CIST 1401 Module 5

SPB (Shortest Path Bridging)

As described in IEEE's 802.1aq standard, a descendent of the Spanning Tree Protocol that can detect and correct for network changes much more quickly.

MSTP (Multiple Spanning Tree Protocol)

As described in IEEE's 802.1s standard, a version of the Spanning Tree Protocol that can detect and correct for network changes much more quickly.

RSTP (Rapid Spanning Tree Protocol)

As described in IEEE's 802.1w standard, a version of the Spanning Tree Protocol that can detect and correct for network changes much more quickly.

How can VLAN hopping attacks be prevented on a network?

Disable auto trunking and move native VLANs to unused VLANs.

router summarization

See route aggregation.

slave name server

See secondary name server.

packet shaper

See traffic shaper.

packet shaping

See traffic shaping.

virtual adapter

See vNIC.

virtual console

See virtual terminal.

WLAN controller

See wireless controller.

Wi-Fi controller

See wireless controller.

discard

Short for discarded packet, which is a packet that arrives at its destination but is then deliberately rejected because issues such as buffer overflow, latency, bottlenecks, or other forms of network congestion delayed the packet beyond its usable time frame.

trunking

The aggregation of multiple logical connections in one physical connection between connectivity devices. In the case of VLANs, a trunk allows two switches to manage and exchange data between multiple VLANs.

network management

The assessment, monitoring, and maintenance of all aspects of a network.

802.1s

The IEEE standard that describes MSTP (Multiple Spanning Tree Protocol), which evolved from STP (Spanning Tree Protocol).

802.1w

The IEEE standard that describes RSTP (Rapid Spanning Tree Protocol), which evolved from STP (Spanning Tree Protocol).

802.1aq

The IEEE standard that describes SPB (Shortest Path Bridging) and that evolved from STP (Spanning Tree Protocol).

802.1D

The IEEE standard that describes, among other things, bridging and STP (Spanning Tree Protocol).

802.1Q

The IEEE standard that specifies how VLAN and trunking information appears in frames and how switches and bridges interpret that information.

data plane

The actual contact made between physical devices and data transmissions as these messages traverse a network.

The first iteration of STP was defined in what IEEE standard below?

802.1d

Which two standards below represent newer versions of STP?

802.1s 802.1w

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

99.99%

Switch Independent Mode

A configuration in which NICs are teamed to multiple switches, which can be nonintelligent switches.

giant

A packet that exceeds the medium's maximum packet size. For example, any Ethernet packet that is larger than 1518 bytes (or 1522 bytes for VLAN packets) is considered a giant.

live streaming video

A video feed issued directly from the source to the user as the camera captures it.

VirtualBox

A virtualization software platform from Oracle.

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

A wireless carrier to handle the voice path.

proxy server

(1) A network host that runs a proxy service. Proxy servers are also called gateways. (2) On a SIP network, a server that accepts requests for location information from user agents, then queries the nearest registrar server on behalf of those user agents. If the recipient user agent is in the SIP proxy server's domain, then that server will also act as a go-between for calls established and terminated between the requesting user agent and the recipient user agent.

host

(1) Any computer or device on a network that provides a resource such as an application or data. (2) In the context of virtualization, the physical computer on which virtualization software operates and manages guests.

network controller

(1) In the context of virtualization, a central console that manages virtual devices, services, and appliances. For example, the newest, not-yet-released Windows Server will provide a Network Controller role for managing both physical and virtual network infrastructure. (2) Sometimes used to refer to a device's NIC or network adapter.

fault tolerance

(1) Techniques that allow data storage or other operations to continue in the event of a failure or fault of one of its components, for example, storing redundant data on multiple storage devices in the event one device fails. (2) A system's ability to continue performing despite an unexpected hardware or software malfunction.

A network with the subnet mask 255.255.255.0 would have what CIDR block?

/24

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

161

What two items make up a Bridge ID?

2 byte priority field MAC address

Which supernet mask below would allow an organization to cover the following networks with one routing entry: 192.168.0.0/24, 192.168.1.0/24, 192.168.2.0/24, 192.168.3.0/24?

255.255.252.0

A CIDR block of /26 is equivalent to what subnet mask below?

255.255.255.192

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

A network with 6 bits remaining for the host portion will have how many usable host addresses?

62

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

79%

What IEEE standard specifies how VLAN information appears in frames and how switches interpret that information?

