Packet classification is an essential function for many applications such as QoS provisioning and network intrusion detection. In this work, we perform random forest classification in the pipelines ...of a hardware switch to classify packets at 100 Gbps line rate. We design, implement, and evaluate the performance of our scheme in a P4 (Programming Protocol-independent Packet Processors) programmable hardware switch. Experimental results show that our scheme can: 1) support a random forest composed of more than 100 decision trees in the pipelines of a hardware switch; and 2) use such a large random forest to classify packets at 100 Gbps line rate. In this paper, we design the match-action rules that are required to implement such a random forest in a P4 hardware switch. Besides, we analytically derive the formulas that give the number of these rules.
Real-time applications such as video conferencing, virtual reality (VR), high-speed train controls, nuclear plant controls, etc. impose stringent limitations on the maximum end-to-end latency that ...their packets can tolerate. In such applications, if a packet arrives at its destination node but misses its deadline, it will be useless. On a network, a packet often needs to pass multiple switches on its way from its source node to its destination node. In some of these switches, the packet may experience large queuing delays and the accumulation of these delays may cause the packet to miss its deadline at its destination node. In this work, we design and implement an earliest-deadline-first (EDF) packet scheduling scheme in P4 hardware switches to overcome this problem. We implement two versions of our scheme that use two queues and six queues respectively for real-time packets to study how the number of queues may affect the performance of our scheme. We evaluate the performance of our scheme under different levels of congestion conditions. Experimental results show that, compared with the baseline scheme that dispatches all real-time packets to the same high-priority queue, our scheme greatly reduces the deadline miss rate of real-time packets when the real-time traffic ratio in the network is between 40% and 80%.
Metering the traffic of a flow and dropping the portion of traffic that exceeds the target rate set by the meter is very important to provide quality of service (QoS) in a network. Most existing ...switches on the market provide the meter function. Although these meters regulate the traffic of a UDP flow very well, according to our tests, they are not TCP-friendly. For example, we found that a TCP flow passing the meter of a commercial switch can only achieve about 10% of the target rate. Based on our studies, we found that this poor performance is due to the bad interactions between the TCP congestion control and the meter function. In this paper, we design and implement a TCP-friendly meter in the packet processing pipelines of a P4 switch. Experimental results show that our meter regulates a TCP flow very well and can maintain its achieved rate within 5% of the target rate. Compared with the meters in several hardware switches, our meter improves the achieved rate of a TCP flow by almost 85% of the target rate.
•Several VZV-encoded replication enzymes per se are localized in the cytoplasm.•The nuclear import of VZV ORF28 can be mediated by ORF16.•ORF16 can enhance the protein abundance of ORF28.•The low ...abundance of ORF28 in cells is due to rapid degradation by the proteasome.•Radicicol, a Hsp90 inhibitor, can disrupt the interaction between ORF16 and ORF28.
Although all herpesviruses utilize a highly conserved replication machinery to amplify their viral genomes, different members may have unique strategies to modulate the assembly of their replication components. Herein, we characterize the subcellular localization of seven essential replication proteins of varicella-zoster virus (VZV) and show that several viral replication enzymes such as the DNA polymerase subunit ORF28, when expressed alone, are localized in the cytoplasm. The nuclear import of ORF28 can be mediated by the viral DNA polymerase processivity factor ORF16. Besides, ORF16 could markedly enhance the protein abundance of ORF28. Noteworthily, an ORF16 mutant that is defective in nuclear transport still retained the ability to enhance ORF28 abundance. The low abundance of ORF28 in transfected cells was due to its rapid degradation mediated by the ubiquitin-proteasome system. We additionally reveal that radicicol, an inhibitor of the chaperone Hsp90, could disrupt the interaction between ORF16 and ORF28, thereby affecting the nuclear entry and protein abundance of ORF28. Collectively, our findings imply that the cytoplasmic retention and rapid degradation of ORF28 may be a key regulatory mechanism for VZV to prevent untimely viral DNA replication, and suggest that Hsp90 is required for the interaction between ORF16 and ORF28.
