Performance Analysis of VPN Impact on 4G LTE and 5G Network Connections
|
Configuration
|
Avg Latency (ms)
|
Max Latency (ms)
|
Stability
|
|---|---|---|---|
|
Leaky RX–TX
|
28.93
|
38059
|
Excellent
|
|
Leaky TX–RX
|
72.08
|
237.02
|
Unacceptable
|
|
Standard Duplexer
|
29.83
|
45.71
|
Excellent
|
|
Amplified Duplexer
|
33.77
|
61.80
|
Moderate
|
Abstract
Virtual Private Networks (VPNs) are widely used to enhance security and privacy in mobile communications, but their impact on network performance remains a critical concern for users and network operators. This study presents a comprehensive analysis of VPN performance overhead across multiple 4G LTE and 5G network configurations, examining throughput, latency, and reliability metrics. We conducted 48 controlled experiments across six different network modes ranging from 4G LTE to 5G with varying bandwidth allocations (10-60 MHz). Our findings reveal that VPN implementations introduce substantial performance penalties, with download speeds degraded by an average of 95.1%, upload speeds reduced by 35.3%, and latency increased by 819.8%. The performance impact is particularly pronounced in high-bandwidth 5G configurations, where the VPN infrastructure appears to create a significant bottleneck that prevents users from realizing the full potential of modern cellular networks. These results have important implications for VPN design, network planning, and user experience optimization in next-generation mobile networks.
1. Introduction
1.1 Background
The proliferation of mobile devices and the increasing sensitivity of data transmitted over cellular networks have driven widespread adoption of Virtual Private Network (VPN) technologies. VPNs provide encryption, authentication, and privacy protection by creating secure tunnels between user devices and remote servers. However, these security benefits come at a cost in terms of network performance due to encryption overhead, additional packet headers, routing inefficiencies, and server processing limitations.
The deployment of 5G networks promises significantly higher throughput and lower latency compared to previous generations of cellular technology. With theoretical peak speeds exceeding 1 Gbps and latency below 10 ms, 5G networks are designed to support demanding applications including augmented reality, cloud gaming, and real-time video streaming. Understanding how VPN implementations perform across different network configurations is essential for optimizing user experience and informing infrastructure investment decisions.
1.2 Methodology
We conducted controlled network performance tests across six device configurations using standardized testing procedures. Each device was tested under identical conditions with and without VPN connectivity, measuring uplink speed, downlink speed, latency characteristics, and packet loss. The network modes tested included:
- 4G LTE with 10 MHz bandwidth
- 5G n3 (3.5 GHz band) with 10 MHz bandwidth
- 5G n78 (3.5 GHz band) with bandwidth allocations of 10, 15, 20, 30, 40, 50, and 60 MHz
A total of 48 test instances were collected, with six devices tested across eight different network configurations. Each test measured multiple performance metrics to provide a comprehensive view of VPN impact.
2. Results
2.1 Throughput Analysis
2.1.1 Downlink Performance
The result shows the severe impact of VPN on download speeds. Across all network configurations, the average downlink speed decreased from 50.96 Mbps with direct connections to just 2.51 Mbps through VPN, representing a 95.1% reduction in throughput.
|
Network Mode
|
Direct (Mbps)
|
VPN (Mbps)
|
Reduction (%)
|
|---|---|---|---|
|
4G LTE 10MHz
|
40.70
|
4.01
|
90.2%
|
|
5G n3 10MHz
|
19.50
|
2.76
|
85.8%
|
|
5G n78 10MHz
|
21.88
|
1.39
|
93.6%
|
|
5G n78 15MHz
|
19.36
|
1.59
|
91.8%
|
|
5G n78 20MHz
|
44.36
|
1.46
|
96.7%
|
|
5G n78 30MHz
|
55.85
|
2.77
|
95.0%
|
|
5G n78 40MHz
|
74.64
|
3.81
|
94.9%
|
|
5G n78 50MHz
|
94.03
|
2.59
|
97.2%
|
|
5G n78 60MHz
|
106.08
|
1.64
|
98.5%
|
|
Overall Average
|
50.96
|
2.51
|
95.1%
|
<Table 1: Average Downlink Performance by Network Mode>
The impact varied by network mode. For 4G LTE networks, direct connections averaged 40.70 Mbps while VPN connections achieved only 4.01 Mbps (90.2% reduction). The degradation was even more pronounced in 5G configurations, particularly at higher bandwidths.
