The Compatibility Mode driver (CMD) has two parts, one for the server and one for the client. At the server, the CMD is viewed as a network adapter. You can bind both protocols to the CMD and it acts like a router when IPX packets need to be sent within the server. Otherwise, the CMD patiently waits in the background, doing nothing and using no resources.
At the workstation, the CMD is invisible because it is an integral part of the new client. It provides the IP communications link required by an IP client. Because NetWare 6 is pure IP, there is no need for IPX at the client.
The IPX Compatibility driver's job is to provide IPX connectivity over the IP network, allowing applications using the IPX stack for communications to function in an IP network. The IPX Compatibility driver also allows IP systems to communicate with IPX systems by using the services of Migration Agents.The IPX Compatibility driver treats the IP network as a virtual IPX network segment (CMD network segment), by encapsulating IPX datagrams inside UDP datagrams, and by resolving RIP and SAP requests through the use of the Service Location Protocol (SLP).
If you want to run IPX applications in your IP network, or you need to connect IP systems with IPX systems, you must ensure that the Service Location Protocol is enabled across the networks, because the IPX Compatibility drivers are dependent on the capabilities of SLP. Customers who want to interconnect IPX and IP systems must introduce at least one Migration Agent on the network.
The default IPX network number (CMD network number) assigned to the virtual IPX network created by the IPX Compatibility drivers is 0xFFFFFFFD. If you want to set up Migration Agents to interconnect IP systems with IPX systems, you must ensure that the CMD network number does not conflict with the internal IPX network number of a server or with the IPX network number of a network segment. You must also ensure that IPX routers are not filtering this address.If you find a system or a segment that conflicts with the CMD network number, you have the option of overriding the default CMD network number by modifying the configuration of IP-only clients and servers. You might find it easier to change the network number of the conflicting system or segment, rather than trying to override the default CMD network number.