network_stuff:ptp
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| network_stuff:ptp [2025/05/17 09:53] – created jotasandoku | network_stuff:ptp [2025/06/17 15:01] (current) – jotasandoku | ||
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| - | Here’s the same PTP explanation formatted in proper **DokuWiki ASCII-style** markup: | ||
| - | |||
| - | ``` | ||
| ===== Precision Time Protocol (PTP) – A Deep Dive for Network Engineers ===== | ===== Precision Time Protocol (PTP) – A Deep Dive for Network Engineers ===== | ||
| Line 16: | Line 13: | ||
| ==== Why NTP Falls Short ==== | ==== Why NTP Falls Short ==== | ||
| - | NTP uses software timestamps and is vulnerable to OS and network delays. This leads to variability and drift. Accuracy is typically 1–50 ms, which is insufficient for ultra-low-latency applications. | + | NTP uses software timestamps and is vulnerable to OS and network delays. This leads to variability and drift. Accuracy is typically |
| PTP solves this by: | PTP solves this by: | ||
| Line 71: | Line 68: | ||
| | Use Cases | IT/general syncing | | Use Cases | IT/general syncing | ||
| | HW Support Needed | No | Yes (for full accuracy) | | | HW Support Needed | No | Yes (for full accuracy) | | ||
| + | |||
| + | ==== Practical Notes and Best Practices ==== | ||
| + | |||
| + | * **Enable hardware timestamping** on all devices where possible — it's essential for precision. | ||
| + | * **Use dedicated VLANs or VRFs** for PTP traffic to eliminate jitter from other traffic types. | ||
| + | * **Deploy boundary clocks** at distribution layer to reduce dependency on transparent clocks. | ||
| + | * **Use GPS-disciplined GMs** (rubidium-based for redundancy) and monitor GNSS lock status. | ||
| + | * **Ensure symmetry in paths** — avoid asymmetric routing or it will break delay calculations. | ||
| + | * **Use `phc2sys` and `ptp4l` on Linux** when implementing software agents (e.g., in servers or appliances). | ||
| + | * **Monitor delay and offset values** constantly — use tools like `pmc` or vendor telemetry APIs. | ||
| + | * **Test failover behavior** with GM outages and validate that slaves shift gracefully. | ||
| + | * **Avoid multicast storms** — ensure IGMP snooping and PTP profile-specific multicast group filtering are properly configured. | ||
| + | * **Log PTP state changes** — especially for MiFID II compliance in finance (e.g., GM sync loss or clock steps). | ||
| ==== Final Notes ==== | ==== Final Notes ==== | ||
| PTP brings **deterministic, | PTP brings **deterministic, | ||
| - | ``` | ||
| - | |||
| - | Let me know if you'd like this added to your notes or exported as a `.txt` or `.pdf` file. | ||
network_stuff/ptp.1747475608.txt.gz · Last modified: by jotasandoku
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