Ewag + Ttg Combo Deployments; Sgtp Service Configuration In Ewag + Ttg Combo Deployments - Cisco ASR 5000 Administration Manual

Enhanced Wireless Access Gateway Overview
Note that in the ASR 5000 chassis the virtual-APN selection can be based on other criteria apart from access gateway
(AGW) address selection like MSISDN range, RAT type, and so on. eWAG uses only AGW address criteria, which is
the RADIUS accounting-client from which the initial Accounting-Start message is received.
This way, the real-APN can be configured with virtual-APN selection based on RADIUS-client for eWAG, clearly
separating out the APN configuration being used by colocated eWAG+GGSN. So, after enabling virtual-APN for
eWAG in colocated chassis as explained above, the configurations under virtual-APN are used only by eWAG callline
and the configurations under real-APN will be used only by the GGSN callline without affecting each other.
Important:
under the real-APN, the call will get dropped with unknown-APN as the reason.
Consider the eWAG+GGSN combo deployment with an SGSN connecting to the GGSN for 3G access. In this case, if
the SGSN service's IP address subnet is 111.2.3.4/24 and the RADIUS accounting-client that is sending Accounting-
Start message to the eWAG is also in the same subnet 111.2.3.4/24, the virtual-APN is configured under real-APN as
follows:
virtual-apn preference 1 apn ewag_corp1 access-gw-addr 111.2.3.4/24
In the above case, when the call is coming through 3G macro-access and landing in GGSN, the virtual-APN criteria
matches for the GGSN call line as the AGW address in this case is SGSN node, which matches the subnet. So, the
GGSN call line will start using virtual-APN profile. In the same way, when the call is coming through Wi-Fi access
through eWAG, then the virtual-APN criteria matches for the eWAG callline as the AGW address in this case is
RADIUS accounting-client which matches the subnet. So the eWAG call line will start using virtual-APN profile as
well. Also, if the eWAG service's IP address subnet matches with the RADIUS accounting-client IP address and there is
a virtual-APN configuration based on this subnet range as AGW address, then both eWAG and GGSN call lines start
using the virtual-APN profiles only ignoring real-APN. This is because AGW address for eWAG call is RADIUS
accounting-client and the AGW address for GGSN call is eWAG (GTP-peer) and both of them are in the same subnet
making the virtual-APN condition to be true for both call lines. It is important to be aware of above possibilities to avoid
any mis-configurations or undetermined behavior.

eWAG + TTG Combo Deployments

Important:
supported, it is available only for lab / testing purposes.
This section lists dependencies and limitations for eWAG + TTG combo deployments.

SGTP Service Configuration in eWAG + TTG Combo Deployments

The eWAG and TTG both require SGTP service configuration, and in a combo deployment they can share the same
SGTP service. Note that eWAG always allocates NASPI value 15, while TTG allocates NSAPI starting from 5
(maximum 15).
In an eWAG + TTG combo deployment sharing the same SGTP service:
 If eWAG call is setup with GTPv1 and TTG call comes up with the same IMSI and NSAPI 15 on same the
SessMgr, only GTPv1 Create PDP Context will be sent by SGTP. If Create PDP Context response for GTPv1
is not received then SGTP will not start with GTPv0. The call will be rejected with disconnect reason "act-
rejected-by-ggsn". The same is true if the TTG call is setup first and then the eWAG call comes up.
OL-28188-02
Note that if the virtual-APN profile configuration is not available for the virtual-APN name specified
In this release, the eWAG + TTG combo deployment option is not fully qualified and is not
Cisco ASR 5000 Enhanced Wireless Access Gateway Administration Guide ▄
Dependencies and Limitations ▀
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