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Telco and ISP Dial Scenarios and Configurations
Large-Scale POPs
DNC-316
Cisco IOS Dial Services Configuration Guide: Network Services
Large-Scale POPs
This section describes how to set up a stack of access servers for a large-scale dial solution in the
following sections:
• Scaling Considerations
• How Stacking Works
• Stack Group of Access Servers Using MMP with an Offload Processor Examples
Scaling Considerations
Because of the significant increase in demand for Internet access, large POPs are required by many
Telcos and ISPs. Internet access configurations can be set up to enable users dialing in with individual
computers to make mixed ISDN multilink or modem connections using a stack of Cisco AS5200
universal access servers running Multichassis Multilink PPP (MMP).
You must consider scalability and call density issues when designing a large-scale dial-in POP. Because
access servers have physical limitations, such as how many dial-in users can be supported on one device,
you should consider the conditions and recommendations described in Table 24.
Note Depending on the size of your POP requirement, you can replace the Cisco AS5200 access
server with a Cisco AS5300, Cisco AS5800, or Cisco AccessPath. This hardware exchange
provides higher call density performance and increases the number of ISDN PRI ports,
channelized ports, and modem ports on each chassis.
Table 24 Recommended Configurations for Different Remote Access Needs
Dial-in Demand You Need to Support Recommended Configuration
PCs dialing in, 75 to 90 percent modem calls,
10 to 25 percent ISDN calls (terminal
adapters or routers), and support for fewer
than 96 (T1) to 116 (E1) simultaneous dial-in
connections.
Two Cisco AS5200 access servers configured
for IP, basic security, MMP, L2F, and no
offload server.
PCs dialing in, less than 50 percent modem
calls, more than 50 percent ISDN calls
(terminal adapters or routers), dial-in only,
and 250 or more simultaneous links into the
offload server.
Three or more Cisco AS5200 access servers
configured for IP, remote security, MMP, and
L2F. Each Cisco AS5200 access server is
configured to offload its segmentation and
reassembly of the multilink sessions onto an
offload server, such as a Cisco 7202 or
Cisco 4700 router.