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A Survey of Recent Advances in Network Planning/Traffic Engineering (TE) Tools


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Designing & managing operational IP networks is a complex, multi-dimensional
task. A fundamental problem before carriers today
is to optimize network performance by better resource allocation to traffic demands.
This requires a systematic evaluation of options, a thorough scenario analysis,
and foolproof verification of network designs, all of which are increasingly
possible only with help from automated TE and planning tools.

In the past few years, significant advances have been made in enhancing existing
tools and developing new ones that help providers rapidly identify potential
performance problems, experiment with solutions, and develop robust designs.
Several techniques from optimization theory, linear programming, and
models of effective bandwidth calculation have been incorporated in such
tools, as have detailed models of several vendor systems.

We present a comparative analysis and an overview of key features of some key
commercially available network planning/TE tools, and outline how
they could be leveraged by carrier network engineering/planning
organizations to perform detailed network analysis, proactive/reactive
TE, and network design.

We first give an overview of the architecture, design philosophy, and canonical
features of modern design tools, and then focus on new enhancements to some
popular tools
as well as key distinguishing features of some newly developed ones.
In particular, we focus on decision support tools for IP network planning
and network analysis, including the latest versions from
WANDL, OPNET, Cariden..

We also present a perspective on current outstanding carrier requirements
for TE/planning tools that was synthesized by our conversations with
several leading Tier 1 and Tier 2 carriers.

Published in: Technology, Business
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A Survey of Recent Advances in Network Planning/Traffic Engineering (TE) Tools

