Enhanced Interior Gateway Routing Protocol for OMNeT++ Vladimír Veselý, Jan Bloudíček and Ondřej Ryšavý Faculty of Information Technology, Brno University of Technology, Božetěchova 2, Brno, Czech Republic Keywords: Enhanced Interior Gateway Routing Protocol, EIGRP, OMNeT++, Dynamic Routing Protocol, Routing, Simulation, ANSA. Abstract: Cisco’s EIGRP is a hybrid routing protocol between distance vector and link-state routing protocols. EIGRP offers routing based on composite metric, which takes into account multiple factors and allows more granular and precise routing decisions based on the current state of the network. Cisco released basic specification of EIGRP as IETF’s RFC draft in the beginning of 2013. This paper introduces one of the first freely available EIGRP design and a simulation model implementation that can be run and tested within OMNeT++ discrete event simulator. 1 INTRODUCTION vector protocol specialized (but not exclusively) for wireless networks that have Network layer serves the purpose of end-to-end data different metric criteria than wired networks. delivery. Routers employ routing tables to make Metric may represent cost, number of host or correct routing decisions by forwarding hop-by-hop any other implementation dependent route the packet closer to receiver. Dynamic routing atribute. Nevertheless, routes with infinity protocols maintain up-to-date content of routing metric 0xFFFF are considered unreachable. tables by exchanging updates about known Babel currently supports both IPv4 and IPv6; networks. Intermediate System to Intermediate System Routing protocols for traditional wired networks (IS-IS) (Oran, 1990) – The first link-state could be divided into three categores: a) distance- protocol ever, which is also capable of working vector where routing is based on information with different metrics simultaneosly. IS-IS was provided by neighbors and each route has one originally intended to be used with Connection- attribute representing distance of network from a less Mode Network Service Protocol given router; b) path-vector which is the same as (concurrent of IP) for ISO/OSI networks, distance vector but routes have more than one however, later was developed implementation attribute; and c) link-state where every router for both IPv4 and IPv6 protocols. IS-IS is by maintains independent view on topology and design agnostic to used address-family and computes the shortest path tree towards all other single instance can carry routing updates for nodes. Additional typology of routing protocol is various network protocols. Formerely used IS- according to type of deployment: a) interior IS metrics were delay and link errorness, gateway protocols (IGP) for routing within one current revision employs only speed of the administrative domain; b) exterior gateway link; protocols (EGP) for routing between autonomous . Open Shortest Path First (OSPFv2 for IPv4 systems (AS). Among typical representants belong: (Moy, 1998), OSPFv3 for IPv4/6 (Coltun, et al., 2008)) – OSPF started as IP alternative to . Routing Information Protocol (RIPv2 for IPv4 IS-IS and later become industrial standard link- (Malkin, 1998), RIPng for IPv6 (Malkin & state routing protocol that has wide-spread Minnear, 1997)) – Distance-vector routing deployment. OSPF uses cost as the metric, protocol that works with hop-count as the where cost is derived from the interface metric. Routes with metric 16 or more are bandwidth. OSPF supports only IP routing considered unreachable; updates; . Babel (Chroboczek, 2011) – Babel is distance- Veselý V., Bloudícekˇ J. and Ryšavý O.. 50 Enhanced Interior Gateway Routing Protocol for OMNeT++. DOI: 10.5220/0005038400500058 In Proceedings of the 4th International Conference on Simulation and Modeling Methodologies, Technologies and Applications (SIMULTECH-2014), pages 50-58 ISBN: 978-989-758-038-3 Copyright c 2014 SCITEPRESS (Science and Technology Publications, Lda.) EnhancedInteriorGatewayRoutingProtocolforOMNeT++ . Border Gateway Protocol (BGPv4) (Rekhter & configurations. This paper outlines a new simulation Hares, 2006) – Extends distance-vector idea by module, which is a part of the ANSA project and having multiple attributes acompanying the which extends functionality of the INET framework single prefix update. BGPv4 is currently the (OMNeTpp/INET, 2014) in OMNeT++ (OMNeTpp, only one EGP that is being used and it is often 2014). refered as policy-control routing protocol. This paper has the following structure. The next Enhanced Interior Gateway Protocol (EIGRP) is section covers a quick overview of existing EIGRP the backward compatible successor of previous implementations (either real or simulation ones). Cisco proprietary Interior Gateway Protocol (IGRP). Section 3 deals with our