\item switch between shared trees and source specific trees\item does not capture transience well\end{comment}\foilhead{\indigo Centralised Dense Mode Configuration}\begin{itemize}\item computes parent-child relationships prior to start of simulation\item Can study membership dynamics\item No response to topology changes\item Only one configuration parameter\begin{program}\small  DM set PruneTimeout \tup{newValue} \; default \(0.5s.\);\end{program}\end{itemize}\begin{comment}\item DVMRP-like \item works well in conjunction with static unicast routing\end{comment}\foilhead{\indigo Dynamic Dense Mode Configuration}\begin{itemize}\item Extension of static dense mode\item As before, computes parent child relationships at start of simulation\item Also recomputes whenever topology changes,  or unicast route updates are received\item Configuration parameters are:  \begin{program}\small    dynamicDM set PruneTimout \tup{newValue} \; default \(0.5s.\);    dynamicDM set ReportRouteTimeout \tup{newvalue} \; default \(1s.\);  \end{program}\end{itemize}\begin{comment}\item one object per node\end{comment}\foilhead{\indigo PIM Dense Mode Configuration}\begin{itemize}\item Extension of static dense mode\item does not compute parent child relationships\item Configuration parameters are:  \begin{program}\small    pimDM set PruneTimout \tup{newValue} \; default \(0.5s.\);  \end{program}\end{itemize}\begin{comment}\item one object per node\end{comment}\foilhead{\indigo Other protocol work in progress}\begin{list}{}{}\item Detailed PIM  \begin{list}{}{}  \item Sparse mode and Dense mode  \end{list}\end{list}\begin{comment}  \item will be a comprehensive implementaiton of PIM\end{comment}\foilhead{\red Multicast Classes}\placefig{mcastArch}\begin{comment}\item \verb|\placefig{mcastArch}|\item mirros unicast route architecture\item global centr mcast comp module\item relies on centr rp compmodule\item default computation for rp\item General Multicast:McastProtocol      -- mcast protocol mechanism (DM, dynamicDM)McastProtoArbiter  -- mcast arbiterClassifier/Replicator/Demuxer   -- mcast classifier (parse pkts, get (s,g,iif), and forward to (s,g,iif) replicator)Classifier/Multicast/Replicator -- replicator for each (s,g, iif) (copy pkts and forward to all oifs)\item Centralized Multicast:CtrMcast     -- install mcast routing entries per nodeCtrMcastComp -- compute mcast trees via unicast routing tableCtrRPComp    -- compute RP Set for shared trees\end{comment}%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%\foilhead{\blue Network Dynamics}The ability to make elements of topology fail/recover.\begin{itemize}\item Model of failure and recovery  --- Exponential, Deterministic, Trace driven, Manual (or one-shot)\item Operates on single link  --- \textsl{i.e.} takes link ``down'' or ``up''\item Operation on single node possible, translated into operation  on collection of links incident on node\end{itemize}\keyword{Network Dynamics}\begin{comment}\item currntly only possible to specify single link or node\item no clustering yet\end{comment}\foilhead{\indigo Specification}\begin{itemize}\item Create an instance of \tup{model}  \begin{program}    $ns \textbf{rtmodel} \tup{model} \tup{parameters} \tup{node|link}  \end{program}  Command returns the handle of the model created\item Perform \tup{operation} at \tup{time} on \tup{node|link};  \begin{program}    $ns \textbf{rtmodel-at} \tup{time} \tup{operation} \tup{node|link}  \end{program}  return handle to newly created instance of model.