chapter 9

In H.323, which protocol below handles call or videoconference signaling?​

H.225

What security standard below was created to protect credit card data and transactions, requiring network segmentation as part of security controls?​

PCI DSS

9. RTP and RTCP operate at which layer of the OSI model? a. Application layer b. Transport layer c. Network layer d. Data Link layer

a. Application layer

3. What port do SNMP agents listen on? a. Port 161 b. Port 21 c. Port 162 d. Port 10162

a. Port 161

1. What federal organization sets strict standards to protect the privacy of patient records? a. CALEA b. HIPAA c. PCI DSS d. IETF

b. HIPAA

8. You're trying to choose a signaling protocol for your company's network because you're about to upgrade to a VoIP system. You need to keep it simple because this is a small company with a simple network. Which protocol should you choose? a. H.323 b. SIP c. MGCP d. Megaco

b. SIP

5. One of your coworkers downloaded several, very large video files for a special project she's working on for a new client. When you run your network monitor later this after- noon, what list will your coworker's computer likely show up on? a. Top talkers b. Top listeners c. Event Viewer d. Discarded packets

b. Top listeners

10. Which QoS technique operates at the OSI layer "2.5"? a. RTP b. DiffServ c. MPLS d. CoS

c. MPLS

7. What kind of phone is a Skype app? a. Analog phone b. IP phone c. Softphone d. Video phone

c. Softphone

2. What command retrieves the next record in an SNMP log? a. snmpget b. snmpwalk c. snmpgetnext d. snmptrap

c. snmpgetnext

6. Your roommate has been hogging the bandwidth on your router lately. What technique can you use to limit the amount of bandwidth his computer can utilize at any one time? a. Interface reset b. Packet shaping c. Caching d. Traffic policing

d. Traffic policing

4. What utility in Linux provides standards for generating, storing, and processing mes- sages about events on a system? a. Event Viewer b. event log c. ls d. syslog

d. syslog

When using DiffServ, what type of forwarding utilizes a minimum departure rate from a given node, which is then assigned to each data stream?

expedited forwarding​

​In a VoIP call, what method of transmission is used between two IP phones?

unicast

The Priority Code Point field in a frame consists of how many bits?​

​3 bits

A server running the SIP protocol listens on what TCP/UDP port for unsecured communications?​

​5060

What percentage of Internet traffic, as estimated by Cisco Systems, will be devoted to video traffic by 2018?​

​79%

A highly available server is available what percentage of the time?​

​99.99%

Which of the following is not a requirement in order to use a softphone?​

​A wireless carrier to handle the voice path.

​Which element of H.323 is a device that provides translation between network devices running the H.323 signaling protocols and devices running other types of signaling protocols?

​H.323 gateway

A computer that provides support for multiple H.323 terminals and manages communication between them is known as what term below?

​MCU

What protocol enables multiple types of Layer 3 protocols to travel over any one of several connection-oriented Layer 2 protocols?​

​MPLS

​On circuit switched portions of a PSTN, what set of standards established by the ITU is used to handle call signaling?

​SS7

Packets that exceed the medium's maximum packet size are known by what term?​

​giants

When a device handles electrical signals improperly, usually resulting from a bad NIC, it is referred to by what term below?​

​jabber

In order for gateways to exchange and translate signaling and control information with each other so that voice and video packets are properly routed through a network, what intermediate device is needed?​

​media gateway controller

​Packets that are smaller than a medium's minimum packet size are known by what term below?

​runts

When using SIP, what term is used to describe end-user devices, which may include workstations, tablet computers, smartphones, or IP phones?​

​user agent client

​What component of SIP is a server that responds to user agent clients' requests for session initiation and termination?

​user agent server

Troubleshooting Network Integrity and Availability

- One way to consider availability is by measuring a system or networks uptime, which is the duration or percentage of time it functions normally between failures. - Redundancy is intended to eliminate single points of failure. To maintain high availability, ensure that critical network elements are redundant. - At the highest level of fault tolerance, a system remains unaffected by even the most drastic problem, such as regional power outage. However, less dramatic faults, such as a malfunctioning NIC on a router can still cause network outages. - Link aggregation is the seamless combination of multiple network interfaces or ports to act as one logical interface. It allows for load balancing or a distribution of traffic over multiple components or links to optimize performance and fault tolerance. - Most organizations rely on more than one DNS server to make sure that requests to resolve host names and IP addresses are always satisfied. - After selecting the appropriate tool for performing your servers data backups, you need to devise a backup strategy for performing reliable backups that provide maximum data protection.

