1. Offense by Ionut Trestian
Analysis of the Increase and Decrease Algorithms for Congestion Avoidance in Computer Networks or: How I Learned to Stop Worrying and Love the Bomb
Offense by Ionut Trestian

2. All the great things that came out of this paper
DDoS
Botnets

3. How did all this happen? Some history
The Internet was started as an academic network
That meant that all entities involved were:
Trustworthy
If not, easily identifiable
I agree that some of the choices made in this paper made sense at that time but …

4. How did all this happen? Some history
Trust region

5. How did all this happen? Some history
It made sense at the time for a few reasons
Almost everyone was trustworthy (more or less)
No real profit from cheating the system (bigger download speeds, but what to use them for)
Technology wasn’t so great at the time so network elements (routers, switches) were dumbed down

6. How did all this happen? The Internet becomes ubiquitous
Trust region
Trust region $

7. A lot of changes since this paper
The million dollar question is:
Where to implement fairness?
Endpoints
Good idea in 1989 because endpoints were honest
Not so good idea now because the Internet has no accountability
Routers
In 1989 routers couldn’t handle such complexity
Seems a good idea now but cannot mess with old paradigms

8. Routers - Back then and today
Cisco AGS
Motorola (about 8 MHz) processor and 1MB of memory, and two 2E dual-Ethernet line cards
Cisco CRS
1000 line-cards at 40 Gbit/s
Every line-card has a 1.2 GHz processor

9. Routers – How did they evolve?
Speed
Fairness

10. Where are we today?
We have unfair endpoints and routers who cannot impose fairness
Therefore we have an unfair network
This leads to the well known problems of today’s Internet:
Spam
DDoS attacks by Botnets
...
And it all happened because of papers like this who advocated a false sense of fairness which is obtained only when everyone behaves

11. Other issues
Not all applications get along with the “saw tooth”-like behavior given by the TCP AIMD (multiplicative decrease usually by factor of 2)
That means that one designs an application to deal well with TCP (TCP friendliness or compatibility !!)
For example streaming or real-time-audio
This leads to a constant tweaking of AIMD to deal well with new applications – IIAD, SQRT, ETC

12. Other issues
What if all the signs of congestion are there but the issue is not congestion?
Authors didn’t imagine all transmission media
Links of today have different characteristics as the authors imagined (wireless)

13. Other issues Lots of important stuff left at the end
Delays in feedback
Asynchronous operation
Estimating the number of users using the resource

14. Conclusions
Really bad paper, among the ones that did a lot of damage to the existing Internet
Lots of other small issues dealing with the constant re-tweaking of the inputs based on whatever is on top
Not clear how to detect congestion