In 5G n78 networks with 60 MHz bandwidth allocation, direct connections achieved impressive speeds ranging from 84.6 to 161.3 Mbps across different devices. However, VPN connections in the same configuration were limited to just 1.3 to 2.3 Mbps, representing throughput reductions of 98-99%. This pattern suggests that the VPN infrastructure itself represents a fundamental bottleneck that prevents users from benefiting from high-bandwidth 5G deployments.
2.1.2 Uplink Performance
Upload speeds showed a more complex pattern. The average uplink speed decreased from 4.82 Mbps for direct connections to 3.12 Mbps through VPN, representing a 35.3% reduction. However, the variability was substantial, with individual test instances showing anywhere from significant improvements to severe degradation.
|
Network Mode
|
Direct (Mbps)
|
VPN (Mbps)
|
Change (%)
|
|---|---|---|---|
|
4G LTE 10MHz
|
8.53
|
3.87
|
-54.6%
|
|
5G n3 10MHz
|
4.62
|
3.46
|
-25.1%
|
|
5G n78 10MHz
|
7.23
|
1.20
|
-83.4%
|
|
5G n78 15MHz
|
6.67
|
1.77
|
-73.5%
|
|
5G n78 20MHz
|
5.21
|
4.44
|
-14.8%
|
|
5G n78 30MHz
|
2.17
|
5.09
|
+134.6%
|
|
5G n78 40MHz
|
2.49
|
3.30
|
+32.5%
|
|
5G n78 50MHz
|
2.44
|
3.33
|
+36.5%
|
|
5G n78 60MHz
|
2.62
|
2.07
|
-21.0%
|
|
Overall Average
|
4.82
|
3.12
|
-35.3%
|
<Table 2: Average Uplink Performance by Network Mode>
In 4G LTE networks, average uplink speeds decreased from 8.53 Mbps to 3.87 Mbps (54.6% reduction). In 5G networks, the pattern was less consistent. Some configurations, particularly 5G n78 at 20-40 MHz, showed instances where VPN uplink speeds actually exceeded or matched direct connection speeds, suggesting that routing or Quality of Service policies may interact in complex ways with VPN traffic.
The 5G n3 configuration showed moderate uplink degradation, with speeds declining from an average of 4.62 Mbps to 3.46 Mbps (25.1% reduction). The relatively better performance compared to downlink may reflect asymmetric VPN server capacity or prioritization of certain traffic types.
2.2 Latency Analysis
2.2.1 Average Latency
VPN usage resulted in dramatic increases in network latency. Average ping times increased from 25.9 ms for direct connections to 238.1 ms through VPN, representing an 819.8% increase. This nearly tenfold increase in latency has significant implications for real-time applications including voice calls, video conferencing, and interactive gaming.
|
Network Mode
|
Direct (Mbps)
|
VPN (Mbps)
|
Increase (%)
|
|---|---|---|---|
|
4G LTE 10MHz
|
26.1
|
282.9
|
+983.9%
|
|
5G n3 10MHz
|
45.0
|
355.2
|
+689.3%
|
|
5G n78 10MHz
|
26.1
|
380.8
|
+1358.6%
|
|
5G n78 15MHz
|
26.8
|
440.8
|
+1545.5%
|
|
5G n78 20MHz
|
26.4
|
305.8
|
+1058.3%
|
|
5G n78 30MHz
|
27.6
|
304.2
|
+1002.2%
|
|
5G n78 40MHz
|
28.8
|
374.1
|
+1198.6%
|
|
5G n78 50MHz
|
27.4
|
376.7
|
+1274.8%
|
|
5G n78 60MHz
|
26.4
|
422.3
|
+1499.6%
|
|
Overall Average
|
25.9
|
238.1
|
+819.8%
|
<Table 3: Average Latency by Network Mode>
The latency impact was relatively consistent across network modes. In 4G LTE, average ping times increased from 26.1 ms to 282.9 ms. In 5G networks, the impact was similar, with direct connection latencies of 25-30 ms increasing to 300-400 ms through VPN in most configurations.