\item Delete route model specified by \tup{handle}  \begin{program}    $ns \textbf{rtmodel-delete} \tup{handle}  \end{program}\end{itemize}\begin{comment}\item interface through thte class simulator\item operates only on node and link\item multiple arguments are ignored\end{comment}\foilhead{\red Models and Configuration}\begin{enumerate}\item Exponential  \begin{sublist}  \item \tup{[startTime], upInterval, downInterval, [endTime]}  \end{sublist}\item Deterministic  \begin{sublist}  \item \tup{[startTime], upInterval, downInterval, [endTime]}  \end{sublist}\item Trace (based)  \begin{sublist}  \item \tup{fileName}  \end{sublist}\item Manual (or one-shot)  \begin{sublist}  \item \tup{operation, time}  \end{sublist}\end{enumerate}\begin{comment}\item time vagaries\item trace file format\item Long form of the \code{rtmodel-at}\end{comment}\foilhead{\red Defining your Own Model}Derive model from the base class, \code{rtModel}\begin{tabularx}{\linewidth}{crX}1. & \proc[]{set-parms} & process model parameters \\2. & \proc[]{set-first-event} & specify the first event \\3. & \proc[]{up}, \proc[]{down} & specify next action \\\end{tabularx}--- Use class rtQueue to schedule events.--- Instance of queue in rtModel class variable, \code{rtq_}\begin{comment}\item comments on each procedure; defaults\item use rtQueue to installe vents\end{comment}\foilhead{\red class rtQueue}Internal class to synchronise topology change activity\begin{tabularx}{\linewidth}{rX}\proc[]{insq} & Given \tup{time}, \tup{object},        and an instance procedure for that object and arguments,        will invoke instance procedure of object at specified time. \\\proc[]{insq-i} & identical to \proc[]{insq}, except \tup{time}        specifies increment when the procedure will be executed\\\proc[]{runq} & executed procedures for the specified time;        finish by invoking \proc[]{notify} for each object \\\proc[]{delq} & remove event for object at specified time\end{tabularx}\begin{comment}\item need for synchronisation: route advertisement staggerring\item possibly obviated by the timer interface in OTcl\end{comment}\foilhead{\red Interface to Unicast Routing}\placefig{uni-nd-intf}\begin{comment}\item Layer of focus in next slide\end{comment}\foilhead{\red Interface to Unicast Routing}\placefig{ndactions}\begin{comment}\item \verb|\placefig{ndactions}|\item sequence of events upto routing interfaces\end{comment}\foilhead{\indigo Deficiencies in the Network Dynamics API}\begin{itemize}\item Link centric\item Node failure not consistent with an operation model\item API cannot specify clusters/clouds\end{itemize}\begin{comment}\item no way to specify other than node or link\item node not reset on failure\item node emulation is broken concept\end{comment}%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%\foilhead{\blue Multicast Transport}Currently, SRM and RTP implemented\begin{itemize}\item goals of implementation:  programmability\item in particular, for SRM: programming timers,session message handling, loss recovery\item and for RTP, mostly programmed in OTcl, with  minimalpacket related statistics counters in C++\end{itemize}\keyword{Multicast Transport}    % 20\begin{comment}\item most implementation is in OTcl, limited C++ handling,\item confined to packet level activities\item for RTP, per packet statistics is in C++\item for SRM, packet forwarding, sending/receipt of packets, andprocessing session messages\end{comment}\foilhead[-3ex]{\indigo Simple SRM configuration}\begin{program}  set ns [new Simulator]          \; preamble initialization;  $ns enableMcast  set node [$ns node]                \; agent to reside on this node;  set group [$ns allocaddr]           \; multicast group for this agent;  {\bfseries{}set srm [new Agent/SRM]}  $srm  set dst_ $group            \; configure the SRM agent;  {\bfseries{}$ns attach-agent $node $srm}  $srm set fid_ 1                \; optional configuration;  {\bfseries{}$srm log [open srmStats.tr w]}   \; log statistics in this file;  {\bfseries{}$srm trace [open srmEvents.tr w]}  \; trace events for this agent;  set packetSize 210  # {\cf{} configure the traffic generator and traffic source}  set s0 [new Agent/CBR/UDP]   \; attach traffic generator to application;  $s0 attach-traffic $exp0  {\bfseries{}$srm(0) traffic-source $s0} \; attach application to SRM agent;  {\bfseries{}$srm(0) set packetSize_ $packetSize} \; to generate repair packets of appropriate size;  {\bfseries{}\fcnref{$srm start}{../ns-2/srm.tcl}{Agent/SRM::start}}  {\bfseries{}\fcnref{$srm start-source}{../ns-2/srm.tcl}{Agent/SRM::start-source}}\end{program}\begin{comment}\item Acquire and configure agent\item Attach agent