Requirements In Wlc; Requirements At Ggsn - Cisco ASR 5000 Administration Manual

▀ Dependencies and Limitations

Requirements in WLC

WLC node capabilities for D-eWAG service:
 Each 3G-SSID served by WLC should be mapped to a VLAN. The default-gateway for this VLAN should be
configured with the IP address of the corresponding VLAN interface at D-eWAG so that any signaling packet
generated for that SSID (like RADIUS Access-Request, DHCP, etc) will reach D-eWAG.
 RADIUS server IP address for the 3G-SSID at WLC should be configured with the D-eWAG service IP address.
This is required since D-eWAG acts as RADIUS Proxy and inspects the authentication exchanges between UE
and 3GPP-AAA for obtaining the 3G attributes required to create PDP-context with the GGSN.
 DHCP server IP address for the 3G-SSID at WLC should be configured with the D-eWAG service IP address.
This is required since D-eWAG acts as DHCP-server and notifies the IP address allocated by GGSN using
DHCP signaling to the UE.
 WLC should be configured to use its VLAN interface's IP as Source-IP for RADIUS/DHCP Relay signaling
packets and not the management interface IP. This is required since D-eWAG verifies the shared-secret for
RADIUS communication based on this IP address.

Requirements at GGSN

The IP-Pool subnet range configured at GGSN for APN network access should have one IP-address dedicated as
default-gateway address for that subnet and not allocated to any UE. This IP address should be configured at D-eWAG
node as default-gateway IP address for that APN.
For example, if the IP-pool subnet range for an APN is 12.0.0.1 to 12.0.0.100, then one IP-address from this range, say
12.0.0.1 is dedicated as default-gateway address for this subnet range. Thus, the GGSN IP-pool configuration in the D-
eWAG-based solution should be changed to { 12.0.0.2 to 12.0.0.100 } range and the IP-address 12.0.0.1 is configured at
D-eWAG node. Also, 12.0.0.1 is conveyed to UE as default-gateway during DHCP-Offer message by D-eWAG so that
it acts as default-gateway for all the uplink data-packets from the UE.
▄ Cisco ASR 5000 Enhanced Wireless Access Gateway Administration Guide
98
DHCP-based Enhanced Wireless Access Gateway Overview