# Report
_Prepared by Madina Gafarova SE-01_
## Lab 10

**Q1: What is a stratum in terms of NTP?**

In terms of NTP, a stratum is simply one layer in a hierarchical network of layers that distribute accurate time across a network of devices.

**Q2: Provide the output of ntpq -p command and describe the meaning of the following fields: remote, refid, st, t, when, poll, reach, delay, offset, and jitter**

Screenshot from the command: ``` ntpq -p ```

I have macOS and for conveniences launch addition instance on AWS.

**remote:** details the NTP servers we’re connected to

**refied:** remote source’s synchronization source. The server is ultimately getting its time from 192.36.143.130

**st:** stratum level of the source (refers to a server’s stratum, which refers to how close the server is from us)

**t:** types available, specifically whether the server is using unicast, broadcast, multicast, or manycast

**when:** refers to how long ago it was since the last time the server was polled.

**poll:** indicates how often the server will be polled

**reach:** indicates success/failure to reach source

**delay:** indicates the roundtrip time, in milliseconds, to receive a reply

**offset:** indicates the time difference

**jitter:** indicates the difference, in milliseconds, between two samples

**Q3: What are the lacks of using the Lamport’s algorithm?**

Lamport timestamp have one big shortcoming: it can’t tell you when two events are concurrent. Because the algorithm provides only partial order.

**Github**
https://github.com/gafmn/Clock-Synchronization