topic Re: IP Multiplex Limit in Operating System - HP-UX

IP Multiplex Limit

JLee_1 — Mon, 03 Apr 2006 13:16:38 GMT

All,
Does anyone know what the limit is on IP Multiplexing? How many IP's can be assigned to one NIC?

Thanks in advance.

Re: IP Multiplex Limit

JLee_1 — Mon, 03 Apr 2006 14:26:09 GMT

Asked and answered. . .
256 is the limit of VIPs you can have on on NIC.

I give myself 10 points ;-)

Re: IP Multiplex Limit

rick jones — Mon, 03 Apr 2006 19:53:36 GMT

Where did you see the limit stated as 256? I was under the impression that for HP-UX 11.X anyway, there was no pre-set limit.

Re: IP Multiplex Limit

Fermin Jamieson — Tue, 04 Apr 2006 15:48:28 GMT

For a single network number, the limit is 253. Using the entire range..

Re: IP Multiplex Limit

rick jones — Tue, 04 Apr 2006 16:03:35 GMT

I believe you may be confusing how many host addresses can exist in a "Class-C" network with how many IP addresses can be assigned to a given network interface under HP-UX.

Indeed, a "Class-C" network has a single octet of host portion (ie the last 8 bytes) and two of those addresses (0 and 255) are reserved, leaving 254 possible IPs. The number is 256 times that for a "Class-B" and another 256 times that for a "Class-A" address.

Of course, IP addresses have been "classless" for years now, so the more general answer is there are (2^N)-2 host addresses available in a given subnet where N is the number of bits in the host portion of the address.

As one can assign IP addresses from multiple subnets to the same NIC under HP-UX, the "per-subnet" limit to the number of host addresses in an IP subnet is _not_ the limit to the number of IP's one can assign to a NIC.