CIS3500 Ch 5

# What is binary 0000 in hex

0 hex

# What is 5 hex in binary. #

0101

# What is 6D in binary

0110-1101

# Every time you double the number of states, how many more bits can you transmit

1 more bit

What is 9 hex in binary

1001

# What is A hex in binary

1010

# What is A6 in binary

1010-0110

# If you need to transmit 7 Gbps 40 meters, what signaling standard and UTP quality standard could you use

10Gbase-T Cat 6 or 6A

# What is F hex in binary

1111

# What is the farthest I can transmit a signal with 100GBASE-SR signaling

150 meters (OM4 SR10)

# How long is the clock cycle if I transmit at 100 Mbps using signaling with four states

2 bits/1 clock cycle 100mbps=0.1 GBPS

If you want to transmit five bits per clock cycle, how many states must the system have

32

# What is binary 0011 in hex

3hex

# If you know that a system has 16 states, how many bits can it send per clock cycle

4

If you wish to transmit three bits per clock cycle, how many states must the system have

4

# If you need to transmit 600 million bits per second 90 meters, what signaling standard and UTP quality standard would you use

600000000=600mbps=0.6Gbps 1000 Base-T Cable 5e,6,6A

# How many wires are there in Ethernet cable

8

# The 802.11ac Wi-Fi standard uses 256 states. How many bits can it send per clock cycle

8

# For LAN fiber, what is the dominant signal wavelength

850 nm

# What are the three wavelength windows used in fiber transmission

850 nm 1310 nm 1550 nm each 50 nm wide

# Before the attack, where does the ARP cache tell the victim to send a frame carrying a packet to the router?

ARP cache that associates known IP destination address with their know EUI-48 address.

What links connect users to workgroup switches

Access Links

What is the most common form of digital transmission

Binary

# Distinguish between binary and digital signaling. # I

Binary- two states- one bit sent in each clock cycle States 1 or 0 Digital- there are a few states-more than 1 bit is sent in each clock cycle(2,4,8,...)

# How would you decide which option to choose

Choose option 1, media are cheap, switches are expensive.

What four things do physical layer standards govern

Connectors Transmission media Plugs Signaling

what switches connect switches to other switches

Core Switches

# Does Ethernet use EUI-48 addresses or IP addresses

EUI-48 addresses

# How does Ethernet use parallel transmission

Ethernet transmits on all 4 pairs in each direction simultaneously.

# What is binary 1111 in hex

F hex

# What is the benefit of parallel transmission

Higher speed

# In Figure 5-28, to which hosts can Host D4 send frames?

Host C3 and Host F6

# If a distance can be spanned by UTP or optical fiber, why would you almost never add an intermediate switch

Media are cheap, switches are expensive.

What is a local area network (LAN)

Network located entirely on customers premises/own network and equipment

# What is the quality designator for multimode optical fiber

OM(optical multimode designations/standards) OM3& OM4 are sold today

# If I wish to run Ethernet over fiber using 100GBASE-SR signaling over 100 meters, what options do I have

OM3 SR10,OM4 SR10 & SR4

# If I wish to run Ethernet over fiber using 1000BASE-SX signaling over 500 meters, what are my options

OM3, OM4

# If I wish to connect two switches with fiber at a speed of 30 Gbps, what options do I have? Which would you choose?

OM3, OM4 10gbase-SR w/ 10GBPS bond 3 cables or bigger w/ OM3, OM4 40gbase-SR4 w/ 40gbps Choose 10gbase-SR w/ 3 cables is cheaper

# Which should I choose? Justify your answer.

OM3, because it's cheaper than OM4

# Which should I choose? Justify your answer.

OM3,SR10 Cheaper

# If I wish to run Ethernet over fiber using 100GBASE-SR10 signaling over 70 meters, what options do I have

OM4 SR10 &SR4 OM3 SR10

# If you need to span 600 meters at 1 Gbps, what options do you have? (Include the possibility of using an intermediate switch.)

Option 1. OM4 1000BASE-SX w/ 1Gbps can transmission distance maximum to 1000 meters. Option 2. Cat 5e UTP physical link + an intermediate switch + Cat 6 UTP physical link

# What are the two names for connectors and jacks

RJ-45 Ethernet Jack

# What protocol do companies use to manage their Ethernet networks

SNMP simple network management protocol

# Where does it tell the victim to send such frames after the attack?

Tell victims to EUI 48 addresses of the attackers routers and attacker's host.