The consistency of latency degradation across different network modes suggests that the primary latency contribution comes from VPN server processing and routing rather than the cellular network itself. Even in low-latency 5G networks, the VPN infrastructure adds approximately 200-350 ms of additional delay.
2.2.2 Latency Variability
Beyond average latency, VPN connections showed significantly higher variability in response times. The standard deviation of ping times increased from an average of 13.4 ms for direct connections to 343.6 ms through VPN, a 2465% increase.
|
Metric
|
Direct (Mbps)
|
VPN (Mbps)
|
Increase (%)
|
|---|---|---|---|
|
Min Ping (ms)
|
16.4
|
115.8
|
+606.1%
|
|
Avg Ping (ms)
|
25.9
|
238.1
|
+819.8%
|
|
Max Ping (ms)
|
70.5
|
783.5
|
+1011.3%
|
|
Std Dev (ms)
|
13.4
|
343.6
|
+2465.7%
|
<Table 4: Latency Variability Metrics>
Maximum ping times were particularly problematic, with some VPN connections experiencing spikes exceeding 5000 ms (5 seconds). In direct connections, maximum ping times averaged 70.5 ms across all configurations. With VPN, this increased to 783.5 ms on average, with individual instances reaching 5290 ms in the most extreme case.
This high variability indicates that VPN connections experience periodic congestion or processing delays that result in severe temporary performance degradation. Such unpredictable behavior is particularly problematic for applications requiring consistent low latency.
2.3 Packet Loss
Packet loss remained minimal in both direct and VPN connections across most test instances, with 46 of 48 tests showing 0% packet loss for both connection types. Two tests showed 5% packet loss specifically in VPN connections, suggesting that while VPN generally maintains connection reliability, occasional instances of packet loss can occur that are not present in direct connections.
The low overall packet loss rates indicate that the VPN infrastructure, while significantly impacting speed and latency, maintains reasonable connection stability and does not frequently drop packets.
2.4 Bandwidth Scaling Effects
A critical finding of this study is that VPN performance does not scale with available network bandwidth. As cellular network bandwidth increased from 10 MHz to 60 MHz in 5G n78 configurations, direct connection speeds increased proportionally, ranging from approximately 20 Mbps to over 160 Mbps for downlink traffic.
|
Bandwidth
|
Direct Downlink (Mbps)
|
VPN Downlink (Mbps)
|
VPN Bottleneck
|
|---|---|---|---|
|
10 MHz
|
21.9
|
1.4
|
93.6% loss
|
|
15 MHz
|
19.4
|
1.6
|
91.8% loss
|
|
20 MHz
|
44.4
|
1.5
|
96.7% loss
|
|
30 MHz
|
55.9
|
2.8
|
95.0% loss
|
|
40 MHz
|
74.6
|
3.8
|
94.9% loss
|
|
50 MHz
|
94.0
|
2.6
|
97.2% loss
|
|
60 MHz
|
106.1
|
1.6
|
98.5% loss
|
<Table 5: Bandwidth Scaling Comparison (5G n78)>
However, VPN throughput remained consistently low regardless of available bandwidth, typically staying between 1-7 Mbps for downlink traffic. This pattern strongly suggests that the VPN implementation has an inherent capacity limitation that prevents it from utilizing high-bandwidth connections effectively.
The bottleneck appears to be on the VPN server side or in the encryption/decryption processing pipeline rather than in the cellular network itself. Users on high-speed 5G networks receive no additional benefit when using VPN compared to those on lower-bandwidth networks, effectively wasting the potential of 5G infrastructure.
