Intel ER8100STUS - Express 8100 Router Reference Manual page 16

Data compression
Timecut mode for dial-
up (switched) links
Backup links
Data compression is available for all WAN link types to improve the throughput.
PPP and Frame Relay
For PPP links (leased lines, dial-up links and ISDN links) and Frame Relay links,
data compression rates of up to 4:1 can be achieved for text data.
X.25
For X.25 links, data compression rates of up to 4:1 can be achieved for text data.
Timecut mode should be selected for dial-up (switched) WAN links.
Note
Operating costs can be excessive otherwise.
When a dial-up (switched) WAN link is in Timecut mode, the link is only acti-
vated when there is queued data. Timecut mode should be selected where trans-
mission costs are dependent on the data transferred, the number of data packets
sent or the duration for which the link is active. Timecut mode ensures that the
WAN link is only established when necessary.
Routing protocols such as RIP and IPX send various routing packets between de-
vices to continually assess the topology of the network. If the standard settings
are used for these settings (for example RIP packets are sent every 30 seconds),
timecut WAN links never get the chance to close down. Routing protocol settings
used on timecut WAN links should be set in accordance with this, and there are
other considerations to be made (for example Watchdog Spoofing and RIP and
SAP Filtering—see Chapter 9 "Novell IPX Routing", p.
Backup links are dial-up (switched) links that can be initialized if another link
should fail or has not been established within a defined time interval. Typically,
a primary WAN link is a 2 Mbps leased line connection, the backup WAN link
is a 64 kbps dial-up connection—the costs of the backup link is therefore depen-
dent on how much the link is used.
A WAN link in Backup mode is only used if the primary link should fail, or if a
connection to it was established from a remote source. Backup links can only be
closed down by the router that started the link.
LAN and WAN Services in the Router
WAN Services
71).
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