Dialing Configuration

Dialing Description

Software Configuration of Dialing

Configuration of Dialing

DDR Configuration Command List

Configure a port to send and receive calling

Customize DDR Network

Monitor and maintain the dialing connection

Dialing Configuration Examples

Example of configuring multi-point dialing

Example of configuring Dialer Rotary Groups

Example of dialing to single point or multiple points by dialer map

Script configuration examples

Dialing Description

Our routers provide users with a perfect dialing solution. 

l          Support dialing port backup, satisfying various backup requirements of users;

l          Support various dialing ports including asynchronous ports and synchronous ports;

l          Provide DDRdial-on-demand routing dialing function, satisfying dialing on demand requirements of users;

l          Dialing link layer supports PPP and SLIP network layer protocol;

Support running various routing protocols such as RIP1/RIP2 or OSPF on dialing ports;

 

Software Configuration of Dialing

This chapter explains how to configure dialing on routers. For configuration commands, see “Configuration Commands of Dialing”.

 

Configuration of Dialing

When routers are connected through PSTN or ISDN by ISDN ports (BRI or PRI), use DDR. When there is no packet needed to be transferred between routers, connection is not established between them; when it is going to transfer packets, enable DDR to establish connections. When the links idle time exceeds the specified time, DDR breaks the connection, so it is a very economic dialing method. Configurations that are needed to be made by users include:  

1) Configure dialing port;

2) Configure interface encapsulation, and the default encapsulation is PPP;

3} Configure DDR;

See the section “Dialing Configuration Examples” below for the configuration of dialing. For dialing commands, see the introduction of dialing commands in the book “WAN Command Reference”. For the detailed information of the configuration of link layer, network layer protocol and routing protocol, see related chapters. 

DDR Configuration Command List

Global configuration command:

interface dialer number

Interface configuration command:

dialer-group number

dialer rotary-group number

dialer string dialer-string

dialer load-threshold enable_threshold disable_threshold

dialer enable-timeout seconds

dialer idle-timeout seconds

dialer fast-idle seconds

dialer priority number

dialer dtr

 

Configure a port to send and receive calling

(1) Send/receive calling to/from a point

To send/receive calling to/from a point, simply make the following configurations, with PPP encapsulation. 

l      Enter the physical interface configuration mode: interface interface-type interface-number

l      Configure the dialing method: line dial

l      Configure IP address: ip address ip-address [ net-mask ]

l     Configure map: dialer map next-hop-address [ name hostname ] [ broadcast ] [ dialer-string]

(2) Send/receive calling to/from multiple points

To send/receive calling to/from multiple points, make the following configurations.  

l       Enter the physical interface configuration mode: interface interface-type interface-number

l      Configure the dialing method: line dial

l       Configure IP address: ip address ip-address [ net-mask ]

l       Configure map: dialer map next-hop-address [ name hostname ] [ broadcast ] dialer-string (For the detailed introduction of the parameters following Dialer map, see Dialing Configuration Commands)

l      Configure several maps

(3) Use dialer interface to configure dialing

l      Define the Dialer interface corresponding to the Dialer, and the command is: interface dialer number

l      Configure IP address for this Dialer rotary group: ip address ip-address [ net-mask ]

l      Configure map: dialer map next-hop-address [ name hostname ] [ broadcast ] [ dialer-string]

l      Assign the physical interface to the Dialer rotary group.  Enter the physical interface, dialer rotary-group dialer-interface, where dialer-interface is the dialer interface bound to this physical interface

The physical interface in Dialer rotary group will use the IP address of Dialer interface.

Customize DDR Network

(1) Set the links idle time

When the links idle time exceeds the specified time, DDR disconnects the link. 

To set the link’s idle time: dialer idle-timeout seconds

(2) Set the idle time of busy port

When a port has already established a link, and another port attempts to establish a new link with it, competition occurs. When the first links idle time exceeds the specified time, DDR disconnects the link. 

To set the idle time of busy port: dialer fast-idle seconds

(3) Set dialing interval

This is the minimum interval that a link should wait to make the next call if it is disconnected because of failure or hang-up. 

To set the link’s disconnection time: dialer enable-timeout seconds

(4) Set the ports wait-for-carrier-time

To set the port’s wait-for-carrier time: dialer wait-for-carrier-time seconds

(5) Set the access control of DDR port

Users can set the packet filtering function of DDR port. Packets going through DDR ports can be divided into two kinds by access control:  

Valid Packet: Packets that pass the access control. After DDR port receives a valid packet, if the corresponding link has already been established, DDR will send the packet through this link, and reset the idle timer. If the corresponding link has not been established, it will begin to call. 

Invalid Packet: Packets that do not pass the access control.  After DDR port receives an invalid packet, if the corresponding link has already been established, DDR will send the packet through this link, and won’t reset the idle timer. If the corresponding link has not been established, it won’t begin to call, and will discard this packet. 

(6) Set the priority of physical interface in the dialer rotary group

Determine the usage sequence of various ports according to their priorities. The lowest is 0, the highest is 255, and the default value is 0. 

