Simu5G 1.8.0

The most significant change in this release is the support for new PDU session types: besides IPv4, a UE can now have an IPv6, IPv4v6, Ethernet or Unstructured session, carried end to end from the UE to the data network. The control plane was rebuilt after 3GPP's division of responsibilities, with a core network control module and control-plane entry points in the base stations, UEs and user plane nodes. GTP-U tunnels now carry per-session TEIDs and, in a 5G core, the QFI. Header compression is modeled as ROHC configured per bearer. This release, like all releases since v1.3.1, was developed by Andras Varga and the OMNeT++ core team.

This release requires INET-4.7.0 and OMNeT++ 6.4.0.

Live Q&A: To discuss this release, I will host an open video call on Wednesday, October 21, 14:00–15:00 CEST (12:00–13:00 UTC) on Google Meet. Anyone is welcome to join, ask questions about the new bearer configuration, migrating existing simulations, or anything else in 1.8.0, or just share feedback. Meeting URL: https://meet.google.com/edr-siof-han

Session types: the UE's sessionType parameter

The session type is the UE's request, as in 3GPP: the PDU session type of
the PDU Session Establishment Request in a 5G core, or the PDN type in an
EPC. The new LteUe parameter sessionType takes "IPv4" (the default),
"IPv6", "IPv4v6", "Ethernet" or "Unstructured". The request travels
with the UE's attach to CoreControl, which establishes the session with
that type. Every node that ends one of the session's tunnels keeps the type,
so the user plane dispatches on the type instead of parsing packets. An EPC
(a PgwStandard anchor) carries the IP types only, and a non-IP session
anchored at a PGW is an error.

One session per UE. In 3GPP a UE may have several PDU sessions at once, e.g.
an IPv4 session to the Internet and an Ethernet session to an industrial LAN,
each with its own type, anchor and bearers. In Simu5G a UE has exactly one,
whose type is selected by its sessionType parameter. This is a deliberate
simplification that keeps configuration simple: one parameter per UE, and no
session reference in the bearer definitions. Future releases may lift this
limitation and offer an alternative configurator that allows multiple sessions
per UE at the cost of requiring more complex configuration.

Bearers are typed by the session of their UE, so the bearer definitions no
longer carry a type. The pduSessionType and upperProtocol fields of
staticDrbs, onDemandDrbs and drbProfiles are gone. A definition that
still has one is an error that names the UE parameter. In v1.7.0 only the
default "IPv4" worked, so in practice the fields can simply be deleted.

The UE passes the session type to its NIC as well, so the cellularNic of
LteUe is now typed by the new IUeCellularNic interface: an ICellularNic
with a sessionType parameter. The built-in UE NICs implement it; a custom UE
NIC must implement it too.

IPv6 and IPv4v6 sessions

• The user plane is address-family neutral. The Binder maps L3Addresses
  to node ids. A UE's addresses are registered by the UE RRC's Registration
  submodule, which follows the cellular interface's configuration as it
  changes during the run: link-local and autoconfigured IPv6 addresses
  appear only after initialization. On an IPv4v6 session, IPv4 and IPv6
  datagrams share the session's bearers, and each goes up as its own
  protocol.

• Neighbor Discovery at the anchor: in a 5G core, the IP link of an IPv6
  session runs between the UE and its anchor UPF (TS 23.502). The new
  Ipv6NdResponder module, present in Upf and PgwStandard when
  hasNdResponder = true (default false), answers the UE's Router
  Solicitations with a Router Advertisement that makes it the UE's default
  router (fe80::1 by default). It also answers reachability probes and
  consumes duplicate address detection. A UPF without a responder throws when
  a UE's link-local IPv6 traffic arrives, instead of leaking it onto the
  data network.

• QFI rule filter expressions are evaluated on every packet of their site.
  For an IPv6 UE this includes its Neighbor Discovery traffic, so the
  examples in the BearerConfigurator and QfiRuleSet documentation now
  guard their expressions with has(udp). For dscpAsQfi rules, the DSCP is
  also read from the IPv6 Traffic Class field.

