EXL307
Packet 4
Packet 1
Packet 2
Packet 3
Pckt
1
2
3
Source IP
10.5.5.201
10.5.5.201
10.5.5.82
Destination IP
10.5.5.31
10.5.5.82
10.5.5.201
Description
Workstation to VIP
LB to CAS-02
CAS-02 to Workstation
10.5.5.201
Packet 1
10.5.5.0 / 24 Network
Packet 3
Packet 2
10.5.5.31
10.5.5.11
Load Balancer
Self IP: 10.5.5.11
VIP: 10.5.5.31
CAS-01
10.5.5.81
CAS-02
10.5.5.82
Packet 4
Packet 3
Packet 2
Packet 1
SNAT
DSR
LBDG
• No modifications to
CAS
• Return traffic
passes through LB
• Most common
• Client IP not on
server logs
• Requires modifying
CAS servers
• Return traffic
doesn’t pass
through LB
• Reduces
persistence options
• Introduces timeout
complexity
• Rarely used
(typically large
media hosters)
• Requires modifying
CAS servers
• Return traffic
passes through LB
• Adds complexity to
network routing
(need static routes)
• Client IP is on
server logs
Exchange 2010 Load Balancing Requirements
Persistence: Required
Persistence: Recommended
Persistence:
Not Required
Outlook Web App
Outlook Anywhere
Offline Address Book
Exchange Control Panel
ActiveSync
AutoDiscover
Exchange Web Services
Address Book Service
POP3
RPC Client Access Service
Remote PowerShell
IMAP4
Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeRPC\ParametersSystem
Value: TCP/IP Port
Type: DWORD
Microsoft.Exchange.AddressBook.Service.Exe.Config
RpcTcpPort
NspiHttpPort
RfrHttpPort
Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeAB\Parameters
Value: RpcTcpPort
Type: DWORD
(SP1)
HTTP-Based Workloads
Workload
Preferred Session Persistence Method
MSIT-Deployed Session Persistence Method
Outlook Web App
1. Client IP
2. App Cookie “OutlookSession”
App Cookie “OutlookSession”
Exchange Control Panel
App Cookie “OutlookSession”
Autodiscover
RPC Client Access
Exchange Address Book
1. Client IP
2. App Cookie “OutlookSession”
1. Client IP
2. Authorization HTTP header
1. Cookie
2. SSL ID
1. Client IP
2. No affinity/persistence
3. App Cookie “OutlookSession”
1. Client IP
2. SSL ID
No affinity/persistence
1. Client IP
1. Client IP
RPC Endpoint Mapper
1. Client IP
Client IP
Post Office Protocol (POP3)
No affinity/persistence
No affinity/persistence
Internet Message Access Protocol (IMAP4)
No affinity/persistence
No affinity/persistence
Exchange ActiveSync
Exchange Web Services
Outlook Anywhere
TCP Socket Oriented
Workloads
Offline Address Book
Authorization HTTP header
App Cookie
SSL Session ID (fallback)
No affinity/persistence
SSL ID
No affinity/persistence
Client IP
Client IP
SSL Offloading
How to Configure SSL Offloading
<exchange install>\ClientAccess\exchweb\ews
httpsTransport httpTransport
web.config
\ClientAccess\Autodiscover
Hardware Load Balancing Vendors
Vendor Name
Product Line
Website
A10
AX Series
http://www.a10networks.com/
Avanu / CAI Networks
Webmux
http://www.avanu.com/products/webmux.htm
Barracuda
Barracuda Load Balancer
http://www.barracudanetworks.com/ns/products/balancer_overview.php
Cisco
ACE (on switch/router)
http://www.cisco.com/en/US/products/ps6906/index.html
Cisco
CSS (dedicated)
http://www.cisco.com/en/US/products/hw/contnetw/ps792/
Citrix Systems
NetScaler
http://www.citrix.com/English/ps2/products/product.asp?contentID=21679
Brocade
ServerIron
http://www.brocade.com/sites/dotcom/products-solutions/products/ethernetswitches-routers/application-delivery/product-details/serveriron-adxseries/index.page
F5
Big IP Local Traffic Manager
http://www.f5.com/products/big-ip/
Kemp
LoadMaster
http://www.kemptechnologies.com/en/load-balancer.html
RadWare
AppDirector
http://www.radware.com/Products/ApplicationDelivery/AppDirector/default.aspx
Kemp Virtual LoadMaster
Kemp Virtual LoadMaster
F5 BIG-IP VirtualEdition
Citrix NetScaler VPX
http://social.technet.microsoft.com/wiki/contents/articles/exchang
e-2010-client-access-array-amp-load-balancing-resources.aspx
mail.contoso.com -> CNAME mail.gtm.contoso.com
F5 Global
Traffic Manager
(GTM)
The F5 GTM attempts to determine
which geography the end user is
connecting from and direct them to
the Local Traffic Manger (LTM) that is
closest.
F5 Local
Traffic
Manager
(SEA)
F5 Local
Traffic
Manager
(HOU)
F5 Local
Traffic
Manager
(CLT)
The regional LTM devices pass the
traffic along to the Client Access
Server that will service the request.
This side of the request is over HTTP
port 80 (unencrypted.)
Seattle CAS Servers
Houston CAS Servers
Charlotte CAS Servers
Scenarios
http://northamerica.msteched.com
www.microsoft.com/teched
www.microsoft.com/learning
http://microsoft.com/technet
http://microsoft.com/msdn