Each attachment to an FDDI network is identified by a unique 48-bit MAC address. By default, the first SunFDDI card takes the host-resident MAC address, which is stored in nonvolatile memory (NVRAM) on the motherboard of the machine. Each subsequent SunFDDI card adopts the card-resident MAC address stored in its own IDPROM.
In general, this convention is sufficient to ensure that each SunFDDI card installed in the machine has a unique MAC address. However, there may be a conflict with other LAN interfaces that also take the host-resident MAC address--for example, an Ethernet (le) interface or a SunFDDI 2.0 (bf) interface. In this event, change the default MAC address assigned to the first SunFDDI card installed in the system.
Use the pf_macid(1M) or the nf_macid(1M) utility to recover the card-resident MAC address, and then modify the system files to override the default MAC address:
# <basedir>/nf_macid nf<inst> <mac_address>
Modify the start-up file on your machine so that the MAC address is assigned correctly when the system is rebooted.
Edit the /etc/rcS.d/S30rootusr.sh file to add the following if statement immediately after the ifconfig command that initializes the interface nf<inst>.
ifconfig $1 plumb if [ $1 = "nf<inst>" ]; then ifconfig nf<inst> ether <mac_address> fi
On most systems, the /etc/rcS.d/S30rootusr.sh file is a hard link to the /etc/rootusr file.
Reboot your machine to assign the new MAC address to the SunFDDI interface.
When a SunFDDI card takes the host-resident MAC address, it can be swapped to another system without affecting the existing network. However, once a station starts sending packets on the network, the Address Resolution Protocol (ARP) updates the ARP tables on other stations to include the MAC address of its interface. The ES-IS protocol performs the same function for SunFDDI OSI running over FDDI. If you swap SunFDDI cards that use the card-resident MAC address, you must wait until the ARP entries time-out, or remove the ARP entries from every active station manually before packets can be routed correctly.