Cisco IOS Release 12.0 Dial Solutions Configuration Guide - Managing Modems [Cisco IOS Software Releases 12.0 Mainline]

Table Of Contents

Managing Modems

Cisco's Implementation

56K Modems

V.110 Terminal Adapters

V.34 Modems

Manageable Versus Basic Modems

Modem Management Topologies

Single Chassis Modem Pooling

List of Terms

Restrictions

Platforms Supported

How It Works

Configure Modem Pooling

Verify Modem Configuration

Physical Partitioning Scenario

Physical Partition Example

Physical Partition with Dial-In and Dial-Out Scenario

Virtual Partitioning Scenario

Virtual Partition Example

Change Modem Configuration

Changing Automatically for Externally Attached Modems

Changing Manually by Sending AT Commands to Integrated Modems

Transmit AT Command Example

Clear a Direct Connect Session from a Second Telnet Session Example

Verify Connection Speed Performance

Collect Modem Statistics

Show Modem Example

Show Modem Summary Example

Show Modem Log Example

Show Modem AT-Mode Example

Time Interval Example

Modem Polling Example

Polling Attempts Example

Automatically Run a Modem Diagnostics Test

How It Works

Preliminary Usage Guidelines

Set Up the Modem Autotest

Modem Autotest Example

Manually Isolating a Back-to-Back Modem Test Example

Display Local Disconnect Reasons

Remove Inoperable Modems

Managing Modems

The Cisco IOS software provides commands that manage modems that reside inside access servers or routers in the form of modem cards. Cisco Systems does not consider external modems, which externally attach to an access server, to be part of its modem management paradigm.

For a complete description of the commands in this chapter, refer to the Dial Solutions Command Reference. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

This chapter consists of the following sections:

•Cisco's Implementation

•Manageable Versus Basic Modems

•Modem Management Topologies

•Single Chassis Modem Pooling

•Change Modem Configuration

•Verify Connection Speed Performance

•Collect Modem Statistics

•Automatically Run a Modem Diagnostics Test

•Display Local Disconnect Reasons

•Remove Inoperable Modems

Cisco's Implementation

Cisco Systems installs the following different types of modems and terminal adapter cards in its access servers and routers:

•56K Modems

•V.110 Terminal Adapters

•V.34 Modems

shows which Cisco access devices provide hardware support for these dial technologies.

Table 18

Type of Modem
or Terminal Adapter

Cisco AccessPath Integrated Access System

Cisco AS5300

Cisco AS5200

Cisco 3600 Series

56K modem card

Yes

Yes

Yes

Yes

V.110 terminal adapter module

No

No

Yes

No

V.34 modem card

Yes

Yes

Yes

Yes

Available Modems and Terminal Adapters

56K Modems

The 56K modems are used for making high-speed connections across digital networks. Ultimately, this means that files transmitted at up to 56 kbps arrive at the desktop nearly twice as fast as standard V.34 (28.8-kbps) connections. The wait for information is reduced by nearly 50 percent.

The 56K modems are ideal for serious Internet multimedia users who want to quickly dial-in to corporate LANs or download web pages containing sound, video, graphics, and other large files over digital networks using standard telephone lines.

Traditional modems assume that both ends of a modem conversation use an analog connection over the public switched telephone network. Data signals are converted from digital to analog and back again to digital, limiting transmission speeds to considerably less than the nominal rate of the modem. The 56K modems, however, assume that one end of the modem conversation has a pure digital connection to the phone network and takes advantage of the high-speed digital connection. This is a new technique where the network is viewed as a digital transmission medium and the data is encoded for transmission over an end user's telephone line, which is also known as the local loop. The downstream data is digitally encoded instead of being modulated. Upstream analog-to-digital communication at the local loop will be less than 56kbps. (This limit to upstream analog modem speed can vary depending on factors such as the local loop connection with the central office and the modem. Downstream digital to analog communication at the local loop can transmit up to 56 kbps. To maximize channel bandwidth for 56 kbps connections, the Integrated Services Digital Network Primary Rate Interface (ISDN PRI) must be used. In the example shown in , a stack of Cisco AS5300s is equipped with 56K modems.)

Figure 219 Remote PC Downloading Files Over the Network at 56 kbps

Special digital signal processor (DSP) software is used in conjunction with 56K modem firmware to enable speeds up to 56 kbps. Both DSP and modem firmware are posted on the Cisco Connection Online (CCO) FTP server for upgrading purposes.

The following prerequisites apply to 56K modems:

•K56flex-compatible modems must be present at both ends of a digital connection in a digital network. K56 requires a client-side modem and a server-side modem. If not, this speed cannot be achieved. All modem connections will fall back to V.34 speeds.

•Only one analog loop can be in the end-to-end communications path.

•You cannot have any A-law to U-law conversions, which exist at some international gateways.

V.110 Terminal Adapters

V.110 is a bit rate adaptation protocol defined by International Telecommunication Union (ITU). V.110 provides a standard method of encapsulating data over Global System for Mobile Telecommunications (GSM) and ISDN networks. A Cisco AS5200 loaded with V.110 terminal adapter modules provides corporate or Internet access to GSM mobile users.