To set the priority of physical interface in the dialer rotary group: dialer priority number

(7) Set the threshold value of traffic in dialer rotary group

After the corresponding threshold value is set, DDR will monitor the ports traffic in real time, if the traffic is high enough to exceed the enabling threshold value, and there is available port in the dialer group, this port will be enabled to increase the dialer groups bandwidth. If the traffic is very low and is below the specified threshold value, redundant ports will be disconnected actively. If the priorities of physical ports have been set, redundant ports will be dialed or disconnected according to their priorities. Select ports with the highest priority when enabling them, and select the ports with the lowest priority when disabling them. 

To set the threshold value of traffic in dialer rotary group:

 dialer load-threshold enable-threshold disable-threshold

(8) Set DTR dialing method

         When DTEs DTR signal is available, begin to dial directly.

Set DTR dialing method:

 dialer dtr

(9) Set the holding queue of dialing port

When a packet arrives at the DDR port, if the connection has not been established, this packet will be discarded. After the holding queue is set, this packet will not be discarded even if the connection has not been established. 

To set the holding queue of dialing port: dialer hold-queue packet-number

Monitor and maintain the dialing connection

To display DDR port information: show dialer interface type number

Router#show dial interface s1/1

Serial1/1 - dialer type = ASYNC

Idle timer (120 secs), Fast idle timer (20 secs)

Wait for carrier (30 secs), Re-enable (15 secs)

Number of active calls = 0

Dial String Successes Failures Last_call Last status

* 0 0 never

The displayed information is explained below: 

Dialer_Strings       the dialing string of this Dialer map

Successes              the number of successful calls of this Dialer map

Failures                  the number of failed calls of this Dialer map

Last_call                the time of the last call of this Dialer map

Idle timer                the time specified by the Dialer idle-timeout command

Fast Idle timer        the time specified by the Dialer fast-idle command

Wait for carrier      the time specified by the Dialer wait-for-carrier command

Re_enable     the time specified by the Dialer enable-timeout command

Dialing Configuration Examples

Example of configuring multi-point dialing

interface s1/1

ip address 131.108.126.1 255.255.255.0

dialer wait-for-carrier-time 100

dialer map 131.108.126.10 5558899

dialer map 131.108.126.15 5555555

Example of configuring Dialer Rotary Groups

The following configuration defines dialer interface, and assigns serial1/1 and serial1/2 to dialer interface.

interface dialer 1

ip address 131.108.2.1 255.255.255.0

ip address 131.126.2.1 255.255.255.0 secondary

dialer map 131.108.2.5 1234567

dialer map 131.126.2.55 7654321

! Interfaces serial 1 and 2 are placed in dialer rotary group 1. All of

! the interface configuration commands

! applied to interface dialer 1 apply to these interfaces.

interface serial1/1

dialer rotary-group dialer 1

interface serial1/2

dialer rotary-group d1

Example of dialing to single point or multiple points by dialer map

See the following illustration

If local router only needs to dial Router A, you can use the command “dialer string” on the interface to configure the dialing string 55555555 as follows: 

interface serial1/1

dialer string 5555555

If the port is set to dial multiple points, you need to configure dialer map. Otherwise, the router can’t distinguish dialing numbers of different destinations. The configuration is as follows: 

interface serial 1/1

dialer map 1.1.1.1 5555555

dialer map 2.2.2.2 6666666

Script configuration examples

As the illustration shows, Router A needs to dial Router B

chat-script dial ABORT ERROR "" "AT Z" OK "ATDT \T" TIMEOUT 30 CONNECT \c

interface async 0/0

dialer map 10.55.0.1 modem-script dial 96837890

Script examples:

Dialing script not only can be used to call Modem, but also can be used to automatically register to the remote DTE when connecting. Thus, scripts can be classified as Modem script and registration script according to their using purpose, and they are different only in purpose, but use the same script language. The following script language is compatible with the dialing script used by UNIX. This script language has the following features: 

l        The script contents are case sensitive, for example, ABORT and abort are different character strings.  

l        The script consists of some predefined keywords and ordered sets of sent character strings and expected character strings. The sent and expected character string pairs of the script begin with sent character strings except keywords.  

 l        All characters embraced by double quotation marks () are treated as a complete character string.  

l         Character strings are separated by a Space.  

l        Every sent character string is automatically followed by a carriage return character, except ended with \c. 

l        The matching method of received contents and expected character strings is arbitrary matching.

1) Examples of MODEM scripts execution

expected and sent character string pair

Execution

ABORT ERROR

If “ERROR” occurs, script’s execution will be stopped

" " "AT Z"

Do not expect to receive character strings, send “AT Z” command directly

CONNECT \c

Expect to receive CONNECT, send no character upon receiving it

TIMEOUT 30

Set the timeout for receiving expected character strings to 30 seconds

OK "ATDT \T"

Expect to receive OK, send dialing string

When MODEM scripts execution is finished, login script is executed, and examples of login scripts execution are listed below

2) Examples of login scripts execution

expected and sent character string pair Execution
ABORT invalid If “invalid” messages occur, script’s execution will be stopped
TIMEOUT 15 Wait 15 seconds
Name: myname If “name” occurs in the received character string, send login name
Word: mypassword If “word” occurs in the received character string, send password