NAT-compatibility testbed: An environment to automatically verify direct connection rate

Cheng Yuan Ho, Fu Yu Wang, Chien-Chao Tseng*, Ying-Dar Lin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


In this article, an NAT-compatibility testbed is designed to automatically conduct the repeated experiments, collect the test results, and verify the direct connection rate (DCR) of any NAT traversal programs. Achieving a high DCR is important because using relays may unnecessarily increase the bandwidth cost, processing load of the relay servers, and the end-to-end packet delay. The NAT-compatibility testbed is constructed with 4 components: two peers, an automatic execution mechanism, NAT devices, and signaling/intermediate servers such as STUN, TURN, and SIP. It is also called the fully meshed testbed because the test result of all NAT combinations is a square. It measures the DCR of ICE, KeyStone, and PJNATH as 53.7%, 59.87%, and 50.93%, respectively. Experimental results show that asymmetric and unexpected direct connectivity check results occur in the real Internet. In order to enhance NAT traversal capability, the findings, like "port prediction" and "call-role sensitivity problem," are also described in the experimental results.

Original languageEnglish
Article number5620993
Pages (from-to)4-6
Number of pages3
JournalIEEE Communications Letters
Issue number1
StatePublished - Jan 2011


  • NAT
  • NAT traversal
  • direct connection
  • testbed


Dive into the research topics of 'NAT-compatibility testbed: An environment to automatically verify direct connection rate'. Together they form a unique fingerprint.

Cite this