Cisco ASR 5000 Series, Обзор продукта

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ASN Gateway Overview
Supported Features ▀
Cisco ASR 5000 Series Product Overview ▄
OL-22938-02
Supported Features
The Access Service Network Gateway (ASN Gateway) provides ASN Gateway control and bearer plane routing
functions:
BS Interface: R6 IP/GRE bearer plane
Inter-ASN handovers to other ASN Gateways: R4 IP/GRE bearer plane
Interactions with AAA management or policy servers: R3 RADIUS interface
Mobile IP Interface to HA in Connectivity Service Network: R3 IP-in-IP tunneling
A Profile C ASN Gateway is one of three alternative designs for radio resource management proposed by the WiMAX
Forum. In a Profile C architecture, the handover control component resides in the base stations. The ASN Gateway
represents a transparent message relay point between neighboring base stations. The Radio Resource Controller (RRC)
component in every BTS periodically polls its neighbors to build a resource availability database that it checks prior to
triggering call handovers.
provides a high performance ASN Gateway platform with the following supported features in the current software
version.
Important:
Not all features are supported on all platforms.
Simple IPv4 Support
A Simple IP model supports non-mobile IP terminals and provides ASN-anchored mobility for fixed, nomadic, or
portable mobility applications. A Simple IP architecture removes dependencies for separate foreign agent and home
agent functions. ASN Gateway handles simultaneous combinations of Simple IP, Mobile IP, or Proxy Mobile IP calls. A
Simple IP model permits the ASN to be combined or split from the CSN, depending upon the need for roaming. The
Simple IP implementation includes a DHCP Proxy Server function for local or AAA-provided IP address assignment.
Simple IP provides a solution for stationary wireless DSL-like applications. It enables mobility on intra-ASN handovers
between neighboring base stations and permits inter-ASN mobility via an R4 interface between ASN Gateways.
DHCP Proxy Server
Compared to 3G wireless technologies such as EV-DO (Evolution-Data Optimized) or PDP (Packet Data Protocol)
Type PPP (Point-to-Point Protocol) contexts in General Packet Radio Service/Wideband Code division Multiple Access
(GPRS/W-CDMA) networks, WiMAX networks do not use a PPP data link layer between access devices and the ASN
Gateway. An alternative approach to IP address allocation is needed in Simple IP and Proxy Mobile IP usage models.
The ASN-GW includes a DHCP proxy/server/relay that interacts with the DHCP client function on the access device. In
a Simple IP usage model, the DHCP server allocates dynamic addresses from a local address pool or fetches static