L24_network_layer_02

L24_network_layer_02 - The Network Layer (Part II): Routing...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 The Network Layer (Part II): Routing Protocols Lecture 24 6.02 Spring 2008 May 5, 2008 Link-state routing protocol Vector routing (esp. distance vector) protocols Data Link Physical Ethernet, WiFi, … Framing, coding, [limited] rxmits, channel access Modulation/demodulation Application HTTP, FTP, SMTP, … Transport TCP, UDP End-to-End Layer Layering in the Internet Network IP Forwarding & routing (and addressing) Everything else! Reliability, integrity, ordering, jitter ctrl, congestion response, … Today
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Network Layer Functions Main goal : ensure best-effort end-to-end connectivity Addressing : How to name nodes? Forwarding : What should each switch do to each packet? Routing : How to build routing tables to ensure that forwarding is correct? Link-state protocols Vector routing protocols Link-State Routing • Conceptually, a two-step process • Each node disseminates information about its links to its neighbors; they re-send to their neighbors, etc • This process allows each node to discover every other node and link • Each node then runs the same local shortest path computation over its version of graph • If each node implements computation correctly and each node has the same graph, then forwarding will work correctly • Each node makes local decision about next hop • Distributed dissemination, centralized computation (at each node, but each node has entire graph)
Background image of page 2
3 First Step: Disseminating Link-State • Each node sends periodic HELLO to all its neighbors • Periodically send LSA (Link-State Advertisement) [node seq#, {nbhr1, cost1, nbhr2, cost2, …}] to all neighbors
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 8

L24_network_layer_02 - The Network Layer (Part II): Routing...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online