Network Management: - SNMP - Software Defined networking

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1 Internet-Technologien (CS262) Network Management: - SNMP - Software Defined networking Christian Tschudin Departement Mathematik und Informatik, Universität Basel 9-1 Chapter 9 Network Management A note on the use of these ppt slides: We re making these slides freely available to all (faculty, students, readers). They re in PowerPoint form so you can add, modify, and delete slides (including this one) and slide content to suit your needs. They obviously represent a lot of work on our part. In return for use, we only ask the following: If you use these slides (e.g., in a class) in substantially unaltered form, that you mention their source (after all, we d like people to use our book!) If you post any slides in substantially unaltered form on a www site, that you note that they are adapted from (or perhaps identical to) our slides, and note our copyright of this material. Computer Networking: A Top Down Approach, 5th edition. Jim Kurose, Keith Ross Addison-Wesley, April Thanks and enjoy! JFK/KWR All material copyright J.F Kurose and K.W. Ross, All Rights Reserved Network 9-2

2 Chapter 9: Network Management Chapter goals: introduction to network management motivation major components Internet network management framework MIB: management information base SMI: data definition language SNMP: protocol for network management security and administration presentation services: ASN.1 Network 9-3 Management Chapter 9 outline What is network management? Internet-standard management framework Structure of Management Information: SMI Management Information Base: MIB SNMP Protocol Operations and Transport Mappings Security and Administration ASN.1 Network 9-4

3 What is network management? autonomous systems (aka network ): 100s or 1000s of interacting hardware/software components other complex systems requiring monitoring, control: jet airplane nuclear power plant others? "Network management includes the deployment, integration and coordination of the hardware, software, and human elements to monitor, test, poll, configure, analyze, evaluate, and control the network and element resources to meet the real-time, operational performance, and Quality of Service requirements at a reasonable cost." Network 9-5 Management Infrastructure for network management definitions: managing entity managing data entity network management protocol agent data managed device agent data managed device agent data agent data managed device managed devices contain managed objects whose data is gathered into a Management Information Base (MIB) managed device Network 9-6

4 Network Management standards OSI CMIP Common Management Information Protocol designed 1980 s: the unifying net management standard too slowly standardized SNMP: Simple Network Management Protocol Internet roots (SGMP) started simple deployed, adopted rapidly growth: size, complexity currently: SNMP V3 de facto network management standard Network 9-7 Management Chapter 9 outline What is network management? Internet-standard management framework Structure of Management Information: SMI Management Information Base: MIB SNMP Protocol Operations and Transport Mappings Security and Administration ASN.1 Network 9-8

5 SNMP overview: 4 key parts Management information base (MIB): distributed information store of network management data Structure of Management Information (SMI): data definition language for MIB objects SNMP protocol convey manager<->managed object info, commands security, administration capabilities major addition in SNMPv3 Network 9-9 Management MIB example: UDP module Object ID Name Type Comments UDPInDatagrams Counter32 total # datagrams delivered at this node UDPNoPorts Counter32 # underliverable datagrams no app at portl UDInErrors Counter32 # undeliverable datagrams all other reasons UDPOutDatagrams Counter32 # datagrams sent udptable SEQUENCE one entry for each port in use by app, gives port # and IP address Network 9-

6 SNMP Naming question: how to name every possible standard object (protocol, data, more..) in every possible network standard?? answer: ISO Object Identifier tree: hierarchical naming of all objects each branchpoint has name, number ISO ISO-ident. Org. US DoD Internet udpindatagrams UDP MIB2 management 9Network Management 14 OSI Object Identifier Tree Network 9-

7 SNMP protocol Two ways to convey MIB info, commands: managing entity managing entity request trap msg response agent data agent data Managed device Managed device request/response mode trap mode 9Network Management 16 SNMP protocol: message types Message type Function GetRequest GetNextRequest GetBulkRequest Mgr-to-agent: get me data (instance,next in list, block) InformRequest Mgr-to-Mgr: here s MIB value SetRequest Response Trap Mgr-to-agent: set MIB value Agent-to-mgr: value, response to Request Agent-to-mgr: inform manager of exceptional event Network 9-

