Can NPR 2000s be installed on a network that implements VLSM and CIDR

[Product_Support]

Issue

Can NPR 2000s be installed on a network that implements VLSM and CIDR?

Environment

I/NET Site

Cause

Can NPR 2000s be installed on a network that implements VLSM and CIDR?

Resolution

If you see anything other than 0 or 255 in the subnet mask of a PC or NPR, this is usually an indication that the customer is using Variable Length Subnet Masking on his network nodes and Classless InterDomain Routing on his commercial routers.

The subnet mask gets logically handed with the TCP\IP address in some way and the router passes through a different address than the host/NPR actually sends. This reduces the number of TCP\IP addresses that a domain must register but the NPR 2000 cannot do this. The customer has the choice of only using PCs to the exclusion of NPRs (and that is a maybe), abandoning the VLSM/CIDR approach, or enabling proxy-arp on his commercial router.