  1. 1. A Survey of Recent Advances in Network Planning/TE Tools Vishal Sharma, Ph.D. Metanoia, Inc. [email_address] Metanoia, Inc. Critical Systems Thinking™ © Copyright 2006 All Rights Reserved
  2. 2. Agenda <ul><li>TE tools in network design process and tool workflow </li></ul><ul><li>Taxonomy of TE tools </li></ul><ul><ul><li>Architecture </li></ul></ul><ul><ul><li>Design </li></ul></ul><ul><ul><li>Functions/features </li></ul></ul><ul><ul><li>New enhancements (last 1-2 years) </li></ul></ul><ul><li>A perspective on current carrier needs </li></ul><ul><li>Operation and key features of representative TE tools </li></ul><ul><ul><li>OPNET’s SP Guru and VNE Server </li></ul></ul><ul><ul><li>Cariden’s MATE </li></ul></ul><ul><ul><li>PARC’s Route Generator (now part of Cisco IPSC) </li></ul></ul>
  3. 3. Traffic Engineering Tools in the Overall Network Design Process We are here Note: In a combined multi-layer network design, this strict division may not hold
  4. 4. TE Tool Workflow: Control Exercised over Varying Timescales
  5. 5. Taxonomy of Modern Tools: Architecture <ul><li>Centralized or distributed? </li></ul><ul><li>Obtaining network topology & utilization info? </li></ul><ul><li>Inputs </li></ul><ul><ul><li>Their formats? </li></ul></ul><ul><ul><li>Interface with n/w elements? </li></ul></ul><ul><li>Outputs </li></ul><ul><ul><li>Their formats? </li></ul></ul><ul><ul><li>Installing routes/LSPs in n/w? </li></ul></ul><ul><li>Path route computation </li></ul><ul><ul><li>On-line, dynamic? </li></ul></ul><ul><ul><li>Off-line, global? </li></ul></ul><ul><ul><li>Combination of above? </li></ul></ul><ul><li>Route computation trigger </li></ul><ul><ul><li>User? Administrator? </li></ul></ul><ul><ul><li>New request(s)? </li></ul></ul><ul><li>Scalability </li></ul><ul><ul><li># of links & nodes handled? </li></ul></ul><ul><ul><li># of flows, LSPs, circuits? </li></ul></ul><ul><ul><li># of constraints handled? </li></ul></ul>
  6. 6. Taxonomy of Modern Tools: Design Philosophy <ul><li>Control-centric </li></ul><ul><ul><li>Long time scales </li></ul></ul><ul><ul><li>Large granularity flows </li></ul></ul><ul><li>Verisimilitude-centric </li></ul><ul><ul><li>Pkt. by pkt. sims. of elements & network </li></ul></ul><ul><ul><li>Traffic trace-based perf. simulations </li></ul></ul><ul><li>Hybrids </li></ul><ul><ul><li>Long time scale analysis for network perf. </li></ul></ul><ul><ul><li>Pkt. level sims. for element & flow performance </li></ul></ul>
  7. 7. Taxonomy of Modern Tools: Design Philosophy
  8. 8. Taxonomy of Modern Tools: Functions/Features by Task
  9. 9. Taxonomy of Modern Tools: Recent Enhancements <ul><li>IGP tuning – Layer 3 traffic engineering </li></ul><ul><li>Incorporation of FRR – bypass, detour </li></ul><ul><li>Routing of VoIP calls – with queueing delay and MOS </li></ul><ul><li>Diff-Serv aware TE – set pool boundaries </li></ul><ul><li>Coupling with physical layer topology </li></ul><ul><li>Multicast support – for multimedia apps. </li></ul><ul><li>Modeling new services – VPLS, PWs, L3 VPNs </li></ul>
  10. 10. Canonical Structure/Organization
  11. 11. A Perspective on Some Current Carrier Requirements <ul><li>Accurate planning models </li></ul><ul><li>IP n/w planning with peering </li></ul><ul><li>Useability and consistency </li></ul><ul><li>Obtain precise traffic matrices </li></ul><ul><li>Good interface with monitoring tools </li></ul><ul><li>Intelligent heuristics </li></ul><ul><li>Extensible architecture </li></ul><ul><li>Application-level performance monitoring </li></ul><ul><li>Multicasting for multi-media services support </li></ul>
  12. 12. OPNET Technologies <ul><li>Founded 1986, ex MIT experts in communication system modeling </li></ul><ul><li>Intelligent network management software </li></ul><ul><li>OPNET Modeler, original flagship product </li></ul><ul><ul><li>Comprehensive, comunication network modeling tool </li></ul></ul><ul><ul><li>Allows for modeling nodes, links, physical characteristics </li></ul></ul><ul><ul><li>In-built models for common communication protocols </li></ul></ul><ul><ul><li>Flexible extensions possible via C-like language </li></ul></ul><ul><li>Solution suites </li></ul><ul><ul><li>Service Providers : SP Guru, WDM Guru, CapEx Optimizer </li></ul></ul><ul><ul><li>System vendors : SP Guru, Modeler, NetBiz </li></ul></ul>
  13. 13. OPNET SP Guru: Components & Features <ul><li>Network simulation and analysis </li></ul>
  14. 14. OPNET SP Guru: Internal Operation <ul><li>Operates in 3 flavors </li></ul><ul><ul><li>Fully-detailed, event-driven simulations </li></ul></ul><ul><ul><li>Partially event-driven simulations </li></ul></ul><ul><ul><li>Analytic simulations </li></ul></ul>
  15. 15. OPNET SP Guru: NetDoctor <ul><li>Rule-based config. & performance verification component </li></ul><ul><li>Diagnoses problems from misconfigs. or protocol conflicts </li></ul>
  16. 16. OPNET SP Guru: VNE Server <ul><li>Collect data from multiple sources </li></ul><ul><li>Merge to create a unified picture, useful for planning, engg., ops. </li></ul>
  17. 17. OPNET Solutions: Key Characteristics <ul><li>NetDoctor for configuration & network operations analysis </li></ul><ul><li>VNE Server </li></ul><ul><ul><li>Automated I/F to various network data components </li></ul></ul><ul><ul><li>Ability to build a complete network view </li></ul></ul><ul><li>Hybrid simulation techniques </li></ul><ul><ul><li>Provide balance between speed and resolution </li></ul></ul><ul><li>Ability to add SP’s own rules, algorithms, modules </li></ul><ul><li>Facility to map actual IP addressing to internal network model </li></ul>