• D2D groupcast remains IPv4-only. An IPv6 multicast packet of a D2D-capable
  UE goes up the session like that of any other UE.

• Examples: VoIP-DL-IPv6, VoIP-UL-IPv6, VoIP-DL-IPv6-Rohc,
  VoIP-DL-IPv4v6 and VoIP-UL-IPv4v6 in nr/standalone;
  VoIP-DL-MultiQfi-IPv6 and VoIP-UL-FilterRules-IPv6 in
  nr/standalone_drb; CBR-DL-IPv6 in nr/standalone_multicell, which
  includes handovers; NeDualConn-VoIP-DL-IPv6 in nr/dualConnectivity; and
  SinglePair-UDP-D2D-IPv6 in lte/d2d. In these examples the UEs, the
  server and the router are IPv6-only, while the transport network (N3, S1-U,
  X2) stays IPv4.

Ethernet sessions

A UE whose sessionType is "Ethernet" (TS 23.501 5.6.10.2) gets the link
layer of an INET Ethernet node, with the cellular NIC as one of its Ethernet
ports. The UPF switches the session's frames in an Ethernet bridge, among
its Ethernet sessions and its N6 Ethernet LAN.

• UE: the new ethernetMode parameter selects what the UE is on that
  link layer. With "host" (the default), the UE is an Ethernet host whose
  raw Ethernet applications (e.g. INET's EthernetSourceApp and
  EthernetSinkApp) use the NIC's MAC address. With "bridge", the UE
  bridges between the cellular NIC and its eth[] interfaces, behind which
  further devices can be connected. The 5GS does not carry the FCS: it is
  removed on entry and rebuilt on exit.

• QoS rules classify a frame by its headers. Their filter expressions
  can read the Ethernet MAC header and the 802.1Q C-TAG and S-TAG (PCP, DEI,
  VID); a module test documents the accessible fields. A dscpAsQfi rule
  does not match a frame, and a dscpAsQfi rule scoped to an Ethernet UE is
  an error.

• UPF: the new EthernetSessionBridge (submodule ethBridge, present
  with hasEthernetBridge = true) is built on INET's BridgingLayer. It
  has one port per session, which is created when the session is
  established and removed, along with its learned addresses, when the
  session is released. Its N6 port is the UPF's dnEth interface, which is
  connected to the dnEthg gate; being the bridge's port, dnEth is not an
  interface of the UPF's network layer. Traffic between two UEs is switched
  at the UPF without passing through N6.

• Not modeled (listed in EthernetSessionBridge's documentation):
  VLAN-scoped flooding, ARP/ND proxying, allowed VLAN and MAC lists, S-TAG
  and C-TAG handling, reporting learned MAC addresses to the SMF, PSA
  relocation, and 5G VN groups. IP over an Ethernet session is not
  configured automatically.

• Restrictions, each an error: an Ethernet session needs a 5G core and an
  anchor UPF with an Ethernet bridge, and it is not supported on a
  D2D-capable UE or together with ROHC.

• Examples: simulations/nr/ethernet, with configs Ethernet-Hosts,
  Ethernet-Bridge (VLAN 42 frames, with PCP 5 mapped to a second QoS flow
  and DRB), Ethernet-Handover and Ethernet-Mixed (Ethernet, IPv4 and
  Unstructured UEs at one UPF).

Unstructured sessions

A UE whose sessionType is "Unstructured" (TS 23.501 5.6.10.3) sends
opaque payload. The anchor UPF carries it to an application server over the
session's N6 point-to-point tunnel, in UDP/IP datagrams (TS 29.561 9.2).

• UE: the new UnstructuredApp (and its send-only and receive-only
  variants, UnstructuredSourceApp and UnstructuredSinkApp) attaches to the
  cellular NIC directly, as no network layer is involved. A UE has at most
  one, in the new unstructuredApp[] submodule vector
  (numUnstructuredApps, default 0).

