To set up the LAN protocols-to-remote-host mapping, use the
x25 map command in interface configuration or X.25
profile configuration mode. To retract a prior mapping, use the
no form of this command.
x25 map protocol address [protocol2 address2 [... [protocol9 address9]]]x121-address [option]
no x25 map protocol address x121-address
Syntax Description
|
protocol
|
Protocol type, entered by keyword. Supported protocols are
entered by keyword, as listed in the Protocols Supported by X.25 table. As many
as nine protocol and address pairs (represented by ellipses in the syntax
example) can be specified on one command line.
|
|
address
|
Protocol address.
|
|
x121-address
|
X.121 address of the remote host.
|
|
option
|
(Optional) Additional functionality that can be specified
for originated calls. Can be any of the options listed in the x25 map Options
table.
|
Command Default
No LAN protocol-to-remote-host mapping is set up.
Command Modes
Interface configuration
X.25 profile configuration
Command History
|
Release
|
Modification
|
|
10.0
|
This command was introduced.
|
|
12.2(13)T
|
The
apollo ,
vines , and
xns arguments were removed because
Apollo Domain, Banyan VINES, and Xerox Network Systems are no longer available
in the Cisco IOS software.
|
|
12.4(6)T
|
The
idle option of this command was
enhanced to support seconds granularity in setting the idle period.
|
|
12.2(33)SRA
|
This command was integrated into Cisco IOS Release
12.2(33)SRA.
|
|
12.2SX
|
This command is supported in the Cisco IOS Release 12.2SX
train. Support in a specific 12.2SX release of this train depends on your
feature set, platform, and platform hardware.
|
Usage Guidelines
Because no defined protocol can dynamically determine LAN
protocol-to-remote-host mappings, you must enter all the information for each
host with which the router may exchange X.25 encapsulation traffic.
Two methods are available to encapsulate traffic: Cisco’s
long-available encapsulation method and the Internet Engineering Task Force
(IETF) standard method defined in RFC 1356; the latter allows hosts to exchange
several protocols over a single virtual circuit. Cisco’s encapsulation method
is the default (for backward compatibility) unless the interface configuration
command specifies the
ietf keyword.
When you configure multiprotocol maps, you can specify a maximum of
nine protocol and address pairs in an
x25 map command. A multiprotocol map can specify a
single address for all the supported protocols. However, if IP and TCP header
compression are both specified, the same IP address must be given for both
protocols.
Encapsulation maps might also specify that traffic between the two
hosts should be compressed, thus increasing the effective bandwidth between
them at the expense of memory and computation time. Because each compression VC
requires memory and computation resources, compression must be used with care
and monitored to maintain acceptable resource usage and overall performance.
Bridging is supported only if you are using Cisco’s traditional
encapsulation method. For correct operation, bridging maps must specify the
broadcast option. Because most datagram
routing protocols rely on broadcasts or multicasts to send routing information
to their neighbors, the
broadcast keyword is needed to run such
routing protocols over X.25.
Open Shortest Path First (OSPF) Protocol treats a nonbroadcast,
multiaccess network such as X.25 in much the same way as it treats a broadcast
network by requiring the selection of a designated router. In earlier releases
of the Cisco IOS software, this selection required manual assignment in the
OSPF configuration using the
neighbor router configuration command. When the
x25 map command is included in the configuration with
the broadcast, and the
ip ospf network command with the broadcast keyword is configured,
there is no need to configure any neighbors manually. OSPF will run over the
X.25 network as a broadcast network. (Refer to the
ip ospf network interface configuration command for more
detail.)
Note |
The OSPF broadcast mechanism assumes that IP class D addresses are
never used for regular traffic over X.25.
|
You can modify the options of an
x25 map command by restating the complete set of
protocols and addresses specified for the map, followed by the desired options.
To delete a map command, you must specify the complete set of protocols and
addresses; the options can be omitted when deleting a map.
Once defined, a map’s protocols and addresses cannot be changed. This
requirement exists because the Cisco IOS software cannot determine whether you
want to add to, delete from, or modify an existing map’s protocol and address
specification, or simply have mistyped the command. To change a map’s protocol
and address specification, you must delete it and create a new map.
A given protocol-address pair cannot be used in more than one map on
the same interface.
The following table lists the protocols supported by X.25.
Table 2. Protocols Supported by X.25
|
Keyword
|
Protocol
|
|
appletalk
|
AppleTalk
|
|
bridge
|
Bridging1
|
|
clns
|
ISO Connectionless Network Service
|
|
compressedtcp
|
TCP/IP header compression
|
|
decnet
|
DECnet
|
|
ip
|
IP
|
|
ipx
|
Novell IPX
|
|
pad
|
Packet assembler/disassembler (PAD) links2
|
|
qllc
|
System Network Architecture (SNA) encapsulation in
X.253
|
Note |
The Connection-Mode Network Service (CMNS) map form is obsolete;
its function is replaced by the enhanced
x25 route command.
|
The following table lists the map options supported by X.25 when you
use the
x25 map command.
Table 3. x25 map Options
|
Option
|
Description
|
|
accept-reverse
|
Causes the Cisco IOS software to accept incoming
reverse-charged calls. If this option is not present, the Cisco IOS software
clears reverse-charged calls unless the interface accepts all reverse-charged
calls.
|
|
broadcast
|
Causes the Cisco IOS software to direct any broadcasts sent
through this interface to the specified X.121 address. This option also
simplifies the configuration of OSPF; see “Usage Guidelines” for more detail.
|
|
cug
group-number
|
Specifies a closed user group (CUG) number (from 1 to 9999)
for the mapping in an outgoing call.
|
|
compress
|
Specifies that X.25 payload compression be used for mapping
the traffic to this host. Each virtual circuit established for compressed
traffic uses a significant amount of memory (for a table of learned data
patterns) and for computation (for compression and decompression of all data).
