Configuring address pools, Address assignment mechanisms, C h a p t e r – Cisco 10000 User Manual
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C H A P T E R
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Cisco 10000 Series Router Software Configuration Guide
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10
Configuring Address Pools
Service providers concerned with the efficient management of IP address space are challenged to
implement an address assignment mechanism that efficiently assigns addresses to remote users from
address pools and effectively manages those pools. Such deployment requires a strategy for dealing with
poorly utilized address pools and pools that run out of addresses. Each remote user assigned an address
must have a route to the remote user configured in the corresponding virtual routing and forwarding
(VRF) instance. Configuration becomes further complicated by the fact that a single PE router can
support hundreds of VRFs, and the provider’s network can have hundreds or thousands of PE routers.
The total number of routes in all VRFs and in the default routing table on a single PE router can grow
enormously, highlighting the need for an address mechanism that provides for route summarization.
To enhance IP address space management, the Cisco 10000 series router supports the following address
pool features:
•
On-Demand Address Pool Manager, page 10-4
—Provides an address assignment mechanism that
dynamically resizes address pools and permits efficient route summarization.
•
Overlapping IP Address Pools, page 10-16
—Enables you to use multiple IP address spaces and
reuse IP addresses among different VPNs supported on the Cisco 10000 series router.
This chapter describes the advantages and disadvantages of address assignment mechanisms currently
deployed, the On-demand Address Pool Manager feature, and the Overlapping IP Address Pools feature:
•
Address Assignment Mechanisms, page 10-1
•
On-Demand Address Pool Manager, page 10-4
•
Overlapping IP Address Pools, page 10-16
Address Assignment Mechanisms
Typically, service providers deploy the following address assignment mechanisms:
•
•
RADIUS-Based Address Assignment, page 10-2
•
DHCP-Based Address Assignment, page 10-3
The following sections describe the advantages and disadvantages of the address assignment
mechanisms.