Allied Telesis AT-S63 - Manual (Page 330)

Chapter 27: Internet Protocol Version 4 Packet Routing
330 Section VII: Routing
Upgrading from AT-S63 Version 1.3.0 or Earlier
When the AT-9400 Switch running AT-S63 version 1.3.0 or earlier is
upgraded to the latest version of the management software, the switch
automatically creates a routing interface that preserves the previous IP
configuration of the unit. If the switch had a static address, the interface is
assigned the same address. If the address was supplied by a DHCP or
BOOTP server, the DHCP or BOOTP client on the interface is activated.
The interface is given the interface number 0 and assigned to the
preexisting management VLAN. Furthermore, the interface is designated
as the local interface of the switch.
For example, a switch with the static IP address 149.55.55.55, subnet
mask 255.2552.255.0, and a management VLAN with a VID of 12 will
have, after the upgrade, a routing interface with the name VLAN12-0 and
the same static IP address and subnet mask.
By retaining the IP configuration, those management functions (e.g.,
remote Telnet management, syslog client, and RADIUS client) that were
operating before the upgrade will continue to operate after the unit is
upgraded to the newest version of the management software. Without this
feature, you would have to restore the switch’s IP configuration by
manually creating a routing interface.
If the switch does not have an IP address and the DHCP and BOOTP
clients are not activated, the upgrade process does not create a routing
interface.