Saturday, April 18, 2015

Random Cisco based networking questions - CCNA - Part 5

Another half a dozen random networking questions for 2015 with a more routing protocol focus this time, 
enjoy :-).

1. Triggered updates (in a routing protocol) are used to speed the convergence process?

A) True
B) False

2. What class of routing protocol is EIGRP?

A) Link state
B) Distance vector
C) Hybrid

3. What is the administrative distance of OSPF?

A) 110
B) 1
C) 120
D) 90
E) 100

4. What command would you use to erase the startup config of a router?

A) erase nvram
B) erase flash
C) delete startup
D) erase startup
E) delete run

5. What is required for VTP to communicate VLAN information between switches?

A) VTP domain must be identical on all switches
B) One switch needs to be a VTP server
C) A router is required
D) Both A and B are correct
E) None of the above

6. What is the structure of the MAC address?

A) 32 bit network ID + 32 bit host ID
B) 14 bit vendor code + 6 bit serial number
C) 24 bit vendor code + 24 bit serial number
D) Network + Host

Searching for what type of nic card you have in your PC? The easiest way is with the MAC address ( not the kind shown below :-)

Image result for MAC

A great link you should bookmark for Vendor/Ethernet/Bluetooth MAC Address Lookup and Search at MACFIND.  This allows you to match your MAC address to its vendor or a vendor to a MAC - I find it very useful :-).

1.  Answer A

A triggered update is sent immediately in response to a change in the network (e.g. A link going down). The router detecting the change immediately sends an update message to its adjacent routers, which then generate their own triggered updates. This process continues until the network converges. Triggered updates occurs independently from the regular routing updates and are intended to speed the convergence process.

2. Answer C

EIGRP is a hybrid routing protocol which uses a combination of distance vector and link state methods to determine the best path. EIGRP is considered an advanced distance vector protocol because EIGRP sends out only incremental updates.

3. Answer A

Administrative distance is used by Cisco routers to select the best path when there are two or more different routes to the same destination from two different routing protocols. Administrative distance defines the reliability of a routing protocol.

Routing Protocol Administrative distance
Directly connected interface 0
Static route out an interface 1
Static route to next-hop address 1
DMNR - Dynamic Mobile Network Routing 3
EIGRP summary route 5
External BGP 20
Internal EIGRP 90
IGRP 100
OSPF 110
IS-IS 115
Routing Information Protocol (RIP) 120
Exterior Gateway Protocol (EGP) 140
On Demand Routing (ODR) 160
External EIGRP 170
Internal BGP 200
Floating Static Route (ex. DHCP-learned) 254
Unknown 255 

(Note : An AD of 255 will cause a router to dump this route from its table)

4. Answer D

To erase the startup configuration use the following command:

Router#erase startup-config
, or

Router#erase startup

5. Answer D

VTP requires the following to communicate VLAN information between switches.  The VTP domain must be identical on all switches and one switch needs to be a VTP server.

6. Answer C

MAC Addresses are 48 bits long and consist of a 24 bit vendor code and a 24 bit serial number.

More coming, please leave comments if you find any errors or want to debate an answer :-)