Cisco ASR 5000 Instruction Manual

Cisco ASR 5000 Enhanced Wireless Access
Gateway Administration Guide
Version 15.0
Last Updated November 30, 2013
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Cisco ASR 5000 Enhanced Wireless Access Gateway Administration Guide
© 2013 Cisco Systems, Inc. All rights reserved.

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CONTENTS
About this Guide ............................................................................................... vii
Conventions Used ..................................................................................................................................viii
Contacting Customer Support..................................................................................................................ix
Additional Information............................................................................................................................... x
Enhanced Wireless Access Gateway Overview............................................ 11
Introduction.............................................................................................................................................12
Platform Requirements...........................................................................................................................13
License Requirements............................................................................................................................14
RADIUS-based Enhanced Wireless Access Gateway Overview ................. 15
Product Overview ...................................................................................................................................16
Network Deployments and Network Interfaces..................................................................................17
Network Deployments....................................................................................................................17
Network Interfaces.........................................................................................................................18
Feature Description ................................................................................................................................19
R-eWAG-WLC/Wi-Fi AAA Interface...................................................................................................19
Control and Data Interfaces...........................................................................................................20
R-eWAG-GGSN Gn' Interface............................................................................................................20
IP Address Allocation.....................................................................................................................21
Network Layer Service Access Point Identifier Allocation.............................................................21
Routing Area Identification Encoding.............................................................................................21
Differentiated Services Code Point Marking ......................................................................................21
Access Point Name Selection............................................................................................................22
Quality of Service Profile Selection....................................................................................................23
GGSN Selection.................................................................................................................................23
GGSN Failover Case..........................................................................................................................23
Network Address Translation and Application Level Gateway Support.............................................23
Virtual APN Support...........................................................................................................................24
Offline Charging Support....................................................................................................................24
Triggers for Charging Information Addition and CDR Closure ......................................................25
Billing Record Transfer ..................................................................................................................25
UE Identity and Location Information Support ...................................................................................25
UE Identity Information Support.....................................................................................................25
UE Location Information Support...................................................................................................26
Lawful Intercept Support ....................................................................................................................26
Bulk Statistics Support .......................................................................................................................26
Threshold Crossing Alerts Support ....................................................................................................27
Congestion Control Support...............................................................................................................28
Redundancy Support..........................................................................................................................29
How it Works ..........................................................................................................................................30
Session Setup ....................................................................................................................................30
Session Setup using Accounting-Interim.......................................................................................33
Session Replacement ........................................................................................................................36
Session Setup Failure........................................................................................................................37
Mandatory AVP Missing / No Resource ........................................................................................38

