Compression Packet Types - Novell NETWARE 6-DOCUMENTATION Manual

Compression Packet Types

Five packet types are used to exchange compression-state information about
packets sent over a connection on which header compression is enabled. Three
of these packet types—slot initialization, reject, and acknowledgment
packets—manage the flow of compressed and uncompressed packets over the
connection; these are the compression protocol packets. The packet type,
along with other information, is indicated in the first byte of a compressed
packet. Compression packet types are defined as follows:
Uncompressed packet —A standard, uncompressed IPX or NCP packet.
A router sends an uncompressed packet when the packet cannot be
compressed or a decision was made not to compress it. When the remote
router receives an uncompressed packet, it simply removes the 1-byte
compression header and passes the packet to IPX.
IPXCON tracks uncompressed packets exchanged on a connection in the
Uncompressed Packets Sent and Uncompressed Packets Received
counters.
Compressed packet —A compressed IPX or NCP packet. Compressed
packets do not contain the standard packet header. Instead, they contain
the number of a compression slot on the receiving router. This slot
contains the information necessary for the compression algorithm to
decompress the packet header before passing the packet to IPX.
IPXCON tracks compressed packets in the Packets Sent and Packets
Received counters.
Slot initialization packet —A compression protocol packet that a router
sends to prepare a compression slot on the receiving router for use.
Initialization packets can prepare new slots or previously used slots for
reuse. The routing software uses two different initialization packets: one
for IPX packets and one for NCP packets.
IPXCON tracks initialization packets in the Initialization Packets Sent
and Initialization Packets Received counters.
Reject packet — A compression protocol packet that a router sends when
it receives another compression protocol packet that it does not
understand.
IPXCON tracks reject packets in the Reject Packets Sent and Reject
Packets Received counters.
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Understanding