Header Compression - Novell NETWARE 6-DOCUMENTATION Manual

Figure 4 Watchdog Spoofing Enabled over an On-Demand Call
Branch Office
Router
Workstation

Header Compression

Main Office
Router
On-Demand Call
Query Response:
"Yes, I am still here."
When watchdog spoofing is enabled on an on-demand call, watchdog packets,
going from a server to a client, cause the router to reply that the workstation
is active without initiating the call. If watchdog spoofing is disabled, an on-
demand call is initiated for each watchdog packet that crosses the connection.
NOTE:
NCP header compression is not used for NCP packets using the Packet
Burst protocol. Because IPX headers are the standard, IPX header compression
TM
is used.
Header compression increases the throughput of IPX and NCP packets over
low-speed serial lines (except for NCP packets using the Packet Burst
protocol). An IPX packet header is 30 bytes and is typically followed by an
upper-layer protocol header, such as an SPX header. Header compression
reduces the size of this combined packet header to just a few bytes.
Header compression is negotiated by the IPXWAN protocol when a call is
established over any WAN connection type. Header compression is not used
on the connection if IPXWAN detects that one of the routers does not support
it. The routers at each end of the connection must have header compression
enabled and must allocate the same number of compression slots.
For more information about header compression, refer to
"Compression Slots" on page 32
"Compression Packet Types" on page 33
Watchdog Query:
"Are you still there?"
Main Office
Accounting Server
31
Understanding