Alcatel Carrier Internetworking Solutions Switch/Router ユーザーズマニュアル

Page 29-18

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.

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

Router 

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 examines 

the IPX header

and “gleans” the source net-
work node address.

➋

➌