The 12 port V.110 terminal adapter connects to the AS5200 TDM bus via the universal carrier card. There can be up to five V.110 modules in one Cisco AS5200, which is capable of terminating 60 V.110 sessions. Modem and V.110 terminal adapter port modules can coexist in the same Cisco AS5200. Based on ISDN Q.931 call bearer information, the Cisco IOS software routes calls to the appropriate port module for termination. For example, analog calls are terminated by the modem modules, GSM calls are serviced by the V.110 terminal adapter modules, and ISDN calls are sent to the PPP termination engine. This flexibility allows providing one telephone number to users for analog, GSM, and ISDN data calls.

shows a dial-in scenario for how V.110 technology can be used with a stack of Cisco AS5200 access servers.

Figure 220 V.110 Dial-In Scenario Using a Stack of Cisco AS5200s

V.34 Modems

Recommendation V.34 is the name of the standard that defines how modems should operate at 28.8 kbps. The previous standard for high speed modem communication was V.32bis, which defined how modems should operate at 14.4 kbps.

Manageable Versus Basic Modems

Depending on which modem license you purchase with your access server or router, Cisco modems are either manageable by the Cisco IOS software do not support the out-of-band management feature. The latter are called "basic" modems.

Manageable modems support the one out-of-band feature, which is used for gathering modem performance statistics and transmitting attention (AT) commands. Basic modems do not support the out-of-band feature nor the functionality associated with manageable modems. As you read through this chapter, note which commands apply to manageable versus basic modems.

provides a summary of the Cisco IOS commands supported by manageable modems versus basic modems.

Table 19 Commands for Manageable versus Basic Modems

Modem Command

Supported by Manageable Modems

Supported by Basic Modems

called-number

Yes

Yes

clear counters (async)

Yes

Yes

clear counters line

Yes

Yes

clear modem

Yes

Yes

clear modem counters

Yes

Yes

clear modempool-counters

Yes

Yes

copy modem

Yes

Yes

modem answer-timeout

Yes

Yes

modem at-mode

Yes

No

modem at-mode-permit

Yes

No

modem autoconfigure discovery

Yes

Yes

modem autoconfigure type

Yes

Yes

modem autotest

Yes

Yes

modem bad

Yes

Yes

modem buffer-size

Yes

No

modem busyout

Yes

Yes

modem country mica

Yes

Yes

modem country microcom_hdms

Yes

Yes

modem hold-reset

Yes

Yes

modem poll retry

Yes

No

modem poll time

Yes

No

modem recovery action

Yes

Yes

modem recovery-time

Yes

No

modem shutdown

Yes

Yes

modem startup-test

Yes

Yes

modem status-poll

Yes

No

modemcap edit

Yes

Yes

modemcap entry

Yes

Yes

modem-pool

Yes

Yes

pool-range

Yes

Yes

show modem

Yes

Yes

show modem at-mode

Yes

No

show modem call-stats

Yes

No

show modem configuration

Yes

No

show modem connect-speeds

Yes

No

show modem cookie

Yes

Yes

show modem csm

Yes

Yes

show modem log

Yes

Yes

show modem mapping

Yes

Yes

show modem mica

Yes

Yes

show modem operational-status

Yes

No

show modem summary

Yes

Yes

show modem test

Yes

Yes

show modem version

Yes

Yes

show modem-pool

Yes

Yes

test modem back-to-back

Yes

Yes

Modem Management Topologies

shows a typical small scale dial scenario for an Internet service provider. Modem management commands are useful for gathering call statistics and upgrading modem firmware for large modem pools.

Figure 221 Small-Scale POP Using a Cisco AS3640 Access Server

shows a large scale dial scenario for an Internet service provider extending over several states in the USA.

Figure 222 Large-Scale POP Network

shows a typical dial scenario for an enterprise network using a Cisco 3640 router.

Figure 223 Typical Dial Scenario for an Enterprise Network

Single Chassis Modem Pooling

Modem pooling assigns physical modems to a single dialed number identification service number (DNIS). It enables you to create pools of physical modems in one access server, assign a unique DNIS to each modem pool, and set maximum simultaneous connect limits.

This feature is used for physically partitioning or virtually partitioning modems inside one network access server. Modem pooling offers these benefits:

•A certain number of modem ports can be guaranteed per DNIS.

•Maximum simultaneous connection limits can be set for each DNIS.

The following subsections are provided:

•Restrictions

•Platforms Supported

•How Modem Pooling Works

•Configuring Modem Pooling

•Verify Modem Configuration

•Physical Partition with Dial-In and Dial-Out

List of Terms

DNIS—Dialed number identification service number. The same DNIS cannot exist in more than one modem pool. Each modem pool must have its own unique DNIS number(s).

Called party number—DNIS number used to dial into an access server. For example, suppose Modem ABC is dialing into Access Server DEF. The DNIS called party number is the number assigned to Access Server DEF.

