Type-Length-Value Research Articles

Python-Based TinyIPFIX in Wireless Sensor Networks

While wireless sensor networks (WSN) offer potential, their limited programmability and energy limitations determine operational challenges. Thus, a TinyIPFIX-based system was designed such that this application layer protocol is now used to exchange data in WSNs efficiently. The new prototype is based on the Espressif ESP32-WROOM-32D Internet-of-Things (IoT) platform, which is becoming famous, as it is inexpensive but powerful compared to older generations of IoT devices. The system implementation is provided in the programming language MicroPython, which provides a simple and efficient implementation, compared to a lower-level programming language. Therefore, this approach focuses on value creation rather than platform-specific implementation difficulties. The system is evaluated in smart home use cases and displays valuable overhead, reliability, and power efficiency. TinyIPFIX outperforms the data overhead of the type–length–value (TLV) paradigm by a factor of 7% when a TinyIPFIX data message carries only two records, and one TinyIPFIX template message is sent per three TinyIPFIX data messages. A further decrease in overhead is observed when the number of data records per message and the number of TinyIPFIX data messages sent per one TinyIPFIX template message increase to larger values. The message delivery between end devices and the application server resides at a very high level, close to 100%, when the transmission reliability is secured with acknowledgments and retransmissions. The energy efficiency resides at the limited level, as the experienced deep sleep power consumption of the ESP32 device resides at the milliwatt level.

MonLink: Piggyback Status Monitoring over LLDP in Software-Defined Energy Internet

While software-defined networking (SDN) has been widely applied in various networking domains including datacenters, WANs (Wide Area Networks), QoS (Quality of Service) provisioning, service function chaining, etc., it also has foreseeable applications in energy internet (EI), which envisions an intelligent energy industry on the basis of (information) internet. Global awareness provided by SDN is especially useful in system monitoring in EI to achieve optimal energy transportation, sharing, etc. Link layer discovery protocol (LLDP) plays a key role in global topology discovery in software-defined energy internet when SDN is applied. Nevertheless, EI-related status information (power loads, etc.) is not collected during the LLDP-based topology discovery process initiated by the SDN controller, which makes the optimal decision making (e.g., efficient energy transportation and sharing) difficult. This paper proposes MonLink, a piggyback status-monitoring scheme over LLDP in software-defined energy internet with SDN-equipped control plane and data plane. MonLink extends the original LLDP by introducing metric type/length/value (TLV) fields so as to collect status information and conduct status monitoring in a piggyback fashion over LLDP during topology discovery simultaneously without the introduction of any newly designed dedicated status monitoring protocol. Several operation modes are derived for MonLink, namely, periodic MonLink, which operates based on periodic timeouts, proactive MonLink, which operates based on explicit API invocations, and adaptive MonLink, which operates sensitively and self-adaptively to status changes. Various northbound APIs are also designed so that upper layer network applications can make full use of the status monitoring facility provided by MonLink. Experiment results indicate that MonLink is a lightweight protocol capable of efficient monitoring of topological and status information with very low traffic overhead, compared with other network monitoring schemes such as sFlow.

Distribution drop fiber in-service fault management in enhanced EPON system

Ethernet passive optical network (EPON) is considered one of the best candidates for next-generation optical access solutions. Practical and cost-effective survivability and maintenance mechanisms are therefore becoming the key issues for continued development of viable EPON solutions. In addition, 80% of faults occur within the first/last mile. Therefore, in this paper, we propose in-service integrated fault management mechanisms at the distribution drop fibers (DDFs) in EPON. The proposed mechanisms can automatically detect and identify any signal anomalies and DDF faults in the physical layer, thus decreasing the operating expense (OpEx) to be incurred in sending off technicians in the field. The mechanisms are two-fold: pre-fault and post-fault. In the pre-fault mechanism, we use optical receiver type/length/value (TLV) code as a sensor for triggering the embedded miniaturized optical-time-domain reflectometry (OTDR), placed at optical network units (ONUs). This mechanism observes and measures the abnormal condition and reports it to the optical line terminal (OLT), via restoration plan fiber link. In post-fault mechanism, we divide the ONUs into several restoration groups (RGs) to guarantee upstream transmission of the affected ONUs. Lastly, the fault dynamic bandwidth allocation for fault management, referred as FDBA, is presented. Simulation results show that the proposed mechanisms can withstand DDF faults without any significant impact on the overall quality of service (QoS) performance, in terms of mean packet delay, queue length, system throughput, and packet loss.

Authentication on LDP (Label Distribution Protocol)

This article proposes a solution for the LDP (Label Distribution Protocol) from the MPLS (Multiprocol Label Switch) architecture. The objective is authenticate, on an end to end basis, the establishment of an LSP (Label Switching Path) between the Ingress LSR (Label Switching Router) and its Egress, to supply the LDP protocol deficiency that doesn't have one end to end authentication mechanism defined for non-adjacent LSRs. Actually authentication defined for the LDP, RFC3036, based on the TCP/MD5 option, is restricted to adjacent LSRs, because depends on a TCP connection between the involved LSRs. In the case of LSPs between non-adjacent LSRs, during the establishment of the first LSP, an end-to-end TCP connection doesn’t exist between these LSRs. So the solution from RFC3036 doesn’t deal with efficient way situations where two LSRs intend to authenticate mutually end-to-end during the establishment of a new LSP This work model of authentication defines mechanisms to the LDP that make possible to carry the authentication fields through the intermediate LSRs transparently end-to-end, allowing of this form that the endpoints of the LSP could be authenticated. The solution makes use of an authentication mechanism based on public-key cryptography attached to the LDP messages that makes possible to the receiver LSR verifies and authenticates the originator of the messages. It provides integrity protection to the information through a hash mechanism and additionally protects against reply attacks through the insertion of a nonce in the LDP messages. It doesn’t provide confidentiality. As requisite, the solution demands that the LDP operate in Ordered control mode and regarding to the distribution modes of the LDP, On-Demand and Unsolicited, both are compatible. There where defined two new TLVs (Type-Length-Value) to the LDP to provide this authentication solution, Hash TLV and Nonce TLV, and a new Code type with the value Authentication Failed for the LDP Status TLV. LDP messages involved in the authentication process are LABEL REQUEST, LABEL MAPPING and LDP NOTIFICATION, these three types of messages give conditions to the LDP to request and send labels for the establishment of LSPs and to notify fails about these operations. This solution was planned for environments where LSPs crosses external multi-domain environments, not trustworthy between themselves and for this reason need a way to authenticate the endpoints of the LSP during its establishment.