▀Contents
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GTP Tunnel Setup Failure .............................................................................................................38
Session Update..................................................................................................................................39
WLC-initiated Accounting Interim...................................................................................................40
GGSN-initiated Update PDP Context ............................................................................................40
Session Teardown..............................................................................................................................41
UE Detach - Accounting Stop ........................................................................................................41
GGSN-initiated DPC ......................................................................................................................42
eWAG Timeouts/Admin Disconnect...............................................................................................43
Dependencies and Limitations................................................................................................................44
eWAG + GGSN Combo Deployments ...............................................................................................44
Virtual APN Configuration in R-eWAG + GGSN Combo Deployments.........................................44
eWAG + TTG Combo Deployments...................................................................................................45
SGTP Service Configuration in R-eWAG + TTG Combo Deployments ........................................45
eWAG + TTG + GGSN Combo Deployments....................................................................................46
Mobility Setup Considerations............................................................................................................46
3G-eWAG-TTG Mobility using Proxy-MIP at GGSN......................................................................46
RADIUS-based Enhanced Wireless Access Gateway Configuration.......... 47
Before You Begin....................................................................................................................................48
R-eWAG Configuration...........................................................................................................................49
Creating and Configuring the R-eWAG Service.................................................................................49
Creating the R-eWAG Service.......................................................................................................49
Configuring the R-eWAG Service ..................................................................................................50
Configuring the APN...........................................................................................................................53
Configuring the SGTP Service ...........................................................................................................54
Configuring NAT/ALG Support...........................................................................................................55
Configuring ECS Rulebase with Firewall-and-NAT Policy.............................................................55
Configuring APN with Firewall-and-NAT Policy.............................................................................55
Configuring Routing Rules and NAT ALG......................................................................................55
Additional Configurations ...................................................................................................................58
Configuring Access Lists................................................................................................................58
Configuring Bulk Statistics .............................................................................................................58
Configuring Congestion Control.....................................................................................................59
Configuring Offline Charging for R-eWAG.....................................................................................60
Configuring Session Recovery.......................................................................................................61
R-eWAG Administration..........................................................................................................................63
Logging Support .................................................................................................................................63
Protocol Monitoring Support...............................................................................................................63
Monitor Protocol.............................................................................................................................63
Monitor Subscriber.........................................................................................................................64
Gathering R-eWAG-related Statistics and Information ......................................................................64
DHCP-based Enhanced Wireless Access Gateway Overview..................... 67
Product Overview ...................................................................................................................................68
Deployment Models............................................................................................................................69
3G-SSID .............................................................................................................................................69
Association Process...........................................................................................................................70
802.1x EAP-SIM/AKA Authentication Process...................................................................................70
IP Address Allocation Process ...........................................................................................................70
Data Traffic between WLAN and 3G Network....................................................................................71
D-eWAG as First-Hop Router to WLAN Network...............................................................................71
D-eWAG as Default Gateway.............................................................................................................71
APN Selection ....................................................................................................................................71
D-eWAG Service in the ASR5000 Chassis........................................................................................72
WLC - D-eWAG Interface...................................................................................................................72

Contents ▀
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Control Plane .................................................................................................................................72
D-eWAG - AAA Interface ...................................................................................................................74
RADIUS CoA/DM Support.............................................................................................................74
RADIUS Accounting Support.........................................................................................................75
D-eWAG - GGSN (Gn') ......................................................................................................................75
GGSN Selection.............................................................................................................................75
GTP Messages ..............................................................................................................................75
IP Address Allocation.....................................................................................................................76
NSAPI Allocation............................................................................................................................77
UE Identity and Location Information Support...............................................................................77
Data-Plane .........................................................................................................................................78
Uplink Data Path............................................................................................................................78
Downlink Data Path .......................................................................................................................78
Overlapping IP Address Support........................................................................................................78
Local Traffic Breakout ........................................................................................................................79
APN Selection................................................................................................................................79
IP Address Allocation.....................................................................................................................79
Controlling Local Traffic Breakout..................................................................................................80
NAT In-line Service Support ..........................................................................................................80
Data Path Flow ..............................................................................................................................81
Data Path Changes........................................................................................................................81
Recovery Support ..........................................................................................................................82
Accounting Support........................................................................................................................82
Differentiated Services Code Point Marking ......................................................................................82
Bulk Statistics Support .......................................................................................................................83
Threshold Crossing Alerts Support ....................................................................................................84
Congestion Control Support...............................................................................................................85
Redundancy Support..........................................................................................................................86
Charging.............................................................................................................................................87
Offline Charging .................................................................................................................................87
Triggers for Charging Information Addition and CDR Closure ......................................................87
Billing Record Transfer ..................................................................................................................88
Lawful Intercept Support ....................................................................................................................88
D-eWAG + R-eWAG Combo Deployment .........................................................................................88
How it Works ..........................................................................................................................................89
Session Setup....................................................................................................................................89
Session Teardown..............................................................................................................................92
Session Teardown - AAA Initiated.................................................................................................92
Session Teardown - GGSN Initiated..............................................................................................93
Session Teardown - UE Initiated ...................................................................................................93
Session Teardown - WLC Initiated................................................................................................94
Session Update..................................................................................................................................94
Session Update - AAA Initiated .....................................................................................................95
Session Update - GGSN Initiated..................................................................................................95
Session Update - WLC Initiated.....................................................................................................96
Dependencies and Limitations ...............................................................................................................97
Deployment Models............................................................................................................................97
Requirements in WLC........................................................................................................................98
Requirements at GGSN .....................................................................................................................98
DHCP-based Enhanced Wireless Access Gateway Configuration ............. 99
Before You Begin .................................................................................................................................100
D-eWAG Configuration.........................................................................................................................101
Creating and Configuring the D-eWAG Service...............................................................................101
Creating the D-eWAG Service.....................................................................................................101

