HyperNAT: Scaling Up Network AddressTranslation with SmartNICs for Clouds

Abstract

Network address translation (NAT) is a basic functionality in cloud gateways. With the increasing traffic volume and number of flows introduced by the cloud tenants, the NAT gateway needs to be implemented on a cluster of servers. We propose to scale up the gateway servers, which could reduce the number of servers so as to reduce the capital expense and operation expense. We design HyperNAT, which leverages smartNICs to improve the server's processing capacity. In HyperNAT, the NAT functionality is distributed on multiple NICs, and the flow space is divided and assigned accordingly. HyperNAT overcomes the challenge that the packets in two directions of one connection need to be processed by the same NAT rule (named two-direction consistency, TDC) by cloning the rule to both data paths of the two directions. Our implementation and evaluation of HyperNAT show that HyperNAT could scale up cloud gateway effectively with low overhead.

A Comprehensive Study on Optimizing Systems with Data Processing Units

“…With the release of off-path Smart-NICs, some researches on off-path SmartNICs appear [25-27, 40, 41, 48]. For example, HyperNAT [26] offloads network address translation to off-path SmartNICs. SKV [27] uses a BlueField SmartNIC to offload data replication in a distributed key-value store.…”

“…Among existing works, some of them have started offloading applications to off-path SmartNICs without understanding the features of the SmartNICs [25,26,40,41]. There are also researchers that characterize the performance of off-path SmartNICs [42].…”

“…However, their performance tests for Smart-NICs are not comprehensive, and they do not summarize any guidelines for using off-path SmartNICs. In addition, most of the works tend to focus on offloading a specific application, such as file system [25], distributed key-value store [27], and network address translation [26]. However, none of them has proposed a universal solution for using off-path SmartNICs for any systems.…”

“…In addition, they tend to have a complete network stack and full operating system, providing high programmability. Therefore, in some recent studies, off-path SmartNICs are used to offload file system [25], network address translation [26], key-value store [27], etc. Although off-path SmartNICs have many advantages over on-path SmartNICs, using them to offload applications can be challenging.…”