IS 451 Exam

Collision and Broadcast Domains

Two devices transmitting on the same medium at the same time cause a collision o CSMA/CD - wired Ethernet method to determine when to send and when a collision occurred o CSMA/CA - wireless Ethernet method to determine when to send o Broadcast - message to all recipients simultaneously FF-FF-FF-FF-FF-FF (Layer 2) or 255.255.255.255 (Layer 3, IPv4) o Each port of a switch/bridge is a collision domain

What port do SNMP listen on

UDP port 161

SNMP NMS listens for traps on what port

UDP port 162

Routers

Use Layer 3 information to choose optimal path (What is the optimal path for every step it needs to go in it message sending) o Filters broadcasts and multicasts, create separate broadcast domains o Have network (IP/host) addresses o Modifies the destination's physical address

MIB - Management Information Base

Virtual information store. Describes the structure of management data on a managed device. Each variable identified by object ID (OID). Vendors define MIBs. MIB II is a standard implemented by all managed devices.

2.4Ghz

2.4Ghz has 11 channels, only 3 non-overlapping (1, 6, 11). Lower frequency has farther range but interference issues More likely to go through walls

Class D Network Address

224-239

Class E Network Address

240 - 255

How many non-overlapping wireless channels are there in the 2.4 GHz band? 1 21 11 3

3

• Hierarchical Design

Access - local and remote workgroup access, individual clients, hubs/switches o Distribution - policy-based connectivity, routing between VLANs o Core - high-speed switching, high reliability, redundancy

Which of these is considered part of the application layer of the OSI Reference Model? FTP Web browser HTTP Outlook

FTP HTTP

Class A Network address

1 - 126

What is the maximum cable transmission distance for a Category 6a cable? There is no maximum distance. 1 km 100 ft 100 m

100 M

Class B Network Address

128-191

What port(s) does SNMP use? 162/TCP 161/TCP 161/UDP 80/TCP

161/UDP

Class B Private Range

172.16.0.0 - 172.31.255.255

Which of these is a private, non-internet routable, IP address? 212.88.101.42 130.85.17.55 31.100.73.14 172.18.143.9 10.14.29.193 192.168.100.5

172.18.143.9 10.14.29.193 192.168.100.5

Class C Network Address

192-223

5Ghz

5Ghz has 21 channels, all non-overlapping. Higher frequency is more susceptible to absorption by surrounding objects, but less interference.

802.11 attributes

802.11b and 802.11g use 2.4Ghz. 802.11a uses 5Ghz. 802.11n and 802.11ac use both frequency bands, as well as multiple antennas (MIMO).

SNMPv3

Adds security, remote configuration, encryption, authentication, message integrity o User-based Security Model Authenticating, encrypting/decrypting SNMP packets o View-based Access Control Model Administering access to the MIB data o Protection against modification of data, masquerading, disclosure, and message stream modification

At what layer of the OSI Reference Model does SNMP operate? Physical Network Transport Application

Application

What is Masquerading? The alteration of data in transit by an unauthorized entity Assuming the identity of another Obtaining the data between parties without their consent or knowledge; wiretapping Encrypting a data stream between parties

Assuming the identity of another

What organization(s) was/were responsible for the standardization of the OSI Reference model? IETF CCITT ANSI ISO

CCITT ISO

Layer 1 of the OSI reference model- PHysical

Cabling Voltage and wave (is it five volts for one or three volts for zero) Network Topology - generally bus, mesh, ring (How are all of these devices connected to each other) Bus: same connection medium Ring: Each devices is connected to two others one on the left one on the right. Star: center switch Mesh: Everything is connected to everything else Machines used: Hubs. Repeaters, Modems, Cabling, Network Adapters, Bits

o VACM:

Checks to see whether a specific type of access to a specific managed object is allowed Access control occurs in the agent, elaborates on concept of community strings

Classful Networking

Class A - 1-126. First octet is part of the network address. Others, hosts. Class B - 128-191. First two octets part of the network address. Class C - 192-223. First three octets part of the network address. Class D - 224-239 (Multicast) Class E - 240-255 (Reserved)

If an organization needed 200 hosts, which class of network would be the most efficient? Class C Class D Class B Class A

Class C

Half-duplex

Communication between two devices whereby transmission takes place in only one direction at a time.

