Section 6: Ethernet Fundamentals

Question 1

Hub

Answer 1

▪ Layer 1 device used to connect multiple network devices/workstations
(Multiport repeater)

Three basic types:
▪ Passive hub - Repeats signal with no amplification
▪ Active hub - Repeats signal with amplification
▪ Smart hub - Active hub with enhanced features like SNMP

Question 2

Bridge

Answer 2

A device that aggregates multiple commnication networks.
(Analyzes source MAC addresses entering the bridge and populates an internal MAC address table.)

Question 3

Switch

Answer 3

▪ Layer 2 device used to connect multiple network segments. (Essentially a multiport bridge)

▪ Switches analyze source MAC addresses, populate an internal MAC address table and make forwarding decisions
▪ Each port represents an individual collision domain
▪ All ports belong to the same broadcast domain

Question 4

Router

Answer 4

▪ Layer 3 device used to connect multiple networks together
▪ Make forwarding decisions based on logical network address (IP addresses (IPv4 or IPv6))
▪ Routers are typically more feature rich and support a broader range of interface types than multilayer switches
▪ Each port is a separate collision domain
▪ Each port is a separate broadcast domain

Question 5

Layer 3 Switch

Answer 5

▪ Layer 3 device used to connect multiple network segments together
▪ Can make Layer 3 routing decisions and interconnect entire networks (like a router), not just network segments (like a switch)

Question 6

Link Aggregation (IEEE Specification)

Answer 6

Link Aggregation (802.3ad)
▪ Combination of multiple physical connections into a single logical connection
▪ Available bandwidth is increased. Congestion is minimized/prevented

Question 7

Power Over Ethernet (PoE)

Answer 7

802.3af
▪ Requires CAT 5 or higher copper cable
▪ Provides up to 15.4 watts of power to device

Question 8

Power Over Ethernet Plus (PoE+)

Answer 8

802.3at
▪ Provides up to 25.5 watts of power to device

Question 9

Port Monitoring or Mirroring

Answer 9

▪ Port mirroring makes a copy of all traffic destined for a port and sends it to another port

Question 10

User Authentication

Answer 10

802.1x
▪ Switches can require users to authenticate themselves before gaining access to the network
▪ Once authenticated, a key is generated and shared between the supplicant (device wanting access) and the switch (authenticator)
▪ Authentication server checks the supplicant’s credentials and creates the key
▪ Key is used to encrypt the traffic coming from and being sent to the client

Question 11

Management Access and Authentication (Switches)

Answer 11

▪ SSH - Remote administration program that allows you to connect to the switch over the network
▪ Console Port - Local administration/management of the switch via a computer and rollover (null-modem) cable. (DB-9 to RJ-45)

Question 12

Out of Band Management

Answer 12

OOB Management -
▪ A network separate from the data network for managing network devices.

Question 13

First-Hop Redundancy Protocol (FHRP)

Answer 13

Designed to protect the default gateway by providing transparent fail-over at the first-hop router.

Layer 3 Switches (Multilayer Switches) and Routers -
▪ Uses Hot-Standby Router Protocol (HSRP) to create virtual IP and MAC addresses to provide active standby routers.

Question 14

GLBP (Other First-Hop Redundancy Protocol)

Answer 14

Gateway Load Balancing Protocol - (Cisco Proprietary)
▪ For Exam just need to know they are another First-Hop Redundancy Protocol but HSRP is most popular/common used in most networks.

Question 15

VRRP (Other First-Hop Redundancy Protocol)

Answer 15

Virtual Router Redundancy Protocol - (Open Source)
▪ For Exam just need to know they are another First-Hop Redundancy Protocol but HSRP is most popular/common used in most networks.

Question 16

CARP (Other First-Hop Redundancy Protocol)

Answer 16

Common Address Redundancy Protocol - (Open Source)
▪ For Exam just need to know they are another First-Hop Redundancy Protocol but HSRP is most popular/common used in most networks.

Question 17

MAC Filtering

Answer 17

Layer 2 -
▪ Permits or denies traffic based on MAC Address

Question 18

Traffic Filtering

Answer 18

▪ Multilayer switches may permit or deny traffic at logical layer using IP addresses (Layer 3) or ports (Layer 4)

Question 19

QoS

Answer 19

Quality of Service -
▪ Forwards traffic based on quality markers.

Question 20

HSRP

Answer 20

Hot-Standby Router Protocol - (Cisco Proprietary Protocol)
▪ Uses virtual IP and MAC addresses to provide an “active router” and a “standby router”

Question 21

STP

Answer 21

Spanning Tree Protocol (STP): A Layer 2 link management protocol (Part of 802.1d standard).

▪ Permits redundant links between switches and prevents bridge (traffic) loops

Question 22

VLAN

Answer 22

Virtual Local Area Network :
A logical grouping of switch ports with its own subnet or broadcast domain. (At the Data Link (layer 2) layer.)

Question 23

VLAN Trunking

Answer 23

Virtual Local Area Network Trunking - A point-to-point link between two network devices that carry more than one VLAN (Part of 802.1q standard)
▪ Multiple VLANs transmitted over the same physical cable
▪ VLANs are each tagged with 4-byte identifier
- Tag Protocol Identifier (TPI)
- Tag Control Identifier (TCI)

Question 24

VPN

Answer 24

Virtual Private Network (VPN)
▪ Creates a secure, virtual tunnel over an untrusted network, like the Internet.

Question 25

VPN Concentrator

Answer 25

▪ A specialized high-performance device that provides multiple secure VPN connections.

(A firewall can also perform this function.)

Question 26

VPN Headend

Answer 26

▪ A specific type of VPN concentrator used to terminate IPSec VPN tunnels within a router or other device.

Question 27

Firewall

Answer 27

(Works at Layers 3 and 4 of the OSI Model)
▪ Network security appliance at the network boundary
▪ Can be software or hardware

Question 28

NGFW

Answer 28

Next-Generation Firewall (NGFW)
▪ Conducts deep packet inspection at Layer 7
▪ Much more powerful than basic stateless or stateful firewalls
▪ Continually connects to cloud resources for latest information on threats

Question 29

IDS / IPS

Answer 29

Intrusion Detection or Prevention System (IDS/IPS)
▪ IDS recognizes attacks through signatures and anomalies
▪ IPS recognizes and responds
▪ Host or network-based devices

Question 30

Proxy Server

Answer 30

▪ A specialized device that makes requests to an external network on behalf of a client

Question 31

Content Engine/Caching Engine

Answer 31

▪ Dedicated appliance that performs the caching functions of a proxy server

Question 32

Content Switch or Load Balancer

Answer 32

▪ Distributes incoming requests across various servers in a server farm