H6 (Network Layer) Flashcards
What are the 4 processes
Addressing end devices
Encapsulating segments into packets with IP Info
Routing
De-encapsulation upon arival
What does the transport layer do
Exchange data between processes
What does the network layer doe
Exchange data between hosts
What are the 3 characteristics of IP
Connectionsless: low overhead
Best effort: no error checking, unreliable
Media Independent
What does connectionless mean
The sender doesn’t know if a packet arrived or if the receiver is present or can open it.
The receiver doesnt know when the packet is coming
What makes IP still reliable
The transport layer
What is fragmentation
Splitting up a packet when it is to big for another medium
How big is the IPv4 header
20 bytes
Version field
0100 or 0110, 4 bits
DS Field
8 bits, concists out of 6 bit DSCP and 2 bit ECN. Used to determine importance of packet.
TTL
8 bits
Protocol
Determines the payload type 8 bit. ICMP (1), TCP(6), UDP(17)
Source + dest mac
64 bits
What is used to identify and validate a packet
The Internet Header Length and the Header checksum
What are IPv4 issues
Address depletion
Routing Table taking up a lot of recources
No end-to-end due to NAT
What are IPv6 benefits
Larger address space
No need for NAT
Improved packet handling: smaller overhead
Traffic class
same as DS
Flow label
same label receives same handling by router
Payload length
Indicates length of paylaod
Next Header
Same as protocol field
An IPv4 header consists out of
Version Internet Header Length DS TTL Protocol Header Checksum Source Dest
An IPv6 header consists out of
Version Traffic class Flow label Payload length Next header Hop limit source dest
