NET464 Homework #06
Due: 05:45pm, 10/25/2022
Part I: Multiple choice (30 points)
1. Which of the following network element is required for Call Center Service?
0. PSAP
0. IAD
0. MSC
0. ACD
1. Which of the following is a major challenge of IP-based call center?
1. Cost efficiency
1. Service availability
1. Virtualization
1. Global presence
1. The routing of 1-800 number is based on _____
2. Origination phone numbe
2. Destination phone numbe
2. IP address
2. Domain name
1. In the case of SIP-based Toll Fraud attack, what is the SIP message used by the hackers to probe the SIP server?
3. PROBE
3. REGISTER
3. MESSAGE
3. SUBSCRIBE
1. What is the protocol to manage security key exchange for VoIP?
4. SIPS (RFC 3261)
4. SRTP (RFC 3711)
4. MIKEY (RFC 3830)
4. IPSec
1. Which SIP message could be easily used to launch a Denial of Service (DoS) attack?
5. INVITE
5. MESSAGE
5. SUBSCRIBE
5. 200 OK
1. Which of the following SIP message does not support authentication? (i.e., cannot be authenticated)
6. REGISTER
6. INVITE
6. BYE from calle
6. BYE from callee
1. Which of the following phone service is required (mandatory service) for facility-based VoIP Service Providers?
7. 0 – operator service
7. 411 service
7. 911 service
7. Collect call service
1. In the E911 service, who is responsible for routing to an incoming call to the PSAP?
8. Local Telephone Switch
8. Tandem Office Switch
8. The calle
8. The operator
1. In the E911 service, how does PSAP get the street address of caller’s location (wired call)?
9. The caller has to give his/her street address to the PSAP over the phone.
9. PSAP queries MSAG which has the caller’s address.
9. Local telephone switch sends the street address to PSAP.
9. The caller uses text message to send his/her address to PSAP.
1. In the IETF I3 standard, what is the SIP address for the 911 service?
10. sip: XXXXXXXXXX
10. sip: XXXXXXXXXX
10. sip:sos@domain
10. sip: XXXXXXXXXX
1. In the IETF I3 standard, how does PSAP gets the user location?
11. Same as the legacy PSTN service via ALI and MSAG
11. The Civil and Geo data is included in the SIP message.
11. Caller sends a separate e-mail to PSAP for location information.
11. IETF I3 does not support location identification.
1. What is the network architecture difference before and after CALEA?
12. Before CALEA, wiretapping by LEA is prohibited by law for any reason.
12. Before CALEA, LEA cannot do wiretapping without the cooperation of the target user.
12. Before CALEA, LEA has a dedicated trunk from LEA to the CO switch.
12. Before CALEA, LEA needs to install IAP at the Central Office switch.
1. What is the network to support NG911 service?
13. PSTN
13. ESINet
13. 3G/4G/5G Network
13. US Government Network
1. Which of the following is a technical challenge for VoIP providers to support CALEA?
14. VoIP bearer traffic may not go through VoIP provider’s network.
14. VoIP signaling traffic does not go through VoIP provider's network.
14. VoIP providers do not keep detailed call records of subscribers.
14. VoIP providers do not have resources and expertise to support CLALEA.
Part II: Questions (20 point) – do not copay-and-paste from lecture notes
1. Read the document: https:
transnexus.com/whitepapers/international-premium-rate-number-market/. Identify the top two countries that are most likely to be used by hackers for the IPRS attack.
Hint: Use the metric of PREMIUM RATE DESTINATIONS BY NUMBER OF PROVIDERS.
1. Draw a network diagram to illustrate IP-based call center. Note: the diagram must show local agents, remote agents, and work-from-home agents.
1. Security protocols for VoIP. (a) what is the security protocol to protect VoIP signaling traffic? (b) what is the security protocol to protect VoIP bearer traffic? Show the protocol stacks of these two protocols.
1. List three security measures to protect the IP-PBX from toll fraud attacks. (do not use protection measures for general data networks).
.
1. Identify three major differences between E911 and NG911 services.
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