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Configuring the D-eWAG Service ................................................................................................102
Configuring DHCP Service...............................................................................................................103
Configuring the Subscriber Template...............................................................................................104
Configuring the SGTP Service .........................................................................................................104
Configuring NAT for Local Traffic Breakout Support........................................................................105
Additional Configurations .................................................................................................................106
Configuring Bulk Statistics ...........................................................................................................106
Configuring Congestion Control...................................................................................................107
Configuring Session Recovery.....................................................................................................108
Configuring Offline Charging for D-eWAG...................................................................................108
D-eWAG Administration........................................................................................................................110
Logging Support ...............................................................................................................................110
Protocol Monitoring Support.............................................................................................................110
Monitor Protocol...........................................................................................................................110
Monitor Subscriber.......................................................................................................................111
Gathering D-eWAG-related Statistics and Information ....................................................................111
RADIUS-based Enhanced Wireless Access Gateway AAA AVP Support 115
DHCP-based Enhanced Wireless Access Gateway AAA AVP Support.... 117
AAA AVP Support in Accounting Messages.........................................................................................118
AAA AVP Support in Authentication Messages....................................................................................121

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About this Guide
This document pertains to the features and functionality that run on and/or that are related to the Cisco® ASR 5000
Chassis.

About this Guide
▀Conventions Used
▄Cisco ASR 5000 Enhanced Wireless Access Gateway Administration Guide
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Conventions Used
The following tables describe the conventions used throughout this documentation.
Icon
Notice Type
Description
Information Note
Provides information about important features or instructions.
Caution
Alerts you of potential damage to a program, device, or system.
Warning
Alerts you of potential personal injury or fatality. May also alert you of potential electrical hazards.
Typeface Conventions
Description
Text represented as a screen
display
This typeface represents displays that appear on your terminal screen, for example:
Login:
Text represented as commands
This typeface represents commands that you enter, for example:
show ip access-list
This document always gives the full form of a command in lowercase letters. Commands
are not case sensitive.
Text represented as a command
variable
This typeface represents a variable that is part of a command, for example:
show card slot_number
slot_number is a variable representing the desired chassis slot number.
Text represented as menu or sub-
menu names
This typeface represents menus and sub-menus that you access within a software
application, for example:
Click the File menu, then click New

About this Guide
Contacting Customer Support ▀
Cisco ASR 5000 Enhanced Wireless Access Gateway Administration Guide ▄
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Contacting Customer Support
Use the information in this section to contact customer support.
Refer to the support area of http://www.cisco.com for up-to-date product documentation or to submit a service request.
A valid username and password are required to access this site. Please contact your Cisco sales or service representative
for additional information.

About this Guide
▀Additional Information
▄Cisco ASR 5000 Enhanced Wireless Access Gateway Administration Guide
x
Additional Information
Refer to the following guides for supplemental information about the system:
Cisco ASR 5000 Installation Guide
Cisco ASR 5000 System Administration Guide
Cisco ASR 5x00 Command Line Interface Reference
Cisco ASR 5x00 Thresholding Configuration Guide
Cisco ASR 5x00 SNMP MIB Reference
Web Element Manager Installation and Administration Guide
Cisco ASR 5x00 AAA Interface Administration and Reference
Cisco ASR 5x00 GTPP Interface Administration and Reference
Cisco ASR 5x00 Release Change Reference
Cisco ASR 5x00 Statistics and Counters Reference
Release notes that accompany updates and upgrades to the StarOS for your service and platform

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Chapter 1
Enhanced Wireless Access Gateway Overview
This chapter provides an overview of the Enhanced Wireless Access Gateway (eWAG).
The following topics are covered in this chapter:
Introduction
Platform Requirements
License Requirements

