Important: Direct tunnel is a licensed Cisco feature. A separate feature license 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.The direct tunnel architecture allows the establishment of a direct user plane (GTP-U) tunnel between the radio access network equipment (RNC) and the GGSN/P-GW.
Once a direct tunnel is established, the SGSN/S-GW continues to handle the control plane (RANAP/GTP-C) signaling and retains the responsibility of making the decision to establish direct tunnel at PDN context activation.
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3G network: The SGSN establishes a user plane (GTP-U) tunnel directly between the RNC and the GGSN, using an Updated PDN Context Request toward the GGSN.
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LTE network: When Gn/Gp interworking with pre-release 8 (3GPP) SGSNs is enabled, the GGSN service on the P-GW supports direct tunnel functionality. The SGSN establishes a user plane (GTP-U) tunnel directly between the RNC and the GGSN/P-GW, using an Update PDN Context Request toward the GGSN/P-GW.
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LTE network: The SGSN establishes a user plane tunnel (GTP-U tunnel over an S12 interface) directly between the RNC and the S-GW, using an Update PDN Context Request toward the S-GW.
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disallowed on the SGSN/S-GW
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allowed on the GGSN/P-GW.
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For more information about operator policies and configuration details, refer to the Operator Policy chapter also in this guide.
Important: If direct tunnel is allowed in the default operator policy, then any incoming call that does not have an applicable operator policy configured will have direct tunnel allowed.Before beginning any of the following procedures, you must have completed (1) the basic service configuration for the SGSN, as described in the Cisco ASR Serving GPRS Support Node Administration Guide, and (2) the creation and configuration of a valid operator policy, as described in the Operator Policy chapter in this guide.
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Step 1
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Configure the SGSN to setup GTP-U direct tunnel between an RNC and an access gateway by applying the example configuration presented in the Enabling Setup of GTP-U Direct Tunnels section below.
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Step 2
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Configure the SGSN to allow GTP-U direct tunnels to an access gateway, for a call filtered on the basis of the APN, by applying the example configuration presented in the Enabling Direct Tunnel per APN section below.
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Important: It is only necessary to complete either step 2 or step 3 as a direct tunnel can not be setup on the basis of call filtering matched with both an APN profile and an IIMEI profile.|
Step 3
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Configure the SGSN to allow GTP-U direct tunnels to a GGSN, for a call filtered on the basis of the IMEI, by applying the example configuration presented in the Enabling Direct Tunnel per IMEI section below.
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Step 4
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Configure the SGSN to allow GTP-U direct tunnel setup from a specific RNC by applying the example configuration presented in the Enabling Direct Tunnel to Specific RNCs section below.
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Step 5
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(Optional) Configure the SGSN to disallow direct tunnel setup to a single GGSN that has been configured to allow it in the APN profile. This command allows the operator to restrict use of a GGSN for any reason, such as load balancing. Refer to the direct-tunnel-disabled-ggsn command in the SGTP Service Configuration Mode chapter of the Command Line Interface Reference.
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Step 6
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Save your configuration to flash memory, an external memory device, and/or a network location using the Exec mode command save configuration. For additional information on how to verify and save configuration files, refer to the System Administration Guide and the Command Line Interface Reference.
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Step 7
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Check that your configuration changes have been saved by using the sample configuration found in the Verifying the SGSN Direct Tunnel Configuration section in this chapter.
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call-control-profile <policy_name>
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By default, APN-based direct tunnel functionality is allowed so any existing direct tunnel configuration must be removed to return to default and to ensure that the setup has not been restricted.
apn-profile <profile_name>
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By default, direct tunnel functionality is enabled for all RNCs.
imei-profile <profile_name>
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By default, direct tunnel functionality is enabled for all RNCs.
context <ctx_name>
iups-service <service_name>
rnc id <rnc_id>
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Command details for configuration can be found in the Command Line Interface Reference.
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show operator-policy full name <policy_name>
Operator Policy Name = oppolicy1
Call Control Profile Name : ccprofile1
IMEI Profile Name : imeiprofile1
APN Profile Name : apnprofile1
APN NI visitors2
APN Profile Name : apnprofile2
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The operator policy itself will only be valid if one or more IMSI ranges have been associated with it - refer to the Operator Policy chapter, in this guide, for details.
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show call-control-profile full name <profile_name>
Call Control Profile Name = ccprofile1
show apn-profile full name <profile_name>
Call Control Profile Name = apnprofile1
Use the following command to display and verify the direct tunnel configuration in the IMEI profile:
show imei-profile full name <profile_name>
IMEI Profile Name = imeiprofile1
show iups-service name <service_name>
context <egress_context_name> -noconfirm
interface <s12_interface_name>
ip address <s12_ipv4_address_primary>
ip address <s12_ipv4_address_secondary>
context <egress_context_name> -noconfirm
gtpu-service <s12_gtpu_egress_service_name>
bind ipv4-address <s12_interface_ip_address>
egtp-service <s12_egtp_egress_service_name>
associate gtpu-service <s12_gtpu_egress_service_name>
gtpc bind address <s12_interface_ip_address>
sgw-service <sgw_service_name> -noconfirm
associate egress-proto gtp egress-context <egress_context_name> egtp-service <s12_egtp_egress_service_name>
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The S12 interface IP address(es) can also be specified as IPv6 addresses using the ipv6 address command.
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