802.1Q

The Shortest Path Bridging protocol is defined in what IEEE standard?

802.1aq

Priority Code Point (PCP)

A 3-bit field in an Ethernet frame's header that is employed in CoS (class of service) configurations on VLANs. CoS works by setting these bits to one of eight levels ranging from 0 to 7, which indicates to the switch the level of priority the message should be given if the port is receiving more traffic than it can forward at any one time.

supernet mask

A 32-bit number that, when combined with a device's IPv4 address, indicates the kind of supernet to which the device belongs. Whereas the subnet mask moves the network prefix to the right, the supernet mask moves the network prefix to the left, thereby taking up fewer digits than the related classful network prefix.

ip helper-address

A Cisco command that can be configured to create and send helper messages to support several types of UDP traffic, including DHCP, TFTP, DNS, and NetBIOS.

DHCP relay agent

A DHCP configuration that provides DHCP service to multiple VLANs. The relay agent receives a DHCP-related message, then creates its own message to send the specified DHCP traffic beyond the broadcast domain.

Event Viewer

A GUI application that allows users to easily view and sort events recorded in the event log on a computer running a Windows-based operating system.

H.225

A Session layer call signaling protocol defined as part of ITU's H.323 multiservice network architecture. H.225 is responsible for call or videoconference setup between nodes on a VoIP or video-over-IP network, indicating node status and requesting additional bandwidth and call termination.

H.245

A Session layer control protocol defined as part of ITU's H.323 multiservice network architecture. H.245 is responsible for controlling a session between two nodes. For example, it ensures that the two nodes are communicating in the same format.

CALEA (Communications Assistance for Law Enforcement Act)

A U.S. federal regulation that requires telecommunications carriers and equipment manufacturers to provide for surveillance capabilities. CALEA was passed by Congress in 1994 after pressure from the FBI, which worried that networks relying solely on digital communications would circumvent traditional wiretapping strategies.

tag

A VLAN identifier added to a frame's header according to specifications in the 802.1Q standard.

full backup

A backup in which all data on all servers is copied to a storage medium, regardless of whether the data is new or changed. A full backup unchecks the archive bit on files it has backed up.

incremental backup

A backup in which only data that has changed since the last full or incremental backup is copied to a storage medium. After backing up files, an incremental backup unchecks the archive bit for every file it has saved.

differential backup

A backup method in which only data that has changed since the last full or incremental backup is copied to a storage medium even if earlier differential backups have been made, and in which that same information is marked for subsequent backup, regardless of whether it has changed. In other words, a differential backup does not uncheck the archive bits for files it backs up.

time-shifted video

A broadcast that is delayed by a few minutes to allow for editing processes and licensing concerns.

wireless controller

A central management console for all of the APs on a network.

H.323 zone

A collection of H.323 terminals, gateways, and MCUs that are managed by a single H.323 gatekeeper.

BID (Bridge ID)

A combination of a 2-byte priority field and a bridge's MAC address, used in STP (Spanning Tree Protocol) to select a root bridge.

snmpwalk

A command issued from an NMS to a managed device to request a sequence of snmpgetnext requests in order to walk through multiple sequential rows in an MIB data table.

snmpget

A command sent from the NMS to a managed device's agent to retrieve data from the device.

snmpgetnext

A command sent from the NMS to a managed device's agent to retrieve data from the next sequential row in the MIB data table.

snmptrap

A command used to program a device's agent to detect certain abnormal conditions and prompt the generation of SNMP trap messages, where the agent sends the NMS unsolicited data once the specified conditions are met.

RTCP (Real-time Transport Control Protocol, or RTP Control Protocol)

A companion protocol to RTP that provides feedback on the quality of a call or videoconference to its participants.

switching

A component of a network's logical topology that determines how connections are created between nodes on the network.

softphone

A computer configured to act like an IP telephone. Softphones present the caller with a graphical representation of a telephone dial pad and can connect to a network via any wired or wireless method.

collector

A computer that gathers event messages from generators.

generator

A computer that is monitored by a syslog-compatible application and that issues event information.

MGC (media gateway controller)

A computer that manages multiple media gateways and facilitates the exchange of call control information between these gateways. It also manages and disseminates information about the paths that voice or video signals take between gateways. Also called a call agent (CA).

