41902 Chapter Notes - Chapter 4-1: Network Layer, Multiprocessing, Fair Queuing
Network Fundamentals
Chapter 4: Network Layer: The Data Plane
Chapter 4.1: Overview of Network Layer
Network layer:
- Transport segment from sending to receiving host. Sending side encapsulates segments into
datagrams. Receiving side delivers segments to transport layer. Network layer protocols are
in every host and router. Router examines header fields in all IP datagrams passing through.
- Two key network-layer functions:
o Routing: determine route taken by packets from source to destination (routing
algorithms)
o Forwarding: oe pakets fro routers iput to appropriate router output
Data Plane:
- Local, per-router function. Determines how a datagram arriving on router input port is
forwarded to router output port. Uses Forwarding function, explained above.
Control Plane:
- Network wide logic. Determines how a datagram is routed among routers along end-end path
from source host to destination host. Uses Routing function, explained above.
- Two approaches to structuring network control plane:
- Traditional routing algorithm: implemented in routers, per-router control (Individual
routing algorithm components in every router interact in the control plane.)
- Software-defined networking (SDN): logically centralized control, implemented in
(remote) servers
Per-router control plane: Individual routing algorithm components in all routers interact in the
control plane.
“erie odel for hael trasportig datagras fro seder to reeier:
- Services for individual datagrams: guaranteed delivery
- Services for a flow of datagrams: ordered datagram delivery, guaranteed minimum bandwidth to
flow, restrictions on changes inter-packet spacing
Chapter 4.2: What’s inside a router
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Document Summary
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