Communications Efficiency

Sandeep K. Singhal, Ph.DDirector, Windows Networking

Microsoft Corporation

Agenda

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

Trends in Enterprise Networking

Server consolidation and growth of data

centers

Increasingly mobile and remote staff

Evolving security requirements

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

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

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

Windows Vista and Windows Server 2008

Windows Vista and Windows Server 2008:Networking Stack Architecture

Win

do

ws

Filterin

g

Platfo

rm

IPv4

802.3

WSK

WSK Clients TDI Clients

NDIS

WLAN 1394 Loop-back

IPv4 Tunnel

IPv6 Tunnel

IPv6

RAWUDPTCP

Next-Generation TCP/IP Stack (tcpip.sys)

AFD

TDX

TDI

Winsock User Mode

Kernel Mode

Key Networking Innovations

• Network performance• Connectivity• Security• PC health management• Scalability• Enterprise quality of service (eQoS)• Peer-to-peer and ad-hoc collaboration

Key Networking Innovations

• Network performance• Connectivity• Security• PC health management• Scalability• Enterprise quality of service (eQoS)• Peer-to-peer and ad-hoc collaboration

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

The Receive Window Limitation

North America

IntercontinentalFiber

Satellite

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

Thr

ough

put

(Mbp

s)Application Performance

with Windows Vista and Windows Server 2008

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

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

Sample CTCP Performance

0

200

400

600

800

1000

1200

1400

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106 113 120 127 134 141 148 155 162 169 176 183 190

Time (sec)

Th

rou

gh

pu

t (M

bp

s)

CTCP

NewReno

• TCP data transfer using Compound-TCP (blue) and vanilla TCP (red) between Bay Area, CA and Tukwila, WA data centers

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

Key Networking Innovations

• Network performance• Connectivity• Security• PC health management• Scalability• Enterprise quality of service (eQoS)• Peer-to-peer and ad-hoc collaboration

Drivers for IPv6

Scalable Network Connectivity

Seamless Application Development platform

End-to-end Authentication

Simplified Ad-hoc Network support

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

IPv6 Migration Strategy

Infrastructure Migration Application Migration Operations Migration

Baseline Architecture

Planning, Training, Testing

Security

Target Architecture

IPv6 Migration ApproachOperations Migration

• Network Management

• Infrastructure Services

• Security

Action Items: Host monitoring Application

configuration License

management Patch update

Application Migration

• Commercial Apps• Line of Business Apps

Action Items: Inventory & Assess

Impact Application porting Application

deployment Proxy for applications

that can’t migrate

Infrastructure Migration

• Tunneling• Dual Stack• Native v6

Action Items: Upgrade to Windows

Vista Ensure DNS supports

IPv6 Deploy ISATAP server

or native addressing

IPv6 Migration:Options and Costs

Method Requirement Cost Availability

Transition Technologies ISATAP, 6to4 Lowest

Many Platforms, Including

Windows 2003

Dual Stack Some hardware upgrades Medium Most hardware

supports v6

Native IPv6All hardware

upgraded, applications

testedHighest

Many software vendors still don’t

support IPv6