• UPF: the N6 side is configured on the UPF's nodeControl module with
  the unstructuredPrefix, unstructuredServer, unstructuredServerPort
  and unstructuredPort parameters. TS 29.561 defines no UDP port for the
  tunnel, so the two port parameters have no default. CoreControl allocates
  an N6 address to each session from the prefix.

• Restrictions, each an error: an Unstructured session needs a 5G core
  and a UE stack with SDAP, and it has a single QoS flow on the default
  bearer. A second bearer, a QoS rule scoped to the UE, reflective QoS, ROHC
  and a D2D-capable UE are rejected. MEC steering does not apply, as it goes
  by the IP destination.

• Examples: simulations/nr/unstructured, with configs Unstructured
  (with an IPv6 data network, the variant TS 29.561 describes),
  Unstructured-Ipv4N6, Unstructured-Handover and Unstructured-Mixed.

Control plane: CoreControl and the nodes' control-plane entry points

The configuration and signaling that v1.7.0 performed from the
BearerConfigurator, the Binder and the UE now run between modules that
correspond to the 3GPP entities, as calls named after the messages they
stand for:

• CoreControl is a new network-level module, next to the Binder and
  the BearerConfigurator. It is the MME and the gateways' control plane of
  an EPC, or the AMF and SMF of a 5G core. It establishes and releases the
  UEs' sessions and programs the nodes that end their tunnels. It also
  delivers the authored QFI rules to their evaluation sites.

• ConnectionControlEnb is the base station's entry point (submodule
  rrc.connectionControl). It owns the node's TEID space and its UEs' DRB
  identities, establishes their bearers, and runs the network side of
  attach, handover and radio link failure. Its D2D variant,
  ConnectionControlEnbD2D, also establishes the sidelink and multicast
  bearers.

• ConnectionControlUe is the UE's entry point. It is the former
  HandoverController, which is renamed because it now does more than
  handovers: measurements and reports, the execution of a commanded
  handover, and attachment and detachment.

• UserPlaneNodeControl (submodule nodeControl of Upf and
  PgwStandard, and so of the MEC host's UPF) is a user plane node's entry
  point, the end of N4/S11 at which its sessions are established, modified
  and deleted.

• The BearerConfigurator is now read-only: it holds the bearer
  definitions and the QoS rule tables, which are read by the base stations
  and by CoreControl. The bearer definition schema is unchanged, apart
  from the removed pduSessionType/upperProtocol fields and the new
  rohc field.

• Attach: a UE leg requests an RRC connection from its serving base
  station, which registers the UE with the core network (INITIAL UE
  MESSAGE). The core network establishes the session and asks the base
  station to set up the session's resources: the tunnels, the UE's uplink
  QoS rules, and its static bearers. As a consequence, static bearers are
  now established UE by UE rather than table entry by table entry. In
  networks where several UEs have several static bearers each, this changes
  module ids and the order in which results are recorded, but not their
  values.

• Handover: the UE leg sends its serving base station a
  MeasurementReport with the serving and the best cell. The base station
  decides through selectHandoverTarget(), an overridable policy hook whose
  default takes the reported cell, so handovers happen where and when they
  did before. The source and the target prepare the handover over Xn
  (HANDOVER REQUEST/ACKNOWLEDGE), carrying the leg's context, including its
  bearer configuration. The source then commands the UE. When the UE
  arrives, the target asks the core network to switch the path (PATH SWITCH
  REQUEST) and releases the source (UE CONTEXT RELEASE). The two X2 control
  messages that announced a handover and stopped the forwarding are no
  longer sent, so the X2 transport's results (SCTP, PPP) change in every
  network with handovers.

• Radio link failure: the node that detects it informs the peer through
  the peer's control-plane entry point, instead of reaching into the peer's
  BearerManagement.

The signaling is modeled as direct calls: no RRC, NAS, S1AP/NGAP or PFCP
messages are transmitted, a procedure takes no time, and procedures have no
explicit state machines, timers or failure cases.

