| Criteria | One-to-all | Star | Bus | Ring |
| Required cabling | Grows quickly
with # of nodes:
(nē-n)/2 |
Only requires one connection for each node | One common bus connection, shared | One cable for each node |
| Expansion potential | Very impractical for large # nodes | Very practical for large #; phone system uses it. However, new line for each user | Very practical for large #; Ethernet uses it | Very practical; requires briefly breaking ring to add node |
| Ease of protocol management | Simple protocol (no collisions!) | Simple; no collisions! | Much more complex to handle collisions | Complexity simpler than bus (uses token) |
| Flexibility for sending messages | Software must be modified for each addition or change | Hub-central, but robust otherwise | Very flexible but
cannot guarantee
response time |
Highly flexible; guaranteed response time |
| Reliability in
case
of problems |
Robust; 1 failure affects only a few | Easy to fix; hub failure affects all unless more paths are installed | With watchdog, very robust, but bus-central | One failed node can stop ring; sol-utions available, however |
Table 18.1: Comparison of several properties of various network topologies.
| Property | AppleTalk | MAP | Ethernet | IEEE-488 |
| Topology | Bus | Ring | Bus | Bus |
| Protocol | SDLC | Token passing | CSMA/CD | Controller/Talker/Listener |
| Modulation | FSK | FSK | Manchester | Baseband |
| Data Rate(s) | 230,400 bps | 5, 10 Mbps | 10M,100M,1G | 1 Mbps |
| Max Distance | 300 m | 500 m | 20 m | |
| Cable | Single twisted pair, shielded | CAT-5; Coax;
Fiber |
Special 24-conductor cable | |
| Serial/Parallel | Serial | Serial | Parallel (8 bits) | |
| Msg Length | 1-1000s bits | Variable | Variable |
Table 18.2: Comparison of several features of four common network protocols
| Property | ISDN | SONET | FDDI | ATM |
| Topology | Bus | Bus | Ring | |
| Protocol | Token passing | Specifies packet only; no physical specification | ||
| Modulation | 5/4 encoding | |||
| Data Rate(s) | 192,000 bps (64+64+16+48) | OC-1 = 51.84Mbps; other multiples | 100Mbps | |
| Max Distance | 2500-6500 m | 100 km | Varies | |
| Cable | Dual twisted pair, shielded | Optical fiber | Optical fiber | Any |
| Serial/Parallel | Serial | Serial | Serial | Serial |
| Msg Length | Variable | Variable | Variable | Variable |
Table 18.3: Comparison of several features of four advanced network protocols