hpux 11.31 & multiple nics on same subnet?

[Doug O'Leary]

Hey;

I know previous version of HPUX don't like having multiple nics on teh same subnet... Is that still the case with 11.31?

I have a client that insists that's what they need; however, I'm pretty sure it's not going to work.

If someone can let me know one way or the other, I'd appreciate it - and, if a link to supporting documentation is available, that'd be an excellent bonus.

Thanks.

Doug O'Leary

[Torsten.]

Like in other hp-ux versions you can use APA, already included in certain OS versions.

[Michael Steele_2]

Yes

As stated, apa

http://forums13.itrc.hp.com/service/forums/questionanswer.do?admit=109447627+1257320936390+28353475&threadId=1250263

http://forums13.itrc.hp.com/service/forums/questionanswer.do?admit=109447627+1257321237694+28353475&threadId=1316178

"...enable a variation on ip_strong_es_model and make certain the app bind()s to the correct source IP..."

I know your switches and other network nodes must be checked for vlan aware for instance.

There is also Vlan tagging which adds an additional octet to the end of the ip.

Sounds complex and expensive and probably hard to maintain and confusing to the average joe network admin.

[MSD Unix Admin]

Neither 11.31 or 11.23 have problems with multiple nics on the same subnet. I'm uncertain about earlier versions but I'd be suprised if they did.

The problem comes with the routing, as theres only one default route and it's bound to one interface. Traffic going external to your network will utilize that interface, so it can create a bottleneck. If you're not using dynamic routing, you can create a point of failure. APA can help with both of these problems.

Depending on why your customers require multiple IP's will designate if APA will be useful for you. It requires your network to support it also. APA is pretty straight forward to setup, just run up SAM and hit the network section, nothing complicated about it (although do be on the console when you start messing with the network interfaces obviously)

[Laurent Menase]

as stated earlier, even 11.11 and 11.0 support to have multiple interface on the same subnet,
But none of them can balance outbound message except using ip_strong_es_model parameter set to 2,and if application/traffic is appropriate
- this requires a minimum patch level and exist on 11.11 to 11.31


Without strong_es_model!=0 all the outbound traffic will be done through 1 interface,

strong_es_model set to 1 or 2 permit to specify route per source address.

with SESM set to 2
for outbound connections, the application must bind on an address or the other in order to be sure to use one or the other interface
for inbound connection the answer will use the interface according to the destination address used for the inbound connection whatever be the ibound interface.