contribution, mainly It is categorized as a hybrid routing protocol which necessary theory, proposed design and subsequent means that it is a crossover between distance-vector implementation. Section 4 presents validation (topology is known based on announcement from scenarios proving corectness of the implementation. neighbors) and link-state protocols (instead of The paper is summarized in Section 5 together with periodic updates, topology changes are propagated unveiling our future plans. immediately). Down below follows the list of main beneficial features of EIGRP: . EIGRP employs Diffusing Update Algorithm 2 STATE OF THE ART (DUAL) (Garcia-Lunes-Aceves, 1993) that effectively propagates any topology change Currently none of vendors other than Cisco supports and minimizes path recomputational time; EIGRP in its active network devices. Despite . Currently EIGRP is the only routing protocol positive campaign targeting wider EIGRP that guarantees loop-free topology even during acceptance, many manufacturers and customers the time when topology is actively converging remain skeptical and rely on a long-time proven towards a new routing state; open solutions like OSPF or IS-IS. The one of the . EIGRP leverages its own reliable transport first publicly available open-source EIGRP routing protocol (even for multicast data transfer); demon is being developed at the University of Žilina . In the contrary to other distance-vector (GitHub/janovic, 2013) within the scope of Quagga protocols, EIGRP is capable of sending event- project (nonGNU, 2013). driven partial bounded updates; A freely available demonstration tool called . It has neighbor discovery and recovery Easy-EIGRP (SourceForge, 2013) exists rather for mechanism to determine route reachibility via educational purposes. particular adjacent node; OPNET simulator has contained EIGRP . EIGRP contains protocol-dependent modules simulation modules even before its public IETF that allow operation over different network release. However, its functionality is limited and it protocols (including IPv4 and IPv6); lacks IPv6 support for EIGRP. Nevertheless, The EIGRP was introduced in 1993 as a cojoint OPNET and its simulation models were used to effort of Cisco and SRI International (Albrightson, conduct several measurement studies comparing et al., May 1994). Initial and later measurements different routing protocols including EIGRP (Wu, revealed that it outperforms other routing protocols 2011). (i.e., speed of convergece, network bandwidth Previously described state of EIGRP deployment utilization, queing delay) (Xu & Trajkovic, 2011). affirmed our decision to offer academic and Despite its beneficial aspects (or maybe because of enterprise community with a full-fledged EIGRP them) it had been protected as one of the major implementation with all usually employed features. Cisco intellectual properties by a bunch of patents The current status of unicast routing support in for nearly twenty years. In the beginning of 2013, OMNeT 4.4.1 and INET 2.2 framework is according basic EIGRP design and functionality were to our best knowledge as follows. The IPv4 (named submitted as a publicly available IETF informational networkLayer) and IPv6 (pragmatically called draft (Savage, et al., 2013). networkLayer6) layers are already parts of INET The project ANSA (Automated Network framework. The framework contains OSPFv2 as the Simulation and Analysis) running at the Faculty of only available dynamic routing protocol. Information Technology is dedicated to develop the During ANSA project development we have variety of software tools that can create simulation extended original simple router module to be dual- models based on real networks and subsequently to stack and enhanced it with a variety of dynamic allow formal analysis and verification of network routing protocols (RIP, RIPng, IS-IS, OSPFv3, 51 SIMULTECH2014-4thInternationalConferenceonSimulationandModelingMethodologies,Technologiesand Applications PIM), thus creating ANSARouter as the compound 3.1 Theory of Operation simulation module based on the standard behavior of Cisco routers. An EIGRP process computes a successor for every The basic goal behind our effort is to support destination. A successor represents the next-hop EIGRP dynamic routing protocol. Hence, we have router where the route to the destination via decided to add missing functionality in form of successor is loop-less and with the shortest distance. simulation module directly connected to Feasible successor (FS) or so called backup next- networkLayer and networkLayer6 as hop is the router that provides loop-less route but depicted on Figure 1. with higher distance. To determine whether particular router is a feasible successor, the router is working with