MCU (multipoint control unit)

A computer that provides support for multiple H.323 terminals (for example, several workstations participating in a videoconference) and manages communication between them. An MCU is also known as a video bridge.

static teaming

A configuration in which both the switch and the host are configured to handle a division of labor between redundant links according to particular rules but without the ability to compensate for errors.

Switch Dependent Mode

A configuration that accomplishes NIC teaming with a single switch.

backup

A copy of data or program files created for archiving or safekeeping.

MIB (Management Information Base)

A database used in network management that contains a list of objects managed by the NMS and their descriptions as well as data about each object's performance.

failure

A deviation from a specified level of system performance for a given period of time. A failure occurs when something doesn't work as promised or as planned.

load balancer

A device that distributes traffic intelligently among multiple computers.

jabber

A device that handles electrical signals improperly, usually affecting the rest of the network. A network analyzer will detect a jabber as a device that is always retransmitting, effectively bringing the network to a halt. A jabber usually results from a bad NIC. Occasionally, it can be caused by outside electrical interference.

hot spare

A duplicate component already installed in a device that can assume the original component's functions in case that component fails.

cold spare

A duplicate component that is not installed, but can be installed in case of a failure.

VLAN pooling

A feature on wireless controllers that groups multiple VLANs into a single VLAN group, or pool, and then dynamically assigns wireless clients to each successive VLAN in the pool.

HIPAA (Health Insurance Portability and Accountability Act)

A federal regulation in the United States, enacted in 1996. One aspect of this regulation addresses the security and privacy of medical records, including those stored or transmitted electronically.

archive bit

A file attribute that can be checked (or set to "on") or unchecked (or set to "off") to indicate whether the file needs to be archived. An operating system checks a file's archive bit when it is created or changed.

ghost

A frame that is not actually a data frame, but rather an aberration caused by a device misinterpreting stray voltage on the wire. Unlike true data frames, ghosts have an invalid pattern at the beginning of the frame pattern.

media gateway

A gateway capable of accepting connections from multiple devices (for example, IP telephones, traditional telephones, IP fax machines, traditional fax machines, and so on) and translating analog signals into packetized, digital signals, and vice versa.

top listener

A host that receives an inordinate amount of data.

top talker

A host that sends inordinate amounts of data.

active-active mode

A link aggregation configuration in which both connections are active as a matter of course. If one link fails, the other maintains the connection.

active-passive mode

A link aggregation configuration in which only one connection is used at a time, with the other being a passive connection that is only activated if the first connection fails.

ANDing

A logical process of combining bits. In ANDing, a bit with a value of 1 combined, or ANDed, with another bit having a value of 1 results in a 1. A bit with a value of 0 ANDed with any other bit (either 0 or 1) results in a 0.

virtual switch

A logically defined device that is created and managed by virtualization software and that operates at the Data Link layer to pass frames between nodes. Ports on a virtual switch connect virtual machines with a network, whether virtual or physical, through the host's physical NIC.

vNIC (virtual network interface card)

A logically defined network interface associated with a virtual machine.

virtual terminal

A machine at the technician's location that provides for remote configuration of a switch.

round-robin DNS

A method of increasing name resolution availability by pointing a host name to a list of multiple IP addresses in a DNS zone file. After pointing a client to one IP address in the list, DNS will point the next client that requests resolution for the same domain name to the next IP address in the list, and so on.

network tap

A monitoring device installed inline with network traffic. A network tap usually has three ports: two ports to send and receive all traffic and a third port that mirrors the traffic, sending it to a computer running monitoring software in promiscuous mode.

TRILL (Transparent Interconnection of Lots of Links)

A multipath, link-state protocol (using IS-IS) developed by the IETF and designed to replace STP.

secondary name server

A name server that can take the place of a primary name server to resolve names and addresses on a network. Secondary name servers poll primary name servers to ensure that their zone information is identical. Also called slave name servers.

polling

A network management application's regular collection of data from managed devices.

medianet

A network that has been optimized for media transmissions.

highly available

A network that is functional a high percentage of time per year, such as 99.99 percent of the time (as opposed to just 99.9 percent of the time).

VLAN (virtual local area network)

A network within a network that is logically defined by grouping ports on a switch so that some of the local traffic on the switch is forced to go through a router. A VLAN can consist of any type of network node in any geographic location and can incorporate nodes connected to different switches.

default VLAN

A preconfigured VLAN on a switch that includes all of the switch's ports and cannot be renamed or deleted. The switch might be preconfigured with other VLANs as well, depending on the device and manufacturer.

