HP-UX Mobile IPv4 A.03.01 Administrator's Guide

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Chapter 10
197
tunnels
The tunnels option queries mipd or miprod and displays information about Mobile IPv4
tunnel interfaces.
Syntax
t[unnels] [-v]
Parameters
-v Verbose option.
Description
The Mobile IPv4 tunnel interfaces are virtual interfaces that Mobile IPv4 uses when it
needs to encapsulate (or tunnel) an IP packet in a second IP packet with a different IP
source or destination address. HP-UX Mobile IPv4 creates the following tunnels:
• On the Home Agent: a tunnel to the Mobile Node’s Care-of Address.
• On the Foreign Agent: a tunnel to the Home Agent.
• On the Correspondent Node, if you are using Route Optimization: a tunnel to the
Mobile Node’s Care-of Address.
The mipadmin utility displays the following information about each Mobile IPv4 tunnel
interface:
• Tunnel Name: name of the tunnel interface, in the form v4tu0:n, where n is the
index number.
• Local Address: the IP address of the tunnel endpoint on the local system.
• Tunnel End Point: the IP address of the tunnel endpoint on the remote system. If
this is a Home Agent or Correspondent Node, this will be the Mobile Node’s Care-of
Address. If this is a Foreign Agent, this will be the Home Agent’s address.
• Mobile Node: the IP address of the Mobile Node using this tunnel (this will be the
source or destination IP address of the inner IP packet).
• Encapsulation: type of encapsulation used for the tunnel. HP-UX Mobile IPv4
supports only IP-in-IP encapsulation.
• Status: Possible values are Ok, Unreachable and Hop limit. Unreachable or Hop
limit indicates that the system recently received an ICMP message (Host or
Network unreachable, or Time Exceeded) for the tunnel endpoint. These conditions
are considered transitory; HP-UX Mobile IPv4 will continue to try to use the tunnel
and will reset the status to Ok after a period of time.
If you specify the -v option, mipadmin also displays the following information:
• TTL: Initial Time to Live (TTL) value for the tunnel’s IP packets. This field is always
0, and the packet will be sent with the system’s default IP TTL value (255 by
default). You can use the ndd utility to view or set the system’s default IP TTL value
(ip_def_ttl parameter for the /dev/ip device). (For more information on ndd, refer
to the ndd(1M) man page.)
• PMTU: Path Maximum Transmission Unit, the smallest MTU of any link that the
packets traverse for the tunnel (in bytes).