Cisco Systems 78-11741-02 Configuring HP Probe Proxy Name Requests, Cisco Implementation of Nhrp

Configuring IP Addressing

Configuring Address Resolution Methods

Configuring HP Probe Proxy Name Requests

HP Probe Proxy support allows the Cisco IOS software to respond to HP Probe Proxy name requests. These requests are typically used at sites that have HP equipment and are already using HP Probe Proxy. Tasks associated with HP Probe Proxy are shown in the following two tables.

To configure HP Probe Proxy, use the following command in interface configuration mode:

Command	Purpose
Router(config-if)# ip probe proxy	Allows the Cisco IOS software to respond to HP Probe Proxy name
	requests.

To configure HP Probe Proxy, use the following command in global configuration mode:

Command	Purpose
Router(config)# ip hp-hosthostname ip-address	Enters the host name of an HP host (for which the router is acting as
	a proxy) into the host table.

See the “HP Hosts on a Network Segment Example” section at the end of this chapter for an example of configuring HP hosts on a network segment.

Configuring the Next Hop Resolution Protocol

Routers, access servers, and hosts can use Next Hop Resolution Protocol (NHRP) to discover the addresses of other routers and hosts connected to a nonbroadcast multiaccess (NBMA) network. Partially meshed NBMA networks are typically configured with multiple logical networks to provide full network layer connectivity. In such configurations, packets might make several hops over the NBMA network before arriving at the exit router (the router nearest the destination network). In addition, such NBMA networks (whether partially or fully meshed) typically require tedious static configurations. These static configurations provide the mapping between network layer addresses (such as IP) and NBMA addresses (such as E.164 addresses for SMDS).

NHRP provides an ARP-like solution that alleviates these NBMA network problems. With NHRP, systems attached to an NBMA network dynamically learn the NBMA address of the other systems that are part of that network, allowing these systems to directly communicate without requiring traffic to use an intermediate hop.

The NBMA network is considered nonbroadcast either because it technically does not support broadcasting (for example, an X.25 network) or because broadcasting is too expensive (for example, an SMDS broadcast group that would otherwise be too large).

The Cisco Implementation of NHRP

The Cisco implementation of NHRP supports the IETF draft version 11 of NBMA Next Hop Resolution Protocol (NHRP).

The Cisco implementation of NHRP supports IP Version 4, Internet Packet Exchange (IPX) network layers, and, at the link layer, ATM, Ethernet, SMDS, and multipoint tunnel networks. Although NHRP is available on Ethernet, NHRP need not be implemented over Ethernet media because Ethernet is capable of broadcasting. Ethernet support is unnecessary (and not provided) for IPX.

Cisco IOS IP Configuration Guide

IPC-18