Cabletron Systems STS16-20R - Manual (Page 110)

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SmartStack STS16-20D/STS16-20R Token Ring Switches Installation and User Guide Switch Configuration
BootP Requests and Parameters
When using BootP to determine its IP address, the SmartStack STS16-20D/STS16-
20R repeats BootP requests at regular intervals, beginning at one second each and
eventually decreasing to every five minutes over time until it receives a valid reply.
If the IP display for the VLAN is accessed from the console (or via Telnet from
another VLAN) during that time, the SmartStack STS16-20D/STS16-20R may
cease using BootP if the parameters are set (on menu exit) in such a way that BootP
would no longer be necessary - for instance, if the IP state is switched from BootP
Always
to IP-Disabled or if an IP address different from 0.0.0.0 or 192.0.2.1 is
specified in any IP state.
Once the SmartStack STS16-20D/STS16-20R has stopped sending BootP requests
on a VLAN, it does not restart sending requests on that VLAN and does not
recognize BootP responses on that VLAN unless the VLAN enters a state where it
would be necessary again.
Besides the switch's IP address, several other parameters in a BootP response are
also recognized and recorded in NVRAM, when received in the same response:
•
Default Gateway (see the note on this page)
•
Subnet Mask
•
TFTP Main Code File Name
•
TFTP Server Address (only recognized if the Bootfile name is present)
One other parameter, the TFTP VLAN, is inferred whenever a TFTP Bootfile name
is present in the BootP response. That is, if the SmartStack STS16-20D/STS16-20R
receives a BootP response that specifies a TFTP Bootfile name, the SmartStack
STS16-20D/STS16-20R automatically records the VLAN on which the response
was received as the TFTP VLAN number. Therefore, the bootfile name should not
be specified on a VLAN from which the TFTP server cannot be accessed, either
directly or through the VLAN’s default gateway (if one exists). More information
on TFTP is available under the section “TFTP” on page 149 in this chapter.
➽ Note: The default gateway accepted is the first one in the list of routers whose net/
subnet address is the same as that of the IP address specified. If no routers are
specified or if none qualify, the gateway address for the VLAN will be zeroed out
and recorded as such in NVRAM when the IP screen is exited.