HSLS R OUTING P ROTOCOL Eleonora Borgia Pervasive Computing & Networking Lab. PerLab IIT – CNR MobileMAN Project - Helsinki – June 7/8, 2004

HSLS characteristics 1.A node wakes up every t e sec and sends a LSU with TTL=2 if there has been a link status change in the last t e sec; 2.Every 2 i-1 * t e sec (with i=1,2,3..) a node wakes up and sends a LSU with TTL= 2 i if there has been a link status change in the last 2 i-1 * t e sec; 3.Every t b sec (t b >t e ) a global LSU (TTL=  ) is sent in the entire network to give a complete overview of the network topology, even if there’s no link changes. High mobility scenario : LSU generated every te sec

Packet format Packet Sequence NumberPacket Length Originator Address TTLPacket TypeValidity Time Link TypeAddress Size Neighbor Address 1 Link TypeAddress Size Neighbor Address 2 OPTIONAL 0123 Packet Header Message Header Message Body

Software Architecture HSLS Initialization Garbage Collector N E S T Communication Packet Mangement Socket Management Processing LSU Hello

Data structures (1) I NTERFACE: it stores internal information of the node (e.g. socket descriptor, wireless information) T OPOLOGY T ABLE: it stores all the links of the network characterized by their status (SYM/ASYM) R OUTING T ABLE: it stores the shortest path to each node of the network T_Sender_AddrT_Destination_AddrT_Link_TypeT_Validity_Time R_Destination_AddrR_Next_HopR_Cost

Data structures (2) S ENT LSU C ACHE: it stores relevant information about sent LSU packets R ECEIVED LSU C ACHE: it stores relevant information about LSU packets coming from other nodes Pkt Number TTL ACK_LSU number Timeout Pkt content Originator address Pkt Number TTL ACK_LSU number Timeout Pkt content SLC entry: RLC entry:

Reliable HSLS The Broadcast problem Introduction of a mechanism to make HSLS reliable: ACK_LSU = LSU (TTL = i-1) received from 1-hop neighbors 1.Node A sends an LSU (TTL = i) in the network; 2.Node A counts the number of ACK_LSU packets received from its 1-hop neighboors in a specific time window T<<t e ; 3.Comparison between (ACK_LSU, threshold): If #ACK_LSU >= threshold, A transmission is correct; If #ACK_LSU < threshold, node A retransmits the same LSU; 4. Explicit unicast ACK in the last hop. C A E B F LSU (TTL =i ) ACK_LSU = LSU (TTL = i-1) E D UNICAST ACK_LSU

Modules Interactions (1) Hello/LSU Init Socket Management Data structures initialization Generation of Hello/LSU message Addition of header PKT and OPTIONAL field sleep.. PKT sent to wireless card

Modules Interactions (2) …waiting for a PKT from the network Processing Phase ProcessingSocket Management OPTIONAL field and/or TT exported to NEST.. forwarding PKT..

LSU Module (1) INIT: SendLSU (TTL =  ); Reset Counter (NumT e, TimeLastChange); Mode = START; LinkChange = false; Expire T e Generate LSU (TT) R = 2 i t.c R<MD<2R Compare (LSU, LastLSUSent) TimeLastChange ++ TimeLastChange = 0; LinkChange = true; =  Expire T p SendLSU (TTL =  ); Reset Counter (NumT e, TimeLastChange); change = false; Update SLC;

LSU Module (2) mode SendLSU (TTL = 2); Mode = HSLS; NumT e ++ Update SLC; LinkChange TRUE FALSE STARTHSLS NumT e ++ Find 2 i exact_div (NumT e, &i, &TTL) TimeLastChange 2i2i SendLSU (TTL =  ); Reset Counter (NumT e, TimeLastChange); change = false; Update SLC; SendLSU (TTL = 2 i+1 ); Update SLC; < 2 i < R >= R >= 2 i

PROCESSING Module (1) Byte = ReceivedPacket () Extract (PKTHeader, MSGHeader) Compare (HostIP, OriginatorAddress) DupPKT = DuplicatePacket (SentLSUCache) DupPKT = DuplicatePacket (ReceivedLSUCache) DupPKT Compare (packetType, LSU&LSU_OPT) Process MSGBody TTL sendExplicitACK ForwardingPKT =  = 0  0 =  (Hello) = 0 > 1

PROCESSING Module (2) Build RouteTree (HostIP) UPDATE algorithm (TT) Link Change Dijikstra RouteTree (HostIP) UPDATE (RT) Extract MD (Max n° hop) UPDATE Kernel Routing Table Packet Type Extract OPTIONAL NO SI LSU_OPT Hello, LSU

Ongoing work HSLS Initialization Garbage Collector N E S T Communication Packet Mangement Socket Management Processing LSU Hello