Simple Network Management Protocol

Communication protocol, data definitions, database schema o Managers/NMS, managed devices, SNMP agents, MIB

Full Duplex

Communication that happens in two directions at the same time.

USM

Communication without authentication and privacy (NoAuthNoPriv) Communication with authentication and without privacy (AuthNoPriv) Communication with authentication and privacy (AuthPriv)

Layer 4 of the OSI reference model - Transport

Connection integrity and potentially multiple connections (like between a server and multiple clients) Flow control, error checking Connection and connectionless protocols Firewalls and ports, TCP (connection protocol) Segments/UDP Datagrams (Connectionless)

In the ISO Network Management Model, for what is Security Management responsible? Quantifying, measuring, and analyzing performance of network components Tracking devices and their hardware and software components Controlling access to network resources according to some well-defined policy Logging, detecting, and responding to errors on the network

Controlling access to network resources according to some well-defined policy

ISO network Management Model

Fault management - log, detect and respond to fault conditions in the network o Configuration management - track devices and their hardware and software configurations o Accounting management - specify, log and control user access to network resources o Performance management - quantify, measure, report, analyze and control performance of network components o Security Management - control access to network resources according to some well-defined policy

Layer 6 of the OSI reference model - Presentation

Formats information between protocols syntax adjustment Data conversion, compression, encryption and decryption (NHTTP header, how is the header formatted, what are the fields, what characters are we using)

Media Access Control (MAC) Layer

How and when devices gain access to the network

Layer 7 of the OSi reference model - Application

Interface between the application and protocol stack Identify communication partners, determine resource available resource sharing HTTP, FTP, SMTP. DNS

Hubs operate at what layer of the OSI Reference Model? Layer 2 Layer 4 Layer 3 Layer 1

Layer 1

Reliability

Layer 2 - Spanning Tree Protocol (802.1d) - prevents loops at Layer 2 Listening - Learning - Forwarding - Blocking o Layer 3 - VRRP and HSRP - Multiple default gateways at Layer 3 VRRP is open standard, HSRP is Cisco proprietary Uses a virtual router as the gateway for clients

Large-scale LAN

Limited to local area, fixed geographical area o Uses LAN technologies, switching and routing o Bus, ring, star, mesh topologies o Evolved from shared (hub) to switched networks Added bandwidth, VLANs, security

LAN (Large scale network)

Limited to local area/fixed to geographical area Lan technologies: Ethernet, Fast Ethernet, Gigabit/10 Gigabit Ethernet Switching and routing technologies

What layer is responsible for frame synchronization? Physical Logical Link Control Network Media Access Control

Logical Link Control`

Layer 3 of the OSI reference model

Logical addressing and communication between devices Works by using routing to deliver messages through intermediate nodes on different networks IPv4 and v6 (Whenever you need to send something to a different network the ip address is nessessary) Fragmentation of large message occur at this layer Routers, routing protocols

Which layer governs how and when devices gain access to the network? Network Media Access Control Logical Link Control Session

Media Access Control

OSI Reference Model

Mostly just a teaching tool Layering model structured into seven layers (physical layer, data-link layer, network layer, transport layer, session layer, presentation layer, application layer) Standardized in 1984. Now replaced by TCP/IP model Still an important teaching tool Began in the 1970s by the International Organization for Standardization and the International Telegraph and Telephone Consultative Committee

TCP/IP model

NITA Network Internet Transport Application Each with their own equivalent.

