The TCP/IP stack does not allow IP forwarding within the intraensemble
data network (IEDN) between two OSA-Express for zBX (OSX) interfaces.
However, the stack does allow IP forwarding within the IEDN by the
sysplex distributor when VIPAROUTE is used. The stack also allows
IP forwarding between an OSX interface and a non-OSX interface.
If an external router is attached to the IEDN, dynamic and static
routing considerations for OSX interfaces are the same as those considerations
for OSD interfaces connected to an external router. However, if no
external router is present on that network, see the following guidelines.
Guidelines: - Implement the IEDN as a flat network, meaning that all addresses
that are reachable through the IEDN are in the same subnet (or IPv6
prefix) as the IEDN. In this configuration, a single route (static
or dynamic) to this subnet enables all addresses on the IEDN to be
reached.
- Static routing might be appropriate in the following cases:
- The IEDN is implemented as a flat network, in which case a single
static route over the OSX interface to the subnet of the IEDN can
reach all destinations in the IEDN.
- A z/OS® host will not be
routing traffic between external networks and the IEDN, so you do
not want to advertise the intraensemble subnet addresses to the external
network.
Tip: If you are using static routing over the
IEDN and there are destination IP addresses on the IBM® zEnterprise® BladeCenter
Extension (zBX)
that are not part of the intraensemble subnet, you must define static
routes to those destination IP addresses on the intraensemble network
by using OSX interfaces.
- Dynamic routing might be appropriate in the following cases:
- You want destinations on the intraensemble subnet to be reachable
from outside the ensemble, and therefore want to advertise the IEDN
addresses to the external network.
- There are destination IP addresses on the zBX that
are not part of the intraensemble subnet, and you do not want to code
individual static routes to reach them (for example, if other hosts
on the IEDN have VIPA addresses that are not in the intraensemble
subnet).