Compound Module ChordModules

File: Overlay/Chord/Chord.ned

Implementation of the Chord KBR overlay as described in "Chord: A Scalable Peer-to-Peer Lookup Protocol for Internet Applications" by I. Stoica et al. published in Transactions on Networking.

Author: Ingmar Baumgart, Markus Mauch

chord: Chord fingerTable: ChordFingerTable successorList: ChordSuccessorList

Usage diagram:

The following diagram shows usage relationships between modules, networks and channels. Unresolved module (and channel) types are missing from the diagram. Click here to see the full picture.

Contains the following modules:

If a module type shows up more than once, that means it has been defined in more than one NED file.

Chord

The main module of the Chord implementation

ChordFingerTable

This modul contains the finger table of the Chord implementation.

ChordSuccessorList

This modul contains the successor list of the Chord implementation.

Parameters:

Name Type Description
localPort numeric

UDP port for Chord messages

debugOutput bool

enable debug output

keyLength numeric

overlay key length in bits

measureNetwInitPhase bool

gather statistics when bootstrapping

collectPerHopDelay bool

delay statistics for single hops

drawOverlayTopology bool

draw arrow to successor node?

hopCountMax numeric

maximum number of overlay hops

joinOnApplicationRequest bool

only join the overlay on application request

iterativeLookup bool

do iterative instead of recursive lookups

useCommonAPIforward bool

forward messages to application in recursive mode

useNextHopRpc bool

use RPCs for route messages

lookupRedundantNodes numeric

number of next hops in each step

lookupParallelPaths numeric

number of parallel paths

lookupParallelRpcs numeric

number of nodes to ask in parallel

lookupSecure bool

true, if all nodes should be identified with a ping

lookupMerge bool

true, if parallel Rpc results should be merged

lookupFailedNodeRpcs bool

communicate failed Nodes

Gates:

Name Direction Description
from_udp input

gate from the UDP layer

to_udp output

gate to the UDP layer

from_app input

gate from the application

to_app output

gate to the application

Unassigned submodule parameters:

Name Type Description
chord.successorListSize numeric

max number of successors in the SuccessorList

chord.joinRetry numeric

after joinRetry unsuccessful join requests, we fetch a need bootstrap node from the BootstrapOracle

chord.stabilizeRetry numeric

retries before a successor is considered failed

chord.joinDelay numeric

delay between join retries (sec)

chord.stabilizeDelay numeric

stabilize interval (sec)

chord.fixfingersDelay numeric

fix_fingers interval (sec)

chord.aggressiveJoinMode bool

use modified (faster) JOIN protocol

chord.extendedFingerTable bool

use the extended finger table?

chord.numFingerCandidates numeric

number of fingers when using extended finger table

chord.proximityRouting bool

use proximity routing

Source code:

module ChordModules

    parameters:
        localPort : numeric,             // UDP port for Chord messages
        debugOutput : bool,              // enable debug output
        keyLength : numeric,             // overlay key length in bits
        measureNetwInitPhase: bool,      // gather statistics when bootstrapping
        collectPerHopDelay : bool,       // delay statistics for single hops
        drawOverlayTopology : bool,      // draw arrow to successor node?
        hopCountMax : numeric,           // maximum number of overlay hops
        // only join the overlay on application request
        joinOnApplicationRequest : bool, 
        // do iterative instead of recursive lookups
        iterativeLookup : bool,     
        // forward messages to application in recursive mode
        useCommonAPIforward : bool,      
        useNextHopRpc : bool,            // use RPCs for route messages

        lookupRedundantNodes : numeric,  // number of next hops in each step
        lookupParallelPaths : numeric,   // number of parallel paths
        lookupParallelRpcs : numeric,    // number of nodes to ask in parallel
        lookupSecure : bool,             // true, if all nodes should be
                                         // identified with a ping
        lookupMerge : bool,              // true, if parallel Rpc results should
                                         // be merged
        lookupFailedNodeRpcs : bool;     // communicate failed Nodes

    gates:
        in: from_udp;   // gate from the UDP layer
        out: to_udp;    // gate to the UDP layer
        in: from_app;   // gate from the application
        out: to_app;    // gate to the application

    submodules:
        chord: Chord;
            parameters: 
                localPort = localPort,          // UDP port for Chord messages
                debugOutput = debugOutput,      // enable debug output
                keyLength = keyLength,          // overlay key length in bits
                // gather statistics when bootstrapping               
                measureNetwInitPhase = measureNetwInitPhase,  
                // delay statistics for single hops
                collectPerHopDelay = collectPerHopDelay, 
                // draw arrow to successor node?     
                drawOverlayTopology = drawOverlayTopology,
                // maximum number of overlay hops    
                hopCountMax = hopCountMax,    
                // only join the overlay on application request  
                joinOnApplicationRequest = joinOnApplicationRequest,
                // forward messages to application in recursive mode
                useCommonAPIforward = useCommonAPIforward,
                // do iterative instead of recursive lookups    
                iterativeLookup = iterativeLookup,
                useNextHopRpc = useNextHopRpc, // use RPCs for route messages
                
                // number of next hops in each step
                lookupRedundantNodes = lookupRedundantNodes,    
                // number of parallel paths
                lookupParallelPaths = lookupParallelPaths, 
                // number of nodes to ask in parallel   
                lookupParallelRpcs = lookupParallelRpcs, 
                // true, if all nodes should be identified with a ping   
                lookupSecure = lookupSecure,  
                // true, if parallel Rpc results should be merged  
                lookupMerge = lookupMerge,    
                // communicate failed Nodes
                lookupFailedNodeRpcs = lookupFailedNodeRpcs;    
            display: "p=60,60;i=block/circle";

        fingerTable: ChordFingerTable;
            display: "p=150,60;i=block/table";
        successorList: ChordSuccessorList;
            display: "p=240,60;i=block/table";

        connections nocheck:
                from_udp --> chord.from_udp++;
                to_udp <-- chord.to_udp++;
                from_app --> chord.from_app;
                to_app <-- chord.to_app;
endmodule