# What harm can the attacker do

The attacker can read the packets and pass them on.

What links connect switches to other switches

Trunk Links

What are four security threats of Ethernet?

Virtual LANs for Network Segregation Initial User Authentication through 802.1X 802.1AE switch-to switch protection ARP cache poisoning (Man-in-the-middle attack)

# Which letters may appear in a hex EUI-48 address

a-f

# Why has Ethernet become the dominant LAN technology?

because of its low costs and adequate performance

# How can some redundant backup links be installed without creating loops?

by using RSTP ( Rapid Spanning Tree protocol)

# If you need to transmit 7 Gbps over 120 meters, what signaling standard and UTP quality standard would you use

cant travel over 100 meters

# Which would you probably use if you wanted to send the signal over installed cabling

cat 6

Explain the key general principle of network design and why you should follow it.

choose least expensive option that will achieve the required speed to save money for others

# In Figure 5-21, what would the maximum data length be if the physical link on the left was OM4 fiber

choose the cheapest

# Why are Ethernet standards formally called 802.3 standards

come out of 802 working group

# What is multimode fiber

core that can admit several modes

# Is the path an Ethernet message takes from the source host to the destination host a physical link, a data link, or a route

data link, but could be physical link if the hosts are close enough

# What propagation problem limits transmission distance in 4-pair UTP

dissipation of the signal which causes attenuation

# Are Ethernet messages packets or frames

frames

# When 802.1X is being used, what happens if an attacker plugs his or her host into a switch?

goes to authentication server, if it isn't authorized , the supplicant is locked out of the network

For what specific purpose were the 2.5GBASE-T and 5GBASE-T standards developed

growing demand for faster wifi can use existing cat 5e and cat 6

# How do fiber cords typically provide full-duplex transmission

has 2 fiber strands that permit simultaneous 2 way transmission

# Why does this wavelength dominate

hasn't had to travel any further

# What is amplitude

height of the wave power(brightness)

# What security threat is 802.1X designed to protect against?

helps authenticate a user before he/she is authorized to use a switch port

# Are Ethernet EUI-48 addresses expressed in hex for humans, devices, or both

humans; computers use binary

# When is the PAD field added

if the data field is less than 46 octets

# What reliability problem does Ethernet have?

if there is a breakdown in a transmission link or switch, there is no way around it.

What type of attack does 802.1AE protect against?

impersonating switches, also encrypts traffic switches.

Why does multimode fiber dominate LAN installations

it has not had to go further than; 850 nm light sources have been fine for lans

# At what layers are Ethernet standards defined

layers 1 and 2 Physical wiring data links/frames and switches

what is the benefit of having a single possible path?

less expensive because switch needs little computation power, just uses table lookup

# How does fiber usually transmit a 1

light is turned on in clock cycle

# What is a mode

light rays enter angle

# What limits transmission distance in multimode fiber

modal dispersion time gap between reflection of m

# In what units are light wavelengths measured

nanometers(nm)

# Do switches know the entire data link between the source and destination host

no

# Is this easy to do?

no

# Are all Ethernet switches manageable

no, only switches have snmp agents are manageable; others are just ordinary nonmanagable switches. ( like the one you have at home)

# What does a switch know

only knows information in its switching table, only knows what port to use to send the frame back out.

# Are the maximum distances for UTP and optical fiber transmission shown in Figure 5-12 and Figure 5-16 distance limits for physical links or data links

physical links but no data links

Compare relative cost and maximum propagation distance for multimode and single-mode fiber.

single is more expensive that multimodes; it can often span many kilometers

What information do 2 flag fields give

specific priority (tag Protocol) and VLAN membership *Tag protocol ID- indicates the gram is tagged. *Tag control information- gives the tagged information. ( three bits)

# Are Ethernet forwarding devices switches or routers

switches

# What are manageable switches

switches that have snmp agents

# Because of this organization, how many possible paths can there be between any two hosts?

there is only one possible path between 2 hosts

# How are switches in an Ethernet LAN organized

they are organized in a hierarchical switch topology.

# What is the security benefit of Ethernet VLANs?

they can enforce segregation of network resources through VLANs (Virtual LANs)

# Why is the signal held constant over each clock cycle

to make sure the other side can adjust and receive/read it

# How is each pair organized

twisted pair

What switches connect users to the network.

work group switches