Cisco Cisco IOS Software Release 12.2(18)SXF
Features
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Cisco IOS Release 12.2(18)SXF
The notifications sent by the GGSN use GTP with message types from the unused space (reserved for
future use) and the following information elements (IEs):
future use) and the following information elements (IEs):
•
Notification type, which indicates the notification condition. For example, this could be a
notification to IOS SLB to reassign the session to an alternate GGSN, when the current GGSN fails
on Call Admission Control (CAC).
notification to IOS SLB to reassign the session to an alternate GGSN, when the current GGSN fails
on Call Admission Control (CAC).
•
Identifier of the relevant session (session key).
•
Other IEs specific to the notification type. For example, for a notification to reassign, GGSN
includes the create response, which it would otherwise have sent to the SGSN. This enables
IOS SLB to relay this response back to SGSN when the maximum number of reassignments due to
notification reach the configured limit.
includes the create response, which it would otherwise have sent to the SGSN. This enables
IOS SLB to relay this response back to SGSN when the maximum number of reassignments due to
notification reach the configured limit.
GGSN-IOS SLB messaging is supported in both dispatched mode and directed modes.
Probes
IOS SLB supports DNS, HTTP, ping, TCP, custom UDP, and WSP probes:
•
A DNS probe sends domain name resolve requests to real servers, and verifies the returned IP
addresses.
addresses.
•
An HTTP probe establishes HTTP connections to real servers, sends HTTP requests to the real
servers, and verifies the responses. HTTP probes are a simple way to verify connectivity for devices
being server load-balanced, and for firewalls being firewall load-balanced (even devices on the other
side of a firewall).
servers, and verifies the responses. HTTP probes are a simple way to verify connectivity for devices
being server load-balanced, and for firewalls being firewall load-balanced (even devices on the other
side of a firewall).
HTTP probes also enable you to monitor applications being server load-balanced. With frequent
probes, the operation of each application is verified, not just connectivity to the application.
probes, the operation of each application is verified, not just connectivity to the application.
HTTP probes do not support HTTP over Secure Socket Layer (HTTPS). That is, you cannot send an
HTTP probe to an SSL server.
HTTP probe to an SSL server.
•
A ping probe pings real servers. Like HTTP probes, ping probes are a simple way to verify
connectivity for devices and firewalls being load-balanced.
connectivity for devices and firewalls being load-balanced.
•
A TCP probe establishes and removes TCP connections. Use TCP probes to detect failures on TCP
port 443 (HTTPS).
port 443 (HTTPS).
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A custom UDP probe can to support a variety of applications and protocols, including:
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RADIUS Accounting/Authorization probes
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GTP Echo probes
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Connectionless WSP probes
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XML-over-UDP probes for CSG user-database load-balancing
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Mobile IP RRQ/RRP
•
A WSP probe simulates requests for wireless content and verifies the retrieved content. Use WSP
probes to detect failures in the Wireless Application Protocol (WAP) stack on port 9201.
probes to detect failures in the Wireless Application Protocol (WAP) stack on port 9201.
You can configure more than one probe, in any combination of supported types, for each server farm, or
for each firewall in a firewall farm.
for each firewall in a firewall farm.