3. Discussion
3.1 Implications for VPN Architecture
The results of this study highlight fundamental limitations in current VPN implementations when applied to high-bandwidth mobile networks. The near-total elimination of 5G performance advantages when using VPN suggests that VPN infrastructure has not scaled to match the capabilities of modern cellular networks.
Several factors may contribute to this bottleneck. First, VPN servers may have insufficient bandwidth allocation to handle the aggregate traffic from multiple users at 5G speeds. Second, encryption and decryption processing may represent a computational bottleneck, particularly if servers are handling large numbers of simultaneous connections. Third, routing inefficiencies may occur if VPN traffic takes suboptimal network paths compared to direct connections.
The asymmetric impact on uplink versus downlink traffic suggests that VPN providers may prioritize or allocate resources differently for different traffic directions. The relatively better uplink performance may indicate that upload capacity is less constrained or that Quality of Service policies favor certain traffic patterns.
3.2 User Experience Considerations
From a user perspective, the performance penalties documented in this study have significant practical implications. Download-intensive activities such as video streaming, file downloads, and software updates will be severely impacted by VPN usage. A user on a high-speed 5G network who might normally download a 1 GB file in approximately 2 minutes would instead require approximately 1 hour through VPN.
The latency increases are particularly concerning for real-time applications. Voice over IP calls, video conferencing, and online gaming all depend on low latency for acceptable user experience. The 200-350 ms additional latency introduced by VPN, combined with high variability, would result in noticeable delays and potential connection quality issues.
Users must therefore make explicit tradeoffs between security/privacy benefits and performance when deciding whether to enable VPN on mobile connections. For time-sensitive or bandwidth-intensive tasks, users may need to temporarily disable VPN, potentially exposing themselves to security risks.
3.3 Network Planning Implications
For mobile network operators investing in 5G infrastructure, these findings suggest that the value proposition of high-speed networks may be diminished for privacy-conscious users who rely on VPN services. If a significant portion of users enable VPN, the network operator’s investment in 5G capacity may not translate into improved user experience.
Network operators might consider several strategies to address this issue. First, they could partner with VPN providers to optimize routing and potentially provide dedicated infrastructure for VPN traffic. Second, they could implement network-level privacy features that reduce users’ perceived need for third-party VPN services. Third, they could provide guidance and transparency to users about VPN performance impacts to set appropriate expectations.
4. Conclusion
This comprehensive study of VPN performance across 4G LTE and 5G networks reveals substantial performance penalties that fundamentally limit the user experience benefits of modern high-bandwidth cellular networks. With download speeds reduced by 95.1%, upload speeds reduced by 35.3%, and latency increased by 819.8%, VPN usage effectively negates most of the performance advantages that 5G networks are designed to provide.
The most concerning finding is that VPN performance does not scale with available network bandwidth. Users on high-speed 5G networks with 100+ Mbps direct connection capabilities are limited to the same 1-7 Mbps throughput as users on much slower networks when VPN is enabled. This suggests fundamental infrastructure limitations in current VPN implementations that prevent them from adapting to next-generation network capabilities.
These findings have important implications for multiple stakeholders. VPN providers must invest in infrastructure improvements and protocol optimizations to support the throughput and latency requirements of 5G users. Network operators should account for VPN usage patterns when planning network capacity and consider strategies to help privacy-conscious users achieve better performance. End users must make informed decisions about when to enable VPN based on their immediate needs for security versus performance.
As mobile networks continue to evolve toward even higher speeds with 5G Advanced and eventual 6G deployments, addressing the VPN performance bottleneck will become increasingly critical. The security and privacy benefits that VPNs provide remain valuable, but they must be delivered in ways that allow users to benefit from the full capabilities of modern network infrastructure.
The path forward requires collaboration between VPN providers, network operators, and standards bodies to develop solutions that provide strong privacy protection without the severe performance penalties documented in this study. Only through such efforts can we ensure that users do not have to choose between security and performance in an increasingly connected world.
This project has received partial funding from the Horizon Europe programme of the European Union under HORIZON-JU-SNS-2022 FIDAL program, grant agreement No. 101096146
English