Sun Microsystems 3U manual Wild card matching one or two hexadecimal digits within

TABLE 5-4Predefined SunATM Variables (Continued)

Variable	Description
?	A wild card matching one or two hexadecimal digits within
	any colon-separated field. For example, $prefix:$anymac:?
	is equivalent to both $prefix:$anymac:?? and
	$prefix:$anymacsel. However, it is not the same as
	$prefix:$anymacsel:0?, which requires that the first digit
	of the selector byte is a 0. This wild card should only be used in
	a entries.
sunmacselN	The concatenation of one of a series of reserved MAC addresses
	and $sel to create a block of reserved ATM ARP server
	addresses. N should be a decimal number in the range 0–199.
localswitch_server	The concatenation of $prefix, a unique reserved MAC
	address, and $sel. When used as a server address, restricts
	server access to clients connected to the local switch only.

In most network configurations, the ATM address assigned to the local interface is $myaddress; using this variable in the l entry makes it possible to use identical aarconfig files on all Classical IP clients using a given server.

The sunmacselN variables can be used in conjunction with a prefix, as well as with known server addresses that are not bound to a particular system. As an example, consider the case where a server that supports 50 clients fails. If the ATM address of the server is specific to that particular server, you must change the s entry on all 50 clients to switch to a backup server. However, if the ATM address used for that server is $prefix:$sunmacsel3, this address is not only guaranteed to be unique, since it uses reserved medium access control (MAC) addresses. You can also simply assign that address to the backup server on the same switch by changing the l entry to an s entry on one system and bringing up a new server with no changes to the clients.

Note –The sunmacselN variables do not include a prefix since a client and server may be on different switches and thus have different local prefix values.

In the case of a single-switch network, you can use localswitch_server as a well-known server address that includes the prefix associated with the local switch and a MAC address. It will restrict server access to clients on the local switch and provide a unique ATM address among all ATM clients connected to that switch. Thus, any host with a network prefix other than that of the local switch will be refused a connection to the ARP server if the ARP server's address is $localswitch_server.

Chapter 5 Editing SunATM Configuration Files 49