IP-PBX

A private switch that accepts and interprets both analog and digital voice signals (although some IP-PBXs do not accept analog lines). It can connect with both traditional PSTN lines and data networks. An IP-PBX transmits and receives IP-based voice signals to and from other network connectivity devices, such as a router or gateway.

CAPWAP (Control and Provisioning of Wireless Access Points)

A proprietary protocol created by Cisco to replace LWAPP. Both LWAPP and CAPWAP make centralized wireless management possible, and both direct all wireless frames to the wireless controller by adding extra headers to the frames.

Link Aggregation Control Protocol (LACP)

A protocol currently defined by IEEE's 802.1AX standard that dynamically coordinates communications between two hosts.

CARP (Common Address Redundancy Protocol)

A protocol that allows a pool of computers or interfaces to share one or more IP addresses. CARP improves availability and can contribute to load balancing among several devices, including servers, firewalls, or routers.

OpenFlow

A protocol that serves as a common language in SDN (software defined networking) to bridge the gap between virtualized service applications and a network's physical devices, ensuring that the applications make decisions rather than the devices themselves operating independently from the virtualized services.

Megaco

A protocol used between media gateway controllers and media gateways. Megaco is poised to replace MGCP on modern converged networks, as it supports a broader range of network technologies, including ATM. Also known as H.248.

baseline

A record of how a network operates under normal conditions (including its performance, error statistics, utilization rate, and so on). Baselines are used for comparison when conditions change.

SNMP response message

A response from a managed device's agent to the NMS providing requested information.

thick AP

A self-contained AP that can do its job without relying on a higher-level management device.

network management system (NMS)

A server or workstation hosting software that serves as a central collection point and management interface for data collected on networked devices.

virtual server

A server that exists as a virtual machine, created and managed by virtualization software on a host, or physical, computer.

video-on-demand (VoD)

A service in which a video stored as an encoded file is delivered to a viewer upon his request.

streaming video

A service in which video signals are compressed and delivered over the Internet in a continuous stream so that a user can watch and listen even before all the data has been transmitted.

SMS (Short Message Service)

A service that transmits text messages.

PCI DSS (Payment Card Industry Data Security Standard)

A set of security guidelines created by the PCI Security Standards Council to protect credit card data and transactions, such as segmenting the parts of a network that have access to sensitive financial information from parts that are more vulnerable to compromise.

SS7 (Signaling System 7)

A set of standards established by the ITU for handling call signaling on circuit-switched portions of the PSTN (Public Switched Telephone Network).c

CIDR notation

A shorthand method for denoting the distinction between network and host bits in an IP address.

thin AP

A simple AP that must be configured from the wireless controller's console in order to function.

stack master

A single switch that hosts the VLAN database for all switches on a network.

BPDU guard

A software configuration on a switch's access ports that blocks certain types of BPDUs from being sent to or received by the devices, such as workstations and servers, connected to these ports. A BPDU guard is necessary because network hosts should not be considered as possible paths to other destinations.

BPDU filter

A software configuration that can be used to disable STP on specific ports, such as the port leading to the network's demarc. A BPDU filter prevents access to network links that should not be considered when plotting STP paths in a network.

network management agent

A software routine that collects information about a device's operation and provides that data to the NMS.

network monitor

A software-based tool that monitors traffic on the network from a server or workstation attached to the network. Network monitors typically can interpret up to Layer 3 of the OSI model.

syslog

A standard for generating, storing, and processing messages about events on a system. Syslog describes methods for detecting and reporting events and specifies the format and contents of messages.

VRRP (Virtual Router Redundancy Protocol)

A standard that assigns a virtual IP address to a group of routers. At first, messages routed to the virtual IP address are handled by the master router. If the master router fails, backup routers stand in line to take over responsibility for the virtual IP address.

Webcast

A streaming video, either on demand or live, that is delivered via the Web.

route aggregation

A supernet configuration implemented for the purpose of reducing the number of routing table entries by combining several entries, one for each network, into one entry that represents multiple networks.

availability

How consistently and reliably a file, device, or connection can be accessed by authorized personnel.

out-of-band management

A switch management option that provides on-site infrastructure access when the network is down or complete remote access in cases of connectivity failures on the network, such as via a cellular signal, in order to interface with a switch.

in-band management

A switch management option, such as Telnet, that uses the existing network and its protocols to interface with a switch.

managed switch

A switch that can be configured via a command-line interface and sometimes can be configured in groups. Usually, they are assigned their own IP addresses. VLANs can only be implemented through managed switches.

unmanaged switch

A switch that provides plug-and-play simplicity with minimal configuration options and has no IP address assigned to it. Unmanaged switches are inexpensive, but their capabilities are limited.

intelligent switch

A switch with configuration capabilities.

