an overview of the recursion process, but before we can go further on how DNS impacts performance, we need to understand how it the DNS protocol works. In the TCP/IP Protocol suite, DNS is an application layer protocol. DNS protocol relies on…

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RUM Vs. Synthetic Data Analysis

When performing statistical analysis on aggregations, it is very important to understand its subsets. This is especially true when interpreting RUM data aggregated across multiple regions, since an end user’s distance from the datacenter hosting the website impacts the performance of the page on end user’s browser. To illustrate this…

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