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Short note: Datagram network
Short answer
A datagram network routes each packet independently with full addresses, without connection setup. Packets may follow different paths and arrive out of order. It is robust and efficient but has variable delay and no guaranteed QoS; the Internet uses this model.
Write a short note on datagram network.
A datagram network is a packet-switched network in which each packet (datagram) is treated independently; there is no connection setup. Every packet carries the full source and destination address, and each router decides the route for it separately using its routing table. The internet (IP) is a datagram network.
+--R2--+
A ----R1 R4---- B
+--R3--+
packets 1,3 via R2; packet 2 via R3
B may receive 1,3,2 (reordering)
Features
- Connectionless: no setup or teardown phase.
- Each packet may follow a different path.
- Packets may arrive out of order, be duplicated or lost; higher layers (e.g. TCP) fix this.
- Routers keep no per-connection state; routing tables depend only on the destination address.
- Resources are not reserved, so delay varies.
Advantages
- No setup delay; good for short, bursty traffic.
- Robust: if a router or link fails, packets are routed around it.
- Efficient use of links.
Disadvantages
- Larger header (full address) in every packet.
- Variable delay, reordering, no guaranteed QoS.
| Point | Datagram | Virtual circuit |
|---|---|---|
| Setup | none | needed |
| Addressing | full address | short VC number |
| Route | per packet | fixed per call |
| Order | not guaranteed | in order |
✓ Answer checked by Claude Opus 5.5 (high effort)