STP (Spanning Tree Protocol)

A switching protocol defined in IEEE 802.1D. STP operates in the Data Link layer to prevent traffic loops by calculating paths that avoid potential loops and by artificially blocking links that would complete a loop. Given changes to a network's links or devices, STP recalculates its paths.

DiffServ (Differentiated Service)

A technique for ensuring QoS by prioritizing traffic, taking into account all types of network traffic, not just the time-sensitive services such as voice and video. DiffServ places information in the DiffServ field in an IPv4 packet. In IPv6 packets, DiffServ uses a similar field known as the Traffic Class field. This information indicates to network routers how the data stream should be forwarded.

Web caching

A technique in which Web pages are stored at an ISP or locally, either on a host or network, and then delivered to requesters more quickly than if they had been obtained from the original source.

cloud backup

A technique in which data is backed up to a central location over the Internet.

PBX (private branch exchange)

A telephone switch used to connect and manage an organization's voice calls.

IP telephone

A telephone used for VoIP on a TCP/IP-based network. IP telephones are designed to transmit and receive only digital signals.

interface monitor

A tool that can monitor traffic at a specific interface between a server or client and the network, but not the entire network.

traffic policing

A traffic-shaping technique in which the volume or rate of traffic traversing an interface is limited to a predefined maximum.

A single switch can manage traffic belonging to several VLANs on a single interface, by configuring which option on the interface?

A trunk port

NIC teaming

A type of link aggregation in which two or more NICs work in tandem to handle traffic to and from a single node.

host-only mode

A type of network connection in which VMs on a host can exchange data with each other and with their host, but they cannot communicate with any nodes beyond the host. In other words, the vNICs never receive or transmit data via the host machine's physical NIC.

bridged mode

A type of network connection in which a vNIC accesses a physical network using the host machine's NIC. In other words, the virtual interface and the physical interface are bridged. The bridged vNIC, however, obtains its own IP address, default gateway, and subnet mask information from the physical LAN's DHCP server.

NAT mode

A type of network connection in which a vNIC relies on the host machine to act as a NAT device. In other words, the VM obtains IP addressing information from its host, rather than a server or router on the physical network. To accomplish this, the virtualization software acts as a DHCP server.

BPDU (Bridge Protocol Data Unit)

A type of network message that transmits STP information between switches.

video phone

A type of phone that includes a screen and can decode compressed video and interpret transport and signaling protocols necessary for conducting videoconference sessions.

circuit-switched

A type of switching in which a connection is established between two network nodes before they begin transmitting data. Bandwidth is dedicated to this connection and remains available until users terminate the communication between the two nodes.

packet-switched

A type of switching in which data is broken into packets before being transported. In packet switching, packets can travel any path on the network to their destination because each packet contains a destination address and sequencing information.

MPLS (multiprotocol label switching)

A type of switching that enables multiple types of Layer 3 protocols to travel over any one of several connection-oriented Layer 2 protocols. 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.

VMware

A vendor that supplies the most popular types of workstation and server virtualization software. Used casually, the term VMware may also refer to the virtualization software distributed by the company.

SNMPv3 (Simple Network Management Protocol version 3)

A version of SNMP similar to SNMPv2, but with authentication, validation, and encryption for messages exchanged between managed devices and the network management console. SNMPv3 is the most secure version of the protocol.

LWAPP (Lightweight Access Point Protocol)

A wireless protocol created by Cisco that makes centralized wireless management possible. LWAPP directs all wireless frames to the wireless controller by adding extra headers to the frames, but it is also considered a lightweight protocol because the headers are relatively small.

virtual workstation

A workstation that exists as a virtual machine, created and managed by virtualization software on a host, or physical, computer.

management console

A workstation, such as a laptop, that is connected to a switch's console port and allows for changes to be made to a switch's configurations.

tagged

An Ethernet frame that is addressed to a specific VLAN.

virtual IP address

An IP address that can be shared by a group of routers.

