UCSB NOC VLAN id calculator
This calculator will help you determine the appropriate 802.1q VLAN id
for a particular UCSB IP network.
Any IP network that lies on a '/26' boundary may be calculated
with the following formula:
where x = IP subnet number
(The IP subnet number is the third octet of the IP address.
For example, 128.111.182.192)
and y = last octet of the IP network address
(the IP network address is the first IP address in a network.
For example, the network address of 128.111.182.192/25
is 128.111.182.128)
Discard the remainder from any division.
( ( y / 64 ) + ( x + 1 ) * 4 ) + offset
Where offset = 0 for 128.111/16 and 1276 for 169.231/16
An easier formula to remember,
but one which only works for '/24', or class 'C' networks, is:
(Subnet * 4 + 4) + offset
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