Calling party number—Telephone number assigned to a calling device. For example, suppose Modem ABC is dialing into Access Server DEF. The calling party number is the number assigned to Modem ABC. Calling party number is similar to Caller ID.

Modem pool—A range of physical modems that are grouped together and assigned one or more DNIS.

Restrictions

The following restrictions apply:

•Modem pooling is not a solution for large scale dial access. It cannot be used to create virtual modem pools across multiple access servers that are connected together. Modem pooling is physically restricted to one access server.

•MICA and Microcom modems support modem pooling. However, only MICA modems support modem pooling for CT1 and CE1 configurations using channel associated signalling (CAS). To use modem pooling with CT1 or CE1 connections, you must reserve at least two modems in the default modem pool. These reserved modems decode DNIS before handing off calls to the modems assigned to modem pools.

If you see many call failures appearing on the access server, try assigning more modems to the default pool. Use the show modem and show modem summary EXEC commands to view the modem call failure and success ratio.

•No MIBs support modem pooling.

•The same DNIS cannot exist in more than one modem pool.

Platforms Supported

Modem pooling is supported on the following access servers:

•Cisco AccessPath

•Cisco AS5300

•Cisco AS5200

How It Works

Modem pooling allows you to control which modem a call connects to, based on DNIS. Without using modem pooling, incoming and outgoing calls are arbitrarily assigned to modems. For example, consider a Cisco AS5300 loaded with a 4-port ISDN PRI card. After an analog modem call comes into the first PRI trunk, the call is greeted by a general pool of B channels and a general pool of modems. Any B channel can be connected to any modem in the access server. A random assignment takes place. Modem resources cannot be controlled.

You can either physically partition or virtually partition your modems to enable different dial-in and dial-out services.

Configure Modem Pooling

You must first decide to physically partition or virtually partition your modems. For more information, see the previous subsection. After you have made this decision, create a modem pool for a dial-in service or specific customer by performing the tasks in the following table, beginning in EXEC configuration mode.

Step

Command

Purpose

1

configure terminal

Access global configuration mode.

2

modem-pool name

Create a modem pool, and assign it a name.

3

pool-range number-number

Assign a range of modems to the pool. A dash (-) is required between the two numbers.

4

called-number number [max-conn number]

Assigns the DNIS to be used for this modem pool.

The max-conn option specifies the maximum number of simultaneous connections allowed for this DNIS. If you do not specify a max-conn value, the default (total number of modems in the pool) is used.¹

5

Ctrl Z

Return to EXEC mode.

6

show configuration

Display the running configuration to verify the modem pool settings. Make changes accordingly.

7

copy running-config startup-config

Save the running configuration to the start-up configuration.

¹The DNIS string can have an integer x to indicate a don't care digit for that position. For example, 555111x.

Note If you have active modem calls on the access server prior to using modem pooling, modem pooling gracefully applies itself to the access server. Modem pooling first waits for active calls to hang up before assigning modems to modem pools and directing calls according to DNIS.

Verify Modem Configuration

To verify the modem configuration, enter the show modem-pool command to view the configuration. This command shows you the structure and activity status for all the modem pools in the access server. See for a description of each display field.
as5300# show modem-pool
modem-pool: System-def-Mpool
modems in pool: 0   active conn: 0
0 no free modems in pool
modem-pool: v90service
modems in pool: 48  active conn: 46
 8 no free modems in pool
 called_party_number: 1234
   max conn allowed: 48, active conn: 46
   8 max-conn exceeded, 8 no free modems in pool
modem-pool: v34service
modems in pool: 48  active conn: 35
 0 no free modems in pool
 called_party_number: 5678
   max conn allowed: 48, active conn: 35
   0 max-conn exceeded, 0 no free modems in pool
Table 20 Show Modem-Pool Field Descriptions

Field

Description

modem-pool

Name of the modem pool. In the previous example, there are three modem pools configured: System-def-Mpool, v34service, and v90service. To set modem pool name, see the modem-pool command.

All the modems not assigned to a modem pool are automatically assigned to the system default pool (displayed as System-def-Mpool).

modems in pool

Number of modems assigned to the modem pool. To assign modems to a pool, see the pool-range command.

active conn

Number of simultaneous active connections for the specified modem pool or called party DNIS number.

no free modems in pool

Number of times incoming calls were rejected because there were no more free modems in the pool to accept the call.

called_party_number

Specified called party DNIS number. This is the number that the remote clients use to dial in to the access server. You can have more than one DNIS number per modem pool. To set the DNIS number, see the called-number command.

max conn allowed

Maximum number of modems that a called party DNIS number can use, which is an overflow protection measure. To set this feature, see the called-number command.

max-conn exceeded

Number of times an incoming call using this called party DNIS number was rejected because the max-conn number parameter specified by the called-number command was exceeded.

For modem pool configuration examples, see the section "Physical Partition with Dial-In and Dial-Out Scenario."

Check the following if you are having trouble:

•Make sure you have not configured the same DNIS for multiple pools.

•Make sure you have not placed the same modem in multiple pools.