CIDR (Classless Interdomain Routing)

An IP addressing and subnetting method in which network and host information is manipulated without adhering to the limitations imposed by traditional network class distinctions. CIDR is also known as classless routing or supernetting. Older routing protocols, such as RIP, are not capable of interpreting CIDR addressing schemes.

classful addressing

An IP addressing convention that adheres to network class distinctions, in which the first 8 bits of a Class A address, the first 16 bits of a Class B address, and the first 24 bits of a Class C address are used for network information.

VLAN hopping attack

An attack in which the attacker generates transmissions that appear, to the switch, to belong to a protected VLAN.

primary name server

An authoritative name server that is queried first on a network when resolution of a name that is not already cached is requested. Also called master name servers.

runt

An erroneously shortened packet.

virtual appliance

An image that includes the appropriate operating system, software, hardware specifications, and application configuration necessary for a prepackaged solution to run properly on a virtual machine.

virtual bridge

An interface connecting a vNIC with a virtual or physical network, or a port on a virtual switch.

ATA (analog telephone adapter)

An internal or externally attached adapter that converts analog telephone signals into packet-switched voice signals and vice versa.

KVM (Kernel-based Virtual Machine)

An open source virtualization package designed for use with Linux systems.

native VLAN

An untagged VLAN on a switch that will automatically receive all untagged frames. Options for native VLANs vary according to the switch manufacturer and model.

managed device

Any network node monitored by the NMS. The device might contain several objects that can be managed, including components such as a processor, memory, hard disk, or NIC, or intangibles such as performance or utilization.

video over IP

Any type of video service, including IPTV, videoconferencing, and streaming video, that delivers video signals over packet-switched networks using the TCP/IP protocol suite.

HSRP (Hot Standby Routing Protocol)

Cisco's proprietary standard, similar to VRRP, that assigns a virtual IP address to a group of routers. At first, messages routed to the virtual IP address are handled by the active router. If the active router fails, standby routers stand in line to take over responsibility for the virtual IP address.

VTP (VLAN trunking protocol)

Cisco's protocol for exchanging VLAN information over trunks. VTP allows one switch on a network to centrally manage all VLANs.

True or False: TCP is preferred over UDP for real time services.

False

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

H.225

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

Which of the following describes a router protocol that is used to assign a virtual IP address to a group of routers so that the routers function as a group?

HSRP VRRP

video bridge

Hardware or software that manages multiple audiovisual sessions so that participants can see and hear each other.

CIDR block

In CIDR notation, the forward slash plus the number of bits used for the network ID. For example, the CIDR block for 199.34.89.0/22 is /22.

supernet

In IPv4, a type of subnet that is created by moving the subnet boundary to the left instead of the right and using bits that normally would be reserved for network information instead of using bits reserved for host information.

user agent server

In SIP terminology, a server that responds to user agent clients' requests for session initiation and termination.

endpoint

In SIP terminology, any client, server, or gateway communicating on the network.

user agent

In SIP terminology, any node that initiates or responds to SIP requests.

user agent client

In SIP terminology, end-user devices such as workstations, tablet computers, smartphones, or IP telephones. A user agent client initiates a SIP connection.

routing prefix

In an IPv6 address, the first four blocks (or 64 bits) that identify the network and serve as the network ID. Also called network prefix.

magic number

In the context of calculating subnets, the difference between 256 and the interesting octet (any octet in the subnet whose value is something other than 0 or 255). The magic number can also be calculated by raising 2 to the power of the number of bits in the host portion of the subnet mask using the formula 2^h=magic number. The magic number can be used to calculate the network IDs in all the subnets of the larger network.

guest

In the context of virtualization, a virtual machine operated and managed by a virtualization program.

automatic failover

In the event of a component failure, the ability of a redundant component to immediately assume the duties of the failed component.

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

traffic shaping

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.

Hyper-V

Microsoft's virtualization software package. Hyper-V was first available with Windows Server 2008, and is now available in some 64-bit versions of Windows 8.1 as well.

What type of VLAN automatically receives all untagged frames?

Native VLAN

redirect server

On a SIP network, a server that accepts and responds to requests from user agents and SIP proxy servers for location information on recipients that belong to external domains.

registrar server

On a SIP network, a server that maintains a database containing information about the locations (network addresses) of each user agent in its domain. When a user agent joins a SIP network, it transmits its location information to the SIP registrar server.

system log

On a computer running a UNIX or Linux operating system, the record of monitored events, which can range in priority from 0 to 7 (where "0" indicates an emergency situation and "7" simply points to information that might help in debugging a problem). You can view and modify system log locations and configurations in the file /etc/syslog.conf on most systems (on some systems, this is the /etc/rsyslog.conf file).