Networks and configurations written for v1.7.0 need these updates:

• Declare CoreControl: every network with base stations needs a
  coreControl: CoreControl submodule next to binder and
  bearerConfigurator. The base stations require it, and initialization
  fails without it.

• Renamed modules: HandoverController is now ConnectionControlUe,
  HandoverControllerD2D is now ConnectionControlUeD2D, and
  IHandoverController is replaced by IConnectionControl. In the Rrc
  compound, handoverController and nrHandoverController are now
  connectionControl and nrConnectionControl, and their conditions
  hasHandoverController and hasNrHandoverController are now
  hasConnectionControl and hasNrConnectionControl. Ini keys of the form
  **.rrc.handoverController.<param> must be updated accordingly.

• Renamed and removed parameters: PhyUe's handoverControllerModule
  and otherHandoverControllerModule are now connectionControlModule and
  otherConnectionControlModule. The bearerConfiguratorModule parameter of
  BearerManagement, Ip2Nic, NrSdap and Registration is replaced by
  connectionControlModule, and TrafficFlowFilter no longer has one. Also
  removed are GtpUser's ipOutInterface and interfaceTableModule,
  DcMux's binderModule, HandoverPacketHolderEnb's
  handoverX2ForwarderModule and HandoverX2Forwarder's
  handoverPacketHolderModule. All of these have defaults, so only
  configurations that override them are affected.

• C++ API: the X2 handover control message (X2HandoverControlMsg,
  X2HandoverCommandIE) and the LteProtocol::ipv4uu dispatch label are
  gone, the Binder's address maps take L3Address, and the Binder no
  longer keeps handover state.

GTP-U: session tunnels with TEIDs, PDU Session Container, End Marker

In v1.7.0 every GTP-U tunnel carried TEID 0, and each node found the UE of a
datagram from its inner IP address. Now:

• Each UE has a session (session ID 1), anchored at the UPF or PGW where it
  was established, for its whole lifetime (SSC mode 1). Each tunnel's TEID
  is allocated by its receiving end. Base stations and UPFs identify the
  session from the TEID, which also works for non-IP sessions and for IPv6
  packets with the unspecified source address.

• The GTP-U header follows TS 29.281. The N3 tunnels of a 5G core carry a
  PDU Session Container extension header (TS 38.415) with the QFI, which
  makes the header 16 bytes instead of 8. This changes the results of
  every network with N3 traffic towards a UPF. The header is serialized in
  the real format, so the QFI is visible in PCAP recordings and survives
  emulation.

• Downlink forwarded over X2 during a handover travels on the target's TEID.
  Dual connectivity bearers have per-bearer X2-U tunnels with their own
  TEIDs, so PDCP PDUs relayed between the master and the secondary no longer
  carry simulation-only metadata across X2.

• At the path switch, the anchor ends the old downlink path with a GTP-U End
  Marker (TS 29.281 7.3.2). The source relays it after the downlink it
  forwards, and the target holds back the downlink of the new path until the
  End Marker arrives (TS 23.502 4.9.1.2.2). Downlink is therefore no longer
  reordered at a handover. This changes the results of every network with
  handovers.

• The base station's user plane is wired directly, as in 3GPP: the cellular
  NIC connects to the base station's user plane relay (see below), not to
  the base station's own IP layer. Traffic between two UEs of the same base
  station is handed straight back to the NIC.

Header compression (ROHC) configured per bearer

In v1.7.0, header compression was a per-node parameter,
headerCompressedSize, which enabled compression on every bearer of the
node and also set the compressed size. In 3GPP it is a per-DRB setting
(TS 38.331 PDCP-Config), normally used only on voice bearers.

• Bearer definitions (staticDrbs, onDemandDrbs, drbProfiles) have a new
  rohc field: true (every modeled profile), false (the default), or
  {profiles: [...]}, which restricts compression to some of the profiles
  "rtp", "udp", "tcp" and "ip". Each packet is compressed with the
  most specific configured profile that fits it, and a packet that no
  profile fits is sent uncompressed. IPv6 datagrams are supported.

