SNMP prefix/addr is broken

[rfdrake]

This probably broke when IPv6 support was added. It turns out that the oids are not available on most routers. We'll need to have two table queries most likely, one for IPv6 and one for IPv4.

[rfdrake]

I just stumbled on this again. From what I remember you could use an IP prefix to group interfaces together. This is useful for point to multipoint circuits. I think we used it in FDDI rings or possibly ethernet long ago.

I think we've worked around this so that it isn't needed. If that isn't true then I'll try to resurrect it, but otherwise my plan is to strip this code.