H.323 gateway

On a network following the H.323 standard, a gateway that provides translation between network devices running H.323 signaling protocols and devices running other types of signaling protocols (for example, SS7 on the PSTN).

H.323 terminal

On a network following the H.323 standard, any node that provides audio, visual, or data information to another node.

AF (Assured Forwarding)

One of two DiffServ forwarding specifications. AF allows routers to assign data streams one of several prioritization levels, but it provides no guarantee that, on a busy network, messages will arrive on time or in sequence. AF is specified in the DiffServ field in an IPv4 packet.

EF (Expedited Forwardidng)

One of two DiffServ forwarding specifications. EF assigns each data stream a minimum departure rate from a given node. This technique circumvents delays that slow normal data from reaching its destination on time and in sequence. EF information is inserted in the DiffServ field of an IPv4 packet.

What protocol is used to provide a common language between virtualized service applications and a network's physical devices?

OpenFlow

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

PCI DSS

SAID (security association identifier)

Part of a VLAN configuration that indicates to other connectivity devices which VLAN a transmission belongs to. By default, Cisco switches assign a VLAN the SAID of 100,000 plus the VLAN number (such as 100,000+12).

CoS (Class of Service)

Quality control techniques performed at Layer 2 on Ethernet frames. Most often, CoS is used to more efficiently route Ethernet traffic between VLANs.

What two standards below have been developed to replace the Spanning Tree Protocol?

SPB TRILL

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

SS7

slash notation

See CIDR notation.

classless routing

See CIDR.

supernetting

See CIDR.

IP phone

See IP telephone.

digital PBX

See IP-PBX.

Softswitch

See MGC.

call agent (CA)

See MGC.

H.248

See Megaco.

IP telephony

See VoIP.

virtual machine manager

See hypervisor.

port bonding

See link aggregation.

content switching

See load balancing.

UC gateway

See media gateway.

network number

See network ID.

network prefix

See network ID.

packet sniffer

See network tap.

master name server

See primary name server.

traffic shaper

Software running on a router, multilayer switch, gateway, server, or even a client workstation that can prioritize traffic according to protocol, IP address, user group, DiffServ flag (in an IP packet), VLAN tag, service, or application.

integrity

The assurance that a network's programs, data, services, devices, and connections have not been altered without authorization. To ensure a network's integrity, it must be protected from anything that might render it unusable, such as corruption, tampering, natural disasters, and viruses.

unified messaging

The centralized management of multiple types of network-based communications, such as voice, video, fax, and messaging services.

extended network prefix

The combination of an IP address's network ID and subnet information. By interpreting the address's extended network prefix, a device can determine the subnet to which an address belongs.

fault management

The detection and signaling of device, link, or component faults.

load balancing

The distribution of traffic over multiple components or links to optimize performance and fault tolerance.

uptime

The duration or percentage of time a system or network functions normally between failures.

hypervisor

The element of virtualization software that manages multiple guest machines and their connections to the host (and by association, to a physical network). A hypervisor is also known as a virtual machine manager.

virtualization

The emulation of all or part of a computer or network.

signaling

The exchange of information between the components of a network or system for the purposes of establishing, monitoring, or releasing connections as well as controlling system operations.

promiscuous mode

The feature of a network adapter that allows it to pick up all frames that pass over the network - not just those destined for the node served by the card.

Differentiated Services Code Point (DSCP)

The first 6 bits of the 8-bit DiffServ field in an IPv4 packet. DSCP indicates to network routers how the data stream should be forwarded.

presence

The indication of a user's availability through states set by the user (such as online, away, busy, or invisible) or by predetermined conditions (such as the time of day or a user's location).

trunk port

The interface on a switch capable of managing traffic from multiple VLANs. A trunk is a link configured between two switches' trunk ports.

access port

The interface on a switch used for an end node. Devices connected to access ports are unaware of VLAN information.

caching

The local storage of frequently needed files that would otherwise be obtained from an external source.

packet loss

The loss of packets due to an unknown protocol, unrecognized port, network noise, or some other anomaly. Lost packets never arrive at their destination.

fault

The malfunction of one component of a system. A fault can result in a failure.

