|
This document gives some useful information on the Datacryptor® x.25 unit
and gives an example of how to set up x.25 units using Cisco routers.
- Datacryptor® x.25 variants
There are two Datacryptor® x.25 variants:
- Datacryptor® EX (Standard speed) - capable of speeds up to 64kbps and
up to 32 encrypted virtual circuits.
- Datacryptor® EH (High speed) - capable of speeds up to 128kbps and up
to 128 encrypted virtual circuits.
- Datacryptor® x.25 setup using Cisco routers
The diagram below shows how to setup two Datacryptor® units and three
Cisco routers as an encrypted x.25 network. The router in the middle
called Router_sw acts as our x.25 network and simply routes x.25
data to create a Virtual Circuit. The command x25
idle 1 means
that the virtual circuit will stay up for a period of 1 minute
of inactivity after which the call will be disconnected. Setting
this value to x25 idle 0 means that the call will stay up indefinitely
(this is the default)
Note that in the configuration below if you want to ping from
a device connected to the ethernet port of either Router_Left or
Router_Right you will need to add a static route e.g. ip
route 192.168.2.0 255.255.255.0 10.10.10.2 on Router_Left and the equivalent
on Router_Right.
Click on picture thumbnail to view diagram
All configuration files for the routers and
Datacryptor® in this diagram can be found in the Appendix section of this
document. Some useful commands which can be used on the central router are:
- show x25 route
- show x25 vc
- debug x25 events
- Datacryptor® x.25 tracing using the Parascope 2000
The diagram, below shows the same network as above but this time
the Parascope 2000 WAN analyser has been put into the circuit. An
x.21 Y cable is used to intercept the link between the network port
of Datacryptor®_Left and Router_sw. See below for details on how to setup
the Parascope software.
Click
on picture thumbnail to view diagram
The Protocol Stack setup should look like this:
Click on picture thumbnail to view diagram
The Quick Start screen should look like this - click on Run to continue:
Click on picture thumbnail to view diagram
Tracing in this manner lets us see both the call negotiation and
the data being passed over the x.25 network.
2 traces were performed - one with the units in encrypt mode, the
other with the units in plain mode. Click here for the plain trace,
click here for the encrypted trace. If you look at the line data
portion of the plain trace packets you will see clear text (a login
session to a Cisco router at the end of the link). In the encrypted
trace the data is unreadable because it is encrypted.
You can see the x.25 call negotiation process in both traces:
Click
on picture thumbnail to view diagram
Frame 45 is the calling packet - see below for the full decode:
Here you can see the Calling Address is 123456789111 - this is the
NUA of Datacryptor®_Left. The Called Address is 123456789222 - this is the
NUA of Datacryptor®_Right. Also note the LCN (Logical Channel Number) as
defined in the Datacryptor®. The LCN defines the logical connection between
the two x.25 devices - you can see that all packets after the initial
Incoming Call do not contain the calling/called address but are simply
denoted by the LCN.
In both traces you can see a lot of RR (Receiver Ready) frames -
these are used to signify that the x25 host is up and ready to accept
more data. You will typically see these when the x.25 call is connected
but no user data is being passed over the link. A discussion of all
the x.25 packet types is beyond the scope of this document - see
http://www.protocols.com/pbook/x25.htm for
more information.
Click on the links below for the config files of the Datacryptor® and Cisco
routers used in the example above.
;Unit Time 13:06:48, 17/07/2003
[GENERAL_INFO]
management_software_version = 2.1.14.4
application_software_version = 1.14.4
bootstrap_software_version = 2.05.1
unit_type = 7
detected_host_cable = 3
detected_net_cable = 3
available_interfaces = 8
UnitName = "A3211040293V"
[GENERAL_CONFIG]
unit_description = "Datacryptor® Link, S/N: A3211040293V"
host_active_interface = 3
network_active_interface = 3
link_mode.line_mode = 0
link_mode.data_algorithm = link_mode.peer_unit_name
link_mode.peer_unit_name =
[SECURITY_CONFIG]
key_update_intervals.kek_lifetime = 2419200
key_update_intervals.dek_lifetime = 86400
movement_alarm_enable = 0
temperature_alarm_enable = 0
erase_button_enable = 3
snmp_mib_view_enable = 1
auto_notify_enable = 1
[SECURITY_CONFIG_PLUS]
use_time_of_day = 0
time_of_day = 3600
[POLL_RETRY]
poll_retry_type = 1
[CONTROL_PORT_CONFIG]
data_bits = 1
stop_bits = 0
baud_rate = 4
parity = 0
[UDP_IP_CONFIG]
control_port_ip_config.ip_address = "2.2.2.2"
control_port_ip_config.net_mask = "255.0.0.0"
network_port_ip_config.ip_address = "1.0.161.77"
network_port_ip_config.net_mask = "255.0.0.0"
ethernet_ip_config.ip_address = "10.10.10.2"
ethernet_ip_config.net_mask = "255.255.255.0"
[DTYPE_CONFIG]
inline_patchbox.host_dce_cts_indication_source = 2
inline_patchbox.host_dce_dcd_source = 3
inline_patchbox.host_dce_dsr_source = 4
inline_patchbox.host_dce_ri_source = 5
inline_patchbox.net_dte_dtr_source = 7
inline_patchbox.net_dte_rts_control_source = 6
safetalk_patchbox.host_dce_cts_indication_source = 1
safetalk_patchbox.host_dce_dcd_source = 3
safetalk_patchbox.host_dce_dsr_source = 4
safetalk_patchbox.host_dce_ri_source = 5
safetalk_patchbox.net_dte_dtr_source = 0
safetalk_patchbox.net_dte_rts_control_source = 0
clock_polarities.transmit_clock_state = 0
clock_polarities.receive_clock_state = 0
network_delay = 10000
terminal_timing = 0
safetalk_condition.condition_operation = 2
safetalk_condition.condition_timeout = 4000
safetalk_condition.net_dte_cts_indication_state = 2
safetalk_condition.net_dte_dcd_state = 2
safetalk_condition.net_dte_dsr_state = 2
safetalk_condition.net_dte_ri_state = 2
safetalk_condition.host_dce_dtr_state = 2
safetalk_condition.host_dce_rts_control_state = 2
[HOST_DATA_GATING]
gate_tx_data = 0
gate_rx_data = 0
[SNMP_IP_CONFIG]
snmp_status = 0
traps_enabled = 1
snmp_location = ""
snmp_contact = ""
ip_forwarding = 1
ip_default_ttl = 16
[SNMP_COMMUNITIES]
community_count = 2
community_1_name = "public"
community_1_access = 0
community_2_name = "private"
community_2_access = 2
[SNMP_TRAP_MANAGERS]
trap_man_count = 1
trap_man_1_address = "10.10.10.100"
trap_man_1_community = "public"
trap_man_1_information = 1
trap_man_1_warning = 1
trap_man_1_minor = 1
trap_man_1_major = 1
trap_man_1_critical = 1
|
)
)
)
)
)