Enhanced Wireless Access Gateway Overview
▀Introduction
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Introduction
Providing a consistent subscriber experience and supporting the ever exploding demand for bandwidth to provide data
services in 3G/4G networks is quickly becoming a big challenge for mobile operators. Widely prevalent Wireless Local
Area Network (WLAN) at public hotspots, private corporate networks, and so on have been viewed as providing a
viable alternative to 3G/4G radio and providing a solution to the overloading of radio networks by providing an
offloading solution. These Interworking WLAN (I-WLAN) provide subscriber access to 3G/4G networks making
services offered by operators universally available.
However, due to the inherent un-trusted nature of WLANs, the I-WLAN solution has been designed keeping security
aspects in view and so is based on IPSec. The IPSec-based solution requires a client to be installed on the UE. At this
point in the evolution of subscriber access from WLANs, the UE client has been a major stumbling block in the
deployment of I-WLANs.
On the other hand, trusted Wi-Fi networks provide a unique opportunity in converting WLANs into seamless extensions
of 3G/4G mobile networks, enabling improved subscriber experience, especially indoors which often suffers poor
cellular coverage, as subscribers are able to reach their 3G/4G services via both mobile and Wi-Fi accesses.
The Cisco® eWAG enables Wi-Fi integration into 3G mobile packet core (MPC), allowing clientless UE attached to
trusted Wireless Local Area Networks (WLANs) seamlessly access 3G services. In this case, the UE does not require a
client, it has no dependencies on the Wi-Fi architecture, and does not realize that it is connecting to a 3G network (3G
access is integrated with the normal UE-WLAN attach procedure).
The Cisco® eWAG can be configured in the following modes:
RADIUS-based eWAG —This solution is based on RADIUS accounting messages generated by the WLAN
network. Here the UE attaches to the WLAN network after authentication and acquires an IP address, and then
the Accounting-Start message generated for the UE session from WLAN network is received at eWAG to
create the corresponding 3G session with the GGSN. This means that the 3G network operator will provide the
3G IP address and the UE has already obtained a Wi-Fi IP address during WLAN attachment procedure. So the
mobility between change of access is not possible as the UE changes its location.
For more information on R-eWAG, refer to the RADIUS-based Enhanced Wireless Access Gateway Overview
chapter.
DHCP-based eWAG —This solution is based on the DHCP protocol and uses the IP address allocated by the
GGSN node for the UE attaching to the WLAN network. The IP address is maintained across the access. There
is no separate IP address space like 3G IP address and Wi-Fi IP address. D-eWAG achieves this by acting as
DHCP-Server to the Wi-Fi network and allocating the IP address to the WLAN UE directly when it tries to
attach to the WLAN network.
For more information on D-eWAG, refer to the DHCP-based Enhanced Wireless Access Gateway Overview
chapter.

Enhanced Wireless Access Gateway Overview
Platform Requirements ▀
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Platform Requirements
The eWAG service is supported on Cisco® ASR 5000 Series chassis running StarOS. The chassis can be configured
with a variety of components to meet specific network deployment requirements. For additional information, refer to the
Installation Guide for the chassis and/or contact your Cisco account representative.

Enhanced Wireless Access Gateway Overview
▀License Requirements
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License Requirements
The eWAG is a licensed Cisco product. Separate session and feature licenses may be required. Contact your Cisco
account representative for detailed information on specific licensing requirements. For information on installing and
verifying licenses, refer to the Managing License Keys section of the Software Management Operations chapter in the
System Administration Guide.

