3Com 4007, Implementation Manual, Page: 540 / 684

540 C
HAPTER
21: A
PPLE
T
ALK
R
OUTING
Transport Layer Protocols
The transport layer and the session layer provide end-to-end services in
the AppleTalk network. These services ensure that routers transmit data
accurately between one another. Each layer includes four protocols that
work together to support these services. This section describes these
protocols and provides more detail for the protocols that you can view
using the Administration Console.
An AppleTalk intranet has four transport layer protocols:
■
Routing Table Maintenance Protocol (RTMP)
■
Appletalk Echo Protocol (AEP)
■
AppleTalk Transaction Protocol (ATP)
■
Name Binding Protocol (NBP)
Routing Table Maintenance Protocol (RTMP) This protocol
maintains information about AppleTalk addresses and connections
between different networks. It specifies that each router:
■
Learns new routes from other routers
■
Deletes a route if the local router has not broadcast the route to the
network for a certain period of time
Each router builds a routing table for dynamic routing operations in an
AppleTalk intranet. Every 10 seconds, each router sends an RTMP data
packet to the network. Routers use the information that they receive in
the RTMP broadcasts to build their routing tables. Each entry in the
routing table contains these items:
■
Network range
■
Distance in hops to the destination network
■
Interface number of the destination network
■
State of each port ( good , suspect , bad , or really bad )