Service Provider WiFi: Support for Integrated Ethernet Over GRE

Generic Routing Encapsulation (GRE) is a tunneling protocol that encapsulates a wide variety of network layer protocols inside virtual point-to-point links over a Layer 3 IPv4 or Layer 3 IPv6 access network.

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Information About Ethernet Over GRE

Ethernet over GRE (EoGRE) is a new aggregation solution for aggregating WiFi traffic from hotspots. This solution enables customer premises equipment (CPE) devices to bridge the Ethernet traffic coming from an end host, and encapsulate the traffic in Ethernet packets over an IP GRE tunnel. When the IP GRE tunnels are terminated on a service provider broadband network gateway, the end host’s traffic is terminated and subscriber sessions are initiated for the end host.

The following figure shows the structure of the Ethernet over GRE.

Figure 1. Ethernet Over GRE Structure

Restrictions for Configuring Ethernet Over GRE

The following features are not supported on the Cisco ASR 1000 Series Aggregation Services Routers:

  • IPsec tunnel between the Cisco ASR 1000 Series Aggregation Services Routers and the CPE devices
  • Native multicast coexistence for subscribers
  • Per-CPE QoS
  • IPv6 subscriber
  • The Cisco Intelligent Services Gateway (ISG) RADIUS proxy initiator
  • QinQ tag for the inner L2 frame
  • High Availability is not supported if ISG is not configured.
  • If the VLAN priority tag inside the EoGRE packet is set to a nonzero value, iWAG ignores the packet

Prerequisites for Configuring Ethernet Over GRE

Before you configure the Ethernet over GRE feature on the Cisco ASR 1000 Series Aggregation Services Routers, ensure that the following prerequisites are met:

  • A physical interface or dot1Q interface should be configured.
  • The ISG policy should not be applied to the physical interface.

Information About Configuring Ethernet Over GRE

The Cisco ASR 1000 Series Aggregation Services Routers serve as a service provider broadband network gateway that:

  • Terminates IPv4 or IPv6 GRE tunnels.
  • Manages the subscriber session for end-host clients.

The EoGRE feature works with legacy residential gateways and CPE devices to terminate the Ethernet L2 traffic in the Cisco ASR 1000 Series Aggregation Services Routers. When configured as an intelligent Wireless Access Gateway (iWAG) with EoGRE access tunneling support, the Cisco ASR 1000 Series Aggregation Services Routers can extend mobility and the ISG services in support of these legacy devices.

The following figure shows the structure of the EoGRE feature with PMIP/GTP integrated for mobility service.

Figure 2. Structure of the EoGRE Feature with PMIP/GTP Integrated for Mobility Service

The following figure shows the structure of the EoGRE feature for simple IP service.

Figure 3. Structure of the EoGRE Feature for Simple IP Service

The EoGRE feature supports the following deployments:

  • EoGRE Deployment with PMIPv6 Integrated for Mobility Service
  • EoGRE Deployment with GTP Integrated for Mobility Service
  • EoGRE Deployment with ISG Integrated for Simple IP Service

EoGRE Deployment with PMIPv6 Integrated for Mobility Service

Proxy Mobile IPv6 (PMIPv6) provides mobility service to the mobile nodes that are connected to the Mobile Access Gateway (MAG) via an EoGRE tunnel. The following figure shows the structure of the EoGRE deployment with PMIPv6 integrated for mobility service.

Figure 4. Structure of the EoGRE Deployment with PMIPv6 Integrated for Mobility Service

Mobile nodes access the mobile internet service over Wi-Fi access points. The access points are either autonomous access points or are connected to the Cisco Wireless LAN Controller (WLC). These access points and WLCs are used as residential gateways or CPE devices. CPEs are preconfigured with a point-to-multipoint GRE IP tunnel to the Cisco ASR 1000 Series Aggregation Services Routers as the MAG. The tunnel from the CPE device can be configured with a static GRE key. The CPEs are provisioned to forward the Ethernet traffic from both public and private customers to the GRE tunnel, and to add a VLAN tag on the Ethernet frame before forwarding the traffic.

As with regular PMIPv6 deployments, the Cisco ASR 1000 Series Aggregation Services Routers can create IP sessions on EoGRE access tunnels similar to the regular IP sessions on the physical Ethernet interfaces, and allocate IP addresses for mobile nodes, either locally or in the proxy mode. Mobility service is provided to the mobile nodes and the tunneled Ethernet traffic is forwarded via IP tunnels to the Local Mobility Anchor (LMA).


Note
When you ping a mobile node from the MAG with a packet size that is larger than that of the path maximum transmission unit (PMTU) that is configured with the DF bit set, the packet will be dropped. However, you will not get the return type as M.M.M (could not fragment). This is reflected in the log messages or error messages.