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Chapter 2
RADIUS-based Enhanced Wireless Access Gateway
Overview
This chapter provides an overview of the RADIUS-based Enhanced Wireless Access Gateway (R-eWAG).
The following topics are covered in this chapter:
Product Overview
Feature Description
How it Works
Dependencies and Limitations

RADIUS-based Enhanced Wireless Access Gateway Overview
▀Product Overview
▄Cisco ASR 5000 Enhanced Wireless Access Gateway Administration Guide
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Product Overview
The Cisco® eWAG enables Wi-Fi integration into 3G mobile packet core (MPC), allowing clientless UE attached to
trusted Wireless Local Area Networks (WLANs) seamlessly access 3G services. In this case, the UE does not require a
client, it has no dependencies on the Wi-Fi architecture, and does not realize that it is connecting to a 3G network (3G
access is integrated with the normal UE-WLAN attach procedure).
Important: The eWAG enables 3GPP MPC access only from trusted Wi-Fi networks—802.1x for authentication
and Wi-Fi encryption is required.
The eWAG enables Wi-Fi sessions to be anchored on GGSN of the existing 3G networks via the Gn’ interface. On the
data plane, the eWAG accepts Layer 3 Wi-Fi packets, encapsulates them into GTP tunnels and sends them to the
GGSN. In the downlink direction, the eWAG de-capsulates the packets and sends them to the Wi-Fi network.
The unique advantages of the eWAG include:
The Cisco® ASR5000 chassis on which the eWAG is deployed is a high capacity chassis that can support
millions of subscribers on a single chassis. Therefore, a single chassis is likely to support large session/capacity
requirements for several years to come.
The Wi-Fi core does not need any enhancement apart from the Wi-Fi AAA, which must act as a RADIUS
accounting client towards the eWAG, with all data traffic routed to eWAG as the default nexthop.
This solution enables optimal use of existing MPC infrastructure—PCRF, OCS, Billing, and so on. Billing and
other 3G/MPC services such as deep packet inspection (DPI) are available to subscribers attached to Wi-Fi via
the GGSN. Apart from the basic IP services, eWAG enables enhanced services such as offload, video
optimization, and on-deck services to the Wi-Fi UE. It also enables policy and charging for the Wi-Fi network,
and enables service providers to provide seamless service experience for subscribers in Wi-Fi network
regardless of their access type.

RADIUS-based Enhanced Wireless Access Gateway Overview
Product Overview ▀
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Figure 1. eWAG-based MPC access from WLAN
Network Deployments and Network Interfaces
This section describes deployment options and network interfaces supported by the R-eWAG.
Network Deployments
The R-eWAG can be deployed in any of the following ways:
Stand-alone R-eWAG deployment on an ASR 5000 chassis.
Combo R-eWAG + GGSN deployment on the same ASR 5000 chassis.
Important: In this release, the following deployment options are not fully qualified and are not supported, these
are available only for lab testing purposes.
Combo R-eWAG + TTG deployment on the same ASR 5000 chassis.
Combo R-eWAG + TTG + GGSN deployment on the same ASR 5000 chassis.

RADIUS-based Enhanced Wireless Access Gateway Overview
▀Product Overview
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Important: For information on dependencies and limitations of these deployment options see the Dependencies
and Limitations section.
Network Interfaces
The Gn’ reference point is located between the R-eWAG and the GGSN supporting GTPv1 and GTPv0 protocols. R-
eWAG supports GTP Path messages towards GGSN. Here, the R-eWAG acts as an SGSN and initiates the PDP Context
Creation procedure. For every UE, the R-eWAG creates one GTP tunnel with the GGSN. The UE’s APN and IMSI are
forwarded to the GGSN in the Create PDP Context Request message. This APN is either the subscribed APN from the
HLR for the connecting user, or the locally configured default APN at the R-eWAG.

