Layer 2 + Layer 3

Question 1

records the source MAC address, port & VLAN, and timestamp of each received frame. The maximum default time an entry will be kept on the table is 300 seconds.

Answer 1

CAM Table

Question 2

a specialized CAM designed for rapid table lookups. provides three results: 0, 1, and “don’t care.” is most useful for building tables for searching on longest matches such as IP routing tables organized by IP prefixes.

Answer 2

TCAM

Question 3

is where all IP Routing information is stored. It is not specific to any routing protocol, rather a repository where all the routing protocols place all of their routes.

Answer 3

Routing Information Base

Question 4

refers to the process by which the router’s CPU or processor is directly involved in the forwarding decision.

Answer 4

Process Switching

Question 5

It is actually a reactive cache-based IP forwarding mechanism i.e. the address lookup uses a route cache to find the IP next-hop, outgoing interface, and outbound layer-2 header. Destination addresses are stored in the high-speed cache to expedite forwardin

Answer 5

Fast Switching

Question 6

switching is a proprietary form of scalable switching intended to tackle the problems associated with demand caching. the information which is conventionally stored in a route cache is split up over several data structures.

Answer 6

Cisco Express Forwarding (CEF)

Question 7

is a technology with which we can create separate virtual routers on a physical route. With these separate virtual routers, we can use router interfaces, routing and forwarding tables isolated with this.

Answer 7

Virtual Routing and Forwarding (VRF)

Question 8

provides a virtual point-to-point private connection and encapsulates and forwards packets over an IP-based network

Answer 8

GRE (Generic Routing Encapsulation)

Question 9

occurs when the router learns the destination IP address for the tunnel interface through the tunnel itself. It removes the previous entry for the tunnel destination IP address from the routing table, making the tunnel’s destination inaccessible

Answer 9

Recursive Routing

Question 10

IP Sec Components

Answer 10

Authentication
Integrity
Confidentiality

Question 10

a key management protocol standard that is used in conjunction with the IP Security (IPSec) standard. IPSec is a feature that provides robust authentication and encryption of IP packets.

Answer 10

IKE (Internet Key Exchange)

Question 11

is a trunking protocol that is developed and proprietary to Cisco which is used to automatically negotiate trunks between Cisco switche

Answer 11

DTP (Dynamic Trunking Protocol)

Question 12

DTP Modes

Answer 12

auto - passively waits
desirable - initiate trunking
nonegotiate - off

Question 12

in networking is an IEEE standard and a part of the IEEE 802.3ad specification that allows you to combine multiple network connections or physical links in our network devices to form a single logical link and enable load balancing in our interfaces.

Answer 12

Link Aggregation Control Protocol (LACP)

Question 13

LACP Configurations Mode

Answer 13

Active
Passive

Question 14

PagP Configuration Mode

Answer 14

Auto
Desirable

Question 15

STP - Ports that are forwarding towards the root

Answer 15

Root Ports

Question 16

STP - Ports that are forwarding away from the root

Answer 16

Designated Ports

Question 17

Root Bridge Election

Answer 17

1. Lowest Bridge Priority
2. Lowest Mac address

Question 18

Root Port Election

Answer 18

1. Lowest accumulated cost on interfaces towards Root Bridge
2. Lowest Sender Bridge ID
3. Lowest Sender Port ID

Question 19

Designated Port Election

Answer 19

1) Root path cost

2) Bridge ID

3) Sender Port ID

Question 20

Cisco specific feature that improves the convergence time of the Spanning-Tree Protocol (STP) in the event of the failure of an uplink.

Answer 20

Uplinkfast

Question 21

enables fast reconvergence due to indirect link failures. The key operation happens when a switch begins receiving inferior BPDUs. When a switch loses the link off its Root Port, it immediately starts sending BPDUs announcing itself as the new Root.

Answer 21

Backbonefast

Question 22

feature that can be enabled on a port to bypass the normal STP initialization process for that port. When enabled on a port, STP will consider the port to be a “designated port” immediately without going through the normal listening and learning states.29 Jan 2023

Answer 22

Portfast

Question 23

allows control of spanning tree participation on a per-port basis. It can be used to exclude specific ports from becoming part of spanning tree operations

Answer 23

BPDU Filter

Question 24

an STP feature that is enabled on a port-by-port basis; it prevents a configured port from becoming a root port. Root guard prevents a downstream switch (often misconfigured or rogue) from becoming a root bridge in a topology.

Answer 24

Root guard

Question 25

is a safety mechanism that shuts down ports configured with STP portfast upon receipt of a BPDU. Assuming that all access ports have portfast enabled, this ensures that a loop cannot accidentally be created if an unauthorized switch is added to a topology

Answer 25

BPDU Guard

Question 26

an enhancement that provide protection from the creation of a loop at layer 2. It relies on the receipt of BPDUs. If no BPDUs are received on a blocked port, it is not allowed to transition to the forwarding state. This prevents a loop from occurring

Answer 26

BPDU Loop Guard

Question 27

allows you to build multiple spanning trees over trunks. You can group and associate VLANs to spanning tree instances. Each instance can have a topology independent of other spanning tree instances. This architecture provides multiple forwarding paths for data traffic and enables load balancing.

Answer 27

Multiple Spanning Tree

Question 28

Things need to match on spanning tree MST

Answer 28

MST configuration name.
MST configuration revision number.
MST instance to VLAN mapping table.