Cisco Q3 Mod 8 & 14 Flashcards
Provides services to allow end devices to exchange data across networks.
The network layer, or OSI Layer 3
End devices must be configured with a unique IP address for identification on the network.
Addressing end devices
The network layer ENCAPSULATES the protocol data unit (PDU) from the transport layer into a packet.
Encapsulation
The network layer provides services to direct the packets to a DESTINATION host on another network.
Routing
When the packet arrives at the network layer of the destination host, the host CHECKS the IP header of the packet.
De-encapsulation
__ ____________ the transport layer (the layer just above the network layer) segment or other data by adding an IP header. The IP header is used to deliver the packet to the destination host.
IP Encapsulation
There is no CONNECTION with the destination established before sending data packets.
CONNECTIONLESS
IP is inherently unreliable because packet delivery is NOT guaranteed.
Best Effort
Operation is independent of the medium (i.e., copper, fiber-optic, or wireless) carrying the data.
Media Independent
(T) IP is connectionless, meaning that no dedicated end-to-end connection is created by IP before data is sent.
CONNECTIONLESS
(T) IP also DOES NOT require additional fields in the header to maintain an established connection.
Best Effort
(T) UNRELIABLE means that IP does not have the capability to manage and recover from undelivered or corrupt packets.
Media Independent
Which OSI layer SENDS segments to be encapsulated in an IPv4 or IPv6 packet?
Transport layer
Which layer is responsible for taking an IP packet and preparing it for TRANSMISSION over the communications medium?
Data Link Layer
What is the term for SPLITTING up an IP packet when forwarding it from one medium to another medium with a smaller MTU?
FRAGMENTATION
Which delivery method does not guarantee that the packet will be delivered fully without ERRORS?
Best Effort
Contains a 4 - bit binary value set to 0100 that identifies this as an IPv4 packet
Version
FORMERLY called the type of service (ToS)
DiffServ
Contains an 8 bit binary value that is used to limit the LIFETIME of a packet.
Time To Live (TTL)
This field is used to identify the next level PROTOCOL
Protocol
This is used to DETECT corruption in the IPv4 header
Header Checksum
This contains a 32 bit binary value that represents the SOURCE IPv4 address of the packet
Source IPv4 Address
This contains a 32 bit binary value the represents the DESTINATION IPv4 address of the packet
Destination IPv4 Address
IHL
The Internet Header Length
What are the two most commonly referenced fields in an IPv4 packet header that indicate where the packet is coming from and where it is going? (Choose two.)
Destination IP address
Source IP address
Which statement is correct about IPv4 packet header fields?
The source and destination IPv4 addresses remain the same while travelling from source to destination
Which field includes common values such as ICMP (1), TCP (6), and UDP (17)?
Protocol
IPv4 has a LIMITED number of unique public addresses available.
IPv4 address depletion
Network Address Translation (NAT) is a technology commonly implemented within IPv4 networks.
Lack of end-to-end connectivity
While NAT has extended the lifespan of IPv4 it was only meant as a transition mechanism to IPv6.
Increased network complexity
IPv6 addresses are based on 128-bit hierarchical addressing as opposed to IPv4 with 32 bits.
Increased address space
The IPv6 header has been simplified with fewer fields.
Improved packet handling
With such a large number of public IPv6 addresses, NAT between a private IPv4 address and a public IPv4 is not needed.
Eliminates the need for NAT
Which three options are major issues associated with IPv4? (Choose three.)
IP address depletion
Increased network complexity and Internet routing table expansion
Lack of end to end connectivity
Which two options are improvements provided by IPv6 as compared to IPv4? (Choose two.)
INcreased the IP address space
uses a simpler header to provide improved packet handling
Which is true of the IPv6 header?
It consists of 40 octets
It contains 8 header fields
Which is true of the IPv6 packet header?
The hop limit field replaces the IPv4 Time to Live field
A host can PING itself by sending a packet to a special IPv4 address of 127.0.0.1 or an IPv6 address ::1, which is referred to as the loopback interface.
Ping
**This is a destination host that is on the same local network as the sending host.
LOCAL host
This is a destination host on a remote network.
Remote Host
Which statement about host forwarding decisions is true?
Local Hosts can reach each other without the need of a router
Which default gateway statement is true?
The default gateway address is the IP address of the router on the local network
Which two commands could be entered on a Windows host to view its IPv4 and IPv6 routing table? (Choose two.)
netstart -r
route print
What is the command used on a Cisco IOS router to view the routing table?
Show IP ROUTE
What does a code of “O” indicate next to a route in the routing table?
A route learned dunamically from OSPF
This type of route is also known as a gateway of last resort.
This route is used to forward traffic to a specific direction when there is not a match in the routing table
Default Route
Which is a characteristic of static routes?
They are manually configured
True or False? A router can be configured with a combination of both static routes and a dynamic routing protocol.
T
Which field in an IPv6 packet is used by the router to determine if a packet has expired and should be dropped?
Hop Limit
Which field in an IPv4 packet header will typically stay the same during its transmission?
Destination ADdress
Which information is used by routers to forward a data packet toward its destination?
Destination IP address
What was the reason for the creation and implementation of IPv6?
To relieve IPv4 address depletion
Which IPv4 address can a host use to ping the loopback interface?
127.0.0.1
A computer has to send a packet to a destination host in the same LAN. How will the packet be sent?
A packet will be sent directly to the destination host
(T) Application layer programs generate data that must be exchanged between source and destination hosts
At the transport layer, each set of data flowing between a source application and a destination application is known as a conversation and is tracked separately. It is the responsibility of the transport layer to maintain and track these multiple conversations.
Tracking Individual Conversations
IP is concerned only with the structure, addressing, and routing of packets. IP does not specify how the delivery or transportation of the packets takes place.
Transport Layer Protocols
IP is concerned only with the structure, addressing, and routing of packets, from original sender to final destination. IP is not responsible for guaranteeing delivery or determining whether a connection between the sender and receiver needs to be established.
Transmission Control Protocol