Cisco Systems 78-11741-02 Wireless Office Headset User Manual


 
Configuring IP Addressing
Configuring Address Resolution Methods
IPC-26
Cisco IOS IP Configuration Guide
Suppressing Forward and Reverse Record Options
To dynamically detect link layer filtering in NBMA networks (for example, SMDS address screens), and
to provide loop detection and diagnostic capabilities, NHRP incorporates a Route Record in request and
reply packets. The Route Record options contain the network (and link layer) addresses of all
intermediate Next Hop Servers between source and destination (in the forward direction) and between
destination and source (in the reverse direction).
By default, Forward Record options and Reverse Record options are included in NHRP request and reply
packets. To suppress the use of these options, use the following command in interface configuration
mode:
Specifying the NHRP Responder Address
If an NHRP requester wants to know which Next Hop Server generates an NHRP reply packet, it can
request that information by including the responder address option in its NHRP request packet. The Next
Hop Server that generates the NHRP reply packet then complies by inserting its own IP address in the
NHRP reply. The Next Hop Server uses the primary IP address of the specified interface.
To specify which interface the Next Hop Server uses for the NHRP responder IP address, use the
following command in interface configuration mode:
If an NHRP reply packet being forwarded by a Next Hop Server contains the IP address of that server,
the Next Hop Server generates an error indication of type “NHRP Loop Detected” and discards the reply.
Changing the Time Period NBMA Addresses Are Advertised as Valid
You can change the length of time that NBMA addresses are advertised as valid in positive NHRP
responses. In this context, advertised means how long the Cisco IOS software tells other routers to keep
the addresses it is providing in NHRP responses. The default length of time is 7200 seconds (2 hours).
To change the length of time, use the following command in interface configuration mode:
Command Purpose
Router(config-if)# no ip nhrp record
Suppresses Forward and Reverse Record options.
Command Purpose
Router(config-if)# ip nhrp responder type number
Specifies which interface the Next Hop Server uses to determine
the NHRP responder address.
Command Purpose
Router(config-if)# ip nhrp holdtime seconds
Specifies the number of seconds that NBMA addresses are
advertised as valid in positive NHRP responses.