Note Modem pools using MICA or Microcom modems support incoming analog calls over ISDN PRI. However, only MICA modems support modem pooling for T1 and E1 configurations with channel associated signaling.

Physical Partitioning Scenario

Physical partitioning uses one access server to function as multiple access servers loaded with different types of modem services (for example, V.34 modems, fax-capable modems, and point-of-sale (POS) modems). Each modem service is part of one physical modem pool and is assigned a unique DNIS number. See .

Figure 224 Modem Pooling Using Physical Partitioning

Physical partitioning can also be used to set up an access server for bidirectional dial access. See .

shows one Cisco AS5300 loaded with 96 MICA modems and configured with two modem pools. One modem pool has 84 modems and collects DNIS. This pool is shared by 400 salespeople who remotely download e-mail from headquarters. The other modem pool contains 12 fax-capable modems and does not collect DNIS. This pool is shared by 40 employees using PCs on a LAN. Each time an outbound call is initiated by a PC, a modem on the Cisco AS5300 is seized and used to fax out or dial out. Not configuring DNIS support in the fax-out modem pool protects the pool from being used by the calls coming in from the field. Regardless of how many salespeople are dialing in or which telephone number they use, the fax-out/dial-out modem pool will always be reserved for the PCs connected to the LAN.

Physical Partition Example

The following example creates one V.34 modem pool and one 56K modem pool on a Cisco AS5200. Each modem pool is configured with its own DNIS. Depending on which DNIS the remote clients dial, they connect to a V.34 Microcom modem or a 56K MICA modem.

The following hardware configuration is used on the Cisco AS5200:

•One 2-port T1 PRI card

•One 48-port card containing four 6-port MICA 56K modem modules and two 12-port Microcom V.34 modem modules

Complete the following steps to configure basic physical partitioning:

Step 1 Enter global configuration mode:
as5200# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
as5200(config)
Step 2 Create modem pool for the 56K MICA modem services using the modem-pool name command. The modem pool is called 56kservices, which spans across four 6-port MICA 56K modem modules.
as5200(config)# modem-pool 56kservices
as5200(config-modem-pool)#
Note You are in modem pool configuration mode after the prompt changes from as5200(config)# to as5200(config-modem-pool)#.

Step 3 Assign a range of modems to the modem pool using the pool-range number-number command. Because all the 56K MICA modems are seated in slot 1, they are assigned TTY line numbers 1 to 24. Use the show line EXEC command to determine the TTY line numbering scheme for your access server.
as5200(config-modem-pool)# pool-range 1-24
Step 4 Assign a DNIS to the modem pool using the called-number number [max-conn number] command. This example uses the DNIS 5551111 to connect to the 56K modems. The maximum simultaneous connection limit is set to 24. The 25th user dialing 5551111 gets a busy signal.
as5200(config-modem-pool)# called-number 5551111 max-conn 24
Step 5 Return to EXEC mode by pressing CTRL Z. After you do this, display the modem pool configuration with the show modem-pool command. In this example, the 56K modems are in the modem pool called 56kservices. The remaining 24 v.34 Microcom modems are still in the default system pool.
as5200(config-modem-pool)# ^Z
as5200# show modem-pool
modem-pool: System-def-Mpool
modems in pool: 24   active conn: 0   
0 no free modems in pool
modem-pool: 56kservices
modems in pool: 24  active conn: 0
 0 no free modems in pool
 called_party_number: 5551111
   max conn allowed: 24, active conn: 0
   0 max-conn exceeded, 0 no free modems in pool
Step 6 Create the modem pool for the Microcom physical partition. After the configuration is complete, the show modem-pool command shows that there are no remaining modems in the system default modem pool.
as5200# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
as5200(config)# modem-pool v34services
as5200(config-modem-pool)# pool-range 25-48
as5200(config-modem-pool)# called-number 5552222 max-conn 24
as5200(config-modem-pool)# ^Z
as5200# show modem-pool
modem-pool: System-def-Mpool
modems in pool: 0   active conn: 0   
0 no free modems in pool
modem-pool: 56kservices
modems in pool: 48  active conn: 0
 0 no free modems in pool
 called_party_number: 5551111
   max conn allowed: 48, active conn: 0
   0 max-conn exceeded, 0 no free modems in pool
modem-pool: v34services
modems in pool: 48  active conn: 0
 0 no free modems in pool
 called_party_number: 5552222
   max conn allowed: 48, active conn: 0
   0 max-conn exceeded, 0 no free modems in pool
as5200# copy running-config startup-config
Physical Partition with Dial-In and Dial-Out Scenario

The following example is for a bidirectional dial scenario using a Cisco AS5300. Two modem pools are configured. One modem pool contains 84 56K MICA modems, which is shared by 400 remote salespeople dialing in to headquarters. The other modem pool contains 12 fax-capable modems, which is shared by 40 employees dialing out of the headquarters LAN using the Cisco DialOut Utility software. See for the network topology.

