Load Balancing
Load Balancing Powered by CISCO
When you select the Dedicated Load Balancing Option, your services are delivered via a dedicated Cisco CSS (Content Services Switch). The Shared Load Balancing Option delivers your services via multiple distributed Cisco CSM’s (Content Switching Module). Both Cisco CSM’s and CSS solutions deliver a high-performance, load-balancing solution, providing your customers with an optimum online experience, meeting the demands of high-speed content delivery networks, tracking network sessions and server load conditions in real time, and directing client requests to the appropriate device. Fault-tolerant configurations maintain full state information and provide true hitless fail over required for mission-critical applications.
CISCO Content Switching Module Features
High Performance
The Cisco CSM performs up to
165,000 new Layer 4 TCP connection setups per second and
up to one million concurrent connections. These connections can be sent to 4000
virtual servers through any of the available switch ports to up to 16,000 real
servers or devices. The capability to use one or any switch port provides a
benefit over products that use distributed architectures requiring the use of
all ports to gain maximum performance.
Network Configurations
The Cisco CSM supports many different network topology types. A Cisco CSM can operate
in a mixed bridged and routed configuration, allowing traffic to flow from the client
side to the server side on the same or on different IP subnets.
IP Protocol Support
The Cisco CSM accommodates a wide range of common IP protocols—including TCP and User
Datagram Protocol (UDP). Additionally, the Cisco CSM supports higher-level protocols,
including HTTP, FTP, Telnet, Real Time Streaming Protocol (RTSP), Domain Name System (DNS),
and Simple Mail Transfer Protocol (SMTP).
Load-Balancing Algorithms
The Cisco CSM supports the following load-balancing algorithms:
- Round Robin
- Weighted Round Robin
- Least Connections
- Weighted Least Connections
- Source and/or Destination IP Hash
(subnet mask also configurable)
- URL Hashing
URL and Cookie-Based Load Balancing
The Cisco CSM allows full regular expression pattern matching for policies based on URLs,
cookies, and HTTP header fields. The Cisco CSM supports any URL or cookie format—allowing
it to load balance existing Web content without requiring URL or cookie format changes.
High Availability
The Cisco CSM continually monitors server and application availability using a variety of
probes, in-band health monitoring, return code checking, and the Dynamic Feedback Protocol (DFP).
When a real server or gateway failure occurs, the Cisco CSM redirects traffic to a different
location. Servers are added and removed without disrupting service—systems easily are scaled up or down.
Connection Redundancy
Two Cisco CSMs can be configured in a fault-tolerant configuration to share state information about user
sessions and provide hitless connection redundancy—an important requirement for e-commerce sites and sites
where encryption is used. If an active Cisco CSM fails, open connections quickly are switched to a standby
Cisco CSM without interruption, providing fail over that is transparent to the user.
User Session Persistence
In many cases it is important that an end user consistently is directed to the same end device for the duration
of a session. This is particularly important where SSL is employed for data encryption or where shopping carts
are used, as in e-commerce environments. The Cisco CSM offers the following solutions to provide session persistence
to ensure that a client request goes to the proper end device:
- Stickiness based on SSL session ID, source IP address, cookie or HTTP redirection
- Cookie insert enabling the ability to use cookies for stickiness even if the back-end application is not able to set a cookie
- Cookie offset and length, allowing an administrator to define the static portion of a dynamic cookie to use for persistence
The Cisco CSM synchronizes persistence information from an active Cisco CSM to backup Cisco CSM to provide a fail o
ver that is transparent to a user.
High Performance Distributed Denial of Service (DDoS) Protection
The Cisco CSM provides a last line of defense for a data center with the ability to fend off malicious traffic, such as
that typical of a SYN attack. In addition to protecting a data center from malicious traffic, the Cisco CSM continues to
operate and forward valid client requests to ensure that services are not interrupted.
Firewall Load Balancing
The Cisco CSM allows organizations to scale firewall protection by distributing traffic across multiple firewall devices
while ensuring that all packets belonging to a particular connection go through the same firewall. Both stealth and regular
firewall’s are supported.
Quality of Service
Using the robust quality of service capabilities of the of the Cisco Catalyst 6500 Series, the Cisco CSM provides the
right level of service to customers, adding the ability to:
- Correctly prioritize mission-critical packets based on Layer 7 rules
- Direct higher priority customers to faster or less loaded servers
Global Server Load Balancing
The Cisco CSM offers multiple options for building a global or geographical load-balanced environment. The Cisco CSM
can act as an authoritative DNS and perform Global Server Load Balancing (GSLB) among geographically dispersed Cisco
CSMs for disaster recovery for small GSLB environments with two to four locations. In addition, the Cisco CSM can report
load information for its virtual IP’s into the Global Site Selector (GSS), an appliance designed for advanced GSLB services,
with the capability to support up to 128 sites. With many different GSLB options, the Cisco CSM offers the ability to scale
GSLB capabilities to meet growth demands.