🚀 go-pugleaf

    I am sure someone has already solved this problem since it seems
like a very  common problem.  Suppose  you have one  class B address
(i.e.  132.64.x.x)  and  have   about  120  small  units   scattered
throughout the USA with each around 20-30 systems connected.  Now in
order to interconnect all these  subnets of 132.64.x.x we use  cisco
routers with many lines.   We want to use  the same class B  net for
the  lines  and  not  some  other  network,  since  that would break
subnetting rules (you  are not allowed  to seperate two  segments of
the same class B via a segment of some other class C or B network).

    So we choose a subnet  mask of 255.255.255.0 for the  individual
units  and  for  the  lines  we  would  like  to  use something like
255.255.255.248.  This  way we  get greater  efficient use  from the
address space, rather than wasting an entire 256 address range space
for each leased line.  If we have 120 lines, we could end up wasting
132.64.1.x-132.64.120.x leaving just about 50% of the address  space
for real work.  Packing the addresses for the leased lines into  one
segment of the class B network - such as 132.64.1.x makes sense  and
should work.  But  for some reason  (perhaps some subnetting  rule),
the cisco will  to not accept  two *different* subnet  masks for the
same class B  network.  The cisco  automatically changes the  subnet
mask for all interfaces with the same class B network address to the
last subnet mask of the last interface set.

I am sure there must be some config command to bypass this problem.
Or is everyone wasting oodles of address space on their leased line
subnets?

Thanks,
Hank Nussbacher