1. Packet Forwarding

Question 1

What is is the standard for VLAN?

Answer 1

802.1Q

Question 2

What fields does VLAN packet contain?

Answer 2

• TPID
• PCP
• DEI
• VLAN ID

Question 3

Where is VLAN 0 used for?

Answer 3

802.1P

Question 4

Where is VLAN 1 used for?

Answer 4

Default VLAN

Question 5

Where is VLAN 2 - 1001 used for?

Answer 5

Normal VLAN range

Question 6

Where is VLAN 1002 - 1005 used for?

Answer 6

Reserved

Question 7

Where is VLAN 1006 - 4096 used for?

Answer 7

Extended VLAN range

Question 8

How is a VLAN created?

Answer 8

The command vlan id or name name

Question 9

What must be done in order to process a VLAN change?

Answer 9

CLI must be placed back to global config mode

Question 10

With what command can you change a port mode?

Answer 10

switchport mode …..

Question 11

How many VLANs can be carried on a trunk port?

Answer 11

Multiple

Question 12

How many VLANs can be carried on an access port?

Answer 12

1

Question 13

How does a trunk port work?

Answer 13

Upon receipt:

• Examines headers
• Removes 802.1Q headers
• Forwarded out to the next port based on MAC

Question 14

What is the native VLAN?

Answer 14

VLAN 1

Question 15

When is traffic advertised/received on the native VLAN?

Answer 15

When there is no 802.1Q tag at the trunk port

Question 16

What is the command to allow certain VLANs to travel accross the trunk port?

Answer 16

switchport trunk allowed vlan ….

Question 17

What is the disadvantage of using the command switchport trunk allowed vlan ….?

Answer 17

It overwrites the list every time u use it

Question 18

What is the MAC address table?

Answer 18

Responsible for identifying the switch ports and VLANs with which a device is associated. Resides in the CAM.

Question 19

What is the CAM table?

Answer 19

Content Addressable Memory. It uses high-speed memory that is faster than typical computer RAM.

Question 20

What is the ARP table?

Answer 20

Address Resolution Protocol. Provides a method of mapping L3 IP to L2 MAC.

Adds the L2 header and sends down to L2 for further processing

Question 21

What is process switching?

Answer 21

When the general-purpose CPU on the router is in charge of packet switching

Question 22

When is process switching preferred over CEF?

Answer 22

• When packets are to complex

- When packets require extra information (ARP)

Question 23

What is Centralized Forwarding?

Answer 23

When a route processer is equipped with a forwarding engine

Question 24

What is Distributed Forwarding?

Answer 24

When the line card is equipped with a forwarding engine

Question 25

How does Centralized Forwarding work?

Answer 25

• Ingress
• Forwarding engine examens header
• Egress

Question 26

How does Distributed Forwarding work?

Answer 26

• Ingress
• Forwarding engine does a lookup
• Local? –> local interface
• Outbound? –> backplane –> Egress

Question 27

What does the software CEF consist of?

Answer 27

• Forwarding Information Base

- Adjacency table

Question 28

What is SSO?

Answer 28

Statefull Switchover, a redundancy feature for routers with 2 routing processors

Question 29

What is SDM template?

Answer 29

Switching Database manager, displayes ratios between CAM tables