James Wheeler

Characterizing routing with radio-to-router information in an airborne network

The current generation of long-range, high capacity, military radios are stove-piped systems that work well in a homogeneous environment, but require significant setup and configuration to interoperate with other radio systems. Each radio provides a subset of disparate link information in nonstandard interfaces and has built-in home-grown or industry-based routers running potentially different routing protocols. In a heterogeneous radio system airborne environment, wireless link characteristics change rapidly, often requiring direct link feedback from the radio to make routing decisions. In recent years, there has been a number of work in developing a common radio-to-router interface that standardizes a subset of per-link information to pass to the network layer for use in dynamic MANET routing. While simulations and emulation tests can provide a baseline for how systems will perform, field-tests are crucial to demonstrate capabilities in real-world operating environments. In this paper, we present measurement results from a field test involving three airborne and two ground assets with various radio systems that test an implementation of RFC4938, a radio-to-router interface protocol, and its interaction with a modified OSPFv3 routing protocol to support dynamic link metrics and OSPF cost generation. The assets participated in the exercise formed a high capacity, dynamically routed aerial IP backbone made of heterogeneous radio technologies over 250 nautical miles (Nm), allowing the passing of military operational traffic.1

Evaluation of a Multihop Airborne IP Backbone with Heterogeneous Radio Technologies

In recent years, there has been increasing interest in the US Department of Defense to build an on-demand airborne network for communications relay utilizing high-capacity, long-range military radio systems. While these systems operate well in a network of homogeneous systems, platforms generally employ multiple heterogeneous radio systems making internetworking difficult due to varying radio characteristics and lack of interoperability. Although simulations and emulation tests can provide a baseline for how systems will perform in a controlled environment, field tests are crucial to demonstrate capabilities in real-world operating environments. In this paper, we present measurement results from a field test involving two airborne platforms forming a dynamically routed aerial IP backbone over 200 nautical miles with various radio systems as part of the C4ISR on-the-move 2010 exercise. We present measurement results on per link performance, radio-to-router interface performance, and multihop network performance results with prototype software on open source platforms. Additionally, key lessons learned and recommendations are given.

Radio-to-router interface technology and its applicability on the tactical edge

Tactical wireless and mobile networks are the primary networking infrastructure in the Global Information Grid (GIG) to provide end-to-end connectivity to the warfighters at the tactical edge. The highly dynamic nature of tactical edge networks raise a number of challenging issues related to data transport and service delivery in the tactical environment. To address some of these issues, DoD waveforms have increasingly leveraged layer 2 link information to make smart cross-layer multihop routing decisions. Although there has been some measure of success in providing higher end-to-end data delivery, the lack of standard interfaces between the radio and router have led to interoperability issues in environments with a heterogeneous mix of radio systems. As a result, there has been increased desire to standardize radio-to-router interfaces (R2RIs) as a means to separate radio and router functionality and to allow greater interoperability between systems. In this article, we examine three R2RI protocols currently being vetted through the Internet Engineering Task Force and currently integrated or under consideration in DoD radio systems (RFC 5578, R2CP, and DLEP), and identify their current use and applicability in the tactical edge. Furthermore, we identify some challenges in implementing any R2RI scheme into emerging systems.

Internet protocol header compression technology and its applicability on the tactical edge

The increased usage of net-centric IP applications at the tactical edge has pushed DoD communications systems to maximize bandwidth efficiency amid a limited availability of RF spectrum. One method of increasing bandwidth efficiency (especially with the desire to move to IPv6), is the use of IP header compression (IPHC) to compress headers from the network layer and above into small identifiers before sending to the link layer. Although widely used in cell phone technology, the tactical edge provides some unique challenges to traditional IPHC techniques including highly dynamic links and link conditions due to potential jamming threats and difficult environments, multi-hop scenarios due to lack of infrastructure, and a highly diverse set of radio systems lacking interoperability. In this article, we examine two common IP header compression schemes, Robust Header Compression (RFC 5225) and IP Header Compression (RFC 2507) and one experimental scheme, MANET IP header compression, and identify their current use and applicability in the tactical edge. Furthermore, we identify some challenges in implementing header compression schemes in emerging systems.

Evaluation of a multi-hop airborne ip backbone with heterogeneous radio technologies

In recent years, there has been increasing interest in the US Department of Defense to build an on-demand airborne network for communications relay utilizing high-capacity, long-range military radio systems. While these systems operate well in a network of homogeneous systems, platforms generally employ multiple heterogeneous radio systems making internetworking difficult due to varying radio characteristics and lack of interoperability. Although simulations and emulation tests can provide a baseline for how systems will perform in a controlled environment, field tests are crucial to demonstrate capabilities in real-world operating environments. In this paper, we present measurement results from a field test involving two airborne platforms forming a dynamically routed aerial IP backbone over 200 nautical miles with various radio systems as part of the C4ISR on-the-move 2010 exercise. We present measurement results on per link performance, radio-to-router interface performance, and multihop network performance results with prototype software on open source platforms. Additionally, key lessons learned and recommendations are given.