Cisco recommends that compression be used with careful consideration of its
impact on overall performance.
|
|
idle
minutes
seconds
|
Idle period in minutes and, optionally, seconds. Accepted
range for the
minutes argument is from 0 to 255
minutes. The default is 0 minutes, which keeps an SVC open indefinitely.
Accepted range for the optional
seconds argument is from 1 to 59
seconds, and the
seconds argument is valid only for setting the idle
period for X.25 encapsulation VCs.
| Note
|
Set the
minutes argument to 0, if the desired
idle period on the X.25 encapsulation VC is fewer than 60 seconds, then enter a
value for the optional
seconds argument.
|
|
|
method
{cisco |
ietf |
snap |
multi }
|
Specifies the encapsulation method. The choices are as
follows:
-
cisco
--Cisco’s
proprietary encapsulation; not available if more than one protocol is to be
carried.
-
ietf
--Default
RFC 1356 operation: protocol identification of single-protocol virtual circuits
and protocol identification within multiprotocol virtual circuits use the
standard encoding, which is compatible with RFC 877. Multiprotocol virtual
circuits are used only if needed.
-
snap
--RFC
1356 operation where IP is identified with SNAP rather than the standard IETF
method (the standard method is compatible with RFC 877).
-
multi
--Forces
a map that specifies a single protocol to set up a multiprotocol VC when a call
is originated; also forces a single-protocol PVC to use multiprotocol data
identification methods for all datagrams sent and received.
|
|
no-incoming
|
Uses the map only to originate calls.
|
|
no-outgoing
|
Does not originate calls when using the map.
|
|
nudata
string
|
Specifies the network user identification in a format
determined by the network administrator (as allowed by the standards). This
option is provided for connecting to non-Cisco equipment that requires an NUID
facility. The string should not exceed 130 characters and must be enclosed in
quotation marks (“ ”) if there are any spaces present. This option only works
only if the router is configured as an X.25 DTE.
|
|
nuid
username
password
|
Specifies that a network user ID (NUID) facility be sent in
the outgoing call with the specified TACACS username and password (in a format
defined by Cisco). This option should be used only when connecting to another
Cisco router. The combined length of the username and password should not
exceed 127 characters. This option works only if the router is configured as an
X.25 DTE.
|
|
nvc
count
|
Sets the maximum number of virtual circuits for this map or
host. The default
count is the x25 nvc setting of the interface. A maximum number of eight
virtual circuits can be configured for each map. Compressed TCP may use only
one virtual circuit.
|
|
packetsize
in-size
out-size
|
Proposes maximum input packet size
(in-size ) and maximum output packet size
(out-size ) for an outgoing call. Both values
typically are the same and must be one of the following values: 16, 32, 64,
128, 256, 512, 1024, 2048, or 4096.
|
|
passive
|
Specifies that the X.25 interface should send compressed
outgoing TCP datagrams only if they were already compressed when they were
received. This option is available only for compressed TCP maps.
|
|
reverse
|
Specifies reverse charging for outgoing calls.
|
|
roa
name
|
Specifies the name defined by the x25 roa command for a list of transit
Recognized Operating Agencies ( ROAs, formerly called Recognized Private
Operating Agencies, or RPOAs) to use in outgoing Call Request packets.
|
|
throughput
in
out
|
Sets the requested throughput class values for input
(in ) and output (out )
throughput across the network for an outgoing call. Values for
in and
out are in bits per second (bps) and
range from 75 to 48000 bps.
|
|
transit-delay
milliseconds
|
Specifies the transit delay value in milliseconds (0 to
65534) for an outgoing call, for networks that support transit delay.
|
|
windowsize
in-size
out-size
|
Proposes the packet count for input window
(in-size ) and output window
(out-size ) for an outgoing call. Both values
typically are the same, must be in the range 1 to 127, and must be less than
the value set by the x25 modulo command.
|
Examples
The following example maps IP address 172.20.2.5 to X.121 address
000000010300. The
broadcast keyword directs any broadcasts sent
through this interface to the specified X.121 address.
interface serial 0
x25 map ip 172.20.2.5 000000010300 broadcast
The following example specifies an ROA name to be used for
originating connections:
x25 roa green_list 23 35 36
interface serial 0
x25 map ip 172.20.170.26 10 roa green_list
The following example specifies an NUID facility to send on calls
originated for the address map:
interface serial 0
x25 map ip 172.20.174.32 2 nudata “Network User ID 35”
Strings can be quoted, but quotation marks are not required unless
embedded blanks are present.
In the following example, the VC times out 10 seconds after the
circuit becomes idle (the setting configured in the
x25 map command, rather than the
x25 idle command):
interface Serial0/0
description connects to tester s1/0
ip address 10.132.0.8 255.255.255.0
encapsulation x25 dce
x25 address 2xx8xx
x25 idle 0 20
x25 map ip 10.132.0.9 2xx9xx idle 0 10
clock rate 64000
end
The settings for the
x25 map command have higher precedence over the
timeout period configured using the
x25 idle command.
Feedback