  18. 18. Cariden Technologies <ul><li>Founded 2001, ex Stanford, experts in OR, statistics, software </li></ul><ul><li>MATE: suite of tools for TE-related tasks </li></ul><ul><ul><li>Data gathering: integrated module or plug-in </li></ul></ul><ul><ul><li>Simulation: OSPF/IS-IS, BGP, MPLS multicast, Diffserv, ... </li></ul></ul><ul><ul><li>Optimization: Offline MPLS LSPs, IGP tuning (unique), chageover </li></ul></ul><ul><li>Control-centric architecture </li></ul><ul><li>Does IGP planning for IP networks </li></ul><ul><li>Emphasis on ease-of-use </li></ul>
  19. 19. MATE TE Process
  20. 20. MATE IGP Traffic Engineering <ul><li>Problems </li></ul><ul><li>Uneven link utilization </li></ul><ul><li>Heuristic/ad-hoc planning </li></ul><ul><li>Coarse capacity upgrade rules (e.g. at 50 or 75%) </li></ul>Above 60% utilization expected in 6 mo! Sample network with projected traffic growth in 6 months Original network state
  21. 21. MATE Routing Optimization [Reproduced with permission: Cariden Technologies] <ul><li>Objectives </li></ul><ul><li>Max. headroom on failure </li></ul><ul><li>Max. normal headroom </li></ul><ul><li>Minimize latency </li></ul><ul><li>Constraints </li></ul><ul><li>Fixed intra-site metrics </li></ul><ul><li>Symmetric weights </li></ul><ul><li>Latency bounds </li></ul><ul><li>Results </li></ul><ul><li>Max. link util. 89%  59% </li></ul><ul><li>Max. link util. on failure 110%  92% </li></ul>All links brought to below 60% utilization under normal conditions
  22. 22. MATE Resilience Capabilities Before (worst case) After (worst case) >> 95% utilization Max. utilization under 92%
  23. 23. MATE: Changeover Example <ul><li>A step-by-step procedure to move network from current to new config. </li></ul><ul><li>Sequence of single metric changes to effect transition </li></ul><ul><li>At each step, continue to meet limits on latency, utilization </li></ul>Extract from a Changeover Plan [Source: Cariden Technologies]
  24. 24. Sample TE Analysis with MATE <ul><li>Presented by Martin Horneffer of DT at NANOG 33 </li></ul>
  25. 25. MATE: Key Distinguishing Characteristics <ul><li>Demand estimation & characterization </li></ul><ul><ul><li>Estimate p2p demands from aggregate node/intf. demands & routing </li></ul></ul><ul><ul><li>Estimate effective b/w per queueing class to meet QoS for demands </li></ul></ul><ul><li>Robust routing changeovers </li></ul><ul><ul><li>Sequence of moves to transition network from one routing/LSP pattern to another via a series of “make-before-break” operations </li></ul></ul><ul><li>IGP metric-tuning based optimization in IP networks </li></ul><ul><li>Practical BGP simulations – peering, load balancing </li></ul><ul><li>Fully cross-platform – supports client/server or client-only model </li></ul>
  26. 26. PARC Technologies 1 <ul><li>Founded 1999, ex Imperial College, London, experts in OR and optimization </li></ul><ul><li>Funded March 2001, $23M from Cisco, CSFB, NTT </li></ul><ul><ul><li>Acquired by Cisco circa July/Aug. 2004 </li></ul></ul><ul><li>Control-centric architecture </li></ul><ul><li>Had products in two areas </li></ul><ul><ul><li>Network analysis: decision support for IP operators & planners </li></ul></ul><ul><ul><li>Route Generator: off-line tool for path computation in MPLS-TE n/ws </li></ul></ul>1 Now part of Cisco IPSC
  27. 27. PARC IP Network Analysis: Modules & Operation <ul><li>Collection of modules for key analysis functions in IP networks </li></ul>
  28. 28. PARC IP Network Analysis: Operation <ul><li>Key idea </li></ul><ul><ul><li>Observe SP network state ... </li></ul></ul><ul><ul><li>Predict how network reacts to a changed environment </li></ul></ul><ul><li>Designed for </li></ul><ul><ul><li>IP-only networks </li></ul></ul><ul><ul><li>IP/MPLS n/wks (with or w/o TE) </li></ul></ul>
  29. 29. PARC Route Generator (RG) <ul><li>Off-line tool for path computation in MPLS-TE networks </li></ul><ul><li>Designed as OEM module to provide </li></ul><ul><ul><li>Bandwidth protection </li></ul></ul><ul><ul><li>Bandwidth plus delay guarantees </li></ul></ul><ul><li>Used in Cisco TunnelBuilder Pro </li></ul><ul><li>Co-exists with on-line & distributed MPLS-TE path placement and computation mechanisms </li></ul>
  30. 30. PARC Route Generator: Features & Operation
  31. 31. PARC Solution Performance: Bandwidth Sharing Efficiency <ul><li>Same bandwidth reused across different failure cases </li></ul>[Reproduced with permission: PARCTechnologies Ltd.] Average Shared Bandwidth per Link 0 1 2 3 4 5 6 7 NET1 22 NET2 54 NET4 101 NET5 236 Network Size (Nodes) Average Shared Bandwidth BR G CSPF NET3 38 Maximum Shared Bandwidth per Link 0 5 10 15 20 25 30 35 Network Size (Nodes) Max Shared Bandwidth BRG CSPF NET1 NET2 54 NET4 101 NET5 236 NET3 38
  32. 32. Key Characteristics of PARC’s Solutions <ul><li>Interacts w/ routers, creates a full model of n/w routing </li></ul><ul><li>Uses measurements to implicitly derive traffic matrices </li></ul><ul><ul><li>Leads to very accurate bounds on aggregate flows </li></ul></ul><ul><li>Tool for intelligent probe placement for n/w data collection </li></ul><ul><li>RG allows provisioning of bandwidth-on-demand services </li></ul><ul><ul><li>Accounts for session duration and CAC </li></ul></ul><ul><li>Advances in algo. hybridization + constraint programming </li></ul><ul><ul><li>Prove problem infeasibility or solution optimality </li></ul></ul>