• Unidirectional mode (U-mode, RFC 3095): each flow has a context. A
  bearer has up to 16 contexts (CIDs 0..15), and when they are all taken,
  the least recently used one is taken over. A context starts in the IR
  state, moves to FO and then to SO, and is periodically refreshed. Header
  sizes and transition counts are parameters of the PDCP TX entity
  (rohcSoHeaderSizes, rohcFoHeaderSizes, rohcIrOverhead,
  rohcIrPackets, rohcFoPackets, rohcIrRefresh, rohcFoRefresh), with
  defaults taken from the open-source ROHC library. Contexts restart at a
  handover. Context damage after losses, O-mode and R-mode, and ROHCv2 are
  not modeled.

• On by default for voice: the new BearerConfigurator parameter
  rohcForDrbProfiles names the QoS profiles that get ROHC when their
  definition does not state rohc. Its default, ["5qi-1", "qci-1"], turns
  compression on for bearers whose definition names the conversational
  voice profile. This changes results for such configurations. In the
  VoIP-UL-CrossLcg example, for instance, the mean frame delay drops from
  19.46 to 17.54 ms. Bearers that carry voice without naming one of these
  profiles are not affected. To restore the previous behavior, set
  rohc: false on the definition or rohcForDrbProfiles = [].

• ROHC applies to IP sessions only. On other session types the policy is
  skipped, and an explicitly stated rohc is an error.

• Migration: setting headerCompressedSize is now an error. Use the
  rohc field instead, and set rohcSoHeaderSizes if you need a specific
  steady-state size. Unlike v1.7.0, each flow's first packets now carry the
  larger IR and FO headers. The unused LteRohcPdu message class is
  removed; the compressed header is represented by RohcHeader.

The UE is an INET StandardHost

LteUe, and with it NrUe, LteCar and NrCar, now extends INET's
StandardHost, with the cellular NIC as one more network interface of the
link layer, next to lo and the eth[] interfaces. The UE used to repeat the
structure of INET's node base modules by hand; it now inherits it, together
with StandardHost's configuration options, and StandardHost's optional
submodules (e.g. clock) become available in the UE.
Simulated traffic is unchanged: in the fingerprints, tplx and ~tNl are
identical, while tilx (module ids) and sz (the scalars of the removed
encap module) change.

Configurations written for v1.7.0 may need these updates:

• IP forwarding: *.ue.ipv4.forwarding = true must become
  *.ue.forwarding = true. StandardHost sets its network layers'
  forwarding from its own parameter, so the old key is silently ignored
  rather than rejected. The emulation examples are updated.

• Radio input gate: the UE's radioIn gate is renamed lteRadioIn,
  because StandardHost already has a radioIn[] gate vector (for its
  wireless LAN interfaces). The gate receives the air frames by direct
  sending and is not connected in networks, so only code that refers to it
  by name is affected.

• encap renamed ethernet: the Ethernet encapsulation of the eth[]
  interfaces (emulation mode) is now StandardHost's ethernet submodule,
  and it exists only when the UE has eth[] interfaces. Parameter settings on
  ue.encap must address ue.ethernet instead.

• ethg[] gates: the UE now has ethg[] gates for its eth[]
  interfaces, as every INET node does. A network containing a UE with
  eth[] interfaces whose ethg[] gates stay unconnected (e.g. emulation)
  must declare connections allowunconnected, as INET requires for
  StandardHost; all emulation examples already do.

• Interface order and name resolution: the UE's interfaces are now
  registered as lo0, the eth[] interfaces, then cellular (previously
  cellular came before the eth[] interfaces). An address given as the
  UE's name, e.g. destAddress = "ue[0]", resolves to the first
  non-loopback interface that has an address; for a UE whose eth[]
  interfaces have IP addresses (emulation), that is now an eth[] address,
  which the core network cannot deliver to, and the traffic is lost without
  an error. Name the cellular interface explicitly in such configurations:
  "ue[0]%cellular". UEs without addressed eth[] interfaces, which
  includes all simulation examples, are unaffected.

