Overview

Point-to-Point Protocol (PPP) provides connectivity between individual hosts used at remote location, including homes and small offices, to ISPs’ networks. It is also making an entry into the wireless domain where the connectivity between devices and service providers is mostly through a point-to-point connection. The key function of the HP-UX PPPv6 software is to handle IPv6 datagrams in addition to IPv4 datagrams, and provide all the required connectivity to end-users from a remote network.

Transport Optional Upgrade Release (TOUR) 1.0 includes IPv6 support for PPP. The TOUR software is available as a web release on http://www.software.hp.com.

The following lists the key features of PPPv6:

Conformance to RFC 2472
Changes to pppd

Conformance to RFC 2472

PPP now conforms to RFC 2472 - IPv6 over PPP. This RFC defines how to transmit IPv6 packets over PPP links as well as the Network Control Protocol (NCP) for establishing and configuring IPv6 over PPP. It also describes how to form IPv6 link-local addresses on PPP links and to negotiate the type compression protocol to be used for compressing or decompressing IPv6 headers transmitted over serial lines.

New pppd Changes

The pppd daemon shipped with HP-UX 11.0 core operating system and later, works with both PPPv4 and PPPv6. The daemon transmits IPv4 as well as IPv6 datagrams over PPP links.

The following lists the changes to pppd:

Two dedicated interfaces for IPv4 and IPv6. Number of pppd instances increased to 128 from 64. pppd startup for IPv6 through an automated script, namely, /etc/ppp/Autostart.ex. Dial-in configuration through a login script, namely, /etc/ppp/Login.ex. Support for filtering IPv4 packets with an IPv6 datagram.

New Command-Line Options

Table 5-1 “New Command-Line Options” lists the new command-line options added to the existing /usr/bin/pppd daemon.

Table 5-1 New Command-Line Options

	Option	Description
	`exec6 exec-cmd`	Pass a script as an argument to this option. When the IPv6 interface comes up, it invokes the `rtradvd` daemon.
	`router6`	Specify this option for clearing, the private flag, on the IPv6 interface being configured by `pppd`. This option clears the private flag on the interface where router advertisement messages will be sent.
Daemon Management Options	`noipv4`	Specify this option to disable IPCP (NCP for IPv4 over PPP) negotiation. No IPv4 datagram will pass through the link. You need to specify this option to establish a point-to-point link for IPv6 packets, that is, to negotiate only IPV6CP messages. Note: To look up the systems file, you must specify the IPv4 destination address, even if you wish to configure only IPv6 datagrams by choosing the `ipv6` and `noipv4` options on the command line.
	`noipv6`	Specify this option to disable IPV6CP negotiation. No IPv6 datagram will pass through the link. Use this option when you do not want to negotiate IPV6CP messages sent by a peer `pppd`.
	`ipv6 local-fid`, `remote-ifid`	Specify two 64-bit interface identifiers separated by a comma, the interface identifier of the local machine, and the expected interface identifier of the remote machine. Both the interface identifiers are optional. However, you need to specify the remote interface identifier, if the auto option is specified.
IP Options	`need-ip6-ifid`	Specify this option to obtain a 64-bit IPv6 interface identifier assigned by the peer for local use.
IP Options	`rfc2472-ifid-neg`	Specify this option if you do not want to send NAK to an option for which you have already sent a NAK while processing the previous IPV6CP configuration options.




	NOTE: All the existing IPv4 options work with IPv6 as well. IPv4 VJ compression and decompression options do not work with IPv6. For information on configuring and using PPP, see Installing and Administering PPP, available at http://www.docs.hp.com/hpux/netcom/index.html/#HP-UX%20LAN.

Neighbor Discovery for IPv6

rtradvd, the router advertisement daemon for IPv6, implements router functionality as specified in RFC 2461- Neighbor Discovery for IP Version 6. The daemon listens to router solicitation and sends router advertisement messages on demand and periodically, as described in the RFC. These advertisements allow any listening host to configure their addresses and some other parameters automatically without manual intervention. They can also choose a default router based on these advertisements.For more information, see “Enabling rtradvd” section in HP-UX IPv6 Transport Administrator’s Guide for TOUR 1.0, available on http://www.docs.hp.com/hpux/netcom/index.html.

Using PPPv6

After you install the TOUR 1.0 software package, you need to complete the following steps to obtain an IP address using the stateless or stateful autoconfiguration method:

If you are an rtradvd user, modify the sample script, /etc/ppp/Exec6.rtradvd.ex, according to your configuration requirements for obtaining a global address.
Run pppd on the command line with the exec6 option as follows:
/usr/bin/pppd exec6 <name and path of the script>
where <name and path of the script> is /etc/ppp/Exec6.rtradvd.ex or a script of your choice.
pppd executes this script, which invokes the IPv6 autoconfiguration daemons that assign an address to a PPP end-point. For more information on the rtradvd options specified in the sample script, type man 4 rtradvd.conf or type man 1m rtradvd at the HP-UX command prompt.