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Managing Service Quality in Emerging IP Networks

Managing Service Quality in Emerging IP Networks. Peter Luff Vice President of Marketing www.visualnetworks.com. The Value of Service Quality Measurement. Planning Track usage by Class of Service, by port Track application usage and identify capacity bottlenecks Validate carrier SLAs

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Managing Service Quality in Emerging IP Networks

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  1. Managing Service Quality in Emerging IP Networks Peter Luff Vice President of Marketing www.visualnetworks.com

  2. The Value of Service Quality Measurement • Planning • Track usage by Class of Service, by port • Track application usage and identify capacity bottlenecks • Validate carrier SLAs • Monitoring • Faults - local loop, port, or connection failure • Threshold events - circuit or traffic related • Troubleshooting • Isolate SP vs Enterprise problem sources to reduce downtime • IP Connectivity failures • Class of Service delivery, latency

  3. The Scope of an IP SLA Internal Enterprise SLA: End to End WAN SLA: Demarc to Demarc Switch to Switch LAN to LAN R R WAN Core WAN CPE LAN CPE WAN CPE LAN CPE Switch Switch SERVER CLIENT WAN Access Internetwork

  4. Today’s Networking Environment

  5. Trends in Private IP Services • Private IP-VPNs are rejuvenating traditional data services • Advent of new IP-aware Frame and ATM services • Robust networks with inherent security • Simple upgrade offloads complexity to the network • Demand for Class of Service (CoS) validation - no CIR for IP • Concerns around provisioning, verification, SLAs

  6. Trends in Public IP Services • Where is the rapid adoption of IP-VPNs? • Remote access is a no-brainer! • International or non-critical locations • Limited adoption of Internet-based IP-VPNs for business-grade site-to-site connectivity • Upside - Flexibility, cost, ubiquity • Expansion choked by concerns over security & management • Lack of meaningful SLGs and management visibility • More enterprises are building their own IP-VPNs • Low adoption of IP-VPN services • Internet access transport needs more visibility, SLGs

  7. Further Market Trends • Carrier SLAs are still anemic! • Heavy averaging; Switch-based data does not reflect reality • Increased demand for applications visibility • Need to understand ORCL, SAP, VoIP impact on the WAN • Continued drive to higher speed networks is raising the stakes on mission-criticality • 56k to T1 migration • More DS-3 Frame Relay • More NxT1 IMA • All raising the need for increased levels of performance visibility

  8. IP Class of Service Measurement • IP Class of Service - technology review • Service Provider CoS implementations • IP performance metrics • Operational challenges

  9. Circuit Connectivity vs. IP Connectionless Connectivity

  10. IP Class of Service - Revision 32 Bits • Type of Service (TOS) • for CoS Marking • Now known as Differentiated Services Code Point (DSCP) • Usually set to 0, but may indicate particular Quality of Service needs from the network • The DSCP defines one of a set of class of service Ver/IHL TOS Total length Identifier Flags Offset TTL Protocol Checksum Source IP Address Destination IP Address Options and Padding IP Data

  11. Ingress Bandwidth Policing Bandwidth Policing -- -- Thresholds X, Y, Z X -- T1 bandwidth Y -- Post PER coming -- Policing IP -- from Policing Bandwidth Customer -- Algorithm Breakdown -- Z Edge -- applied at Router -- Provider Edge Router (PER) -- High Priority -- Mid Priority Low Priority Best Effort

  12. Egress Weighted Queuing Each class is given a percentage of egress bandwidth Incoming Traffic placed in appropriate queue Traffic flows to the user port Provider Edge Router

  13. Bandwidth Maximization with IP and CoS PVC A Traditional Highest Priority Site to Site Second Highest Frame PVC B Priority Relay or ATM Lowest Priority network PVC C Additional high priority traffic that needs to flow on PVC C is being clipped by the PVC CIR, however PVC A and PVC B are using their bandwidth for lower priority traffic With Class of Service use within a connectionless Highest Priority Network network based IP Routing based VPN and Second Highest VPN, bandwidth is connectivity with CoS Priority used by the done by support IP network highest priority Lowest Priority traffic regardless of destination

  14. Service Implementation Example (1) • ePVC for IPeFR • User defined CAR for the ePVC • Three classes of service • Bursty High • 79% of ePVC CAR • Bursty Low • 20% of ePVC CAR • Best Effort • 1% of ePVC CAR • All policed traffic marked as best effort

  15. Service Implementation Example (2) • Four classes of service • Real Time • Customer defined % of ePVC CAR • Bursty High and Bursty Low • 4:1, 3:1, or 2:1 ratio of remaining ePVC CAR BW • Best Effort • 1% of ePVC CAR • All policed traffic marked as best effort

  16. Service Implementation Example (3) • Premium IP PVC • Customer defined CAR for the PVC • Three classes of service • Premium • User defined % of CAR • Premium Priority • Remaining CAR BW • Best Effort • All traffic above CAR

  17. SLA Metrics SLA for Frame Relay SLA for IP Availability based on DLCI up/down status, per LMI status messages Availability- based on test transaction status every 5 minutes Round Trip Delay Calculated based on test transactions between DLCI endpoints Round Trip Delay Calculated based on test transactions between IP endpoints Frame Delivery Ratio vs. CIR (above/below, offered/delivered) Packet Delivery Ratio adjusted per CoS policing threshold NO CIR! Done on DLCI pair site to site Done on IP subnet pairs

  18. Measurement of IP SLA Metrics IP Network Router DSU DSU Router IP available seconds (by connection): Continuously accumulated into 15 minute history buckets Monitor response to test packet & maintain availability timer on response Monitor response to test packet & maintain availability timer on response IP DDR (by connection): Continuously accumulated into 15 minute history buckets PACKETS OFFERED TOTAL PACKETS DELIVERED TOTAL PACKETS DELIVERED PACKETS OFFERED IP Round-trip delay (by connection): Minimum of 1 sample per 15 minute history bucket IP ECHO REQUEST IP ECHO REPLY IP ECHO REPLY IP ECHO REQUEST

  19. Operational Challenges in IP Networks • How do I hold my service provider accountable for site-to-site IP-VPN performance? • How do I get visibility into the performance of new IP-aware frame relay services? • How do I verify I am getting the IP Class of Service performance I am paying for? • How do my key applications perform across new IP-VPN services? • How do I verify connectivity to remote IP subnets? • How does VoIP traffic impact network performance?

  20. Real-time view of IP SLA metrics PDR and RTD between subnets Availability based on 5 minute samples Site-to-Site IP SLA in Real Time

  21. “Unknown” traffic classification to identify mis-configured router Collected for 8 Classes Support TOS/DSCP bit ranges Access Channel IP CoS Ingress and Egress Throughput

  22. Site-to-Site IP circuit visibility Application visibility per IP connection Verify end-to-end reachability IP Circuit Summary Subnet-to-Subnet

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