QoS (Quality of Service) Assurance

- QoS is a measure of how well a network service matches its expected performance. From the point of view of a person using VoIP or video over IP, high QoS translates into an uninterupted , accurate, and faithful reproduction of audio or visual input. - To prioritize traffic, DiffServ places information in the DiffServ field, also called Differentiated Services Code POint(DSCP), in a IPv4 packet. In IPv6 packets, DiffServ uses a similar field known as the Traffic Class Field. - MPLS can operate over Ethernet frames, but it is more often used with other Layer 2 protocols. In fact, one of its benefits is the ability to use packet-switched technologies over traditionally circuit-switched networks. MPLS can also create end-to-end paths that act like circuit-switched connections. - A tagged frame contains a 3-bit field in the frame header called the Priority Code Point, or PCP. CoS works by setting these bits to one of eight levels ranging from 0 to 7, which indicates to the switch what level of priority that message should be given if the port is receiving more traffic than it can forward at any one time.

Monitoring and Managing Network Traffic

- Th elist of objects and their descriptions that is managed by the NMS is kept in the MIB (management information base), which also contains data about an object's performance in a database format that can be mined and analyzed. - The syslog protocol is a standard for generating, storing, and processing messages about events on a system. - The effective utilization of interface system and event logs can help to identify and prevent many types of complications. - Traffic shaping, also called packet shaping, involves manipulating certain characteristics of packets, data streams, or connections to manage the type and amount of traffic traversing a network or interface at any moment. - Caching is the local storage of frequently needed files that would otherwise be obtained from an external source.

Unified Communications Technologies

- The greatest advantage to packet switching lies in the fact that it does not waste bandwidth by holding a connection open until a message reaches it destination, as circuit switching does. Ethernet network and the Internet are the most common examples of packet-switched networks. - One difference between IP phones and softphones is that a softphones versatile connectivity makes it an optimal VoIP solution for traveling employees and telecommuters -Cisco estimates that by 2018, about 79 percent of the traffic carried by the internet will be video traffic, thats nearly one million minutes of video content transmitted every second -In a unicast transmission a single node issues a stream of data to one other node. A multicast transmission is directed at several points at once. - A video bridge manages multiple audiovisual sessions so that participants can see and hear each other. Video bridges may exist as a piece of hardware or software. - Signaling protocols set up and manage sessions between clients. -On a VoIP or video-over-IP network, logical channels are identified as port numbers at each IP address. One logical channel is assigned to each transmission direction.These channels are distinct from the channels used for H.225 call signaling. They are also different from channels used to exchange the actual voice or video signals. - SIP is an Application layer signaling and control protocol for multiservice, packet-based networks, and travels over either TCP or UDP. The protocols developers modeled it on HTTP. - MGCP and Megaco are commonly used on multiservice networks that support a number of media gateways Either one can operate in conjunction with H.323 or SIP call signaling and control protocols. -UDP is preferred over TCP for real-time services, such as telephone conversations and video-conferences where data is transferred as it is created, because it requires less overhead and, as a result, can transport messages more quickly. -RTP alone does not provide any mechanisms to detect whether or not it's successful. For that, it relies on a companion protocol, RTCP. - Recipients of RTP data use RTCP to issue information about the number and percentage of messages lost and delay suffered between the sender and receiver. RTCP also maintains identifying information for RTP sources.

Fundamentals of Network Managment

-Several disciplines fall under the heading of network management, but all share the goals of enhancing efficiency and performance while preventing costly downtime or loss. - Baseline Measurements allow you to compare future performance increases or decreases caused by network changes or events with past network performance. Obtaining baseline measurements is the only way to know for certain whether a pattern of usage has changed. - In addition to internal policies, a network manager must consider state and federal regulations.

SNMP agents receive requests from an NMS on what port number?​

161