DSR Source Routing Workbench

DSR Source Routing Workbench

Step through DSR route discovery, source-route forwarding, route-cache replies, and route-error repair

animation
networking
routing
manet
dsr
Interactive DSR animation for learning Dynamic Source Routing in mobile ad-hoc networks, including RREQ flooding, RREP return, packet source-route headers, cache hits, intermediate cache replies, and route maintenance.
Animation DSR Source Routing Reactive MANET

DSR Source Routing Workbench

Watch a mobile ad-hoc source discover a route only when it needs one, then carry the complete hop-by-hop route inside each data packet. The key skill is deciding when DSR floods, when it trusts a cache, and what happens when a cached link breaks.

Step 1/1Process progress
ReadyPacket type
No routeSource route
Header 0%Teaching overhead

Scenarios

Controls

Choose Step or Play

What To Watch

DSR separates route discovery from packet forwarding. After discovery, the packet header tells every relay exactly where to send the packet next.

RREQ floodRoute Requests carry a route record and duplicate requests are suppressed.
RREP routeThe reply returns a complete route to the source, often by reversing the discovered path.
Header pathData packets carry the source route, so intermediate nodes do not need a next-hop table.
RERR repairA broken link removes stale cached routes and may trigger a new discovery.

MANET Route Discovery Scene

Ready
No packet yetMessage type
No fields selectedImportant fields
No route action yetRouting decision

Source Route Header

Inspected Route Cache

Learning Diagnosis

Reactive discovery pendingStep forward to see whether the source must flood or can use a cached route.
No source route yetOnce a route is known, the complete hop list is carried in the data packet.
Cache state pendingRoute caches save discovery traffic but stale entries must be removed after errors.

Event Transcript

Quick Reference
Route Request (RREQ)Broadcast by the source on a cache miss. Each forwarding node appends itself to the route record and suppresses duplicates for the same request id.
Route Reply (RREP)Returns a complete route to the initiator. In this teaching model links are bidirectional, so the reply can follow the reverse path.
Source Route HeaderData packets carry the route. Relays forward by reading the next address in the header, not by consulting a periodic routing table.
How To Read The Animation
  • Blue dashed links are Route Request flooding.
  • Orange dashed links are Route Reply or Route Error control traffic returning toward the source.
  • Green links are the active source route carried by a data packet.
  • The route-cache panel shows the selected node's remembered routes at the current step.
Technical Accuracy Notes
  • DSR is reactive: it discovers routes on demand instead of sending periodic table advertisements.
  • The animation uses bidirectional links and a simplified request-id model to keep the route record visible.
  • The overhead metric is a teaching estimate: 8 bytes of option fields plus 4 bytes per IPv4 route address, compared with the selected payload size.
  • Real DSR implementations include additional packet options, cache policies, timers, acknowledgments, and salvaging rules not fully modeled here.
Source Links
RFC 4728: The Dynamic Source Routing Protocol (DSR) for Mobile Ad Hoc Networks for IPv4 IETF Datatracker version of RFC 4728 ns-3 DSR model documentation
Try
Select Cache reply with Packet size 128 bytes, then Step from RREQ flooding into the cached RREP.
Observe
Source route becomes A-B-D-F without reaching F, while Teaching overhead grows by each address carried in the 4-hop DATA header.
Explain
An intermediate cache can append a known suffix to the RREQ record, saving flood work; a later link error must remove that stale 4-node path.