Figure 225 Modem Pooling Used for Bidirectional Dialing

The following hardware configuration is used on the Cisco AS5300:

•One 4-port T1 PRI card

•Two 48-port cards containing fourteen 6-port MICA 56K modem modules and two 6-port MICA fax capable modem modules

Complete the following steps to configure physical partitioning with dial-in and dial-out capability:

Step 1 Create the 56K modem pool for the 400 remote salespeople. This modem pool contains 84 modems, which are reserved for the dial-in calls. To get access, the salespeople dial the DNIS 5553333. The total number of simultaneous calls is limited to 84. The 85th call and above is rejected. The modem dialin line configuration command is used to prevent modems 1 to 84 from dialing out.
as5300# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
as5300(config)# modem-pool 56ksalesfolks
as5300(config-modem-pool)# pool-range 1-84
as5300(config-modem-pool)# called-number 5553333 max-conn 84
as5300(config-modem-pool)# exit
as5300(config)# line 1 84
as5300(config-line)# modem dialin
as5300(config-line)# transport input all
as5300(config-line)# rotary 1
as5300(config-line)# autoselect ppp
as5300(config-line)# exit
as5300(config)# 
Step 2 Create the dial-out/ fax-out modem pool for the 40 local employees connected to the headquarters LAN. This modem pool contains 12 fax-capable MICA modems. No DNIS is assigned to the pool. Because lines 85 to 96 are used for the fax-out/ dial-out modem services, the async lines are configured for reverse telnet. This is needed for the telnet extensions to work with the dial-out application, which is installed on the LAN PCs.
as5300(config)# modem-pool dialoutfolks
as5300(config-modem-pool)# pool-range 85-96
as5300(config-modem-pool)# exit
as5300(config)# line 85-96
as5300(config-line)# refuse-message z [!NMM!] No Modems Available z
as5300(config-line)# exec-timeout 0 0
as5300(config-line)# autoselect during-login
as5300(config-line)# autoselect ppp
as5300(config-line)# modem inout
as5300(config-line)# rotary 1
as5300(config-line)# transport preferred telnet
as5300(config-line)# transport input all
as5300(config-line)# exit
as5300(config)# 
Step 3 Configure the group asynchronous interface, which assigns core protocol characteristics to all the asynchronous interfaces in the system. Regardless of the direction that the modems are dialing, all modems in the access server leverage this group asynchronous configuration.
as5300(config)# interface group-async 1
as5300(config-if)# ip unnumbered ethernet 0
as5300(config-if)# encapsulation ppp
as5300(config-if)# async mode interactive
as5300(config-if)# ppp authentication chap pap paplocal
as5300(config-if)# peer default ip address pool bidir_dial_pool
as5300(config-if)# no cdp enable
as5300(config-if)# no ip mroute cache
as5300(config-if)# no ip route cache
as5300(config-if)# async dynamic routing
as5300(config-if)# async dynamic address
as5300(config-if)# group range 1-96
Building configuration...
as5300(config-if)# exit
as5300(config)#
Step 4 Create an IP address pool for all the dial-in clients and dial-out clients. Both types of clients borrow addresses from this shared pool.
as5300(config)# ip local pool bidir_dial_pool 10.4.1.1 10.4.1.96
as5300(config)# ^z
as5300# copy running-config startup-config 
Step 5 (Optional) If you are using CiscoSecure AAA and a remote TACACS server, the following security statements must be included on the access server:
aaa new-model
aaa authentication login default tacacs+
aaa authentication login noaaa local
aaa authentication login logintac tacacs+
aaa authentication ppp ppptac tacacs+
aaa authentication ppp paplocal local
aaa authorization exec tacacs+
aaa authorization network tacacs+
aaa authorization reverse-access tacacs+
aaa accounting exec start-stop tacacs+
aaa accounting network start-stop tacacs+
aaa accounting update newinfo
enable password cisco
You should also include the host name, timeout interval, and authentication key:
tacacs-server host 10.4.1.10
tacacs-server timeout 20
tacacs-server key nas1
Virtual Partitioning Scenario

Virtual partitioning creates one large modem pool on one access server, but assigns different DNIS numbers to different customers. Each incoming DNIS consumes resources from the same modem pool, but a maximum connect option is set for each DNIS.

shows two ISP customers leasing modems from another service provider. Each ISP is assigned its own DNIS number and range of modems. Each ISP is guaranteed a certain number of physical modem ports for simultaneous connections. After an ISP uses up all the modems assigned to its DNIS, a busy signal is issued.

Figure 226 Modem Pooling Using Virtual Partitioning

Virtual partitioning essentially resells modem banks to customers, such as a small size ISP. However, keep in mind that modem pooling is a single chassis solution, not a multichassis solution. Modem pooling is not a solution for reselling ports on a large scale basis.

Virtual Partition Example

The following example creates one modem pool on a Cisco AS5300 for two ISP customers. The shared modem pool is called isp56kpool. However, both ISP customers are assigned different DNIS numbers and limited to a maximum number of simultaneous connections.

See for the network topology.

