CCNP - Packet Forwarding

Question 1

What does CSMA/CD stand for?

Answer 1

Carrier Sense Multiple Access/Collision Detection

Question 2

What is CSMA/CD used for? CSMA/CD is used in what type of network?

Answer 2

Ensure that only one device talks at a time in a collision domain Wired Networks

Question 3

What is a collision domain? What is a network device where collisions can occur?

Answer 3

shared media that connects different network devices same media network where packet collisions can occur. ex. hubs, switches

Question 4

What is the broadcast address used with MAC addressing?

Answer 4

FF:FF:FF:FF:FF:FF

Question 5

What is a broadcast domain?

Answer 5

where a broadcast message can reach all devices on a subnet

Question 6

What network devices are used to separate boundaries of broadcast domains?

Answer 6

routers

Question 7

Is each port on a hub in the same or different collision domain?

Answer 7

same domain

Question 8

Rather then flooding all the traffic out every port, what do switches maintain in order to forward traffic to the destination MAC address Where is that routing data stored?

Answer 8

MAC Address Table CAM or TCAM Table

Question 9

What occurs when there is an unknown unicast?

Answer 9

is flooded to every switch port

Question 10

What is a VLAN? Do VLANs create single or multiple broadcast domains on the same network switch?

Answer 10

Virtual Local Area Network multiple broadcast domains

Question 11

What term are VLANs also know as?

Answer 11

SVI (Switch Virtual Interface)

Question 12

By default do network devices in a VLAN communicate with other devices in a different VLANs

Answer 12

no

Question 13

Can access ports be assigned to multiple or a single VLAN?

Answer 13

single VLAN

Question 14

When packets are transmitted or received on an access port are 802.1Q tags included?

Answer 14

not included

Question 15

What does the MAC Address table contain?

Answer 15

forwarding information of mac addresses mapped to assigned ports.

Question 16

In the OSI model, which layer does all traffic start?

Answer 16

Layer 7 the application layer.

Question 17

The ARP protocol is responsible for?

Answer 17

mapping mac addresses to switch ports

Question 18

What three ways can packets be configured to route?

Answer 18

static route entry default-gateway routing protocol

Question 19

What is a static route?

Answer 19

manually configured route to a destination network

Question 20

What is a default-gateway?

Answer 20

default static route for all network traffic

Question 21

What is a routing protocol used for?

Answer 21

route and distribute data and network information

Question 22

What is a Routing Information Base-RIB?

Answer 22

Default routing table

Question 23

What would be considered a routed interface?

Answer 23

any interface on a router

Question 24

What does packet switching relate to?

Answer 24

Way packets are moved to/from the input interface to the output interface or interfaces to CEF

Question 25

Process switching requires what to be personally involved with every forwarding decision? What layer does process switching take place?

Answer 25

CPU - every packet is inspected by the CPU (Software) L3

Question 26

How does fast-switching work?

Answer 26

Packet passes and forward from the CPU once then stored in fast-switching route cache for faster access

Question 27

How does Cisco Express Forwarding CEF work? Benefit of using Cisco Express Forwarding CEF

Answer 27

CEF caches routing information in the FIB (Forwarding Information Base) and Layer 2 next hop address in an adjacent table. (all in L2 data plane) Ability to forward more packets faster

Question 28

How does CEF handle routing information in specialized ASICs?

Answer 28

Layer 3 routing table (RIB) is copied down into the (hardware level) L2 data plane and stored in both FIB (Forwarding Information Base) and (next hop) adjacent tables

Question 29

What does ASIC stand for? What are ASIC used for?

Answer 29

Application Specific Integrated Circuit Integrated circuit (IC) for a particular use, rather for general-purpose use

Question 30

What does TCAM stand for? What is the TCAM used for? Is TCAM an extension of the CAM architecture? True/False

Answer 30

Ternary Content Addressable Memory allowing the matching and evaluation of packets on more than one field. True

Question 31

How are the TCAM entries stored?

Answer 31

Value, Mask and Result (VMR format)

Question 32

What does the value in a TCAM indicate? What are those values?

Answer 32

value that should be searched IP address and protocol fields

Question 33

What does the mask in a TCAM indicate?

Answer 33

field of interest that should be queried

Question 34

What does the results in TCAM indicate?

Answer 34

action that should be taken with a match on the value and mask

Question 35

What does CAM stand for? What is CAM used for?

Answer 35

Content Addressable Memory Store mac address and port information in a MAC address table

Question 36

What do multi-layer switches use to forward frames and packets at wire speed?

Answer 36

ASIC hardware

Question 37

What is centralized forwarding architecture?

Answer 37

When RP engine "route processor" is equipped to make all packet switching decisions/CPU.

Question 38

What is distributed forwarding architecture?

Answer 38

When a packet is received on the ingress line card and then forwarded to the local forwarding engine.

Question 39

What does the CEF - Software Forwarding Information base consist of?

Answer 39

Forwarding information base and Adjacent Table

Question 40

What is the main advantage of distributed forwarding architecture Hardware CEF?

Answer 40

offloading packet switching responsibilities to line cards dCEF improves packet throughput performance.

Question 41

What is the process of dCEF?

Answer 41

CEF data structures are downloaded to the forwarding ASIC and the CPUs of all the line cards to allow for switching to be done at the distribution level "data plane"

Question 42

What is a RP route processor responsible for?

Answer 42

learning the network topology and building the route table "RIB"

Question 43

Can a "RP" Routing Processor failure trigger routing protocol adjacency to reset resulting in packet loss and instability? True/False

Answer 43

True

Question 44

What does the redundancy feature in stateful switchover (SSO) allows Cisco routers with two RPs to do?

Answer 44

synchronize router configuration and control plane state information

Question 45

The process of mirroring information between "RPs" Route Processors is referred to as what?

Answer 45

checkpointing

Question 46

During stateful switchover what two things happen immediately?

Answer 46

"RP" Route Processor immediately takes control and prevents problems such as interface link flaps.

Question 47

What does CSMA/CA stand for? What is CSMA/CA used for? CSMA/CA is used in what type of network?

Answer 47

Carrier Sense Multiple Access / Collision Avoidance Reduces the possibility of a collision Wireless Networks

Question 48

Is each port on a bridge, switch, router in the same or different collision domain?

Answer 48

separate domain

Question 49

How many results does CAM tables provide?

Answer 49

only two results: 0 (true) or 1 (false)

Question 50

How many results does TCAM tables provide?

Answer 50

three results 0, 1, and "X-don't care."

Question 51

What does the forwarding engine perform?

Answer 51

Packet lookup and determines if that outbound interface is local, it forwards packet out a local interface. If the outbound interface is located on a different line card, packet is sent across the switch fabric, back plane, directly to the egress line card bypassing the RP.