Question 1.1. (TCO A) In the context of the PSTN, routing
_____. (Points : 5)
is required for
calls covering long distances and multiple switches
Both A and C
effectively
creates a dedicated circuit
is an index or
table
Question 2.2. (TCO A) Time Division Multiplexing (TDM)
_____. (Points : 5)
is the means by
which calls are carried on trunks
uses multiple
frames
enables
simultaneous calls on a single physical connection
All of the
above
Question 3.3. (TCO B) In a VoIP system, voice is _____.
(Points : 5)
digitized
analog
packetized
Both A and C
Question 4.4. (TCO B) Address discovery refers to _____.
(Points : 5)
a reverse phone
directory look-up
determining the destination of the call after
initiation
recording the
sending address after the call is terminated
the national
phone number database
Briefly describe SS7 in terms of what it does, and its major
characteristics
SS7 is
characterized with high speed circuit switching as well as out of band
signaling using signal transfer points STPs, service switching SSPs and service
control points SCPs which are collectively known as SS7 nodes. Out of band
signaling is that do not take place over the same path as the data transfer, a
separate digital channel is created that is called a signaling link where
messages are exchanged between network elements of 64 kilobit per second.
SS7
architecture is created in such a way so that any node could be exchanged
signaling with any other SS7 capable node. The SS7 network are used for
wireless services like personal communication services PCS, mobile subscriber
authentication and wireless roaming. It is also used for local number
portability LPN, toll free (800/888) and toll (900) wireless services, enhanced
call services such as number display, call forwarding and three way calling and
for secured and efficient worldwide telecommunications (Rouse, 2016).
What is the purpose of a VoIP gateway?
VoIP is
a piece of hardware having standard purpose of converting TDM telephony traffic
from the PSTN into digital IP packets to transport over the IP network such as
LAN. VoIP are simple. It works as a bridge between the PSTN and IP network.
Based upon where the voice traffic originates from a VoIP gateway converts the
voice into proper form in order to be receipt by the destination network. When
the voice traffic originates from PSTN, the VoIP gateway converts the analog
voice signal into digital signal.
Then this digital signal is compressed through a codec also
broken into series of packets which are transferred across the IP network
through a signaling protocol. On the other hand when the voice traffic
originates from the IP network, VoIP gateway decompresses the digital packets
into digital signal which is then converted into analog signal to be sent
across the PSTN. The lost common VoIP protocols are SIP, SCCP, MGCP and H.323
(Voipsupply.com, 2016).
Reference
Rouse, M. (2016, 9 4). Signaling System 7 (SS7). Retrieved
from searchnetworking.techtarget.com:
http://searchnetworking.techtarget.com/definition/Signaling-System-7
Voipsupply.com. (2016, 9 4). VoIP Gateway Overview.
Retrieved from voipsupply.com: http://www.voipsupply.com/overview-of-voip-gateways