The following hardware configuration is used on the Cisco AS5300:

•One 4-port T1 PRI card

•Two 48-port cards containing sixteen 6-port MICA 56K modem modules

Perform the following steps to configure virtual partitioning:

Step 1 Enter global configuration mode:
as5300# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
as5300(config)
Step 2 Create the shared modem pool for the 56K MICA modem services. This modem pool is called isp56kpool, which spans across sixteen 6-port MICA 56K modem modules.
as5300(config)# modem-pool isp56kpool
as5300(config-modem-pool)#
Step 3 Assign all the modems to the modem pool using the pool-range number-number command. Use the show line EXEC command to determine your TTY line numbering scheme.
as5300(config-modem-pool)# pool-range 1-96
Step 4 Assign a unique DNIS to each ISP customer using the called-number number [max-conn number] command. In this example, the max-conn number option limits each ISP to 48 simultaneous connections. The 49th user to dial either DNIS will get busy signal.
as5300(config-modem-pool)# called-number 5551111 max-conn 48
as5300(config-modem-pool)# called-number 5552222 max-conn 48
Step 5 Return to EXEC mode by pressing CTRL Z. After you do this, display the modem pool configuration with the show modem-pool command. In this example, all the 56K modems are in the isp56kpool modem pool. The output also shows two DNIS numbers configured: 5551111 and 5552222.
as5300(config-modem-pool)# ^Z
as5300# show modem-pool
modem-pool: System-def-Mpool
modems in pool: 0   active conn: 0   
0 no free modems in pool
modem-pool: isp56kpool
modems in pool: 96  active conn: 0
 0 no free modems in pool
 called_party_number: 5551111
   max conn allowed: 48, active conn: 0
   0 max-conn exceeded, 0 no free modems in pool
 called_party_number: 5552222
   max conn allowed: 48, active conn: 0
   0 max-conn exceeded, 0 no free modems in pool
as5300# copy running-config startup-config 
Change Modem Configuration

You can automatically change the running configuration for external modems (not embedded in modem cards) by issuing a single command. Additionally, you can change an integrated modem's running configuration by sending individual AT commands:

•Changing Automatically for Externally Attached Modems

•Changing Manually by Sending AT Commands to Integrated Modems

Changing Automatically for Externally Attached Modems

The Cisco IOS software can issue initialization strings automatically for most types of modems externally attached to an access server. A modem initialization string is a series of parameter settings that are sent to your modem to configure it to interact with the access server in a specified way. The Cisco IOS software defines seven initialization strings that have been found to properly initialize most modems so that the modems function properly with Cisco access servers. These initialization strings have the following names:

•Codex_3260

•Usr_courier

•Usr_sportster

•Hayes_optima

•Global_village

•Viva

•Telebit_t3000

Note Internal or integrated modems, such as those used by the Cisco AS5200 and Cisco AS5300, are preconfigured by Cisco Systems and do not need to be initialized.

If you do not know which of these modem strings is appropriate for your modems, issue the modem autoconfigure discovery line configuration command, as shown in the following example:
2511# configure terminal 
2511(config)# line 1 16
2511(config-line)# modem autoconfigure discovery
2511(config-line)# Ctrl-Z
2511# copy running-config startup-config
The Cisco IOS software first tries the first of these strings to see if the modem initializes properly. If not, the Cisco IOS software cycles to the next string and repeats the process until the appropriate string is found. If none of the strings properly initializes the modem, you must manually configure the modem.

If you know that your modem can be configured using an initialization string from one of these scripts, you can issue the modem autoconfigure type modem-name command, where modem-name is one of the strings in the preceding list. If you list a specific modem type, initialization proceeds more quickly.

To display the list of modems for which the router has modem string entries, issue the show modemcap command. You can change a modem value that was returned from the show modemcap EXEC command. For example, you might want to add the factory default, &F, entry to the configuration file. To do this, enter the modemcap edit modem-name attribute value line configuration command. Configure one attribute of one modem at a time.

The following example shows how to enter line configuration mode and issue the modem autoconfigure type modem-name command for a US Robotics Sportster modem.
2511(config-line)# modem autoconfigure type usr_sportster
For more information about the recommended strings for any type of modem, refer to the section "Sample Modem Strings" in the appendix "Configuring Modem Support and Chat Scripts" in the Dial Solutions Command Reference. If you have access to Cisco Connection Online (CCO), you can also access the following URL for more information (which is subject to change without notice):

http://www.cisco.com/warp/public/76/4.html

Changing Manually by Sending AT Commands to Integrated Modems

Manageable Microcom modems have an out-of-band feature, which is used to poll modem statistics and transmit AT commands. The Cisco IOS software uses a direct connect session to transfer information through this out-of-band feature. To send AT commands to a Microcom modem, you must permit a direct connect session for a specified modem, open a direct connect session, send AT commands to a modem, and clear the directly connected session from the modem when you are finished.

Note This sections does not describe how to send AT commands to MICA digital modems. If your system uses MICA modems, refer to the publication AT Command Set and Register Summary for MICA Six-Port Modules.

