I have been looking at a multi host data centre and am using MPLS to securely share certain resources and considering what architecture considerations for Network Management.
Lets define the problem. Network Management is software and servers that collect data from my network equipment and presents it to me in some useful form. Add to this some documentation and process support tools such as a wiki that holds documentation or a service such as helpdesk package.
The servers have to have IP addresses but what addresses to allocate ? If I use something from the RFC1918 addressing then it is possible that a given VRF might need to use that range. I don’t need the hassle of buying and maintaining routable addresses (although for a very large data centre this would be easy enough to do).
So I spent some time researching the RFC’s and found this little gem.
RFC 2544 – Introduction
RFC2544 Benchmarking Methodology for Network Interconnect Devices
ì This document defines a specific set of tests that vendors can use to measure and report the performance characteristics of network devices. The results of these tests will provide the user comparable data from different vendors with which to evaluate these devices.î
The remainder RFC, which must be a precursor Scott Bradner setting up his testing lab, of this discusses benchmarking and test schemas. Deep inside this RFC you will find references to 198.18/16 IP addresses. I did a search across the RFCs on this address and found RFC3330
RFC 3330 – Special-Use IPv4 Addresses
This RFC outlines which address ranges are not routed on the Internet and shows the allocation that have been recovered to prolong the life of IPV4. But searching in here find this:
198.18.0.0/15 - This block has been allocated for use in benchmark tests of network interconnect devices. Its use is documented in [RFC 2544].
So a careful read of the RFC 3330 shows that this address range is not scheduled for allocation on the Internet and has been allocated for use by testing companies so that if they publish their configurations and results, you can use the same addresses to do the same tests yourself
I have found the IP address allocation for my Network Management zone in my design. It is not commonly used by customer platforms, because is is a bogon network it is secure to use.