Comparing radio-to-router interface implementations on experimental CoTs and open source routers

In highly dynamic wireless environments, link metrics such as link quality, availability, and others have become increasingly important to enable smart multi-hop routing decisions. In recent years, a number of radio-to-router interface (R2RI) protocols such as Point-to-Point over Ethernet RFC5578, Dynamic Link Exchange Protocol (DLEP), and Radio-Router Control Protocol (R2CP) have emerged to address the need to have a common set of link metrics exposed from the radio to the router to enhance multi-hop routing decisions. To fully evaluate R2RI functionality and specifications, differing implementations of both radio/client and router/server-side R2RI protocols must be prototyped and tested. In this paper, we present comparison tests of each of the three (3) radio-to-router interfaces with two (2) router/server-side R2RI experimental/beta R2RI implementations: one on a commercial Cisco router, and one on an open source Quagga platform. The goal of the comparison is not necessarily to provide a holistic performance comparison (as much of the code is experimental), but to highlight implementation differences and potential issues. In many cases, issues are already resolved in future releases.1

A testbed to support Radio-to-Router interface testing and evaluation

In highly dynamic airborne and wireless environments, per link information becomes crucial in effectively routing packets throughout the network and preserving application QoS. In recent years, a number of radio-to-router protocols such as Point-to-Point over Ethernet RFC55781, Dynamic Link Exchange Protocol (DLEP), and Radio-to-Router Control Protocol (R2CP) have emerged to provide per link information from radio-to-router to help make more informed routing decisions on highly dynamic links operating at various data rates and to possibly provide flow control. In addition, integrating and testing radio-to-router protocols with both unicast and multicast routing protocols designed to operate in MANET environments provides fundamental insights into the their performance and real-world utility. To effectively evaluate each of the Radio-to-Router protocols and understand some of the practical implementation issues, a flexible testbed supporting multiple emulated DoD radios and their link characteristics, as well as multiple open source and commercial routers that support radio-aware routing is needed. In this paper, we present a 6-node testbed that supports emulation of several directional, electronic switch-beam, and omnidirectional radio technologies as well as routing technologies to help automate evaluation and testing of RFC5578, DLEP, and R2CP. Specifically, we describe the system setup, some challenges with supporting current DoD radio technologies and temporary solutions, and provide some examples of results and data derived from multiple runs on the emulation network.2

Characterizing Routing with Radio-to-Router Information in a Heterogeneous Airborne Network

The current generation of long-range, high capacity, military radios are stove-piped systems that work well in a homogeneous environment, but lack interoperability with other radio systems. Each radio provides a subset of disparate link information in non-standard interfaces and has built-in home-grown routers running different routing protocols. In a heterogeneous radio system airborne environment, wireless link characteristics change rapidly, often requiring direct link feedback from the radio to make routing decisions. In recent years, much work has been done in developing a common radio-to-router interface (R2RI) that standardizes a subset of per-link information to pass to the network layer for use in dynamic MANET routing. While simulations and emulation tests can provide a baseline for how systems might perform, field-tests are crucial to demonstrate capabilities in real-world operating environments. In this paper, we present measurement results from a field test involving several air and ground assets with various radio systems that test an implementation of RFC4938, a radio-to-router interface protocol, and its interaction with a dynamic MANET routing protocol. The assets formed a high capacity, dynamically routed aerial IP backbone made of heterogeneous radio technologies over 250 nautical miles (Nm), allowing the passing of military traffic.

A comparison of IP header compression schemes in MANETs

The desire to increase bandwidth efficiency in an all-IP infrastructure in the presence of reduced spectrum and increasing demand for connectivity has led to several developments in IP header compression techniques. In recent years, there have been several IP header compression schemes developed in industry specifically for wireless networks including RObust Header Compression (ROHC) and IP Header Compression (RFC 2507). ROHC and IPHC (RFC 2507) have been adopted by several commercial cellular networks and military networks as one of the techniques for implementing IP header compression. In addition to ROHC and IPHC which were designed primarily for one-hop wireless networks, MANET IP Header Compression (MIPHC) was defined to help bridge the gap to multi-hop MANETs. To evaluate the effectiveness of IP header compression schemes on multi-hop MANETs and other networks, we implement simulation models of ROHC, IPHC, and MIPHC and evaluate their performance under various conditions in a mobile ad hoc network. The results show that although ROHC was designed specifically for one-hop cellular networks and context is required to be maintained per hop per IP flow, its performance is fairly good in multi-hop MANETs.

Characterizing Routing with CoTS Radio-to-Router Information in an Airborne Network

In recent years, there has been increasing interest in the DoD to build an on-demand airborne network for communications relay. To that end, several high capacity, long-range military radios were developed to address the need for a high capacity airborne backbone. While radios build links thus forming the basic elements of connectivity, platforms generally employ multiple stove-piped, non-interoperable radio systems that make internetworking to build multi-hop end-to-end paths, di‐cult. While simulations and emulation tests can provide a baseline for how systems will perform in a controlled environment, fleld-tests are crucial to demonstrate capabilities in real-world operating environments. In this paper, we present measurement results from a fleld test involving two airborne platforms forming an airbridge between two ground assets with various radio systems as part of the Joint Expeditionary Forces Experiment (JEFX) 2010 exercise. We present per link performance, radio-to-router interface performance, and multi-hop network performance results with prototype software on open source platforms as well as beta software running on commercial routers. Additionally, key lessons learned and recommendations are given. The assets participated in the exercise formed a high capacity, dynamically routed aerial IP backbone made of heterogeneous radio technologies over 300 nautical miles (Nm), allowing the passing of military operational tra‐c. a