Words and Phrases
Choose techniques to launch discovery
Two techniques are available for launching Spiral Discovery:
- Provide a Discovery Seed to identify each Node you want NNMi to Discover.
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Auto-Discovery (in Default Tenant only): Configure either Discovery Seeds or Ping Sweep (ICMP ping), or both as starting points for Auto-Discovery. NNMi requests information about all known neighboring devices and then discovers the neighboring devices within the Default Tenant's address range.
Ping Sweep works only with IPv4 addresses. In Wide Area Networks (WANs) such as ATM, Frame Relay, and Point-to-Point (where ARP cache is not available), the Ping Sweep locates nodes for Auto-Discovery to use when gathering neighbor information and evaluating IPv4 subnet connection rules.
NNMi discovers any devices that comply with your Auto-Discovery Rule configurations and creates a record of each device in the NNMi database. If the device supports SNMP, all addresses for that device are combined into one Node object. If the device does not support SNMP, NNMi queries DNS to determines the hostname. If this hostname matches another non-SNMP node, NNMi merges the information to create only one node with multiple associated addresses.
Two additional methods are possible for launching Discovery:
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NNMi administrators can initiate Discovery for a particular Node using the Actions > Polling > Configuration Poll menu item.
You can also right-click any object in a table or map view to access the items available within the Actions menu.Each time you select Actions > Polling > Configuration Poll, NNMi also applies any Custom Poller Policy to the nodes in its specified Node Group. This determines which instances should be polled.
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Auto-Discovery also uses the source IP address from SNMP traps as Discovery Hints for new addresses. If your Auto-Discovery Rules' IP Ranges include that new IP address, NNMi uses the Trap Hint for initial discovery of that address. NNMi then requests the Node's current Management Address (the address from which the node's SNMP Agent responds) and uses that IP address for all further communication. NNMi calculates whether the new address belongs to a previously discovered Node or a new Node.
Discovery seeds for auto-discovery in default tenant
Discovery seeds are optional for the Nodes in the Default Tenant, but required for each Node assigned to any other Tenant.
Caution If your network uses any of the following IPv4 translation protocols, you must create a unique Tenant (other than Default Tenant) for each domain of nodes with addresses determined by the following protocols:
- Static Network Address Translation (NAT)
- Dynamic Network Address Translation (NAT)
- Dynamic Port Address Translation (PAT/NAPT)
A discovery seed is a specific node that you want NNMi to discover. For example, a discovery seed might be a core router in your management environment.
Each discovery seed is identified by hostname (not case-sensitive) or IP address, and Initial Discovery Tenant assignment. When you add a discovery seed, NNMi immediately tries to discover that device (without waiting until the next regularly scheduled discovery interval). If discovery is not successful, NNMi tries again 10 minutes later, and continues trying. The time between each attempt is doubled until the time reaches 1 week or equals your current discovery interval.
NNMi discovers seed addresses regardless of how you configure Auto-Discovery Rule definitions or the Excluded IP Addresses filter.
Nodes configured as discovery seeds are always discovered and added to the topology database. If you change your mind and delete a discovery seed configuration, the node is not automatically deleted from the topology database.
If you configure one or more Auto-Discovery Rules, note the following:
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If Discover Matching Nodes
is enabled for an Auto-Discovery Rule, NNMi uses each discovery seed as a starting point to gather information about neighboring devices to expand discovery.You can use the Ping Sweep option in your Auto-Discovery Rules in addition to or instead of Discovery Seeds.
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If Discover Matching Nodes
is disabled for an Auto-Discovery Rule, no devices matching that rule's criteria are discovered and added to the topology database unless:-
The device's address is a discovery seed.
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The device's address is reported as a neighbor to another discovered address.
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Ping sweep for auto-discovery in default tenant
Default Tenant only: You have two choices for Auto-Discovery starting points. Use either or both to best advantage for Nodes configured for the Default Tenant in your network environment:
- Discovery Seeds
You designate specific hostnames (not case-sensitive) or IP addresses where Auto-Discovery starts gathering neighbor information. -
Ping Sweep
NNMi issues ICMP pings to certain addresses gathered from neighbor information.Note Ping Sweep works only with IPv4 addresses and only in 16-bit subnets. All nodes discovered using Auto-Discovery are assigned to the Default Tenant.
Ping Sweep sends ICMP ping commands to IP addresses in the ranges defined in your Auto-Discovery rules. Ping Sweep enforces the following limits to the ICMP pings:
- For each specific IP address range, NNMi issues pings across a maximum of the last two octets in the IPv4 address range. This is equivalent to a /16 subnet
- ICMP pings are limited to 500 at one time. This avoids flooding your network or causing spam detection tools to set off an alarm.
Ping Sweep is useful in wide area networks such as ATM, Frame Relay, and Point-to-Point that do not contain an Address Resolution Protocol (ARP) cache.
Use these guidelines if any of the following are true:
- You want NNMi to discover only what you specify.
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Your network includes nodes with addresses provided by any of the following protocols:
- Static Network Address Translation (NAT)
- Dynamic Network Address Translation (NAT)
- Dynamic Port Address Translation (PAT/NAPT)
- You want to control which Nodes each NNMi user sees.
After you set your configuration according to these guidelines, when a new device is added to your network, NNMi does not discover that device unless you configure another discovery seed to identify that device.
| Task | How |
|---|---|
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Do not include any Auto-Discovery Rules. Auto-Discovery Rules can only be used to find devices assigned to the Default Tenant. |
None are required for this strategy. |
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NNMi provides one Default Tenant. If you do not define any additional Tenants, all nodes belong to the Default Tenant and all NNMi users can see all Nodes within the Default Tenant. Configure a Tenant for each subset of devices you want to identify within your network environment for network segmentation or security purposes. NNMi users can then be assigned to the appropriate Tenant. Caution If your network uses any of the following address translation protocols, you must create a unique Tenant (other than Default Tenant) for each domain of nodes with addresses determined by the following protocols:
Each member node must be identified with a discovery Seed configuration (see next row in this table). All members of a Router Redundancy Group must be assigned to the same Tenant (visible in the Node form's Basic Attributes and in the Tenants column of the Inventory > Nodes view). The NNMi administrator configures the Tenants. |
Configure tenants. |
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In Discovery Configuration's Seeds view, for each device you want NNMi to discover:
Then configure NNMi to monitor your SNMP devices. |
Specify discovery seeds: Designate which devices to be discovered |
You control how often Spiral Discovery checks the discovered nodes based on a Rediscovery Interval setting.