CISCO-SLB-HEALTH-MON-MIB

An extension to the CISCO-SLB-EXT-MIB for SLB health monitoring probes. SLB: Server Load Balancing. Server load balancing provides for the balancing of packets and connections arriving at the SLB device across a number of other devices, such as real servers, firewalls, or caches. A system containing an SLB device typically exhibits higher performance, scalability, and reliability than any of the devices being load balanced. An SLB device determines how to handle incoming frames and connections according to the contents of incoming data and various configuration options. In determining how to handle incoming data, an SLB device may examine the data at any OSI layer, including Layer 7. This MIB includes information on the health monitoring probes that can be used for monitoring the health of real servers. Health checking provides the ability of the content switch to detect if a server is available for load balancing. Health probes used for health checking allow testing various application level functionality. The active probes are sent at regular intervals and the lack of a response can lead to a specific server or and entire group of servers being declared as not available. Following probes are based on TCP: http, https, smtp, telnet, ftp, tcp, script, ldap, tacacs, sip, echo, finger. Following probes are based on UDP: tftp, udp, sip, echo,. Acronyms and terms: SLB Server Load Balancing VIP Virtual Server IP address NAT Network Address Translation SF Serverfarm FT Fault Tolerance SSL Secure Sockets Layer TLS Transport Layer Security Server Farm : Contains cluster of Real Server Real Server : Real Servers are physical devices assigned to a server farm. Real servers provide services that are load balanced. Health Probe : The mechanisms to monitor the health of real servers or rservers. Virtual IP : The IP through which the real server is reached during load balancing. Probe Instance : An instance of the probe identified by cslbxProbeName. A probe instance is created for every probe association. For example: When a probe is associated with a real server a probe instance is created for that probe. Probe Port : This mechanism introduces the capability Inheritance for the probe instance to inherit the virtual ip address port or the the real server port (identified by cshMonServerfarmRealServerPort) when the probe port (identified by cslbxProbePort) is not configured. The precedence of inheritance is as follows 1. Probe's configured port 2. Real server port 3. Virtual ip address port 4. Probes default port identified by cslbxProbePort. Examples: Scenario 1: Probe's configured port = 100 Real server port = 200 Virtual ip address port = 300 Probe's default port = 80 Inherited port of the probe instance = 100 Scenario 2: Probe's configured port = not configured Real server port = 200 Virtual ip address port = 300 Probe's default port = 80 Inherited port of the probe instance = 200 Scenario 3: Probe's configured port = not configured Real server port = not configured Virtual ip address port = 300 Probe's default port = 80 Inherited port of the probe instance = 300 Scenario 4: Probe's configured port = not configured Real server port = not configured Virtual ip address port = not configured Probe's default port = 80 Inherited port of the probe instance = 80 Scenario 5: There can be scenarios wherein there may be multiple inherited ports for a probe instance. There are configurations where multiple virtual ip addresses with different ports share the same probe instance and the probe has no configured port or real server port attached. In that case the shared probe instance has multiple inherited ports. A typical scenario might be Probe's configured port = not configured Real server port = not configured Ports of the virtual ip addresses which shares the probe instance = 300,400 Probe's default port = 80 Inherited port of the probe instance = 300,400