Virtual vpn in the cloud

5.3
 
Results for UDP traffic 
To ensure good link quality, packet loss of the network is maintained below 1% [35]. 
UDP throughput and jitter are calculated between different combinations of encryption 
and hashing algorithms for different packet sizes of 1500, 1000, 500 and 250.
5.3.1
 
Throughput analysis 
Figure 16: UDP throughput at different MTUs 
Similar algorithmic performance is observed by UDP packets, where 
AES128-MD5 performs the best followed by AES256-MD5 and AES128-SHA256. Reasons 
being the same due to the deteriorative performance by SHA in comparison to MD5 and the 
superiority of AES over 3DES.

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5.3.2
 
Jitter analysis 
Figure 17: UDP Jitter at different MTUs 
Jitter is considered among different combinations of encryption and hashing 
algorithms with different packet sizes. The jitter for tunneled traffic is observed to be more 
than in non-tunneled/plaintext traffic, due to additional overhead introduced for data 
encryption. Extra cryptographic overheads increase network complexity thus increasing jitter 
in the network. DES is observed to exhibit the maximum delay in comparison to the other 
combinations, because of similar reasons involving hardware compatibility, weak and slower 
keys and longer time period.
5.4
 
 
Results for resource allocation
•
VM provisioning latency 
According to the NFV Service Quality Metrics document published by ETSI [43], 
VM provisioning latency is the time elapsed between a VM provisioning request being 
presented and the corresponding response being returned. The average value required for 
VM resource allocation is measured and evaluated below along with 95% confidence 
interval. 
Average 
23.4 sec 
≈
23 seconds 
Half-length 95 % Confidence Interval 
0.72
≈
1 

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