IPv6 Datagram Format and Addressing Rules Quiz

Study Notes

IPv6 Datagram Format

27 fixed-length 40-byte header with no fragmentation allowed
Priority: identifies priority among datagrams in a flow
Next header: identifies upper layer protocol for data
Ver: identifies the version of the IP protocol
Pri: indicates the priority of the datagram
Flow label: identifies a specific flow of datagrams
Hop limit: specifies the number of hops the datagram can travel
Payload length: specifies the length of the payload
Next header: specifies the next header in the datagram
Source address: 128-bit address of the source
Destination address: 128-bit address of the destination
Data: the actual payload of the datagram

Transition from IPv4 to IPv6

Not all routers can be upgraded simultaneously
No "flag days" for transition
Tunneling: IPv6 datagram carried as payload in IPv4 datagram among IPv4 routers
IPv4 header fields: IPv4 source and destination addresses
IPv6 header fields: IPv6 source and destination addresses
UDP/TCP payload: IPv6 datagram carried as payload in IPv4 datagram

Network Layer

Interplay between routing and forwarding
Routing algorithm determines end-end-path through network
Routing algorithm determines local forwarding table
Forwarding table determines local forwarding at this router
Graph abstraction: represents network as a graph of nodes and edges
Graph abstraction: costs associated with each link

ICMP

Internet control message protocol
Used by hosts and routers to communicate network-level information
Network-layer "above" IP
Error reporting: unreachable host, network, port, protocol
Echo request/reply (used by ping)
ICMP messages carried in IP datagrams
ICMP message format: type, code, plus first 8 bytes of IP datagram causing error

Traceroute and ICMP

Source sends series of UDP segments to destination
First set has TTL = 1, second set has TTL = 2, etc.
When nth set of datagrams arrives at nth router, router discards datagrams and sends source ICMP messages (type 11, code 0)
ICMP messages include name of router and IP address

DHCP

More than just IP addresses
Can return address of first-hop router for client, name and IP address of DNS server, and network mask
Address allocation: gets allocated portion of its provider ISP's address space
Hierarchical addressing: allows efficient advertisement of routing information

Description

Test your understanding of the IPv6 datagram format, including its header fields and priority, as well as the transition from IPv4 to IPv6. Learn about the key differences between the two protocols and how they impact network communication.