# Public Transit Latency

## Overview

Public IP Transit - Network Latency displays real-time average latency between Zenlayer PoPs over the public internet. This module reflects latency performance across our global 220+ Tbps IP transit network, offering insights into public routing quality between various regions and ISPs. It helps users monitor public network health, compare performance with private backbone routes, and optimize global traffic delivery strategies. It usually has the following common use cases:

### Common Use Cases

<table><thead><tr><th width="184.84765625">Scenario</th><th>Description</th></tr></thead><tbody><tr><td>Public network benchmarking</td><td>Assess end-to-end latency over the public internet across global regions</td></tr><tr><td>Route comparison</td><td>Compare public IP transit latency against Zenlayer’s private backbone</td></tr><tr><td>ISP path evaluation</td><td>Identify high-latency or underperforming public paths between cities</td></tr><tr><td>Performance troubleshooting</td><td>Detect cross-border congestion or irregular routing behavior</td></tr></tbody></table>

## Procedures

<div align="left"><figure><img src="https://3201622183-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F9X3FDdkCL2HzhbPpPMFt%2Fuploads%2FPZA6a3ruvmVVyvBuB06j%2Fimage.png?alt=media&#x26;token=e556d691-34e1-4d67-876d-6efbffbabdcf" alt=""><figcaption></figcaption></figure></div>

### Parameter Explanation

<table><thead><tr><th width="197.03125">Parameter</th><th>Description</th></tr></thead><tbody><tr><td>PoP Node</td><td>A Zenlayer Point of Presence participating in public IP transit. Each row/column represents a PoP city.</td></tr><tr><td>Average Latency (ms)</td><td>The average round-trip latency between two PoPs over the public internet within the past 24 hours.</td></tr><tr><td>Region Tag</td><td>PoPs are grouped and color-coded by geographic region (e.g., Asia Pacific, Europe, North America).</td></tr></tbody></table>

1. Input or select cities one or more cities to include in the latency matrix.\
   The chart displays average round-trip latency (ms) between selected PoPs over the past 24 hours.&#x20;
2. Hover over any cell to see the city pair and latency value.

## FAQ

**Q1: What does the latency value represent?**\
A1: It shows the average round-trip latency between two PoPs over the public IP transit network, measured over the past 24 hours.

**Q2: Why is latency higher than on the private backbone?**\
A2: Public internet routing is subject to congestion, ISP peering arrangements, and less predictable path selection compared to Zenlayer's controlled private backbone.

**Q3: Can I export the latency data?**\
A3: Export functionality is not currently available. Please contact Zenlayer support or your account manager for detailed reporting needs.

**Q4: How often is the data updated?**\
A4: Latency data is continuously measured and reflects the average over the most recent 24-hour period.