Filter
Top Products
Configuring IP Addressing
Configuring Address Resolution Methods
IPC-21
Cisco IOS IP Configuration Guide
Enabling NHRP on an Interface
To enable NHRP for an interface on a router, use the following command in interface configuration
mode. In general, all NHRP stations within a logical NBMA network must be configured with the same
network identifier.
See the “Logical NBMA Example” section and the “NHRP over ATM Example” section at the end of
this chapter for examples of enabling NHRP.
Configuring a Static IP-to-NBMA Address Mapping for a Station
To participate in NHRP, a station connected to an NBMA network should be configured with the IP and
NBMA addresses of its Next Hop Servers. The format of the NBMA address depends on the medium
you are using. For example, ATM uses an NSAP address, Ethernet uses a MAC address, and SMDS uses
an E.164 address.
These Next Hop Servers may also be the default or peer routers of the station, so their addresses can be
obtained from the network layer forwarding table of the station.
If the station is attached to several link layer networks (including logical NBMA networks), the station
should also be configured to receive routing information from its Next Hop Servers and peer routers so
that it can determine which IP networks are reachable through which link layer networks.
To configure static IP-to-NBMA address mapping on a station (host or router), use the following
command in interface configuration mode:
Statically Configuring a Next Hop Server
A Next Hop Server normally uses the network layer forwarding table to determine where to forward
NHRP packets, and to find the egress point from an NBMA network. A Next Hop Server may alternately
be statically configured with a set of IP address prefixes that correspond to the IP addresses of the
stations it serves, and their logical NBMA network identifiers.
To statically configure a Next Hop Server, use the following command in interface configuration mode:
To configure multiple networks that the Next Hop Server serves, repeat the ip nhrp nhs command with
the same Next Hop Server address, but different IP network addresses. To configure additional Next Hop
Servers, repeat the ip nhrp nhs command.
Command Purpose
Router(config-if)# ip nhrp network-id number
Enables NHRP on an interface.
Command Purpose
Router(config-if)# ip nhrp map ip-address
nbma-address
Configures static IP-to-NBMA address mapping.
Command Purpose
Router(config-if)# ip nhrp nhs nhs-address
[net-address [netmask]]
Statically configures a Next Hop Server.