1. Making Routers Last Longer with ViAggre
Spam???
Presented by
Shiva Srivastava
Ionut Trestian

2. This paper There are research papers There are Twitter papers
You can decrease RIB and FIB only by router configuration changes
65 characters !!
You can decrease RIB and FIB only by router configuration changes but packets take longer paths
96 characters !!

3. Main drawback No need to change routers
That means that we use the same routers at lower capacity
But if packets travel longer don’t we consume more power with the extra forwarding?
Which is fine, but …

4. Some math Biggest fragmentation one can have given by:
255x255x255 = about 16 million prefixes.
Actually lower than that (close to a few millions) for various reasons
Paper says that FIB carries now about 1 million such prefixes
To me the problem seems completely solved one upgrade away

5. Some other problems
Unpopular prefixes used to get the short end of the stick in current deployments (big delays, jitter etc)
They seem to get the short end of the stick in ViAggre too because even ViAggre seems to treat popular prefixes better

6. Some other problems
Authors assume that no architecture changes will occur but if one deploys ViAggre wouldn’t the ISPs tend to use older/slower routers inside their network leading to worse performance?
Maybe the performance benefits we are seeing is because you deploy ViAggre over newer/faster routers
It seems to me that now you start designing your network according to ViAggre so it induces architecture changes !!

7. Making Routers last forever and never upgrade!
Everybody lets just use IBM 5150, you know we can just upgrade the memory, it will be great!

8. Design
Only a short term solution, that is going to prevent from upgrading..?!
Effectively reducing routers by assigning them as aggregate routers.
Design flaw: They try to send all the traffic through one router: Congestion

9. Design goals are nonsense!
They cannot attain the full potential of their own ViAggre system as their design goals restrict them
They only try to reduce the size of the routing tables, which is not even that effective.
Why should we use a half solution to a problem that does not even work to its full potential.

10. Design I – Achieves nothing!
Unnecessary complication by advertising! And again waste of bandwidth.
Can cause looping of packets, use tunnels to prevent them but yet again unnecessary complication!
Routers have to maintain separate LSP mappings
Figure 1 just shows how its making things more complex unnecessarily.

11. Robustness This system makes the network more prone to crashing!
If any aggregation point fails all the network is transferred to second closest point… AGAIN CONGESTION !

12. Horrible design flaws.
ISPs should configure so they can use ViAggre!----- Why would you put energy in making a short term fix.
The ViAggre system wont work on popular prefixes! As they have to maintain whole table
For the rest of the network they need the ISP’s to be smart in designating routers to aggregate virtual prefixes! Then what good are they for?

13. Horrible Design Flaw II
This method increases path length and causes unnecessary traffic!
Greedy algorithm is too greedy and not efficient and can cause the network to crash!

14. Tier ISP study: How Bad ViAggre is?
They had no information about the link weights, they just assumed it to be distance weighted!
Create too much complexity in the network!
They are basically stalling the problem and not fixing it.
They would have to upgrade anyways because of newer technologies and higher data rate.

15. ISP study’s
They are not sure about popular prefix ISP traffic which renders ViAggre useless
Figure six shows how they are actually affecting the network 100%!
No traffic matrices hence cannot analyze load increase across routers. – Isn’t that’s what they are studying?

16. 2nd and 3rd tier ISP: Not Useful
Cannot use it, the ones who could have actually used it.
Maybe they can reduce FIB size on them but it isn't worth the trouble at this point.

17. Deployment Test system is way too small, no realization of real world.
Only ‘Configuration approach’ – Only few popular prefix add too many configuration lines.
Their test tool is too specific to their system!
Design too maybe good – Too short term!

18. Conclusions - Extreme Dumbness
Their Goal: Reduce Monetary cost.
Their Achievement: Increase Management Overhead cost and effectively doing nothing.
Add more slow fat routers---- We thought they were trying to use the old ones!
Basically remodel the whole network for stupid ViAggree
Finally they try to tell ISP’s that they should do something!