Recently, NB-IoT, LTE Cat-M1, Sigfox, and LoRa have been proposed as promising Low-Power Wide Area Networks (LPWANs) technologies for Internet-of-Things (IoT) applications. These technologies are ...aimed for IoT applications such as smart meters that can tolerate long transmission delays and only need a narrow band to periodically transmit a small amount of data. Although the performances of these technologies have been studied or compared in the literature, most comparisons were conducted in non-mobile conditions. In this work, we used a drone flying at 70 km/hr along a 10 km motorway to act as a mobile IoT end device to do the performance measurements. In this paper, we report and compare the performances of these technologies in such high-speed mobile conditions in the air.
An intrusion detection system (IDS) checks the content of headers and payload of packets to detect intrusions from the network. It is an essential function for network security. Traditionally, an ...IDS, such as Snort, which is a widely used open source IDS, is implemented as a program running in the user space on a hardware server. Recently, with the availability of Extended BPF (eBPF) in the Linux kernel, efficiently checking and filtering arriving packets directly in the kernel becomes feasible. In this work, we design and implement an IDS that has two parts working together. The first part runs in the Linux kernel. Its uses eBPF to perform fast patterns matching to pre-drop a very large portion of packets that have no chance to match any rule. The second part runs in the user space. It examines the packets left by the first part to find the rules that match them. Using a modified version of the registered ruleset of Snort, experimental results show that the maximum throughput of our IDS system can outperform that of Snort by a factor of 3 under many tested conditions.
Aggregating multiple small packets into a large packet provides many advantages. For example, multiple small packets can share a single copy of common Ethernet/IP/UDP headers to reduce the percentage ...of network bandwidth spent on transmitting headers. In the past, packet aggregation and disaggregation were done by a server CPU or a switch CPU, resulting in low throughputs. In this paper, we design and implement packet aggregation and disaggregation functions in the packet processing pipelines of P4 switches. Our novel designs allow packets with various sizes of payload to be aggregated and disaggregated purely in the data plane of a P4 switch. Experimental results show that the achieved throughputs of our aggregation and disaggregation methods can reach 100 Gbps, which is the line rate of the used P4 switch.
In this paper, we compare and evaluate the correctness, performance, and scalability of EstiNet OpenFlow simulator, EstiNet OpenFlow emulator, and Mininet OpenFlow emulator over a set of grid ...networks. The popular Floodlight OpenFlow controller is used without any modification to control the simulated/emulated OpenFlow switches created in these tools. We performed experiments over a set of N × N grid networks, where N = 5, 6, ..., 31 and used the real-world ping program to observe whether the average RTTs reported by these ping packets are correct or not over these tools. We found that in EstiNet simulation, the simulated results of the average RTT are always correct and repeatable, but EstiNet simulator needs more time to finish the simulation when the network size becomes larger. As for emulation, we found that Mininet emulator generated strange results that cannot be explained over some network sizes. In addition, Mininet emulator spends a huge amount of time on its program launch, network setup, and resource releasing when the network size is large. As for EstiNet emulator, we found that it generated good performance and scalability and it used less time to obtain results.
In many Internet of Things (IoT) applications, large numbers of small sensor data are delivered in the network, which may cause heavy traffics. To reduce the number of messages delivered from the ...sensor devices to the IoT server, a promising approach is to aggregate several small IoT messages into a large packet before they are delivered through the network. When the packets arrive at the destination, they are disaggregated into the original IoT messages. In the existing solutions, packet aggregation/disaggregation is performed by software at the server, which results in long delays and low throughputs. To resolve the above issue, this paper utilizes the programmable Software Defined Networking (SDN) switch to program quick packet aggregation and disaggregation. Specifically, we consider the Programming Protocol-Independent Packet Processor (P4) technology. We design and develop novel P4 programs for aggregation and disaggregation in commercial P4 switches. Our study indicates that packet aggregation can be achieved in a P4 switch with its line rate (without extra packet processing cost). On the other hand, to disaggregate a packet that combines
IoT messages, the processing time is about the same as processing
individual IoT messages. Our implementation conducts IoT message aggregation at the highest bit rate (100 Gbps) that has not been found in the literature. We further propose to provide a small buffer in the P4 switch to significantly reduce the processing power for disaggregating a packet.
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