
Configuring Dial Services
4-6 114062 Rev. B
Asynchronous PPP
Asynchronous PPP provides communication for asynchronous interfaces on the
AN, ASN, and ANH (using the Dual Sync Net Module); ARN (using any Serial
Expansion Module); and BLN and BCN
(using the Octal Sync Net Module).
There are several advantages to asynchronous communications:
• Low cost -- Analog lines are less expensive than high-speed digital lines.
Asynchronous modems are less expensive than synchronous modems. You
can also dial directly into the router without using a terminal server or other
port-concentration devices.
• Effective use of router hardware -- You can use an available serial port on
the router for a dial-up application.
• Line availability -- Analog lines are available in most locations, enabling you
to dial in from any remote location.
• Throughput -- With the V.34 standard, throughput for asynchronous modems
is 28.8 Kb/s. Using the V.42bis compression standard, throughput can be
higher.
Figure
4-4 shows a network that uses asynchronous PPP over modem lines.
Figure 4-4. Using Asynchronous PPP over Modem Lines
Using low-cost asynchronous modems makes asynchronous PPP ideal for
customers with small networks who are trying to lower expenses.
MODEM
DS0028A
MODEM
MODEM
PSTN
Kommentare zu diesen Handbüchern