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Drag and Drop 2

May 8th, 2014 in ROUTE 642-902 Go to comments

Here you will find answers to Drag and Drop Questions – Part 2

Question 1

Header_fields.jpg

 

Answer:

Identifies the source of the packet: Router ID

Identifies the area to which the packet belongs: Area ID

Contains the authentication type. All OSPF protocol exchanges are authenticated: Authentication Type

Checks contents of the entire packet for any damage suffered during transmission: Checksum

Contains authentication information: Authentication

Contains encapsulated upper-layer information: Data

Question 2

LSA_Names.jpg

 

Answer:

Maintains the list of routers connected to the network: Network-LSA

Describes the collected states of the routers interfaces to an area: Router-LSA

Describes a route to a destination in another autonomous system: AS-external-LSA

Describes a route to a destination outside the area: Summary-LSA

Question 3

A virtual private network (VPN) is a computer network that is layered on the top of an underlying computer network. VPNs are of different technologies, such as Trusted VPNs, Secure VPNs, and Hybrid VPNs, each having distinct requirements. Drag the various VPN names to their appropriate places.

VPN_names.jpg

 

Answer:

All traffic on the VPN must be encrypted and authenticated: Secure VPN

The routing and addressing used must be established before the VPN is created: Trusted VPN

The address boundaries must be extremely clear: Hybrid VPN

Question 4

IPv6 to IPv4 transition methods

IPv4_to_IPv6_transition_methods.jpg

 

Answer:

NAT-PT

6 to 4 tunnels

GRE tunnels

ISATAP tunnels

Question 5

IP tunneling is a method to encapsulate IP datagram within IP datagrams, which allows datagrams intended for one IP address to be wrapped and redirected to another IP address. IPv6 packets are encapsulated directly behind the IPv4 header. Drag the header fields to the appropriate places:

Tunneling_Header_Fiels.jpg

 

Answer:

The correct order is:

IPv4 Header | IPv6 Header | Extension Headers | Upper Layer PDU

Explanation

The structure of a normal IPv6 packet is:

IPv6 Header | Extension Headers | Upper Layer PDU

The IPv6 header is always present and is a fixed size of 40 bytes. Zero or more extension headers can be present and are of varying lengths. The upper layer protocol data unit (PDU) usually consists of an upper layer protocol header and its payload (for example, an ICMPv6 message, a UDP message, or a TCP segment).

Because “IPv6 packets are encapsulated directly behind the IPv4 header” so we can deduce an IPv4 Header must be placed before an IPv6 header.

Question 6

Drag each OSPF states into correct definition.

OSPF_states.jpg

 

Answer and Explanation

The OSPF states below are described in the correct order when OSPF adjacency is formed:

Down: No information has been received, but Hello packets can still be sent to the neighbor
Init: A Hello packet is received, but the ID of the receiving router was not included in the Hello packet.
2-way: Each router see its own Router ID in the neighbor field of the Hello packet; there is a DR/BDR election.
Exstart: The routers and their DR and BDR establish a master-slave relationship.
Exchange: Routers exchange DBD packets that describe the contents of the entire link-state database.
Loading: Based on the information provided by the DBDs, routers send link-state request packets
Full: All the router and network LSAs are exchanged and the router databases are synchronized

A detailed explanation of OSPF states can be found here: http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13685-13.html.

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