38
Internetwork Packet Exchange
Internetwork Packet Exchange
103-000176-001
August 29, 2001
Novell Confidential
Manual
99a
38
July 17, 2001
Figure 6
IAMG Implementation
The IAMG allows multiple gateways to be connected between the customer
network and backbone network in parallel. All such gateways on a customer's
network share a single gateway address. If a gateway receives a packet from
the backbone network with an unknown mapping on the gateway network, the
packet is forwarded to all other IAMGs advertising the same gateway address.
If necessary, the packet is split into multiple segments using the IPX
fragmentation module so that the packet can be forwarded with a new header
attached.
If not all gateways support the IPX fragmentation specification, the IAMG is
designed to allow the gateways to run in parallel. In this automatic mode of
operation, some packets might be lost during the learn cycle. When the
gateway that created the mapping receives the forwarded data packets from
the backbone, an update reporting the mapping is returned to the gateway that
initially received the packet. Because more packets probably will follow, the
gateway learns the new mapping.
The IAMG discards any packet destined for the gateway that has the broadcast
node address so that outside clients cannot cause an excessive number of
broadcasts within a network. NetBIOS broadcasts (packet type 20) cannot be
used on a network attached to an interface that has the IAMG enabled.
Broadcasts to networks other than the gateway address are allowed.
Backbone Network
Customer
Network
Backbone
Services
Backbone
Service
Gateway Address
01014000
IPX Address
Mapping Gateway
NetWare
Workstation
NetWare
File Server
00001234