For more information about PMIPv6 and the ISG configurations for the iWAG, see the Intelligent Wireless Gateway Configuration Guide.

EoGRE Deployment with GTP Integrated for Mobility Service

GPRS Tunneling Protocol (GTP) provides mobility service to the mobile nodes that are connected to the iWAG via an EoGRE tunnel, as shown in the following figure.

Figure 5. Structure of the EoGRE Deployment with GTP Integrated for Mobility Service

For more information about the GTP and ISG configurations for the iWAG, see the Intelligent Wireless Gateway Configuration Guide.

EoGRE Deployment with ISG Integrated for Simple IP Service

The ISG provides simple IP service to mobile nodes that are connected to ISG via the EoGRE tunnel, as shown in the following figure. The Cisco ASR 1000 Series Aggregation Services Routers use the ISG framework to allocate IP sessions for authenticated subscribers. Simple IP subscribers are provided ISG services, including Internet access, but are not provided access to mobility services via GTP or PMIPv6.

Figure 6. Structure of the EoGRE Deployment with ISG Integrated for Simple IP Service

Supported Features

The following features are supported as part of the EoGRE feature on the Cisco ASR 1000 Series Aggregation Services Routers:

  • Ethernet over GRE traffic termination on the routers
  • Frames can have up to one dot1Q VLAN tag
  • L2-connected IPv4 mobile nodes
  • GRE tunnel for IPv4 or IPv6
  • ISG and PMIPv6 or GTP integrated with the EoGRE tunnel
  • ISG initiator-unclassified MAC, DHCP, DNAv4
  • Subscriber roaming

How to Configure the EoGRE Feature

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. interface interface-name
  4. ip unnumbered loopback interface-name or ip address ip-address
  5. tunnel source interface-type interface-number
  6. (For simple IP mode) mac-address H.H.H
  7. tunnel mode ethernet gre ipv4 or tunnel mode ethernet gre ipv6
  8. (Optional) tunnel vlan vlan-id
  9. end

DETAILED STEPS

  Command or Action Purpose
Step 1

enable

Example:

 
Router> enable

Enables the privileged EXEC mode.

Enter your password, if prompted.

Step 2

configure terminal

Example:


Router# configure terminal

Enters the global configuration mode.

Step 3

interface interface-name

Example:


Router(config)# interface Tunnel 0

Specifies the logical interface for the EoGRE tunnel.

Step 4

ip unnumbered loopback interface-name or ip address ip-address

Example:


Router(config-if)# ip unnumbered loopback 0 

or

Router(config-if)# ip address 20.1.1.2 255.255.255.0

For PMIPv6 and GTP scenarios, an unnumbered address or a specified IP address can be configured on the tunnel interface.

For a simple IP scenario, only a specified IP address can be configured on the tunnel interface. This IP address can be used as a default gateway IP address.

Step 5

tunnel source interface-type interface-number

Example:

Router(config-if)# tunnel source Loopback 0

Sets the source interface for the EoGRE tunnel interface.

Step 6

(For simple IP mode) mac-address H.H.H

Example:

Router(config-if)# mac-address 0000.5e00.5213

Sets the source MAC address for the EoGRE tunnel interface. The MAC address is mandatory for simple IP deployment. For PMIPv6/GTP, the default MAC address associated with EoGRE Tunnel is 0000.5e00.5213.

Step 7

tunnel mode ethernet gre ipv4 or tunnel mode ethernet gre ipv6

Example:


Router(config-if)# tunnel mode ethernet gre ipv4

or

Router(config-if)# tunnel mode ethernet gre ipv6

Sets the EoGRE encapsulation mode for the tunnel interface for IPv4.

or

Sets the EoGRE encapsulation mode for the tunnel interface for IPv6.

Step 8

(Optional) tunnel vlan vlan-id

Example:



Router(config-if)# tunnel vlan 1000

(Optional) Sets the VLAN ID of the EoGRE tunnel.

Step 9

end

Example:



Router(config-if)# end

Ends the current configuration session.

