Configure Header And Payload Compression Refresh Rates; Table H-3. Compression Performance - Comtec CDM-840 Installation And Operation Manual

CDM-840 Remote Router
Appendix H
H.2.3 C onfigure Header and P ayload C ompres s ion R efres h R ates
Use the 'Configuration | WAN | Compression' page (Figure H-3) to define the Header and
Payload Compression Refresh Rates. These settings control how many compressed header
packets are sent before a single full header packet is sent.
The supported refresh rates are based on the runtime characterization that there will be, at
most, 600 packets seen between refreshes. Additionally, even though the runtime supports
64,000 Tx compression sessions, it is only necessary to have context storage for a small number
over those 600 packets. Based on this specification, the CDM-840's compression performance is
defined in Table H-3 (±5% with different compression refresh rates).
Packet Size
40
420
800
1200
1472
While some compressed header traffic can be lost during deteriorated satellite link
conditions, the CDM-840 tries to minimize that when Adaptive Coding and
Modulation (ACM) is enabled (Figure H-4). Sending a full packet allows the return of
the traffic stream; you may increase the Refresh Rate (smaller value) when poor
satellite link conditions are prevalent or, conversely, decrease the rate (larger value)
under clear sky condition operations.
Figure H-3. Configuration | WAN | Compression Page

Table H-3. Compression Performance

% Savings per Compression Refresh Rate
1 25
23% 50%
40% 51%
46% 53%
49% 54%
50% 55%
50
53%
51%
53%
54%
55%
H–7
MN-CDM840
Revision 3
300 600
53% 55%
51% 51%
53% 53%
53% 54%
55% 55%