D-Link DFL-260 Product Manual - Page 155

Specifying Hosts, Grace Period, Minimum Number of Hosts, Available, Method, IP Address, Port Number

Page 155 highlights

4.2.4. Host Monitoring for Route Failover Chapter 4. Routing As part of Route Properties Host Monitoring can be enabled and a single route can have multiple hosts associated with it for monitoring. Multiple hosts can provide a higher certainty that any network problem resides in the local network rather than because one remote host itself is down. In association with Host Monitoring there are two numerical parameters for a route: Grace Period Minimum Number of Hosts Available This is the period of time after startup or after reconfiguration of the NetDefend Firewall which NetDefendOS will wait before starting Route Monitoring. This waiting period allows time for all network links to initialize once the firewall comes online. This is the minimum number of hosts that must be considered to be accessible before the route is deemed to have failed. The criteria for host accessibility are described below. Specifying Hosts For each host specified for host monitoring there are a number of property parameters that should be set: • Method The method by which the host is to be polled. This can be one of: • ICMP - ICMP "Ping" polling. An IP address must be specified for this. • TCP - A TCP connection is established to and then disconnected from the host. An IP address must be specified for this. • HTTP - A normal HTTP server request using a URL. A URL must be specified for this as well as a text string which is the beginning (or complete) text of a valid response. If no text is specified, any response from the server will be valid. • IP Address The IP address of the host when using the ICMP or TCP option. • Port Number The port number for polling when using the TCP option. • Interval The interval in milliseconds between polling attempts. The default setting is 10,000 and the minimum value allowed is 100 ms. • Sample The number of polling attempts used as a sample size for calculating the Percentage Loss and the Average Latency. This value cannot be less than 1. • Maximum Failed Poll Attempts The maximum permissible number of polling attempts that fail. If this number is exceeded then the host is considered unreachable. • Max Average Latency The maximum number of milliseconds allowable between a poll request and the response. If this threshold is exceeded then the host is considered unreachable. Average Latency is calculated by averaging the response times from the host. If a polling attempt receives no response then it is not included in the averaging calculation. 155

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As part of
Route Properties
Host Monitoring can be enabled and a single route can have multiple
hosts associated with it for monitoring. Multiple hosts can provide a higher certainty that any
network problem resides in the local network rather than because one remote host itself is down.
In association with Host Monitoring there are two numerical parameters for a route:
Grace Period
This is the period of time after startup or after reconfiguration
of the NetDefend Firewall which NetDefendOS will wait
before starting Route Monitoring. This waiting period allows
time for all network links to initialize once the firewall comes
online.
Minimum Number of Hosts
Available
This is the minimum number of hosts that must be considered
to be accessible before the route is deemed to have failed. The
criteria for host accessibility are described below.
Specifying Hosts
For each host specified for host monitoring there are a number of property parameters that should be
set:
Method
The method by which the host is to be polled. This can be one of:
ICMP
- ICMP "Ping" polling. An IP address must be specified for this.
TCP
- A TCP connection is established to and then disconnected from the host. An IP
address must be specified for this.
HTTP
- A normal HTTP server request using a URL. A URL must be specified for this as
well as a text string which is the beginning (or complete) text of a valid response. If no text
is specified, any response from the server will be valid.
IP Address
The IP address of the host when using the
ICMP
or
TCP
option.
Port Number
The port number for polling when using the
TCP
option.
Interval
The interval in milliseconds between polling attempts. The default setting is 10,000 and the
minimum value allowed is 100 ms.
Sample
The number of polling attempts used as a sample size for calculating the
Percentage Loss
and
the
Average Latency
. This value cannot be less than 1.
Maximum Failed Poll Attempts
The maximum permissible number of polling attempts that fail. If this number is exceeded then
the host is considered unreachable.
Max Average Latency
The maximum number of milliseconds allowable between a poll request and the response. If this
threshold is exceeded then the host is considered unreachable. Average Latency is calculated by
averaging the response times from the host. If a polling attempt receives no response then it is
not included in the averaging calculation.
4.2.4. Host Monitoring for Route
Failover
Chapter 4. Routing
155