What is IWF
Despite a lot of LTE deployment in major part of the word there is still a good amount of legacy network exist which is based on SS7 i.e. CAP for charging and MAP for HLR functions. For reducing a risk of network outage lot of operators feels to have a requirement of Interworking Function which can convert the SS7(CAP/MAP) signalling to Diameter Signalling or vice-versa which created the milestone for IWF requirement and increases the ROI of existing network.
Use Case of IWF
LTE-EPC uses Diameter to access the core nodes like HSS, EIR for the network and OCS for charging. When EPC is interworking with legacy PLMN, there is a need to use existing legacy elements like the HLR, EIR and Prepaid SCP with SS7 with TDM or Sigtran with IP. Also when HSS, EIR and OCS are deployed or upgraded to use Diameter there may be a need for them to be used by legacy elements using SS7. In above cases we need a node which can convert the SS7 signalling to diameter signaling or vice-versa.
Standard: The 3GPP defines an IWF between Diameter and MAP in the spec 29.305 whereas there is no corresponding standard for Diameter to CAP.
Variants of IWF
Diameter to MAP
Diameter to CAP
Diameter to Radius
Diameter IPv4 to Diameter IPv6
Diameter TCP to Diameter SCTP
Vendors for IWF
F5 Technologies - http://www.f5.com/pdf/solution-profiles/ss7-interworking-solution-profile.pdf
Squire Technologies - http://www.squire-technologies.co.uk/products/ss7-map-to-diameter-interworking-function-functionality
Jinny Software - http://www.jinnysoftware.com/operator-challenges/managing-the-transition-to-4g-networks/diameter-signalling-management/diameter-gateway-iwf/
Diametriq Software - http://diametriq.com/diameter-interworking/
Dialogic - http://www.dialogic.com/en/products/diameter-signaling-controller/bordernet-diameter-services-helix.aspx
Broad Forward - http://www.broadforward.com/bfx-for-ss7/
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