Configuring a Classical Internet Protocol Interface

Classical Internet Protocol (Classical IP), specified by RFC 1577, is one way of supporting the TCP/IP and UDP/IP protocols in an ATM environment. In Classical IP, an ATM ARP server is used to resolve IP addresses to ATM addresses, replacing the traditional ARP protocol. In this configuration, each host must register with the ARP server when the ATM interface is brought up. For more information on the Classical IP protocols, see "Classical Internet Protocol" on page 47.

ATM ARP is used instead of the traditional ARP because ATM does not support broadcast (a network capability providing transmission from one point to all points on a network). Because Classical IP over ATM does not support broadcast, you cannot use the ypbind UNIX command with the -broadcast option to automatically locate the NIS server (ypserver) on a Classical IP ATM subnet.

If you are planning to run NIS over your ATM network, use the ypinit -c command to specify the list of NIS servers (ypservers). See the ypinit(1M) man page for details of setting up the ypserver. Be sure that the IP addresses of the ypservers are listed in the /etc/hosts file.

The Routing Information Protocol (RIP) also uses the broadcast feature of IP, so it is not supported under the Classical IP environment. In the Solaris operating environment, RIP is implemented by the daemon in.routed.

If you are using Classical IP only, you must explicitly add the routes to the routers in the ATM subnet. You can also specify one router as the default router to provide connectivity outside of the ATM subnet. See the route(1M) man page for information on using the route command to add specific router entries and to add a default router.

Editing the /etc/opt/SUNWconn/atm/aarconfig File

The /etc/opt/SUNWconn/atm/aarconfig file contains the required configuration information for each interface that uses Classical IP. One entry is required for each SunATM interface. It allows you to specify IP to ATM address translation, permanent virtual circuits (PVCs) to destinations, and the address of the ATM ARP server. The environment allows for a mix of PVCs and switched virtual circuits (SVCs).

Each time the /etc/opt/SUNWconn/atm/aarconfig file is modified, run the ATM ARP setup program, aarsetup, which is in the /etc/opt/SUNWconn/bin directory.

Every node, or client, has both an IP address and either an ATM address or a virtual circuit identifier (VCI). See "ATM Address Resolution", for ATM addressing scheme information.

In the IP-ATM address table shown in the /etc/opt/SUNWconn/atm/aarconfig file:

• Interface is the last part of the device name (ba0, for example).

• Hostname is either an IP address in "dot" notation or the name of a host that should be locally available unless a non-ATM network connection also exists.

• ATM Address consists of 20 octets with each octet represented by a one- or two-digit hexadecimal number and separated by colons.

• The VCI field is a positive decimal integer.

• An unused field is denoted by a hyphen.

Table 3-3 lists the flags, including configuration flags, and the options they provide.

Table 3-3 /etc/opt/SUNWconn/atm/aarconfig File Flag Descriptions

Flag	Description
l	Represents the ATM address of the local interface on ARP clients or systems not using an ARP server for ATM address resolution, and can be used to assign an ATM address to the host. Hostname should not appear; ATM Address should be provided if, and only if, SVCs are used. If you provide an s entry to use an ARP server (see below), you must also provide an ATM Address (a server is meaningful only in an SVC environment). See Table 3-4.
L	Represents the ATM address of the local interface on an ARP server. Hostname should not appear; ATM Address is required. See Table 3-4.
s	Specifies a connection to the ATM ARP server. Either ATM Address or VCI (in the case of a PVC connection) should appear, but not both. Hostname should not appear. The s entry is required on all clients that need to communicate with the server for ATM address resolution. See Table 3-4.
t	Represents an IP to ATM address/VCI entry. aarsetup adds these entries into the local table. Any t entries on the server must contain ATM Address and may also contain VCI if PVC communication between the server and client is desired. In addition, there are some cases when a t entry may be useful on an ARP client system. If a client wants to communicate with another system over PVCs, the PVC to be used is provided in a t entry containing VCI; or if a client wishes to cache frequently used addresses to avoid frequent ARP requests, a t entry containing ATM Address may be provided. See Table 3-4.   Note: If your naming service (NIS+ or DNS) server is an ATM host, you must provide the hostname to IP address resolution for the hosts included in t entries, either by using the IP address in the Hostname field of the t entry, or by adding an entry to the local /etc/hosts file.
t6	Represents an IP to ATM address/VCI entry. aarsetup adds these entries to the address cache. Any VC indicates an IPv6 PVC. An ATM address indicates a statically configured IPv6 SVC. The t6 entry is the only way to configure destination hosts for communication over IPv6
a	Represents an address that may have access to this host. If no a entries appear in the aarconfig file, access to the host is unrestricted. Including a entries allows access to be restricted to known hosts. As an alternative to listing individual addresses, the ATM address field may contain a prefix, followed by the wildcard $anymacsel, which matches any 7-byte ESI/Selector combination following the given prefix. This allows access by any host connected to the switch that is specified by the given prefix. Hostname and VCI should not appear; ATM Address is required. See Table 3-4.
m	Notifies the system that the entire ATM address, including the network prefix, must be configured manually on this interface. If your interface is connected to a switch that does not support ILMI address registration, you must include this option in your /etc/opt/SUNWconn/atm/aarconfig file. Note that you may not use the variables $myaddress, $prefix, and $localswitch_server (which use the switch prefix obtained from the switch via ILMI) if ILMI address registration is disabled.

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Note -

Although SunATM supports PVC connections to a server for ARP traffic, RFC 1577 does not specify this case. For interoperability with other implementations, connections to the server should use SVCs.

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Note -

For two hosts to communicate over PVCs, corresponding PVC connections must also be established in the ATM switch fabric.

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Table 3-4 describes the required, optional, and illegal fields for each flag type. If a field is unused, it is represented by a hyphen.

Table 3-4 /etc/opt/SUNWconn/atm/aarconfig File Flag Requirements and Options

Interface *	Host	ATM Address	VCI	Flags	*
required	illegal	SVC only	illegal	l	local information
required	illegal	required	illegal	L	local information on server
required	illegal	required	illegal	a	access list entry
required	required	or*	or*	t	permanent table entry
required	required	xor**	xor**	t6	IPv6 table entries PVC & SVC
required	illegal	xor**	xor**	s	server address/PVC
required	illegal	illegal	illegal	m	manual address registration
*or - Means one or the other required, but using both is also legal. **xor - Means one or the other required, but using both is illegal.

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Note -

Group entries in the aarconfig file in a designated order: the local (l or L) entry first, followed by any other flags in any order. You only need to maintain the ordering within entries for each physical interface; for example, all of the ba0 entries can appear first, and then all of the ba1 entries, etc.

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