2. Communications Efficiency Sandeep K. Singhal, Ph.D Director, Windows Networking Microsoft Corporation

3. Agenda Trends in enterprise networking Windows Vista and Windows Server 2008 Collaboration with MoD Looking into the future Summary

4. Trends in Enterprise Networking Server consolidation and growth of data centers Increasingly mobile and remote staff Evolving security requirements

5. Trends in Enterprise Networking Single networking fabric for web, file, database, and backup Increased network traffic load on servers Increased load on Internet firewalls Server consolidation and growth of data centers Increasingly mobile and remote staff Evolving security requirements

6. Trends in Enterprise Networking Single networking fabric for web, file, database, and backup Increased network traffic load on servers Increased load on Internet firewalls Server consolidation and growth of data centers Remote access solutions stretch experience, support, and management Greater reliance on WAN (over Internet) links from branch offices Multiple client access technologies and devices Increasingly mobile and remote staff Evolving security requirements

7. Trends in Enterprise Networking Single networking fabric for web, file, database, and backup Increased network traffic load on servers Increased load on Internet firewalls Server consolidation and growth of data centers Remote access solutions stretch experience, support, and management Greater reliance on WAN (over Internet) links from branch offices Multiple client access technologies (e.g., WLAN, WWAN, satellite) and devices (smartphones, laptops, unmanaged home PCs, etc.) Increasingly mobile and remote staff Enterprise edge disappearing with mobile workforce & devices Heterogeneous user population (contractors, vendors) require securing resources in addition to networks Federation and regulatory needs require policy-based isolation domains Evolving security requirements

8. Windows Vista and Windows Server 2008

9. Windows Vista and Windows Server 2008: Networking Stack Architecture Windows Filtering Platform IPv4 802.3 WSK WSK Clients TDI Clients NDIS WLAN 1394 Loop- back IPv4 Tunnel IPv6 Tunnel IPv6 RAW UDPTCP Next-Generation TCP/IP Stack (tcpip.sys) AFD TDX TDI Winsock User Mode Kernel Mode

10. Key Networking Innovations Network performance Connectivity Security PC health management Scalability Enterprise quality of service (eQoS) Peer-to-peer and ad-hoc collaboration

11. Key Networking Innovations Network performance Connectivity Security PC health management Scalability Enterprise quality of service (eQoS) Peer-to-peer and ad-hoc collaboration

12. The Performance Challenge Network stack implementations limited by – Static default configurations picked to match most common environments – Protocols designed more than a decade ago Poor network performance under – High latency (e.g., access to resources across the continent) – High bandwidth (e.g., fiber to the home [FTTH]) – Losses (e.g., WLAN, WWAN, satellite networks) Network performance is key determinant of performance of most applications

13. The Receive Window Limitation North America Intercontinental Fiber Satellite

14. Autotuning Receive Window Problem: Network performance limited on high-latency WAN (such as satellite or FTTH) – TCP default receive window limits throughput to 5Mbps on a 100ms (coast to coast) connection – Even lower throughput on higher latency like inter-continent or satellite Solution: Windows Vista and Windows Server 2008 adjust TCP Receive Window for each connection over time – Window scaling (RFC 1323) enabled by default with scale factor of 8 – Estimates bandwidth delay product and application read-rate Impact: Applications see faster uploads/downloads – SMB file copy between Redmond and Australia improved 10x – Backup between Bay area and Tukwila data center improved 40x – Benefit varies depending on spare capacity

15. Throughput (Mbps) Application Performance with Windows Vista and Windows Server 2008

16. Microsoft.com and Receive Window Auto-Tuning Replicating data between Redmond and Bay Area – 1 Gbps dedicated connectivity Default configurations On Windows Server 2003 SP1: – 100Mbps NICs, 10Mbps throughput On Windows Vista: – 100Mbps NICs, 80Mbps throughput – 1000Mbps NICs, 400Mbps throughput (memory to memory copy) File copy from disk to disk limited to 250Mbps due to disk bottleneck 40X

17. Protocol Limitations: Dealing with High Bandwidth Scenario: Replication between geographically distributed data centers connected by gigabit links – TCP protocols cuts down sending rate dramatically on losses and increases sending rate slowly < 1 in 83000 packet loss rate to fully occupy a 1Gbps/100ms link Solution: Compound TCP utilizes loss and delay information to rapidly ramp up sending rate without causing losses – Fairness is important: <10% impact on existing TCP connections – Enabled by default on Windows Server 2008 (only send side support needed) Impact: Faster data center replication – Microsoft.com replication time reduced by half

18. Sample CTCP Performance TCP data transfer using Compound-TCP (blue) and vanilla TCP (red) between Bay Area, CA and Tukwila, WA data centers

19. Protocol Limitations: Dealing with Random Losses Scenario: Wireless networks like GPRS, UMTS, WLAN – Losses interpreted by TCP as indication of congestion – Link layer recovery exacerbates problem as TCP does recovery at its own layer (spurious retransmissions) – Large change in round trip times causes fatal TCP connectivity loss Solution: – Detect spurious retransmissions using Forward Retransmission Timeout Recovery (FRTO) and Delayed Selective Acknowledgement (DSACK) mechanisms (IETF based) Avoid unnecessary retransmission and also reduction in sending rate – RTT resiliency mechanism Impact: Improved wireless performance – 10-30% throughput improvement in GPRS scenarios

20. Key Networking Innovations Network performance Connectivity Security PC health management Scalability Enterprise quality of service (eQoS) Peer-to-peer and ad-hoc collaboration

21. Drivers for IPv6 Scalable Network Connectivity Seamless Application Development platform End-to-end Authentication Simplified Ad-hoc Network support

22. IPv6: Ready, Real and Required with Windows Vista and Windows Server 2008 Ready – Enabled by default and preferred on Windows Vista and Windows Server 2008 – All out-of-box applications, services, and interfaces support IPv6 (dual stack or native) – IPv6 is being deeply integrated across our entire product line Real – Usable on existing IPv4 networks – Transition technologies (ISATAP, 6to4, Teredo) enable low-cost, automatic IPv6 deployment Required – Scenarios such as Windows Meeting Space and Remote Assistance have unique value in IPv6 networks

23. IPv6 Migration Strategy Infrastructure MigrationApplication MigrationOperations Migration Baseline Architecture Planning, Training, Testing Security Target Architecture

24. IPv6 Migration Approach Operations Migration Network ManagementNetwork Management Infrastructure ServicesInfrastructure Services SecuritySecurity Action Items: Host monitoring Application configuration License management Patch update Application Migration Commercial AppsCommercial Apps Line of Business AppsLine of Business Apps Action Items: Inventory & Assess Impact Application porting Application deployment Proxy for applications that can’t migrate Infrastructure Migration TunnelingTunneling Dual StackDual Stack Native v6Native v6 Action Items: Upgrade to Windows Vista Ensure DNS supports IPv6 Deploy ISATAP server or native addressing

25. IPv6 Migration: Options and Costs MethodRequirementCostAvailability Transition Technologies ISATAP, 6to4Lowest Many Platforms, Including Windows 2003 Dual Stack Some hardware upgrades Medium Most hardware supports v6 Native IPv6 All hardware upgraded, applications tested Highest Many software vendors still don’t support IPv6