Technical data

Design Architecture
Dial Solutions Quick Configuration Guide
1-4
Design Architecture
The following sections provide the framework for this case study:
• Service Definitions
• Layer 3 IP Design
• IP Subnet Rationale
• Call Processing Components
Service Definitions
In this case study, the Cisco AS5300 offers three basic services: async shell, async PPP,
and sync PPP. See Table 1-2.
These services are based on real needs as requested by the remote sites. To access these services,
remote devices connect to the Cisco AS5300 via the PSTN.
Table 1-2 Services Provided by Headquarters
Service Term Purpose Physical Data Path
1
1. This is the equipment and interface path used to deliver calls into the Cisco AS5300. See Figure 1-5.
Security
Method Used
Async shell Provides access to Cisco IOS terminal
services (no PPP) to do the following:
2
• Change passwords
• Access menus
• Troubleshoot modem connections using a
simple environment
• Access other network resources via telnet
2. Terminal services provided by the Cisco AS5300’s integrated modems are terminated on TTY and VTY lines. The Cisco IOS shell
is called the EXEC, which you can reach via a modem. The Cisco IOS shell is secured using “login” security. Authentication
security associated with the EXEC is referred to as login. Sites offering terminal services can use menus to improve the user
friendliness of the environment. For tips on how to create menus, see the Configuration Fundamentals Configuration Guide.
Client modems, POTS
3
,
Cisco IOS integrated
modems, lines, and
asynchronous interfaces
3. POTS = Plain old telephone service.
Login
Async PPP • Provides IP (and multi-protocol)
connectivity for remote node modem users
• Supports any Internet application available
using IP such as e-mail, web browsing,
FTP, and Telnet.
Client modems, POTS
3
,
Cisco IOS integrated
modems, lines, and
asynchronous interfaces
PPP
(CHAP, PAP, or
login)
Sync PPP • Provides IP (and multi-protocol)
connectivity for BRI or PRI attached
remote sites.
• Supports any Internet application available
using IP such as e-mail, web browsing,
FTP, and Telnet
4
.
4. Terminal services via a shell are not available to synchronous link users (for example, ISDN routers and terminal adapters via a BRI
channel). Only an asynchronous shell is available.
End-to-end ISDN using
B channels over a digital
synchronous path, calls
use interface serial
channels (for example,
S0:1, S0:2, and so forth)
PPP
(CHAP or PAP)