3Com 4007, Implementation Manual, Page: 560 / 684

560 C
HAPTER
21: A
PPLE
T
ALK
R
OUTING
AppleTalk Statistics
You can view statistics for the following AppleTalk protocols:
■
Datagram Delivery Protocol (DDP)
■
Routing Table Maintenance Protocol
■
Zone Information Protocol
■
Name Binding Protocol
Datagram Delivery
Protocol (DDP)
AppleTalk extends the normal node-to-node delivery of packets to a
process-to-process delivery. The processes running on AppleTalk nodes
exchange data packets through logical sockets that are assigned by the
Datagram Delivery Protocol. DDP provides a best-effort, socket-to-socket
delivery of datagrams — packets exchanged using DDP — over the
AppleTalk network.
Datagram delivery is the key service on which other AppleTalk services are
built. All other AppleTalk services, such as RTMP, NBP, and ZIP, rely on DDP
for packet delivery, as illustrated in Figure 63 earlier in this chapter.
Your system allows you to view a variety of DDP statistics, including:
■
inBcastErrors — Number of dropped DDP datagrams for which the
system was not their final destination and they were sent to the
broadcast MAC address
■
inCsumErrors — Number of DDP datagrams that were dropped
because of a checksum error
■
inDiscards — Number of DDP Datagrams that were discarded during
routing
■
inForwards — Total number of packets that were forwarded,
including those with errors
■
inLocals — Number of DDP datagrams for which an attempt was
made to forward them to their final destination
■
inNoClients — Number of DDP datagrams that were dropped for
unknown DDP types
■
inNoRoutes — Number of DDP datagrams that were dropped for
unknown routes
■
inReceives — Total number of packets that were received, including
those with errors