Seite 1 von 1

"Routing Table Size" in Exercise 4d

Verfasst: 19. Nov 2010 14:18
von Pan
Hi,

I'd like to ask which slide to stick to when calculating the "routing table size".

On Page 25 it says:
Basic Chord keeps track of predecessor and successor
Finger tables not needed for correctness
But on Page 30 it says:
Predecessor links, finger tables – Only needed to improve performance
So it's a np-hard problem to decide whether "predecessor" is necessary for the "minimum size" or not. :roll:

Re: "Routing Table Size" in Exercise 4d

Verfasst: 19. Nov 2010 15:39
von BadTaste
Please consider the case for an efficient routing procedure.

Re: "Routing Table Size" in Exercise 4d

Verfasst: 19. Nov 2010 20:03
von Juri
Hi,

i had another question to this task...

a finger table looks like this as known from the above tasks and slides: (i, targetID, successor), where targedID = Hash(IP_Comp_X) and succ = Hash(IP_Comp_Y)...where do we save 32bit-IP-Addresses and 16-bit-Ports in the finger table?

maybe i missed something...thank you for any help :wink:

Re: "Routing Table Size" in Exercise 4d

Verfasst: 19. Nov 2010 22:15
von Juri
Hi,

question solved...for everybody that had the same question see on page 4 of the Paper about Chorde "pdf-file", left side and last paragraph..

Re: "Routing Table Size" in Exercise 4d

Verfasst: 20. Nov 2010 15:32
von kaiserj
hey juri,

von welchem "pdf-file" sprichst du da?

Re: "Routing Table Size" in Exercise 4d

Verfasst: 21. Nov 2010 19:52
von E.d.u.
Denke das hier:
Chord:A scalable peer‐to-­peer lookup service for Internet applications

Re: "Routing Table Size" in Exercise 4d

Verfasst: 22. Nov 2010 21:39
von mister_tt
Here is the link to the paper: http://pdos.csail.mit.edu/papers/chord: ... igcomm.pdf

The problem is that the paper says that the finger and the routing table is exactly the same thing. It says:
Each node, n, maintains a routing table with (at most) m entries, called the finger table.
The only difference is that the task asks for the size of the complete routing table, but what is the difference? A complete routing table as stated in the task does not make sense at all, right? Because why should I have an entry for every node in the system? If I have that, I do not need Chord... :?:

Re: "Routing Table Size" in Exercise 4d

Verfasst: 22. Nov 2010 21:47
von BadTaste
Hi,
in the exercise, complete means all information that can be used during routing as discussed in the lecture.
I.e., finger table + ....

Re: "Routing Table Size" in Exercise 4d

Verfasst: 22. Nov 2010 21:51
von mister_tt
So you mean successor (which is stored in the finger table anyway), predecessor and finger table?

Re: "Routing Table Size" in Exercise 4d

Verfasst: 22. Nov 2010 21:54
von BadTaste
no further comment :mrgreen:

Re: "Routing Table Size" in Exercise 4d

Verfasst: 22. Nov 2010 21:56
von mister_tt
:evil: