User's Manual

704 CHAPTER 17: USING 3COM NETWORK DIRECTOR ON A MULTI-SITE NETWORK
Issues and Techniques when Configuring the Retry/Timeout
Hierarchy
When configuring the Retry/Timeout hierarchy in a multi-site network
there are various issues to look out for, and techniques that may be
employed to address them:
■ Before starting to configure the retry/timeout hierarchy, it is important
to correctly identify the local and remote sites with regards to the PC
that 3Com Network Director is running on. Where possible, each site
should be identified by the IP subnets that are unique to that site.
■ If your network is configured such that the IP addresses within a
subnet are allocated to different sites and the numbers of retries and
timeout periods that you have determined for these sites differ then
you will be unable to override the whole map settings at the subnet
level such that you satisfy the requirements of the different sites. For
example, you may have allocated an IP range from within a particular
subnet for use by dial-in users, while the remainder of the subnet is in
use by the local site.
■ In order to cope with this situation you will need to first determine
one site to treat as the home of the subnet. In the example given
above, this would likely be the local site. The numbers of retries and
timeout periods for the subnet should be configured appropriate for
the site that you select as the home of the subnet. Having done this
you will then need to override the subnet settings for each device that
is on that subnet, but that is not located at the local site.
It is only really necessary to override the subnet settings for a device
where the device is not located at the home site of the subnet if you
intend to monitor or manage that device. In the example given above
you may decide that, as they will likely be user’s PCs, you will not monitor
or manage any of the discovered dial-in devices on the subnet, in which
case it would not be necessary to override the subnet settings for those
devices.
Routers and layer-3 switches inherit their settings from the whole map
settings, not from the subnets that they are members of. As a result, in
order to configure the correct settings for all devices at a site you will
need to apply the settings not only to each subnet that covers that site,
but also to each router and layer-3 switch that is located at that site.
If you have determined that the appropriate numbers of retries and
timeout periods for a large number of remote sites are identical then it