The LTE/EPC model has been enhanced with new features:
* SGW, PGW and MME are full nodes.
* There are P2P links between core network nodes.
* New S5 interface between SGW and PGW nodes based on GTPv2-C protocol.
* Allow simulations with multiple SGWs and PGWs.
LTE eNB RRC is extended to support:
* S1 signalling with the core network is initiated after the
RRC connection establishment procedure is finished.
* New ATTACH_REQUEST state to wait for finalization of the S1
signalling with the core network.
* New InitialContextSetupRequest primitive of the S1 SAP that is
received by the eNB RRC when the S1 signalling from the core network
is finished.
Squashed commit of the following from mrequena:epc-upgrade:
lte: Clarify that e2e is IPv4/IPv6 and core network is IPv4-only
lte: Remove duplicated example from wscript
lte: Add new features of the EPC upgrade to CHANGES.html
lte: Remove duplicated example
lte: (fixes#3027) S1 signalling is done before RRC connection establishment is finished
lte: Add new ATTACH_REQUEST state in eNB RRC
lte: cast a uint8_t when logging
lte: Fix doxygen comments and doc typos
lte: Add documentation for EPC split
lte: Use protocolNumber in new EpcPgwApplication
lte: Add doxygen doc for EpcSgwApplication class
lte: Add doxygen doc for EpcPgwApplication class
lte: Add doxygen doc for EpcMmeApplication class
lte: PreSerialize/PreDesearialize are only used in the derived messages
lte: Command line parameters take precedence over parameters in config file
lte: Rename number of node pairs variable
lte: Add IPv6 support to new PgwApplication
lte: Change to new pgw node
lte: Number of nodes has changed after EPC split
lte: InitialUeMessage cannot be called if simulation is not started
lte: Change some names of addresses and clean debug code
lte: New GetPacketFilters method
lte: Add new files to build system
lte: Don't need to build the GtpcHeader by hand, just the message
lte: GTPC messages derived from GtpcHeader
lte: Add new PGW Application
lte: Add new SGW Application
lte: Add new MME Application
lte: Add new GTP-C protocol header
lte: Split SGW/PGW/MME in different nodes
lte: Add new example