Example: Configuring the EoGRE Feature


aaa new-model  
!  
aaa group server radius AAA_SERVER_CAR  
server-private 5.3.1.76 auth-port 2145 acct-port 2146 key cisco  
!  
aaa authentication login default none  
aaa authentication login ISG_PROXY_LIST group AAA_SERVER_CAR  
aaa authorization network ISG_PROXY_LIST group AAA_SERVER_CAR   
aaa authorization subscriber-service default local group AAA_SERVER_CAR   
aaa accounting network PROXY_TO_CAR  
action-type start-stop  
group AAA_SERVER_CAR  
!  
aaa accounting network ISG_PROXY_LIST start-stop group AAA_SERVER_CAR  
!  
aaa server radius dynamic-author  
client 5.3.1.76 server-key cisco  
auth-type any  
ignore server-key  
!  
!  
ip dhcp excluded-address 172.16.254.254  
!  
ip dhcp pool ISG_SIMPLE_IP  
 network 172.16.0.0 255.255.0.0  
 default-router 172.16.254.254  
 domain-name cisco.com  
!  
policy-map type control EOGRE_L2_ISG  
 class type control always event session-start  
  2 authorize aaa list ISG_PROXY_LIST password cisco identifier mac-address  
  4 set-timer IP_UNAUTH_TIMER 5  
 !  
 class type control always event service-start  
  1 service-policy type service identifier service-name  
  2 collect identifier nas-port  
 !  
!  
interface Loopback0  
 ip address 9.9.9.9 255.255.255.255    
interface GigabitEthernet1/0/0  
ip address 192.168.0.9 255.255.255.0  
negotiation auto  
!  
interface GigabitEthernet1/0/0.778  
description "to ASR5K GGSN"  
encapsulation dot1Q 778  
ip address 172.16.199.9 255.255.255.0    
!    
interface Tunnel10  
 description "EoGRE Tunnel for Simple IP subscribers"  
 mac-address 0000.5e00.5213  
 ip address 172.16.254.254 255.255.0.0  
 no ip redirects  
 tunnel source 172.16.199.9  
 tunnel mode ethernet gre ipv4  
 service-policy type control EOGRE_L2_ISG  
 ip subscriber l2-connected  
  initiator unclassified mac-address  
  initiator dhcp    
interface Tunnel100  
description "IPv4 EoGRE Tunnel for PMIP/GTP subscribers"  
 ip unnumbered Loopback0  
 tunnel source GigabitEthernet1/0/0  
 tunnel mode ethernet gre ipv4  
 tunnel vlan 100  
 service-policy type control EOGRE_L2_ISG  
 ip subscriber l2-connected  
  initiator unclassified mac-address  
  initiator dhcp  
!  
interface Tunnel200  
description "IPv6 EoGRE Tunnel for PMIP/GTP subscribers"  
 ip unnumbered Loopback0  
 tunnel source 2001:161::9  
 tunnel mode ethernet gre ipv6  
 tunnel vlan 200  
service-policy type control EOGRE_L2_ISG  
 ip subscriber l2-connected  
  initiator unclassified mac-address  
  initiator dhcp  
!  
mcsa  
 enable sessionmgr  
!  
ipv6 mobile pmipv6-domain D1  
 replay-protection timestamp window 255  
lma LMA_5K  
  ipv4-address 192.168.199.1  
!  
ipv6 mobile pmipv6-mag M1 domain D1  
sessionmgr  
 role 3GPP  
 address ipv4 9.9.9.9  
interface Tunnel100  
 interface Tunnel200  
 lma LMA_5K D1  
  ipv4-address 192.168.199.1  
  encap gre-ipv4  
!  
ntp master  
!  
gtp  
 information-element rat-type wlan  
 interface local GigabitEthernet1/0/0.778  
 apn 1  
  apn-name gtp.com  
  ip address ggsn 172.16.199.1  
  fixed link-layer address 00ab.00cd.00ef  
  default-gw 20.100.254.254 prefix-len 16  
  dns-server 20.100.254.254  
  dhcp-server 20.100.254.254  
!  
end
You can use the following commands to check and show subscriber session information: 

show ip dhcp sip statistics
show subscriber statistics
show subscriber session
show ipv6 mobile pmipv6 mag binding
show gtp pdp-context all
show interface tunnel-name

Additional References

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

iWAG commands

Cisco IOS Intelligent Wireless Access Gateway Command Reference

MIBs

MIB

MIBs Link

No new or modified MIBs are supported by this feature.

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

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Link

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Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

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Feature Information for Configuring Ethernet Over GRE

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 1. Feature Information for Configuring the Ethernet Over GRE Feature
Feature Name Releases Feature Information

Service Provider WiFi: Integrated Ethernet Over GRE

3.9.1S

This feature enables the Ethernet over Generic Routing Encapsulation (EoGRE) tunnel to be used as a service provider WiFi access interface from CPE devices. A Cisco ASR 1000 Series Aggregation Services Router is used as an L2 aggregator to terminate L2 traffic at the GRE tunnel interface and provide L3 services.

In Cisco IOS XE Release 3.9.1S, this feature is implemented on the Cisco ASR 1000 Series Aggregation Services Routers.

The following sections provide information about this feature: