Routing and Remote Access Service
Routing and Remote Access Service |
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The IPX components of the Routing and Remote Access service are shown in Figure 2.4.
Figure 2.4 IP Multicast and the Routing and Remote Access Service
The following sections describe typical IPX routing processes in terms of the Routing and Remote Access service IPX routing components.
An incoming packet is handed first to the IPX forwarder driver, which finds a route and then hands it to the IPX filtering driver to check for input filters and output filters. If approved for acceptance by the input filters and for forwarding by the output filters, the packet is handed back to the IPX forwarder driver, which forwards the packet over the appropriate interface using NDIS. If the input or output filters do not permit the packet to be forwarded or if a route is not found, the packet is silently discarded.
An incoming packet is handed first to the IPX forwarder driver, which notes that the packet is not to be routed (the destination IPX internetwork address is the router or a broadcast address) and then hands it to the IPX filtering driver to check for input filters. If accepted by the input filters, the packet is handed up to IPX/SPX, which processes the packet normally. If the packet is not accepted by the input filters, the packet is silently discarded.
An outgoing IPX packet is handed by the IPX/SPX driver to the IPX filtering driver, which checks for output filters. If approved for sending by the output filters, the packet is handed to the IPX forwarder driver, which sends the packet using the best route over the appropriate interface using NDIS. If the packet is not approved by the output filters, the packet is silently discarded. If a route is not found, a RIP GetLocalTarget message is sent. For more information about IPX routing processes, see "IPX Routing" in this book.
The RIP for IPX and SAP routing protocols operate like any other Windows Sockets application sending and receiving IPX packets.
Based on information received by the routing protocol, the routing protocol updates routes in the Route Table Manager and, based on the best route, the table of best routes is updated in the IPX forwarder driver.