The user plane relay

The nodes that end GTP-U tunnels (eNodeB, gNodeB, Upf and
PgwStandard) now have a relay submodule, a UserPlaneRelay: the "relay"
of the 3GPP user plane protocol stacks, i.e. the TrafficFlowFilter that
picks the tunnel and the GtpUser that tunnels. The base stations'
gtpUserX2 stays a submodule of the node. In Upf and PgwStandard, an
INET MessageDispatcher (rd) below the relay passes the user data to the
data network interface (dnPpp), the Ethernet session bridge or the
Neighbor Discovery responder, by the service it is for.

Configurations and code written for v1.7.0 may need these updates:

• Submodule paths: the gtpUser and trafficFlowFilter of a base
  station are now relay.gtpUser and relay.trafficFlowFilter, and the
  gtp_user and trafficFlowFilter of Upf and PgwStandard are now
  relay.gtpUser and relay.trafficFlowFilter. Ini keys that address them
  must be updated accordingly.

• Gate names, named after what the gates carry: GtpUser's
  trafficFlowFilterGate and pppGate are now userDataIn and
  userDataOut, and TrafficFlowFilter's internetFilterGateIn and
  gtpUserGateOut are now in and out. Only networks that use these
  modules outside the Simu5G nodes, and code that refers to the gates by
  name, are affected.

Core network nodes: the N6 interface, and IPv6 on the nodes themselves

• The data-network interface of Upf and PgwStandard (dnPpp) is no
  longer in the node's interface table. It belongs to the user plane, which
  is wired around the node's network layer, and when the node's own IP stack
  routed over it, the result was a crash: at the first IPv6 Neighbor
  Discovery message with hasIpv6 = true, or at a UPF's own IPv4 traffic
  towards the data network. The address configurator no longer assigns
  dnPpp a subnet, so automatically assigned addresses elsewhere in the
  network may be numbered differently. In the examples this affects
  nr/mec/requestResponseApp, whose results change.

• A base station with hasIpv6 = true no longer crashes. Its network layer
  sends Neighbor Discovery to the cellular NIC, which is wired to the user
  plane rather than to the network layer. As a workaround, the new
  cellularNdSink (CellularNicNdSink) discards these packets.

Other

• D2dBinder declared in the network: a network with D2D-capable nodes
  (hasD2D = true) must now declare a d2dBinder: D2dBinder submodule next
  to binder. It is no longer created on the fly by the first D2D module that
  needs it, and initialization fails without it. The D2D example networks
  declare it.

• Bug fixes:

  • Header compression on a 5G core bearer with a suppressed SDAP header
    aborted the simulation at the first packet.
  • A handover target built a static bearer without its configuration, so
    the bearer lost header compression (causing an abort at the first
    downlink packet), its QoS profile and its SDAP QFI mapping. In addition,
    an on-demand bearer at the target could take the static bearer's DRB
    id. The bearer configuration now travels with the handover context.
    On-demand bearers keep their DRB ids across a handover, which swaps
    bearer entity names in some results.
  • Downlink that the handover source forwarded after the handover had
    completed was held at the target indefinitely, i.e. lost.
  • UE-to-UE traffic through the core network towards a UE attached
    nowhere aborted the simulation; it is now dropped. For an NE-DC
    destination UE, such traffic was tunneled to the secondary instead of
    the master.
  • The QoS-aware scheduler of a base station whose first QoS profiles
    arrived after the scheduler's creation never saw any profiles.
  • CbrSender, BurstSender and VoipSender waited forever, sending
    nothing, when destAddress was a literal address, or of the forms
    host(ipv6) or host%interface.
  • ROHC treated the payload of a non-first IPv4 fragment as a transport
    header.
  • X2 handover data was routed to X2 gate 0 by default, which is the CoMP
    manager's gate when CoMP is enabled.
  • The master eNodeB of the dual-connectivity examples (dualConnectivity,
    dualConnectivity_multicell, test_numerology, test_tdd) ran a D2D stack,
    although none of their UEs is D2D-capable.
  • Serializing an application packet, as PCAP recording, emulation and
    computed checksums do, aborted the simulation: CbrPacket and
    BurstPacket had no serializer, and VoipPacket could not be
    serialized at VoipSender's default packet size of 40 bytes. The VoIP
    packet's wire format no longer contains the receiver's arrival and
    playout times. In addition, a deserialized VoipPacket lost its
    timestamp, so VoipReceiver computed wrong end-to-end delays in
    emulation.
  • Memory leaks: the H-ARQ mirror buffers and the conflict graph of the
    D2D base station MAC, the per-SDU bookkeeping of the NR RLC AM TX
    entity, and the flow descriptor of every RLC RX entity were never
    freed.

