TSM 6350G Final Exam
EXAM C
Spring Semester 2013: April 25, 2013
 NO CELL PHONES, PCS, COMPUTERS, OR ANY OTHER ELECTRONICS. CLASS NOTES ONLY. THIS IS A 2 HOUR TEST!!!
 Write clearly and IN INK. Think about your answer(s) before writing, or try writing your answers in a scratch blue book, and
then transferring to the blue book your will hand in. (-25 pts if you do not write in ink).
 All problems are to be answered in a blue book. Put your name on the BACK of your blue book. (-10 points if you put
your name on the front). USE ONLY ONE BLUE BOOK! (-10 points if you use more than one Blue Book).
 PUT THE EXAM LETTER (A, B, C, OR D) ON THE FRONT OF THE BLUE BOOK. PLEASE ALSO PUT THE NUMBER OF THE EXAM ON
THE FRONT OF THE BLUE BOOK (E.G., 1,2,OR 3). THE EXAM IS CORRECTLY IDENTIFIED AS A1, B3, C2, ETC. (-100 pts if you
leave out the exam letter or number. e.g., we won't grade it.)
 The TAs will xxxx out all white space when you hand in your blue book(s). You can pick up your exam from Professor
O’Reilly next week. Have a great summer!
1. The most likely place for congestion on a wireless network is a)over the best effort (internet) APN between the S-GW and
the P-GW, b) between the P-Gateway and the IMS Core, c) over the radio access network, d)None of these, QoS is provided
on the Evolved Packet Core. (5 pts)
2. XML is used to describe a) data returned form an ENUM query b) Initial filter criteria, c)user profile data d)all of the above.
(5pts)
3. IMS is a 3GPP architecture designed for a) wireless networks, b) wireline networks, c) cable networks d) A and B e) MS is a
service architecture that is independent of the underlying access network. (5 pts)
4. The DIAMETER protocol is used in a wireless network to handle transactions between the a)The HSS and the S-CSCF,
b)Media Control Function and the HSS, c)Application Servers and the HSS, d)The HSS and a MME e) All of the above f) A and
B, g) A and D h)A, B, and D i)B and D j)A,B,C, and D k) None of the above, l)I have no idea, this is a pathological question. (10
pts)
5. GIANT WIRELESS TELECOM INC is designing a network node to process international calls to/from the PSTN (G711 codec)
from/to VoLTE phones (AMR Wideband codec). Your job is to size the number of transcoding ports that are required for this
node. Please assume that the offered load is 5 calls/min, each calls is 5 minutes long, the probability of blocking is 1% and
that the AMR wideband codec used is 12.65 kb/s. (The AMR wideband codec supports several bit rates but for this problem
you can assume 15.85 kb/s, which is sufficient to audio clarity that is superior to G711. You can use the ERLANG Table on
the back of this exam, and you can assume that Erlang B is OK to use – that there is no queuing of calls). How many
transcoding ports should you make available to support the given level of blocking? What is the bandwidth required on the
IP side of the transcoding network element? {Assume 20 msec packets, Ethernet frames with 20 bytes overhead,
IP/RTP/UDP also contributes 20 bytes of overhead.} (20 pts)
6. GIANT WIRELESS TELECOM INC provides a video telephony service over LTE with CIF quality (350 x 288 pixels) at 15 frames
per second; the bandwidth of that service is about 750 kp/s, and it uses an IMS network with QoS. Your boss (the CTO) is
mad at you because the Wall Street Journal has run an article that features an over the top competitor (Woogle), who claims
a better service with a high resolution service. How is this possible? (2 sentences max). (10 pts)
7. Where would you go to demonstrate why GIANT TELECOM's service is better than Woogle's? a )Roaming on to fly-by-night’s
wireless network in Moscow’s Sheremetyevo airport? B)Outer Mongolia at midnight? c) Grand Central Station at rush
hour? (5 pts)
8. In an IMS network, you would expect there to be more DIAMETER messages than SIP messages. TRUE OR FALSE. (5 pts)
9. QoS Policy is a)part of a user’s profile in the subscriber data base, b)supported by the P-CSCF query to the I-CSCF (Mw
interface), c)defined in the SIP (ISC) interface between Application Servers and the S-CSCF, d)applied by the PCRF after
conversation with the P-Gateway . (5 pts)
10. ENUM a) is a protocol implemented by DNS servers, b) provides routing in an IMS network when the S-CSCF does not know
the location of a SIP endpoint c) a separate 3GPP protocol defined for routing and name lookup d)all of the above e) A and B
f) B and C. (5 pts)
11. The Serving-CSCF provides functionality that is similar to which standard SIP network element? (5 pts)
___________________________________________________________________________________________
12. An mobile APN (Access Point Name) is an example of what folks in the rest of the IP Datacom world would call a (5 pts)
_______________________________________________________________________________
13. webRTC defines a signaling protocol, but it does not define the protocols used for media transport. TRUE or FALSE. (5 pts)
14. Presence in an IMS network uses XMPP to provide notification of a terminal’s presence state. TRUE or FALSE. (5 pts)
15. Immersive video (or telepresence) is usually used in context with high definition video sessions. TRUE or FALSE (5 pts)
16. Emergency Contact Mgmt services rely only on SMS to provide immediate emergency information. TRUE or FALSE. (5 pts)
17. A Session Border Controller’s primary function is to act as a firewall to protect against http: denial of service attacks. TRUE
or FALSE. (5 pts)
18. A 4G/VoLTE mobile phone may have more than one IP Address. Assuming that the address space is IPV4 (probably NOT
true, most operators will be using IPV6 rather than IPV4), which address below would likely be used for the IMS APN, and
which address would likely to be used for the internet APN. (2.5 pts for each of A and B)
A) 10.121.12.121
____________________________________
B) 4.2.131.18
____________________________________
19. I have completed my class and instructor evaluation using the NEU TRACE system. TRUE OR FALSE. (ZERO pts)
ERLANG B TABLE 2
Ports
140
120
Ports
100
80
60
40
20
0
0
2000
4000
6000
Offered
Load (mou)
150
300
450
600
750
900
1050
1200
1500
1800
Ports
7
11
15
18
21
24
27
30
36
42
Offered
Load
(mou)
2100
2400
3000
3600
4200
4800
5400
6000
Ports
47
53
64
75
85
96
107
117