If you want to become a low-level programmer, it will come in handy to know the basics of computer networks.
I have listed a couple of good sources for understanding the OSI models and network layers. There are some terms below as well to get started with.
What is the OSI Model?
Network Starter Pack
XDP: eXpress Data Path
IGMP: Internet Group Management Protocol
OSI Model: Open System Interconnection Model
DPDK: Data Plane Development Kit
NIC: Network Interface Card
DRAM: Dynamic Random Access Memory
MMU: Memory Management Unit
TLS: Transport Layer Security
Egress: Traffic that exits a network boundary
Ingress: Traffic that enters a network boundary
Time synchronization problems exist in many systems. The solution for it is to coordinate the time of independent clocks, such that if you ask “what time is it” from all machines in different locations, they all give the same answer. These machines could be running from any server from any location in the world. There are some terms that are good to know when working on such problems. I have listed some of them below:
Relative offset: Offset between any two clocks
Synchronization: Minimization of relative offset regardless of the accuracy
Clock offset: The differences between two clocks of machines
Clock skew: frequency at time T – the true frequency
Relative skew: Skew between any two clocks
Jitter: Short-term variation in frequency
Wander: Longer-term variation in frequency
PTP: Precision Time Protocol
NTP: Network Time Protocol
TSC: Time Stamp Counter
There are different types of clocks such as:
System Clock: Measures Unix Time (count since 1 Jan. 1970)
Steady Clock: Count ticks of constant clock ticks (since reboot time)
High-Resolution Clock: Counts the smallest tick of the clock
UTC Clock: Measures since 00:00:00 UTC 1970
Tai Clock: Measures 00:00:00 1958
Now, let’s go over one of the time protocols, called PTP.
Below you can see a PTP exchange between a server and a client scenario.
