On the Impact of Mobile Network Delays on Connection Establishment Performance of a Carrier Grade NAT Device

IPv4 addresses are nearly exhausted worldwide. For some time until IPv6 becomes pervasive as an ultimate solution, deployment of Carrier Grade NAT (CGN) devices becomes necessary, especially in the mobile carriers' networks which anticipate a large and growing number of new users. In this context, we tackle the evaluation of the impact of inserting a CGN device in the network, and in conjunction with the mobile network communication delays. We compare the Connection Establishment Rate (CER) with or without a CGN device, also with or without the emulated mobile network communication delays. Against our anticipation, the types of time-varying mobile network delays do not have a significant impact on CER. The effect of the changing delay fades away in the aggregation of many user traffic at the core part of the network, even though the time-varying mobile network communication delays are individually and separately emulated for each user. To the best of our knowledge, this is the first to study the relationship between the CGN performance and the mobile network's communication delays. The result suggests that modeling the aggregate traffic trend (such as the constant delay portion in the network dynamics) is more important rather than emulating each user's traffic separately.