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Peter Ruzicka. Results and research directions in ATM and optical networks. Shmuel Zaks. Technion, Israel. zaks@cs.technion.ac.il www.cs.technion.ac.il/~zaks. References. Works of C. Kaklamanis G. Gambossi E. Kranakis L. Bechetti D. Krizanc D. Peleg
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Peter Ruzicka Sirocco 2004
Results and research directions in ATM and optical networks Shmuel Zaks Technion, Israel zaks@cs.technion.ac.il www.cs.technion.ac.il/~zaks Sirocco 2004
References Works of C. Kaklamanis G. Gambossi E. Kranakis L. Bechetti D. Krizanc D. Peleg A. Pelc J.C. Bermond I. Vrt’o A. Rosenberg V. Stacho L. Gargano and many more and many more … Works with O. Gerstel T. Eilam M. Shalom M. Feigelstein I. Cidon S. Moran M. Flammini Sirocco 2004
graph-theoretic models • algorithmic issues • greedy constructions • recursive constructions • complexity issues • approximation algorithms • dynamic and fault-tolerance • combinatorial design issues • upper and lower bounds analysis • … • many open problems Sirocco 2004
Outline • ATM networks model • Optical networks model • Discussion – ATM networks • Discussion – Optical networks Sirocco 2004
ATM - Asynchronous Transfer Mode Transmission and multiplexing technique Industry standard for high-speed networks graph theoretic model Gerstel, Cidon, Zaks Sirocco 2004
Communication • Virtual • path • Virtual channel concatenation of complete paths concatenation of partial paths Sirocco 2004
Cost • Virtual path • Virtual channel • load = 3 (space) Other parameters hop count = 2 (time) stretch factor = 4/3 Sirocco 2004
Example: Find a layout, to connect a given node with all others, with given bounds on the load and the hop count Sirocco 2004
Outline • ATM networks model • Discussion – ATM networks • Optical networks model • Discussion – Optical networks Sirocco 2004
Problem 1: Given a network, pairs of nodes and bounds h andl, find a virtual path layout to connect these nodes with the load bounded by l and the hop count bounded by h. Sirocco 2004
Problem 1a: Given a network and a bound on the load l and a bound h on the hop count, find a layout, to connect a given node with all others (one-to-all). a. worst-case. b. average case. Note: consider it for a given stretch factor. Sirocco 2004
Problem 1b: Given a network and a bound on the load l and a bound h on the hop count, find a layout, to connect every two nodes (all-to-all). a. worst-case. b. average case. Note: consider it for a given stretch factor. Sirocco 2004
Problem 2: Input:Graph G, integers h, l > 0 , and a vertex v. Question: is there a VP layout for G, by which v can reach all other nodes, with hop count bounded by h and load bounded by l ? Sirocco 2004
load hop 12 3 .... P P P … 1 P NP NP … 2 NP … … … 3 … … … … ... Flammini, Eilam, Zaks Sirocco 2004
Problem 1: Given a network, pairs of nodes and bounds h andl, find a virtual path layout to connect these nodes with the load bounded by l and the hop count bounded by h. tree, mesh general directed path network Gertsel, Wool, Zaks Feighelstein, Zaks Sirocco 2004
Case 1: shortest paths (stretch factor = 1) T(l,h) T(l-1,h) T(l,h-1) Sirocco 2004
Use of binary trees Sirocco 2004
Case 2:any paths (stretch factor > 1) TL(l,h) TL(l-1,h) TL(l,h-1) TR(l-1,h-1) Sirocco 2004
T(l,h-1) T(l,h-1) T(l-1,h-1) T(l-1,h) T(l-1,h) T(l-1,h-1) Sirocco 2004
l=3, h=2 Sirocco 2004
Golomb Sirocco 2004
Use of ternary trees Sirocco 2004
Using spheres The l1-norm|v|of an l-dimensional vectorv = (x1 ,...,xl ) is defined as |v| = |x1| + |x2| + ... + |xl| ex: |(1,-3,0,2)| = |1|+|-3|+|0|+|2| = 6 Sirocco 2004
Sp(l,r) - The l-dimensional l1-Sphere of radius h: the set of lattice points v=(x1,...,xl) with distance at most h from the origin. Sp(2,3):2-dimensional l1-Sphere of radius3. point with l1-distance 3 from the origin. Sirocco 2004
Covering Radius - The l - dimensional Covering Radius of N is the radius of the smallest l-dimensional sphere containing at least Npoints |Sp(2,0)| = 1 |Sp(2,1)| = 5 |Sp(2,2)| = 13 |Sp(2,3)| = 25 Sirocco 2004
For every ATM Chain Layouts with N nodes and maximal load l: minimal radius of a layout with load l and N nodes minimal radius of an l-dimensional sphere with at least N internal points Sirocco 2004
load = 3 dimension 3 radius = 4 hop = 4 (1,0,0) (1,-1,0) (1,-2,0) (1,-3,0) (0,0,0) (0,-1,0) (-1,1,0) (-1,0,0) (-1,-1,1) (-1,-1,0) (-2,0,0) Sirocco 2004
the tree T(l,h) fills the sphere Sp(l,h)!!! |T(l,h)| = |T(h,l)| , hence |Sp(l,h)| = |Sp(h,l)| Sirocco 2004
Sp(2,1): 2-dimensional l1-Sphere of radius1. Sp(1,2): 1-dimensional l1-Sphere of radius2. Sirocco 2004
For Upper Bound Using volume formulas, to Achieve bounds on h, given N and l Sirocco 2004
Problem:Given a chain network with N nodes and a given bound on the maximum load, find an optimal layout with minimum hop count (or diameter ) between all pairs of nodes. Bounds for in: Kranakis, Krizanc, Pelc Stacho, Vrt’o Aiello, Bhatt, Chung, Rosenberg, Sitaraman Sirocco 2004
For every graphG with diameter D(G) and radius R(G): R(G) D(G) 2 R(G) Then: Sirocco 2004
one-to-all, all-to-all, some-to-some Problem 3: Design and analyze approximation algorithms for general network. Problem 4: Solvethese problems to other measures (like load on the vertices, or bounded stretch factor) Sirocco 2004
Problem 7: Extend the duality results. Problem 8: Extend the use of geometry. Sirocco 2004
what are the input and the output? • network: tree, mesh, general, directed • cost measure • average vs. worst case • complexity • approximation algorithms • routing • dynamic, distributed • … More Problem and parameters cost of anarchy? Sirocco 2004
Outline • ATM networks model • Optical networks model • Discussion – ATM networks • Discussion – Optical networks Sirocco 2004
1st generation the fiber serves as a transmission medium Electronic switch Optic fiber Sirocco 2004
2nd generation Optical switch Sirocco 2004
A virtual topology Sirocco 2004