8 SNMP security and administration encryption: DES-encrypt SNMP message authentication: compute, send MIC(m,k): compute hash (MIC) over message (m), secret shared key (k) protection against playback: use nonce view-based access control SNMP entity maintains database of access rights, policies for various users database itself accessible as managed object! 9Network Management 19 Software Defined Networking Jennifer Rexford COS 461: Computer Networks Lectures: MW 10-10:50am in Architecture N101

9 Networks are Hard to Manage Operating a network is expensive More than half the cost of a network Yet, operator error causes most outages Buggy software in the equipment Routers with 20+ million lines of code Cascading failures, vulnerabilities, etc. The network is in the way Especially a problem in data centers and home networks Rethinking the Division of Labor 35

10 Traditional Computer Networks Data plane: Packet streaming Forward, filter, buffer, mark, rate-limit, and measure packets Traditional Computer Networks Control plane: Distributed algorithms Track topology changes, compute routes, install forwarding rules

11 Traditional Computer Networks Management plane: Human time scale Collect measurements and configure the equipment Death to the Control Plane! Simpler management No need to invert control-plane operations Faster pace of innovation Less dependence on vendors and standards Easier interoperability Compatibility only in wire protocols Simpler, cheaper equipment Minimal software

12 Software Defined Networking (SDN) Logically-centralized control Smart, slow API to the data plane (e.g., OpenFlow) Dumb, fast Switches 41 OpenFlow Networks

13 Data-Plane: Simple Packet Handling Simple packet-handling rules Pattern: match packet header bits Actions: drop, forward, modify, send to controller Priority: disambiguate overlapping patterns Counters: #bytes and #packets src=1.2.*.*, dest=3.4.5.* drop src = *.*.*.*, dest=3.4.*.* forward(2) src= , dest=*.*.*.* send to controller 43 Unifies Different Kinds of Boxes Router Match: longest destination IP prefix Action: forward out a link Firewall Match: IP addresses and TCP/UDP port numbers Action: permit or deny Switch Match: destination MAC address Action: forward or flood NAT Match: IP address and port Action: rewrite address and port

14 44 Controller: Programmability Controller Application Network OS Events from switches Topology changes, Traffic statistics, Arriving packets Commands to switches (Un)install rules, Query statistics, Send packets Example OpenFlow Applications Dynamic access control Seamless mobility/migration Server load balancing Network virtualization Using multiple wireless access points Energy-efficient networking Adaptive traffic monitoring Denial-of-Service attack detection See

15 E.g.: Dynamic Access Control Inspect first packet of a connection Consult the access control policy Install rules to block or route traffic E.g.: Seamless Mobility/Migration See host send traffic at new location Modify rules to reroute the traffic

16 48 E.g.: Server Load Balancing Pre-install load-balancing policy Split traffic based on source IP src=0* src=1* 49 E.g.: Network Virtualization Controller #1 Controller #2 Controller #3 Partition the space of packet headers

17 51 A Helpful Analogy From Nick McKeown s talk Making SDN Work at the Open Networking Summit, April 2012 Mainframes Ap Ap Ap Ap Ap Ap Ap Ap Ap Ap Ap p p p p p p p p p p p Specialized Applications Specialized Operating System Specialized Hardware Vertically integrated Closed, proprietary Slow innovation Small industry Open Window Interface Lin Mac s o ux o OS (OS) r r Open Interface Microprocesso r Horizontal Open interfaces Rapid innovation Huge industry

18 Routers/Switches Ap Ap Ap Ap Ap Ap Ap Ap Ap Ap Ap p p p p p p p p p p p Specialized Features Specialized Control Plane Specialized Hardware Vertically integrated Closed, proprietary Slow innovation Open Interface Control Plane or Control Plane or Control Plane Open Interface Merchant Switching Chips Horizontal Open interfaces Rapid innovation 54 Challenges

19 55 Heterogeneous Switches Number of packet-handling rules Range of matches and actions Multi-stage pipeline of packet processing Offload some control-plane functionality (?) access control MAC look-up IP look-up 56 Controller Delay and Overhead Controller is much slower the the switch Processing packets leads to delay and overhead Need to keep most packets in the fast path packets

20 57 Distributed Controller Controller Application For scalability and reliability Controller Application Partition and replicate state Network OS Network OS 58 Testing and Debugging OpenFlow makes programming possible Network-wide view at controller Direct control over data plane Plenty of room for bugs Still a complex, distributed system Need for testing techniques Controller applications Controller and switches Rules installed in the switches