Virtual Transport - adjacentlink/emane GitHub Wiki

• Features
• Configuration Parameters
• Example XML
• Statistics
• Statistic Tables

The Virtual Transport creates a virtual interface for use as the emulation/application domain boundary. IP packets routed to the virtual device are encapsulated and transmitted to their respective NEM for downstream processing. Packets received over-the-air are processed up the NEM stack and transmitted to the NEM’s respective virtual transport for injection back into the kernel IP stack.

The newly created virtual interface is assigned an Ethernet address derived from the NEM Id associated with the transport using the following format: 02:02:00:00:XX:XX , where XX:XX is the 16 bit NEM Id. This allows easy mapping of Ethernet MAC addresses to NEM Ids for unicast frames. Multicast and broadcast frames map to the NEM broadcast address 0xFFFF.

Virtual Transport capabilities include the following:

1. IPv4 and IPv6 Capable - Supports IPv4 and IPv6 virtual interface address assignments and packet processing.

2. Flow Control - Supports flow control with a corresponding flow control capable NEM layer in order to provide feedback between the emulation stack and application domain socket queues.

3. Virtual Interface Management - Supports configuring virtual interface addresses or can be configured to allow virtual interfaces to be managed externally, for example via DHCP.

4. Raw Transport Interoperability - Supports interoperability with Raw Transport emulation/application domain boundaries using ARP caching to learn network/NEM Id associations.

5. Bitrate Enforcement - Supports bitrate enforcement for use with models that do not limit bitrate based on emulation implementation.

6. Broadcast Only Mode - Supports forced NEM broadcasting of all IP packet types: unicast, broadcast and multicast.

The following configuration parameters are available to tailor layer functionality:

• address
• arpcacheenable
• arpmodeenable
• bitrate
• broadcastmodeenable
• device
• devicepath
• flowcontrolenable
• mask

IPv4 or IPv6 virutal device address.

Type: inetaddr
Running-State Modifiable: no
Occurrence Range: [1,1]

Enable ARP request/reply monitoring to map Ethernet address to NEM.

Type: bool
Running-State Modifiable: no
Occurrence Range: [1,1]
Value Range: [no,yes]
Default Value(s): yes

Enable ARP on the virtual device.

Type: bool
Running-State Modifiable: no
Occurrence Range: [1,1]
Value Range: [no,yes]
Default Value(s): yes

Transport bitrate in bps. This is the total allowable throughput for the transport combined in both directions (upstream and downstream). A value of 0 disables the bitrate feature.

Type: uint64
Running-State Modifiable: no
Occurrence Range: [1,1]
Value Range: [0,18446744073709551615]
Default Value(s): 0

Broadcast all packets to all NEMs.

Type: bool
Running-State Modifiable: no
Occurrence Range: [1,1]
Value Range: [no,yes]
Default Value(s): no

Virtual device name.

Type: string
Running-State Modifiable: no
Occurrence Range: [1,1]
Default Value(s): emane0

Path to the tuntap device.

Type: string
Running-State Modifiable: no
Occurrence Range: [1,1]
Default Value(s): /dev/net/tun

Enables downstream traffic flow control with a corresponding flow control capable NEM layer.

Type: bool
Running-State Modifiable: no
Occurrence Range: [1,1]
Value Range: [no,yes]
Default Value(s): no

IPv4 or IPv6 virutal device addres network mask.

Type: inetaddr
Running-State Modifiable: no
Occurrence Range: [1,1]

Typically the Virtual Transport definition is pretty sparse.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE transport SYSTEM "file:///usr/share/emane/dtd/transport.dtd">
<transport library="transvirtual"/>

Most of the time you will need to specify a different address for each NEM and good place to do that is in the emulator platform definition file.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE platform SYSTEM "file:///usr/share/emane/dtd/platform.dtd">
<platform>
  <param name="otamanagerchannelenable" value="on"/>
  <param name="otamanagerdevice" value="eth0"/>
  <param name="otamanagergroup" value="224.1.2.8:45702"/>
  <param name="eventservicegroup" value="224.1.2.8:45703"/>
  <param name="eventservicedevice" value="eth0"/>

  <nem id="1" definition="rfpipenem.xml">
    <transport definition="transvirtual.xml">
      <param name="address" value="fd53:dc9a:f36d:4950:0:0:0:1"/>
    </transport>
  </nem>
</platform>

The below statistics can be accessed using emanesh.

The below statistics can be accessed using emanesh.