Open a direct connect session by issuing the modem at-mode slot/port command in Privileged EXEC mode. From here, you can transmit AT commands directly from your terminal session window to the internal Microcom modems. Most incoming or outgoing calls on the modems are not interrupted when you open a direct connect session and transmit AT commands. However, some AT commands interrupt a call—for example, the ATH command, which hangs up a call. Open and close one direct connect session at a time. Beware that multiple open sessions slow down modem performance.

Refer to the AT command set that came with your router for a complete list of AT commands that you can transmit to the modems.

For Microcom modems, you can clear or terminate an active directly connected session in two ways:

•Press Ctrl-C after transmitting all AT commands as instructed by the system when you enter AT command mode.

•Enter a second Telnet session and enable the clear modem at-mode slot/port command in EXEC configuration mode. This method is used for closing a directly connected session that may have been mistakenly left open by the first Telnet session.

Transmit AT Command Example

The following example opens a directly connected session on modem 1/1, enters AT command mode on modem 1/1, and transmits the at%v and at\s commands via the out-of-band feature on modem 1/1:
router# modem at-mode 1/1
You are now entering AT command mode on modem (slot 1 / port 1).
Please type CTRL-C to exit AT command mode.
at%v
MNP Class 10 V.34/V.FC Modem Rev 1.0/85
OK
at\s
IDLE           000:00:00
LAST DIAL      
NET ADDR:      FFFFFFFFFFFF
MODEM HW: SA 2W United States
4 RTS 5 CTS 6 DSR - CD 20 DTR - RI 
MODULATION     IDLE
MODEM BPS      28800  AT%G0   
MODEM FLOW     OFF    AT\G0
MODEM MODE     AUT    AT\N3
V.23 OPR.      OFF    AT%F0
AUTO ANS.      ON     ATS0=1
SERIAL BPS     115200 AT%U0   
BPS ADJUST     OFF    AT\J0
SPT BPS ADJ.   0      AT\W0
ANSWER MESSGS  ON     ATQ0   
SERIAL FLOW    BHW    AT\Q3
PASS XON/XOFF  OFF    AT\X0
PARITY         8N     AT
The manageable modem returns "OK" if the AT command you transmit is successfully enabled.

Clear a Direct Connect Session from a Second Telnet Session Example

The following examples are for Microcom modems.

The following example shows how to execute the modem at-mode command from a Telnet session:
router# modem at-mode 1/1
The following example shows how to execute the clear modem at-mode command from a second Telnet session while the first Telnet session is connected to the modem:
router# clear modem at-mode 1/1
clear "modem at-mode" for modem 1/1 [confirm] <press Return>
router#
The following output is displayed in the first Telnet session after the modem is cleared by the second Telnet session:
Direct connect session cleared by vty0 (171.69.1.164)
Verify Connection Speed Performance

Making sure that your modems are connecting at the correct connection speeds is an important aspect of managing modems. To display modem connection speed statistics for a specific modem or range of modems, use the following EXEC commands:

Step

Command

Purpose

1

show modem connect-speeds [max-speed [slot]]

Displays connection speed statistics for all the modems.

2

show modem [slot/port | group number]

Displays a high-level performance report for all the modems or a single modem.You must type in the forward slash.

These commands also provide performance information to investigate possible bad or corrupt modems or T1/E1 lines. For example, suppose you have an access server that is fully populated with V.34 modems. If you notice that modem 1/0 is only getting V.34 connections 50% of the time, whereas all the other modems are getting V.34 connections 80% of the time, then modem 1/0 is probably malfunctioning or bad. If you are reading low connection speeds across all the modems, you may have a faulty channelized T1 or ISDN PRI line connection.

To display connection speed information for all modems running in your system, use the show modem connect-speeds max-speed EXEC command. Because most terminal screens are not wide enough to display the entire range of connection speeds at one time (for example, 75 to 56000 bps), the max-speed variable is used. This variable specifies the contents of a shifting baud-rate window, which provides you with a snap shot of the modem connection speeds for your system. Replace the max-speed argument with the maximum connect speed that you want to view. You can specify from 12000 to 56000 bps. If you are interested in viewing a snap shot of lower baud rates, specify a lower connection speed. If you are interested in viewing a snap shot of higher baud rates, specify a higher connection speed.

