6.9 Channel-to-Channel Adapters

6.9.1 Introduction

The Channel-to-Channel Adapter device statements define CTC adapters to the Hercules configuration.
All of the communications emulation implemented within Hercules use a CTCA (Channel-to-Channel
Adapter) type device. Depending on the type, the CTCA device will provide either a point-to-point or a
virtual network adapter interface to the driving system's TCP/IP stack or in the case of CTCT, a true
CTCA connection to another instance of Hercules via a TCP/IP connection.

All current emulations, with the exception of VMNET and CTCT use the Universal TUN/TAP driver on
Linux and TunTap32 (WinPCap) on the Windows platforms which creates a network interface on the
driving system which allow Hercules to present frames to, and receive frames from the TCP/IP stack. This
network interface is configured on Linux platforms by the ‘hercifc’ program which is invoked by Hercules
after the TUN/TAP device is opened.

The following are the emulation types currently supported:

6.9.2 CTCI (Channel-to-Channel link to TCP/IP stack)

6.9.2.1 Function

The CTCI is a point-to-point connection with the TCP/IP stack of the driving system on which Hercules is
running.

6.9.2.2 Syntax

Descriptive

-n --name]

---mask]

---mac

---mtu ]



*Linux
only

[-i --ibuff



*Windows only

[-k --kbuff 4



*Windows only

[-d --debug]

guestip hostip

Diagram

Êʬ¬¬ ¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬Ê

-n ¬¬¬¬§¬¬¬ name

--

ʬ¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬Ê

-s ¬¬¬¬¬¬§¬¬¬ mask

--netmask

ʬ¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬Ê

-m ¬
¬¬¬§¬¬¬§¬¬¬¬¬¬¬¬¬¬ mac ¬¬¬¬¬¬¬¬¬¬«

--

ʬ¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬Ê

-t ¬
¬¬¬§¬¬¬ mtu

--

ʬ¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬Ê

-i ¬¬¬¬¬§¬¬¬§¬¬¬ ibuff ¬¬¬«

--

ʬ¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬Ê

-k ¬¬¬¬¬§¬¬¬§¬¬¬ kbuff ¬¬¬«

--

ʬ¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬§¬¬¬ guestip ¬¬¬ hostip ¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬ÊÍ

-d ¬¬¬¬¬¬«

--debug

6.9.2.3 Parameter

devaddr

This is the device address.

CTCI

This specifies the CTCI device/protocol type.

-n name

For Linux: Specifies the name of the tunnel device to use. The default name is
“/dev/net/tun”, which is correct for version 2.4 and above of the Linux kernel.

For Windows: Identifies the host network adapter. If your network adapter does
not have a permanent (static) IP address assigned to it (e.g. you use DHCP and
have a dynamic IP assigned) then instead of specifying an IP address as the
second parameter in the device statement, you must specify the MAC address of
the adapter. In this case the second argument (hostip) must be coded as “0.0.0.0”.
This is simply a placeholder because two IP addresses are expected to satisfy the
device definition syntax.

--dev name

This is the same as “-n name”.

-s mask

This is the netmask to be configured on the link. Note: Since this is a point-to-point
link netmask is meaningless from the perspective of the actual network device.

--netmask mask

This is the same as “-s mask”.