RADIUS-based Enhanced Wireless Access Gateway Overview
Feature Description ▀
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Feature Description
This section presents general description of features supported by the R-eWAG.
RADIUS AAA Support
Differentiated Services Code Point Marking
Access Point Name Selection
Quality of Service Profile Selection
GGSN Selection
GGSN Failover Case
Network Address Translation and Application Level Gateway Support
Virtual APN Support
Offline Charging Support
UE Identity and Location Information Support
Lawful Intercept Support
Bulk Statistics Support
Threshold Crossing Alerts Support
Congestion Control Support
Redundancy Support
R-eWAG-WLC/Wi-Fi AAA Interface
The R-eWAG provisions a RADIUS server, as defined in RFC 2865, which enables the R-eWAG to act as a RADIUS
accounting server supporting receiving and responding to RADIUS accounting messages as defined in RFC 2866.
For the list of RADIUS attributes supported by R-eWAG, refer to the RADIUS-based Enhanced Wireless Access
Gateway AAA AVP Support appendix.
The R-eWAG provisions configuring one or more RADIUS clients (with corresponding authentication keys) to create a
trusted set of AAA. The R-eWAG discards RADIUS messages from any device that is not in the RADIUS client list.
The R-eWAG authenticates each RADIUS message using a configured authentication key. The R-eWAG creates a new
PDP context (for a subscriber session) upon receiving a valid RADIUS Accounting Start Request.
No 3GPP interface has been defined between WLAN and MPC. Therefore, RADIUS messages generated by core Wi-Fi
network (for example, from WLAN AAA client (WLC or ISG)) are used to provide WLAN session information (Wi-Fi
IP address of UE) to MPC and set up access side association. For this, RADIUS accounting messages
(Start/Interim/Stop) are used.
Many attributes required by MPC (IMSI, MSISDN, APN, Charging-Characteristics, and others) are not inherent in
WLAN access interactions. So, these have to be populated by a WLAN network entity after obtaining it from the MPC.
This enrichment is done by the Wi-Fi AAA. The Wi-Fi AAA interacts with the MPC AAA to obtain these attributes
when UE authentication (EAP over 802.1x) is initiated during initial WLAN attach. Wi-Fi AAA caches these attributes.
After successful authentication and session establishment, WLAN AAA-client (WLC or ISG) generates Accounting-
Start message. This message is proxied by Wi-Fi AAA, enriched with MPC-related attributes, and sent to R-eWAG.

RADIUS-based Enhanced Wireless Access Gateway Overview
▀Feature Description
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Here, Wi-Fi AAA acts as the RADIUS accounting client and R-eWAG as the RADIUS accounting server. R-eWAG
extracts the necessary attributes required to create the GTP tunnel to GGSN. R-eWAG resolves the APN to get the
GGSN address to which to create the GTP tunnel. In this release, the PDP context will be created with a dynamic IP
address. On successful creation of the GTP tunnel, R-eWAG creates the association between the GGSN-assigned IP
address and the Wi-Fi IP address.
All IP data packets generated by the UE in the WLAN are directed to the R-eWAG. The R-eWAG NATs the outer
source IP address (Wi-Fi IP address) with the GGSN-assigned IP address (MPC IP address) and forwards it to the
GGSN via the GTP tunnel. The application servers in the PDN identify the UE by the GGSN-assigned IP address.
In the downlink direction, the R-eWAG NATs the outer destination address (MPC IP address) to the Wi-Fi IP address
so that it is correctly routed to the UE in the WLAN.
Control and Data Interfaces
eWAG supports the following control and data interfaces:
WLC/Wi-Fi AAA –R-eWAG:
Control Plane: The following RADIUS messages are supported on this interface:
Accounting Start
Accounting Interim
Accounting Stop
Disconnect Request
Data Plane: There is direct IP connectivity between WLC and R-eWAG. R-eWAG receives the original
IP packets generated by UE in WLAN. There could be other network elements (routers) between
WLC and R-eWAG, which can provide Layer 2 or Layer 3 tunneling to route the WLAN-generated
packets across the public network.
Important: In this release, R-eWAG does not support Tunneling (IP over GRE).
ICMP Processing: ICMP packets in the downlink direction are remapped and sent to the UE.
eWAG –GGSN (Gn’):
PDP Activation Messages: The following messages are supported over the Gn’ reference point:
Create PDP Context Request / Response
Update PDP Context Request / Response: R-eWAG-initiated Update PDP Context scenario is
supported as explained in the Session Update Call Flow section.
Delete PDP Context Request / Response
Error Indication
Version Not Supported
GTP Payload Forwarding
GTP Echo
R-eWAG-GGSN Gn' Interface