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IBM SC30-3865-04 User Manual

Page 387

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Selecting the

destination only option causes the router to deny shortcut requests

from any NHRP client if any IP packets are being filtered to the destination address.
If NHRP clients should not be trusted,

destination only should be selected.

destination only might be the best option when NHRP clients are non-routers with
multiple IP addresses or non-router clients that transmit packet that originate from
other sources.

NHRP clients that reside in the routers use the NHRP shortcut routes to forward
packets from other sources: therefore, if

source and destination is configured and

the router receives a shortcut request from a router, the router applies the IP filters
the same way as when

destination only is selected.

NHRP Access Controls

NHRP access controls for denying shortcuts to certain IP addresses may be defined
by adding those addresses to both the exclude list and disallowed-router-to-router
shortcuts.

ATM Network ID

Since an server may have more than one ATM adapter, it may be connected to two
different or unassociated networks. This must be considered when deciding when
shortcut VCs should be allowed.

You can determine which interfaces should be treated as if they are connected to
the same physical ATM network by assigning each ATM interface a Network-ID by
using the set command at the

ATM Interface Config>

prompt as described in the

“Using and Configuring ATM” chapter in

Software User’s Guide

ATM interfaces with the same Network-ID are considered to belong to the same
network. By default, all ATM interfaces are assigned to Network-ID 0.

Configuring the LANE Shortcuts Interface (LSI)

The NHRP LANE Shortcut Interface (LSI) is automatically created for each ATM
adapter when NHRP is enabled for the router. The LSI uses default values for the
following parameters.

v

ESI

v

Selector

v

Use Best Effort Service for Data VCCs

v

Peak Cell Rate of outbound Data VCCs

v

Sustained Cell Rate of outbound VCCs

v

Use ATM adapter’s universally administered MAC address for source

The default values may be modified using the change command from the

NHRP

Advanced config>

prompt. See “Change” on page 363.

Configuring Devices in an ATM Network

If you have a NHRP client/server and its configuration requires you to give the ATM
address of the router NHRP server, you must select the proper ATM address. You
must use an address associated with an

ATM interface

in the device, and an IP

address must be assigned to this interface. The last two digits of the router ATM

Using NHRP

Chapter 11. Using NHRP

357