H.323 gatekeeper

The nerve center for networks that adhere to H.323. Gatekeepers authorize and authenticate terminals and gateways, manage bandwidth, and oversee call routing, accounting, and billing. Gatekeepers are optional on H.323 networks.

PSTN (Public Switched Telephone Network)

The network of lines and carrier equipment that provides telephone service to most homes and businesses. Now, except for the local loop, nearly all of the PSTN uses digital transmission. Its traffic is carried by fiber-optic or copper twisted-pair cable, microwave, and satellite connections.

performance management

The ongoing assessment of how well network links, devices, and components keep up with the demands made on them.

SNMPv1 (Simple Network Management Protocol version 1)

The original version of SNMP, released in 1988. Because of its limited features, it is rarely used on modern networks.

root port

The port on a bridge that is closest to the root bridge. On any bridge, the root port is the only port that can forward frames toward the root bridge.

designated port

The port on a segment (which is the link between two bridges) that provides the shortest path to a specific destination. Only the designated port on a segment can transmit network traffic because STP disables links that are not part of the shortest path.

network ID

The portion of an IP address common to all nodes on the same network or subnet.

route prefix

The prefix in an IPv6 address that identifies a route. Because route prefixes vary in length, slash notation is used to define them. For example, the route prefix indicated by 2608:FE10::/32 includes all subnets whose prefixes begin with 2608:FE1O and, consequently, all interfaces whose IP addresses begin with 2608:FE10.

control plane

The process of decision making, such as routing, blocking, and forwarding, that is performed by protocols.

Internet telephony

The provision of VoIP-based telephone service over the Internet.

videoconferencing

The real-time reception and transmission of images and audio among two or more locations.

link aggregation

The seamless combination of multiple network interfaces or ports to act as one logical interface.

SNMPv2 (Simple Network Management Protocol version 2)

The second version of SNMP, which improved on SNMPv1 with faster performance and slightly better security, among other features.

event log

The service on Windows-based operating systems that records events; also, the ongoing record of such events.

root bridge

The single bridge on a network selected by STP to provide the basis for all subsequent path calculations. Also called master bridge.

redundancy

The use of more than one identical component, device, or connection for storing, processing, or transporting data. Redundancy is intended to eliminate single points of failure and is the most common method of achieving fault tolerance.

prefix mask

The usually optional slash notation at the end of an IPv6 address that indicates the number of bits used by the network prefix.

software defined networking (SDN)

The virtualization of network services in which a network controller manages these services instead of the services being directly managed by the hardware devices involved.

real-time services

Time-sensitive services provided over a network, such as telephone conversations and videoconferences, where data is transferred as it is created.

drop

To discard a packet at its destination because issues such as buffer overflow, latency, bottlenecks, or other forms of network congestion delayed the packet beyond its usable time frame.

True or False: CALEA requires telecommunications carriers and equipment manufacturers to provide for surveillance capabilities.

True

True or False: Most UNIX and Linux desktop operating systems provide a GUI application for easily viewing and filtering the information in system logs.

True

True or False: The SNMP version 3 protocol introduces authentication, validation, and encryption for messages exchanged between devices and the network management console.

True

True or False: Wireshark or any other monitoring software running on a single computer connected to a switch doesn't see all the traffic on a network, but only the traffic the switch sends to it, which includes broadcast traffic and traffic specifically addressed to the computer.

True

unified voice services

VoIP when used in cloud-based PBX systems.

In order to allow communication between VLANs for exchange of data, what must be used?

a router

STP selects the root bridge based on which parameter?

bridge ID (BID)

Which network type allows a vNIC to access a network directly using the host machine's NIC?

bridged mode

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

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

giants

Which virtual network type allows VMs to communicate with each other on the same host, but disallows communication with other nodes on the network?

host-only mode

Telnet and SSH are known as what type of management system?

in-band

Which of the following is not a valid reason for using virtualization?

increase performance

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

The management option that can provide on-site infrastructure access when the network is down or complete remote access in cases of connectivity failures on the network, such as via a cellular signal, is known as?

out-of-band management

In an IPv6 address, the first 64 bits of the address are known as what?

routing prefix

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

runts

Which two properties indicate to other connectivity devices which VLAN a transmission belongs to?

security association identifier & SAID

With VTP, the VLAN database is stored on a switch known as which option below?

stack master

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

unicast

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