to node\item open log and trace files as required\item configure a traffic generator and traffic source\item attqach application to agent\item notice setting packet size\item start agent and traffic source separately\end{comment}\foilhead{\indigo Class Hierarchies}\placefig{srmhierarchy}\begin{comment}\item Separate loss recovery objects\item separate session message handling object\item Loss detection is in C++,\item loss recovery is in OTcl\item number of bottlenecks in memory are expected\item wait for scaling issues following\end{comment}\foilhead{\indigo Loss Detection}\begin{list}{}{}\itemTriggered by receipt of data or control messages\item\begin{program}  $agent \textbf{request} \tup{sender} \tup{list of messages}\end{program}\itemActual loss recovery occurs in OTcl through special purposeloss recovery  objects\end{list}\begin{comment}\item single reqeust helps speedup scheduling\item also help schedule request periods for statis gathering simple\end{comment}\foilhead{\indigo Loss Recovery}\begin{itemize}\item Each loss is handled by separate ``SRM'' object.\item Nodes schedule ``request'' or ``repair'' objects following  a data loss\item Each loss recovery object handles its own scheduling and messaging  activity\end{itemize}\begin{comment}\item each agent also receives its messages\item relies on agent being able to receive its own messages\end{comment}\foilhead{\indigo Session messages}\begin{itemize}\item One session message handling object per agent\item Responsible for sending periodic session messages\item Session message interval controlled by class variable,   \code{sessionDelay_}\item Two types of session functions implemented:  \begin{subenum}  \item SRM/Session uses default fixed interval session message sending  \item SRM/Session/logScaled uses $\log({\rm groupSize\_}) * {\rm      sessionDelay\_}$  to send next advertisement.   \end{subenum}\end{itemize}\begin{comment}\item advantages etc.\end{comment}\foilhead{\indigo Statistics}\begin{enumerate}\item Agent---response to Data Loss:  Detection and Recovery\item Loss Object---Per Loss recovery Statistics \end{enumerate}\begin{comment}\item data loss measures ave-recovery delay, ave dups\item used by adaptive algorithm to adjust the recovery parameters\item Loss recovery objects write out to log file when they terminate\end{comment}\foilhead{\indigo Tracing}\begin{itemize}\item Per event tracing by loss recovery objects\item Sample trace file is:\begin{program} 3.5543 n 1 m <1:1> r 0 Q DETECT 3.5543 n 1 m <1:1> r 1 Q INTERVALS C1 2.0 C2 0.0 d 0.0105 i 1 3.5543 n 1 m <1:1> r 1 Q NTIMER at 3.57527 ... 3.5753 n 1 m <1:1> r 2 Q NACK IGNORE-BACKOFF 3.59627 3.5828 n 3 m <1:1> r 0 Q DETECT 3.5828 n 3 m <1:1> r 1 Q NTIMER at 3.6468 3.5854 n 0 m <1:1> r 0 P NACK from 257 3.5854 n 0 m <1:1> r 1 P RTIMER at 3.59586 3.5886 n 2 m <1:1> r 2 Q NTIMER at 3.67262 3.5886 n 2 m <1:1> r 2 Q NACK IGNORE-BACKOFF 3.63062 3.5959 n 0 m <1:1> r 1 P SENDREP ...\end{program}\end{itemize}\begin{comment}\item done by loss objects\end{comment}\foilhead{\indigo RTP}\begin{itemize}\item Session/RTP tracks incoming data, and sends periodic delivery  reports.\item Agent/CBR/RTP sends data to the group at a specified rate.\end{itemize}\begin{comment}\item need slides on RTP\item RTPSource adjunct class to set src id, but not clear it if  generatesdata.\item report-interval, session bw etc. can be controlled.\item CBR agent generates data, and when it recvs from outsidehands it to session to generate report\end{comment}\foilhead[-2ex]{\blue Multicast Transport Starter Kit}\begin{itemize}\item Code and Documentation:  SRM and RTP\item Multiple flavours of multicast    {\small  includes Dense mode, Sparse mode, centralised multicast, session level  multicast  }\item Multiple flavours of unicast and network dynamics  {\small  Ability to study the problem under dynamic topologies, including  partition scenarios  }\item Multiple physical layers including broadcast and wireless LANs\item building a catalog of canonical topologies\item Examples in \nsf{tcl/ex}\item test suite in development\end{itemize}