See the Dial Solutions Command Reference for a complete description of each of the fields displayed in the following example:
router# show modem connect-speeds 33600
  transmit connect speeds
  Mdm   14400  16800  19200  21600  24000  26400  28800  31200  33600 TotCnt
* 0/0       0      0      0      0      0      0      4      4      1      9
* 0/1       2      0      0      0      0      0      3      3      1      9
  0/2       2      0      0      0      0      1      2      4      1     10
* 0/3       0      0      0      1      0      0      3      4      1      9
* 0/4       1      0      0      0      0      2      2      1      1      7
* 0/5       0      0      0      0      0      0      4      4      1      9
* 0/6       0      0      0      0      0      1      3      3      1      8
* 0/7       0      0      0      2      0      0      4      3      1     10
* 0/8       2      0      0      0      0      0      3      4      1     10
* 0/9       0      0      0      0      0      0      4      3      0      7
* 0/10      1      0      0      0      0      1      3      2      1      8
* 0/11      0      0      0      0      0      0      4      3      1      8
  0/12      1      0      0      0      0      0      4      2      1      8
* 0/13      0      0      0      0      0      0      4      2      1      7
* 0/14      1      0      0      0      0      1      2      2      1      7
* 0/15      0      0      0      0      0      0      4      2      1      7
* 0/16      0      0      0      1      0      0      3      2      1      7
* 0/17      1      0      0      0      0      0      4      2      1      8
* 0/18      1      0      0      0      0      0      3      3      1      8
* 0/19      0      0      0      0      0      0      5      3      1      9
* 0/20      0      0      0      0      0      0      4      2      1      7
* 0/21      1      0      0      0      0      0      4      2      0      7
* 0/22      0      0      0      0      0      0      7      9      1     17
* 0/23      0      0      0      0      0      2      2      3      1      8
* 2/0       0      0      0      1      0      0      3      3      1      8
* 2/1       0      0      0      0      0      0      5      2      1      8
* 2/2       0      0      0      1      0      0      4      1      1      7
* 2/3       1      0      0      0      0      0      4      2      1      8
* 2/4       0      0      0      0      0      0      5      2      1      8
* 2/5       0      0      0      0      0      0      4      3      1      8
* 2/6       0      0      0      0      0      0      3      2      1      6
* 2/7       1      0      0      0      0      1      3      2      0      7
* 2/8       1      0      0      0      0      0      3      2      1      7
* 2/9       0      0      0      0      0      1      3      2      1      7
* 2/10      2      0      0      0      0      2      1      0      1      6
* 2/11      0      0      0      1      0      1      3      5      1     11
* 2/12      0      0      0      0      0      0      5      2      1      8
* 2/13      1      0      0      0      0      0      5      0      1      7
* 2/14      1      0      0      0      0      0      3      3      1      8
* 2/15      1      0      0      0      0      1      2      3      1      8
* 2/16      0      0      0      0      0      0      4      3      1      8
* 2/17      0      0      0      0      0      0      5     11      0     16
* 2/18      0      0      0      1      0      1      1      2      1      6
* 2/19      0      0      0      0      0      0      2      3      1      6
* 2/20      1      0      0      0      0      2      3      9      1     16
* 2/21      1      0      0      0      0      0      4      1      1      7
* 2/22      0      0      0      1      0      0      2      3      1      7
* 2/23      0      0      0      0      0      1      3      3      1      8
 Tot       23      0      0      9      0     18    165    141     44    400
 Tot %      5      0      0      2      0      4     41     35     11
  receive connect speeds
  Mdm   14400  16800  19200  21600  24000  26400  28800  31200  33600 TotCnt
* 0/0       0      0      0      0      0      4      1      3      1      9
* 0/1       2      0      0      0      0      3      1      2      1      9
  0/2       2      0      0      0      0      3      1      3      1     10
* 0/3       0      0      0      1      0      3      4      0      1      9
* 0/4       1      0      0      0      0      4      0      1      1      7
* 0/5       0      0      0      0      0      4      3      1      1      9
* 0/6       0      0      0      0      0      4      0      3      1      8
* 0/7       0      0      0      2      0      4      1      2      1     10
* 0/8       2      0      0      0      0      3      0      5      0     10
* 0/9       0      0      0      0      0      4      2      0      1      7
* 0/10      1      0      0      0      0      4      0      2      1      8
* 0/11      0      0      0      0      0      4      0      3      1      8
  0/12      1      0      0      0      0      2      2      2      1      8
* 0/13      0      0      0      0      0      4      1      1      1      7
* 0/14      1      0      0      0      0      2      3      0      1      7
* 0/15      0      0      0      0      0      4      1      1      1      7
* 0/16      0      0      0      1      0      3      2      0      1      7
* 0/17      1      0      0      0      0      4      1      1      1      8
* 0/18      1      0      0      0      0      3      2      1      1      8
* 0/19      0      0      0      0      0      5      1      2      1      9
* 0/20      0      0      0      0      0      4      0      3      0      7
* 0/21      1      0      0      0      0      4      0      1      1      7
* 0/22      0      0      0      0      0      6      6      4      1     17
* 0/23      0      0      0      0      0      4      2      1      1      8
* 2/0       0      0      0      1      0      3      1      2      1      8
* 2/1       0      0      0      0      0      3      3      1      1      8
* 2/2       0      0      0      1      0      4      0      1      1      7
* 2/3       1      0      0      0      0      3      2      1      1      8
* 2/4       0      0      0      0      0      4      2      1      1      8
* 2/5       0      0      0      0      0      4      1      2      1      8
* 2/6       0      0      0      0      0      3      0      3      0      6
* 2/7       1      0      0      0      1      2      2      0      1      7
* 2/8       1      0      0      0      0      3      0      2      1      7
* 2/9       0      0      0      0      0      4      1      1      1      7
* 2/10      2      0      0      0      0      3      0      0      1      6
* 2/11      0      0      0      1      0      3      1      5      1     11
* 