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Spring Term 2013 ADVANCED COMPUTER NETWORKS Assignment 7: Layer7 Switching and High Performance Networking Assigned on: 25 April 2013 Due by: 9 May 2013 Question 1: To access services from the data center, we need to locate a “close-by” data center, balance load across machines in a data center and target machines where the user’s state is kept. Explain which techniques can be utilized to achieve these three requirements. Question 2: The paper: “TCP Splicing for Application Layer Proxy Performance” [1] discusses in detail several subtleties of implementing the TCP Splice in the proxy. Please explain briefly how the TCP options are handled in the TCP Splice implementation: • TCP “urgent data” • Selective Acknowledgements • Maximum Segment Size Question 3: Read the paper “The Landscape of Computer Architecture” [2] and answer the following questions: • What trends does Figure 1 show? • What is the implication of these trends? Question 4: Explain briefly what are direct networks and indirect networks, and compare these two types of networks. Question 5: a) Data centers operated as one large layer 2 network allow virtual machines to be migrated without the need of changing the VMs IP address. Describe why Ethernet as it is does not scale well to such large deployments? b) VL2 and PortLand share similar approaches in several aspects in providing large layer-2 networks for data centers. For example, they both use multi-rooted tree topologies. Please describe two other areas where both methods share similar approaches. Please give succinct answers in the bullet form. Hint: think about addressing. c) Identify one potential weakness of each of the two approaches Portland and VL2. Hand In Instructions This is a paper exercise. Please hand it in during the exercise session or email to your assistants by the due date. References [1] David A. Maltz and Pravin Bhagwat. “TCP Splicing for Application Layer Proxy Performance”. IBM Research Report 21139 (Computer Science/Mathematics), IBM Research Division, 1998. [2] “The Landscape of Computer Architecture”, John Shalf, NERSC/LBNL, presented at ISC07, Dresden, June 25, 2007. [3] Radhika Niranjan Mysore, Andreas Pamboris, Nathan Farrington, Nelson Huang, Pardis Miri, Sivasankar Radhakrishnan, Vikram Subramanya, and Amin Vahdat. 2009. “PortLand: a scalable fault-tolerant layer 2 data center network fabric”. SIGCOMM Comput. Commun. Rev. 39, 4 (August 2009), 39-50. [4] Albert Greenberg, James R. Hamilton, Navendu Jain, Srikanth Kandula, Changhoon Kim, Parantap Lahiri, David A. Maltz, Parveen Patel, and Sudipta Sengupta. 2009. VL2: a scalable and flexible data center network. In Proceedings of the ACM SIGCOMM 2009 conference on Data communication (SIGCOMM ’09). ACM, New York, NY, USA, 51-62. 2