Dhcp Service Configuration; Dhcp Service Creation - Cisco ASR 5000 Series Administration Manual

▀ DHCP Service Configuration

DHCP Service Configuration
The system can be configured to use the Dynamic Host Control Protocol (DHCP) to assign IP addresses for PDP
contexts. IP address assignment using DHCP is done using one of two methods as configured within an APN:
DHCP-proxy: The system acts as a proxy for client (MS) and initiates the DHCP Discovery Request on behalf
of client (MS). Once it receives an allocated IP address from DHCP server in response to DHCP Discovery
Request, it assigns the received IP address to the MS. This allocated address must be matched with the an
address configured in an IP address pool on the system. This complete procedure is not visible to MS.
As the number of addresses in memory decreases, the system solicits additional addresses from the DHCP
server. If the number of addresses stored in memory rises above the configured limit, they are released back to
the DHCP server.
DHCP-relay: The system acts as a relay for client (MS) and forwards the DHCP Discovery Request received
from client (MS). Once it receives an allocated IP address from DHCP server in response to DHCP Discovery
Request, it assigns the received IP address to the MS.
Regardless of the DHCP method, there are parameters that must first be configured that specify the DHCP servers to
communicate with and how the IP address are handled. These parameters are configured as part of a DHCP service.
Important:
DHCP-based IP allocation. For more information on commands that configure additional DHCP server parameters and
working of these commands, refer DHCP Service Configuration Mode Commands chapter of Command Line Interface
Reference.
These instructions assume that you have already configured the system level configuration as described in System
Administration Guide and GGSN service as described in GGSN Service Configuration section of this chapter.
To configure the DHCP service:
Step 1
Create the DHCP service in system context and bind it by applying the example configuration in the DHCP Service
Creation section.
Step 2
Configure the DHCP servers and minimum and maximum allowable lease times that are accepted in responses from
DHCP servers by applying the example configuration in the DHCP Server Parameter Configuration section.
Step 3 Verify your DHCP Service configuration by following the steps in the DHCP Service Configuration Verification
section.
Step 4
Save your configuration as described in theVerifying and Saving Your Configuration chapter.

DHCP Service Creation

Use the following example to create the DHCP service to support DHCP-based address assignment:
▄ Cisco ASR 5000 Series Gateway GPRS Support Node Administration Guide
This section provides the minimum instruction set for configuring a DHCP service on system for
GGSN Service Configuration Procedures
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