Frame Relay IPX Routing
Page 29-18

Frame Relay IPX Routing

Frame Relay IPX and IP routing differ in the way they determine the address of a router at
each end of a virtual circuit. Instead of using Inverse ARP, IPX uses a process called “glean-
ing” to determine routing information. In gleaning, the IPX routing protocol on one end of a
virtual circuit obtains the network node number for the router at other end of the virtual
circuit.
A WSX or router continuously receives RIP and SAP updates on a given virtual circuit. When it
receives the first such broadcast, the IPX process looks at, or gleans, the source address from
the frame’s IPX header. When the router needs to send traffic on that router later, it uses the
source address it just obtained as the destination address for that router. The following
diagram illustrates IPX Gleaning.
IPX Gleaning
Not all Routers support IPX gleaning. If you need to interoperate with a Router that does not
support gleaning, then you may need to statically map addresses on that Router.
The configuration of WSX routing services is described in Configuring a WAN Routing Service
on page 29-59.
RRouter sends WSX a SAP or RIP update.
The source address of the Router port is
included in the IPX header.
When the WSX needs to send traffic
to the same router, it uses the
source address just gleaned from the
broadcast frame as the destination
address for traffic to this router.
➊
WSX
R
Frame Relay
Network WSX examines the IPX header
and “gleans” the source net-
work node address.
➋
➌
WSX