Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 1 A Decentralized Approach for Topology Discovery in Home Networks 2008 YU-ANTL Lab Seminar January 24, 2009 Shahnaza Tursunova Advanced Networking Technology Lab. (YU-ANTL) Dept. of Information & Comm. Eng, Graduate School, Yeungnam University, KOREA (Tel : ; Fax :

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 2 Outline  Introduction  Related Work  Topology Discovery in Home Network  Representation and display  Basic operations  Handling message loss  System configuration  QoS Measure  Bridge detection  Conclusion

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 3 Introduction  Motivation  A concept of home networks has been emerged  Evolution of networking technologies from simple control signals to various applications  sharing Internet access, sharing local resources, multimedia delivery and etc.  More heterogeneous devices are connected to home networks  Ethernet, IEEE 1394, wireless networks

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 4 Introduction (2)  Motivation Various devices and heterogeneous network media in home network  Topology of home network tends to be dynamically changed over time – Home network devices frequently turned on/off  Important to discover home network topology timely for managing and utilizing Home network users  Do not have experiences or knowledge of network management  Need for effective tools to help users discovering topologies and managing  Challenges Many tools are available for topology discovery – Are not directly applicable to home networks  They mostly use SNMP for topology discovery – May not be available in home environments  They are mainly interested in Layer 3 topologies – Layer 1 and 3 information is important in home networks  They are developed for network administrators – Require knowledge of network management

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 5 Introduction (3)  In this paper Novel topology discovery system for home networks  Designed to work with minimal efforts of users – No need for any complicated configuration nor any efforts  Fully distributed  Detects heterogeneous physical network media – It is important to figure out network media for QoS management  Detects Layer 2 network elements (bridge, switch)  Provides temporal bandwidth usage information for QoS management – May be useful to deliver multimedia stream among home devices

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 6 Related Work  Most routing protocols (RIP, OSPF, DSR, and AODV) include topology discover function Are not directly applicable to home networks  Since they are developed for routing – Topology discovery focuses on discovering routers and detecting changes in path information  Most of them discover partial topology (entire topology is too large to maintain) – Includes only their one-hop/two-hop neighbors  Topology discovery for network management – mostly focus on how to represent large-scale networks Based on ICMP (ping and traceroute) to discover Layer 3 topology [4,5] Commercial softwares based on SNMP are available [6, 7]  Discovery Layer 2 connectivity Cisco’s Discovery Protocol [8], and Bay Networks’ Optivity Enterprise [9] discover Layer 2 devices based on vendor-specific extensions to SNMP MIB [10]  Discovery topology in home network Generic architecture has been proposed in [11] for extending Home Bus System (HBS) to support multiple links  Uses centralized server and SNMP  Proposed system in this paper – Does not require specific system support such as SNMP – It is gully distributed

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 7 Topology Discovery in Home Networks  Basic operations are similar to typical distributed systems for network management Maintaining the global topology Periodically sending a packet to its neighbors for informing it alive Upon detecting its neighbor detached/attached, informing others

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 8 Topology Discovery in Home Networks (2)  Representation and Display Representation of the discovered topology is based on XML  Topology can be easily adopted to other applications Simple program to provide graphical display of the topology imported from a XML  Programmed by JAVA and uses DOM parser

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 9 Topology Discovery in Home Networks (3)  Representation and Display (cont.)

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 10 Topology Discovery in Home Networks (4)  Basic operations Each node periodically sends a TTL_UPDATE message  To inform its alive to its neighbors Based on TTL_UPDATE, the system detects the following two basic events:  Joining of a new node  Leaving of a node – Single node or a node which is already connected to other network To reduce message exchange complexity  All the messages are sent via link level broadcasting  Before sending a message, each node waits for receiving the message to avoid multiply sending of the message

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 11 Topology Discovery in Home Networks (5) Merging of two networks

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 12 Topology Discovery in Home Networks (6) Merging of two networks (cont)

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 13 Topology Discovery in Home Networks (7) Detachment of a node

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 14 Topology Discovery in Home Networks (8)  Handling message loss System exchanges UDP messages via broadcast System maintains message history instead of sending back acknowledgement  To reduce message complexity  SeqNum j = (SeqNum j-1 + 1) Received message  Compare own message history with the message history in the message  If identical -> update the message history with the source ID and sequence number of the current message  If no: the sender/receiver missed the previous message (ADD has been lost) – Exchange AADD and take the superset of their topology  If DEL has been lost – Fixed through TTL expiration timeout Message losses are mostly detected by TTL_UPDATE

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 15 Topology Discovery in Home Networks (9)  System configuration  IP address is not enough to identify each node  Left of a node is detected within 13 seconds (TTLCheckInterval+ExpireTime)

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 16 Topology Discovery in Home Networks (10)  QoS Measure Periodically measures the temporal available bandwidth of each link  To monitor usage of home networks  Can be used for QoS routing for applications consuming large bandwidth  Packet-pair technique have been used [2, 3] Each node works as either  An active QoS measurer – sends probe packets periodically  A passive receiver – calculates the available bandwidth

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 17 Topology Discovery in Home Networks (11)  Bridge detection Links connected through a bridge are observed as a single network in IP layer  It is useful to detect bridges for distinguishing physical locations of nodes Bridge maintains a list of hosts connected a link, and does not forward a packet to other link when the sender and the receiver of the packet are on the same link  Monitor packets from node A  List of destinations maintained by node – A {A, B, C, D} – B and C {B, C, D} – D {D}

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 18 Topology Discovery in Home Networks (12)  Bridge detection (cont.)  Each node operates as an observer, and one of them works as the detector NICs of observers need to be configured as the promiscuous mode  They can monitor packets destined to other nodes

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 19 Conclusion  In this paper  Presented a novel system for topology discovery in home networks  Fully distributed  Performing well without any configuration efforts from users  Distinguishing physical network media  Responding to topology changes quickly  Providing information on available bandwidth for QoS management  Detecting links in Layer 2 as well as in Layer 3

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 20 References [1] Euiyul Ko and Ikjun Yeom, “A Decentralized Approach for Topology Discovery in Home Networks,” IEEE Transactions on Consumer Electronics, Vol. 52, No. 3, August [2] J-C. Bolot, “End-to-end packet delay and loss behavior in the internet, ” Proc. ACM SIGCOMM’93, September [3] K. Lai, and M. Baker, “Measuring link bandwidths using a deterministic model of packet delay, ” Proc. ACM SIGCOMM’00, August [4] R. Siamwalla, R. Sharma, and S. Keshav “Discovering Internet topology,” Submitted to Infocom'99. [5] R. Covindan and H. Tangmunarunkit “Heuristics for Internet map discovery,” Proc. IEEE INFOCOM’00, pp , March, [6] HP Management Software, [7] IBM Tivoli software, [8] Cisco Discovery Protocol, [9] Bay Networks’ Optivity Enterprise, [10] Y. Beritbart, M. Garofalakis, B. Jai, C. Martin, R. Rastogi, and A. Silberschatz, “Topology discovery in heterogeneous IP networks: the NetInventory system,” IEEE/ACM Transactions on Networking, Vol. 12, No. 3, pp , June, [11] E. Topalis, G. Orphanos, S. Koubias, G. Papadopoulos, “A generic network management architecture targeted to support home automation networks and home internet connectivity,” IEEE Transactions on Consumer Electronics, Vol. 46, Issue. 1, pp , February, 2000.

Advanced Networking Tech. Lab. Yeungnam University (YU-ANTL) YU-ANTL Lab. Seminar Shahnaza Tursunova 21 Thank you for your attention!