CS 240: Network Routing

1
CS 240 Network Routing

• Michalis Faloutsos

2
Class Overview

• Expose you the general principles and highlight
  some interesting topics in routing
• Background in networks is necessary
• The class is project based
• Given interest/participation, we will skip the
  quiz
• Participation is required
• Ideal for people that want to get involved in
  networks research
• See my web page for more information

3
Use The Blackboard

• Update your email to receive updates
• Check your grades through there

4
What is Routing?
5
Routing

• Routing is the necessary functions to ensure that
  data from one host will reach another host
• The role of routing starts once the data leaves
  the first communicating entity
• Simply put, routing is responsible for finding,
  establishing and maintaining communication the
  path

6
Routing and Layers
application transport network link physical
application transport network link physical
Routing

• Routing takes place at the network layer
• Routing is under the transport layer
• Routing is unaware of end-to-end issues
  (always?)
• Routing is above the link layer
• Communication between adjacent nodes happens

7
Toy Routing Example
A
B

• Alexandros wants to talk to Biswanath
• Routing determines and uses the orange path
• Is this a good path?

8
Routing is Critical

• For me, routing is the most fundamental
  networking function
• It is also the most fun part in networking
• What makes it interesting
• There are many conflicting trade-offs
• Routing operates with partial or out-of-date
  knowledge
• It has to handle changes and failures
• More recently, it has to handle mobility

9
Requirements in Routing

• Scale to large networks, many users
• Robustness deal with changes
• Fault-tolerance deal with failures
• Use resources efficiently accommodate more
• Provide Quality of Service (QoS) guarantees

10
I. Routing View Optimization

• Given a graph with weights
• Each edge may have more than one weight, cost,
  delay
• Find a path that optimizes some criteria

2
A
4
1
2
3
5
3
B
2
2
4
4
2
6
11
II. Routing View Functional

• Routing can support several communication needs
• Unicast or point-to-point routing
• Multicasting
• One-to-many, i.e. video distribution
• Many-to-many, i.e. teleconference
• Reporting Many-to-one, i.e. sensor network
• Broadcasting one to all
• Anycasting one to some

12
III. Routing View Hierarchical

• Following the Internet hierarchy
• Autonomous Systems an network managed by a
  single authority, e.g. an Internet service
  provider (ISP)
• Intradomain routing routing within a privately
  owned network
• Interdomain routing routing between domains
• Different capabilities and criteria
• Intradomain full control, interest to optimize
  resources
• Inerdomain distributed, focus on scalability and
  policy (BGP)

13
IV. Routing View Network Specific

• Internet routing
• Static hosts
• Mobile hosts
• ATM routing
• Ad hoc network routing everything moves
• Sensor networks reporting

14
Some of the Topics

• Routing as an optimization problem
• Multicast routing
• BGP routing (emphasis)
• Ad hoc routing
• Sensor routing issues

15
You Need to Start Thinking for a Topic

• Projects maximum two in a team
• Literature surveys possible, but not full marks
• BGP routing modeling, stability,performance
• Adhoc networks scalable routing approaches
• Current work DART by Jakob Eriksson
• Theoretical work
• multicast routing
• Modeling application layer multicasting