Layer 2 of the OSI reference model - Data Link

Necessary for a data connection between two endpoints Split into two layers: Media Access Control and Logical Link Layer Mac address = physical address. Whenever you are sending data between addressing, you are using the MAC address. becuase we need to know physically where it is located Physical addressing and communication MAC layer LLC layer Switches - similar to hubs, recieves information and sends it to the port where it knows its the right destination, vlans, bridges, ARP, SPanning tree, ethernet, Vlans and Trunking frames

Which layer of the OSI Reference Model provides logical addressing for endpoints? Data Link Application Network Transport

Network

ISO model Internet Layer Equivalent

Network Layer

ISO model Network Access Layer Equivalent

Physical and Data Link

Your data needs to be rendered in UNICODE format. What layer of the OSI Reference Model is responsible for this? Application Transport Physical Presentation

Presentation

Private and reserved addresses

Private and reserved addresses Whenever the host bits are all 0: network identifier Whenever the host bits are all 1: broadcast address Loopback (127.0.0.0/8): host refers to itself Not routable address: • 10.0.0.0/8 (one Class A network) • 172.16.0.0 to 172.31.255.255 (16 Class B networks) • 192.168.0.0/16 (256 Class C networks)

What is the job of an SNMP manager? Store and retrieve management information as defined in the MIB Query agents Set variables in agents Send traps to agent on important event

Query Agents Set Variables in Agents

While using a remote desktop connection, your Internet link has a momentary issue. When resolved, your remote desktop connection resumes right where it left off. What layer of the OSI Reference Model made that happen? Data Link Presentation Application Session

Session

ISO model Application layer equivalent

Session, Presentation and Application

Simplex

Single-frequency radio; transmissions can occur in either direction but not simultaneously in both; when one party transmits, the other can only receive, and the party that is transmitting is unable to receive.

Single mode Fiber

Speeds up to 100Gbps and higher, distances hundreds of miles or more. Uses highly tuned laser optics, small core. Links between buildings. A type of fiber optic cableing

Category 6a Cable

Speeds up to 10Gbps, 4 wire pairs, max length of 100m, field termination harder

Multi-mode Fiber

Speeds up to 10Gbps, distances up to 2km. Can use cheaper LEDs, larger core size. Links within a building or room (data center).

Category 5e Cable Type

Speeds up to 1Gbps. 4 wire pairs, max length of 100m

The Structure of Management Information states that each object should have what? Field Syntax Name Encryption

Syntax Name

VLANs

Systems are in same broadcast domain (makes them smaller) o No physical proximity constraints, can span networking equipment using trunking protocols o Router required to communicate to hosts in a different VLAN o Can provide security and easier network management o 80/20 rule: 80% of the traffic should stay local to the VLAN o Trunk - high-speed connection between devices Switches use trunking protocol to exchange information about VLAN configuration Tags added to all frames travelling on the trunk with VLAN information o Can be assigned by port, protocol, or user-defined value

PLaNT SPA

The layer

If you need to send multiple connections to the same endpoint, or if a server needs to be able to receive multiple requests, what layer of the OSI Reference Model is primarily involved? Session Network Data Link Transport

Transport

It may be necessary (but is optional) to acknowledge that your messages have been received, and that they have been received in order. What layer of the OSI Reference Model ensures this is the case? Session Transport Correct answer Network Application

Transport

ISO model Transport layer equivalent

Transport layer

Subnet Advantages

easier management, security. Usually implemented with VLANs on switched networks

Logical Link Control (LLC) layer

identifies and encapsulates network layer protocols Error checking and frame synchronization

Subnet

logical division of a network. Made by "borrowing bits" from the host portion of an IP address. Subnet mask shows how many bits were borrowed. CIDR notation

Layer 5 of the OSI reference model - Session

manages connections between local and remote applications duplex communications checkpoints and verificiation BIOS. NetBIOS

• SMI - Structure of Management Information

o Language used to define information residing in a managed object o Name (object ID), syntax (type), and encoding. Subset of ASN.1: independent of machinespecific encoding