System information

22 IBM and Cisco LAN Switching: Interoperability and Migration Guide
NHRP and MPOA
The Next Hop Resolution Protocol (NHRP) and Multiprotocol over ATM
(MPOA) are extensions of LAN emulation to layer 3.
Cisco IOS provides support for NHRP and MPOA, client as well as server.
Clients are supported on most router and switch products with an ATM uplink.
Only IP is supported by Cisco’s MPOA implementations, whereas IBM
products support both IP and IPX.
This means that IPX traffic cannot be shortcut routed between Cisco MPOA
clients. It may still be routed to and from a Cisco LEC by the MSS or a Cisco
router. Alternatively, IPX traffic can be bridged, just as nonroutable traffic can
be bridged by MSS or Cisco router. Both the IBM and Cisco products support
transparent, source-route, and translational bridging.
Classical IP and multi-protocol encapsulation
Classical IP (RFC 1577) connects ATM user stations employing IP. In
principle the user stations themselves provide all the layer-3 connectivity
functions. However, MSS is often used as an ARP server or as a bridge to
emulated LAN segments. Cisco IOS provides the same functions.
Multi-protocol encapsulation (RFC 1483) connects ATM user stations
employing IP and IPX as well as nonroutable protocols. Both MSS and Cisco
can bridge between RFC 1483 stations and stations on other logical or
physical interfaces.
SNA support
MSS and Cisco IOS support equivalent sets of Data Link Switching (DLSw).
There are some differences in the APPN support provided by MSS and Cisco
IOS. If you need to migrate an MSS in an APPN network, IBM Global
Services contacts for your country are found at
http://www.ibm.com/planetwide. This migration is beyond the scope of this
redbook.
Super VLAN, shortcut bridging, and broadcast management
Though fully based on international and industry standards, these functions
are IBM proprietary and therefore do not interoperate with Cisco’s
implementations.
This does not prevent you from continuing to use these or any other MSS
functions in a mixed network. We have seen that Cisco’s implementation of
MPOA clients work very well with the MPOA server in MSS. You may also
continue to use MSS for dynamic protocol filtering, but do not attempt to use it