Chapter 9: Telecommunication and Soft Switching
Syllabus: AEiE09
Coverage: AEiE0901 through AEiE0906
Status: DRAFT - syllabus and assigned-question pass complete; independent source audit pending
Exam use: Telecommunication concepts, propagation and fading recognition, traffic calculations, switching distinctions, IP-header facts, and softswitch architecture cues
Chapter map
| Code |
Title |
Fast recognition cue |
AEiE0901 |
Telecommunication and wireless communication |
Media, propagation, handover, Rayleigh fading |
AEiE0902 |
Equalization and diversity techniques |
ISI mitigation versus independent fading paths |
AEiE0903 |
Switching systems and Traffic engineering |
Softswitch, signaling, Erlang traffic, ISDN |
AEiE0904 |
Data communication switching techniques |
Circuit, datagram, virtual circuit, spread spectrum |
AEiE0905 |
IP switching |
Ipsilon, flow classification, IP packet, TTL |
AEiE0906 |
Soft switching |
Architecture, VoIP, number mapping, xDSL |
Chapter rapid-revision sheet
| Topic |
Must-remember point |
| Free-space propagation |
Received power falls as \(1/d^2\) in ideal free space |
| Rayleigh fading |
No dominant LOS component |
| Reflection/diffraction/scattering |
Main multipath mechanisms |
| Equalization |
Mitigates ISI and channel distortion |
| Diversity |
Mitigates fading via independent replicas |
| Space diversity |
Multiple antennas |
| Traffic intensity |
\(A=\lambda h\) Erlangs |
| Busy hour |
Peak design hour |
| GoS |
Blocking or delay quality measure |
| ISDN B channel |
64 kbit/s |
| Circuit switching |
Dedicated path after setup |
| Datagram network |
Packets routed independently |
| Virtual circuit |
Logical packet path after setup |
| TTL |
Hop-count limiter in IP header |
| Softswitch |
Control plane separated from media plane |
| xDSL |
Broadband over copper telephone loop |
Assigned-question audit
| Target |
Deciding fact |
Result |
set1-049 |
diversity across independently faded branches mitigates small-scale fading |
Supported by AEiE0901/AEiE0902 |
set1-050 |
packetization enables statistical multiplexing and efficient shared-resource use |
Supported by AEiE0904 |
set1-051 |
DFE is the nonlinear equalizer that uses previous decisions to cancel postcursor ISI |
Supported by AEiE0902 |
set1-052 |
one ISDN B channel carries 64 kbit/s |
Supported by AEiE0903 |
set1-053 |
IPv4 TTL is decremented by routers and bounds packet lifetime in hops |
Supported by AEiE0905 |
set1-054 |
an ADSL splitter/microfilter separates low-frequency POTS from high-frequency DSL |
Supported by AEiE0906 |
set1-093 |
optical fiber is guided; radio, microwave, and free space are unguided |
Supported by AEiE0901 |
set1-094 |
adaptive equalization tracks the channel to compensate ISI |
Supported by AEiE0902 |
set1-095 |
teletraffic intensity is measured in Erlangs |
Supported by AEiE0903 |
set1-096 |
ADSL, VDSL, SDSL, and HDSL belong to the xDSL family |
Supported by AEiE0906 |
Sources and verification note
- Primary coverage authority:
syllab.md Chapter 9 (AEiE0901 to AEiE0906).
- Style and coverage intent:
notes/01-basic-electrical-electronics/ and notes/PLAN.md.
- Recommended wireless verification: Rappaport, Wireless Communications; Goldsmith, Wireless Communications; Proakis and Salehi, Digital Communications.
- Recommended teletraffic and access verification: ITU-T E-series and I.412 for traffic/ISDN; ITU-T G.992.x and Broadband Forum material for ADSL.
- Recommended packet and softswitch verification: RFC 791/1812 for IPv4 TTL; RFC 3261 and RFC 6116 for SIP/ENUM; ITU-T H.248 for media-gateway control.
- Assigned-question wording was reviewed so each item has one defensible answer; recognition-oriented facts remain in the notes rather than duplicated option lists.