Pubali Bank Limited Officer (IT) Preliminary Exam: 2012প্রশ্ন ও সমাধান

Correct answer: (a) transceiver

A media converter joins two different media, most often copper twisted pair and optical fibre. On one side it receives electrical signals and on the other it transmits them as light, and the reverse in the other direction, so it is a transmitter and a receiver in one box: a transceiver. It does exactly what a pluggable fibre transceiver (for example an SFP module) does inside a switch, only as a separate unit. In Ethernet (IEEE 802.3) terms, the device that attaches equipment to a particular medium is the transceiver, also called a Medium Attachment Unit.

Why the other options are wrong

• (b) hub: A multiport repeater that copies the signal to all ports on the same kind of medium; it does not convert copper to fibre.
• (c) modem: Modulates digital data onto an analog carrier (and demodulates it), for example over a telephone line; it does not convert between cable media.
• (d) repeater: Regenerates a weakened signal on the same medium to extend distance; input and output media are the same.

Tip: Media converter = standalone transceiver (copper ↔ fibre); built into a switch, the same job is done by an SFP transceiver.

Sources: medium access unit (MAU) (ATIS Telecom Glossary); transceiver (ATIS Telecom Glossary)

Correct answer: (b) Cost

OSPF describes every route with one dimensionless number called cost. Each router interface is given a cost (the lower the cost, the more attractive the link), and the cost of a path is the sum of the outgoing-interface costs along it. Every router runs the SPF (Dijkstra) calculation on its link-state database and installs the path with the lowest total cost. Many implementations set the default interface cost from the link bandwidth (faster link → smaller cost), but the value OSPF actually compares is the cost.

Why the other options are wrong

• (a) Latency: OSPF does not measure delay; latency is not part of its metric.
• (c) Bandwidth: Bandwidth can be used to calculate a default cost, but OSPF compares costs, not bandwidth figures, and an administrator can set any cost regardless of bandwidth.
• (d) Next hop: The next hop is the result of the route calculation (the neighbour a packet is sent to), not a metric for comparing paths.

Tip: RIP → hop count; OSPF → cost; EIGRP → composite (bandwidth + delay); BGP → path attributes such as AS_PATH.

Source: RFC 2328: OSPF Version 2; Introduction to OSPF (Juniper Networks, Junos OS documentation)

Correct answer: (c) HTTPS

HTTPS runs HTTP inside a TLS session (default TCP port 443). TLS authenticates the server with its certificate and encrypts and integrity-protects the traffic, so credentials and data cannot be read or altered in transit. It is the only secure connection method in the list.

Why the other options are wrong

• (a) HTTP: plain HTTP (port 80) sends requests, responses and any login details unencrypted.
• (b) RCP: the BSD remote-copy command relies on trusted host names and does not encrypt the transfer.
• (d) TELNET: sends the whole session, including the password, in clear text; SSH was designed to replace telnet and rlogin with a much more secure channel.

Tip: Secure replacements: HTTP → HTTPS, Telnet → SSH, RCP/FTP → SCP/SFTP.

Source: RFC 9110: HTTP Semantics; RFC 4251: The Secure Shell (SSH) Protocol Architecture

Correct answer: (b) Layer 3

A basic (stateless) packet-filtering firewall judges each packet on its own by reading header fields: source and destination IP address, the protocol (TCP, UDP, ICMP) and, optionally, the TCP/UDP port numbers. It never looks at the packet's content. NIST states that, in their most basic form, packet-filter firewalls operate at the network layer, which is OSI Layer 3. A router with access control lists (ACLs) is the classic example.

Why the other options are wrong

• (a) Layer 1: the physical layer only carries bits over cable or radio; there are no addresses or headers to filter on.
• (c) Layer 7: inspecting application data (URLs, HTTP methods, mail commands) is the job of application firewalls and proxy gateways, not of a basic packet filter.
• (d) Layer 4: a packet filter may also match port numbers, which are Layer 4 fields, but its core decision is IP-based. Tracking TCP connections (stateful inspection) is the more advanced firewall type built on top of packet filtering.

Exam note: Some notes describe packet filters as working at "Layer 3 and 4" because they can read port numbers. With one answer allowed, the standard answer is Layer 3, the network layer, as NIST states.

Tip: Packet filter → Layer 3; stateful inspection → adds Layer 4 session tracking; application/proxy firewall → Layer 7.

Source: Guidelines on Firewalls and Firewall Policy (NIST SP 800-41 Rev. 1)

Correct answer: (a) FireWire

IEEE 1394 is a high-speed serial bus standard for connecting computers and peripherals, sold commercially as FireWire (Apple's name; Sony marketed it as i.LINK). It defines both the physical layer and the data-link layer, supports hot-plugging, and provides isochronous transfers with guaranteed bandwidth, which is why it was popular for digital camcorders, audio interfaces and external drives. FireWire 400 corresponds to IEEE 1394a and FireWire 800 to IEEE 1394b.

Why the other options are wrong

• (b) USB 2.0: USB is defined by the USB Implementers Forum's own specifications, not by IEEE 1394.
• (c) iSCSI: iSCSI carries SCSI commands over TCP/IP networks and is an IETF protocol (RFC 7143), not an IEEE bus standard.
• (d) Parallel: The PC parallel (printer) port is standardised as IEEE 1284, a different standard.

Tip: 1394 = FireWire; 1284 = parallel port; 802.3 = Ethernet; 802.11 = Wi-Fi.

Source: IEEE 1394 Standard (IEEE Technology Navigator)

Correct answer: (a) keeps historical data

A logger's job is to record data over time so that it can be looked at later. In a Cisco Unified ICM / Contact Center Enterprise system the Logger is the database component (on Microsoft SQL Server) that stores the configuration data and the historical data about calls, agents and skill groups. It also forwards that history to the Historical Data Server, which holds it for long-term reporting.

Why the other options are wrong

• (b) keeps all the data for delivery purpose: A logger stores records for reporting and audit; it does not deliver calls or messages.
• (c) keeps the code for the tracking: A logger stores data, not program code; the routing scripts are executed by the Call Router.
• (d) keeps automatic call distribution: Distributing calls to agents is the job of the ACD (Automatic Call Distributor), not the logger.

Tip: Logger = recorder of history; ACD = distributor of calls; Router = decision maker.

Sources: Serviceability Guide for Cisco Unified ICM/Contact Center Enterprise, Release 12.6(1) — Product Architecture; Pre-installation Planning Guide for Cisco Unified Intelligent Contact Management, Release 12.6(1) — Cisco Unified ICM Overview

Correct answer: (a) Cisco Intelligent Contact Management

ICM stands for Intelligent Contact Management. Cisco Unified ICM is the routing and reporting core of Cisco's enterprise contact-center solution: its Call Router decides, in real time, which site, skill group or agent should handle each call or contact, using data that Peripheral Gateways collect from ACDs and IVRs, while the Logger stores configuration and historical data. Cisco's own planning guide is titled "Cisco Unified Intelligent Contact Management".

Why the other options are wrong

• (b) Cisco intellectual connection management: Both words are wrong: "intellectual" for Intelligent and "connection" for Contact.
• (c) Cisco isolated contact management: "Isolated" is wrong; ICM spreads contacts across sites rather than isolating them.
• (d) Cisco recovery management: It does not even match the letters I-C-M.

Tip: ICM = Intelligent Contact Management, the "brain" of Cisco Unified Contact Center Enterprise.

Source: Pre-installation Planning Guide for Cisco Unified Intelligent Contact Management, Release 12.6(1) — Cisco Unified ICM Overview