• Node layouts: LteUe, NrUe, Upf and PgwStandard are laid out on
  INET's node-base grid. The UPF and the PGW are drawn as two stacks: the
  core network node's own stack, and the user plane relay with its
  data-network interfaces. In eNodeB and gNodeB, the cellular NIC is
  drawn in a box of its own to the right of the node's stack, as it is not
  an interface of the node's network layer. The cellular NICs are taller,
  with their upper modules in two columns, one per direction.

• Inspectors: the runtime state of the modules (counters, tables,
  per-UE and per-bearer state) is now WATCHed throughout, so it can be
  examined in Qtenv's inspectors. Watches of mere copies of parameters
  were removed, and the obsolete WATCH_MAP, WATCH_VECTOR etc. macros
  were replaced by plain WATCH(), which displays containers since
  OMNeT++ 6.4.

• Documentation: the NED documentation was revised throughout. All
  parameter and gate comments were reworded where they were unclear, and
  wrong ones were fixed (e.g. swapped address and port comments in two MEC
  apps). Every example network now describes its topology, and incorrect
  3GPP deployment-option claims were removed. The index page now has
  starting points for browsing. README, INSTALL and the website were
  brought up to date (opp_env as the recommended installation method, the
  development history since v1.3), and the website now serves the NED
  documentation of the latest release instead of that of v1.3.0.

Validation

• Fingerprint tests: every change was checked against the fingerprint
  suite in release and debug mode. The suite grew from 202 to 222
  configurations with the IPv6, IPv4v6, ROHC, Ethernet and Unstructured
  examples, and with a static bearer that hands over with header
  compression. Changes meant to preserve behavior had to leave the
  fingerprints unchanged, or, where module ids or the order of
  same-instant events moved, to leave ~tNl and the recorded results'
  values unchanged.

• Module tests: the new tests/module suite, modeled on INET's, runs
  small simulations and checks their outcome (make moduletests). It covers
  the configurations a session cannot have, checking both the exit code and
  the error message, the frame fields that an Ethernet session's QoS rules
  can read, and core networks whose nodes run IPv6. A module test may carry
  C++ code, e.g. module classes of its own; the runner compiles it into a
  test executable linked with Simu5G and INET.

• Unit tests: RohcCompression covers profile selection, state
  transitions, refreshes and CID allocation. EthernetSessionBridging
  checks the UPF's bridge against TS 23.501 5.8.2.5.3, one case per sentence
  of the spec. VLAN-scoped flooding, which is not modeled, is a recorded
  expected failure. AppPacketSerializers serializes the packets of the
  CBR, burst and VoIP senders at several sizes and checks that they read
  back as sent.

Requires INET 4.7 and OMNeT++ 6.4

Simu5G now requires INET 4.7 and OMNeT++ 6.4; INET 4.5.4 and OMNeT++ 6.3 are no
longer supported. The newer INET is needed for the IPv6 sessions (INET 4.7 has
significantly improved IPv6 support), and the newer OMNeT++ for the newly added
WATCHes that display complex data structures. CI builds against INET-4.7.0 and
OMNeT++ 6.4.0, and the fingerprint baselines were re-recorded for them. ~tNl
did not move in any configuration, so the upgrade itself does not affect the
traffic between network nodes.