Key Considerations 751values. See “Determining Appropriate Retry and Timeout Periods” onpage 701 for details of how to do determine appropriate values.If you have already determined what appear to be appropriate values forthe remote site then the problem may be caused by the amount of trafficgenerated by the discovery process itself. If that is the case then you mayeither try increasing the values further still to allow for the overhead ofthe discovery process, or try focusing the discovery on those devices thatare most important for you to monitor and manage. Details of the latterapproach are given in “Configuring Discovery” on page 710.If you try increasing the numbers of retries and timeout periods to allowof the overhead of the discovery process then be aware that this willincrease the time it takes 3Com Network Director to determine that adevice at that site has stopped responding when it is monitoring ormanaging that device.See “Determining Appropriate Retry and Timeout Periods” on page 701for more information on the issues that this causes.Problems withDiscovering WANRoutersDepending upon your network configuration you may find thatdiscovering a subnet that a WAN router has an IP address on fails todiscover the WAN router, does not determine the features andconfiguration of the WAN router, or only shows the WAN router as aMAC-only device in the map. There are various reasons why this mayoccur:■ If the WAN router is owned and managed by your service providerthen 3Com Network Director will be unlikely to be able to discoverthem at all. While the onus for the management of the WAN router ison your service provider in such a network configuration, note thatthis will prevent you from being able to monitor the utilization of yourWAN links from within 3Com Network Director.■ The WAN router may have had its SNMP community strings changedfrom the factory defaults. 3Com recommends that you change theSNMP community strings from their factory defaults on allSNMP-capable devices in your network, as this will increase thesecurity of your network infrastructure. If you have changed the SNMPcommunity strings of your WAN router then you should enter the newvalues in the Community Strings step of the Network Discoverywizard. See “Community Strings Pane” on page 118 for more details.
