16-Port and 32-Port Asynchronous Network Modules for Cisco 3600 Series Routers

Description

Cisco 3600 series routers now support 16- and 32-port network modules for asynchronous connections. These devices are high density modules that support speeds up to 134.4 kbps. Depending on which module you install in the router, you can have up to 16 or 32 modem connections to each module at any given time. The Cisco 3640 can support up to 96 dialin ports.

Prerequisites

Before configuring the Cisco IOS software, you should be familiar with configuring lines and asynchronous interfaces with Cisco routers. Also, understanding the slot and unit numbering scheme as described in the "Overview" chapter of the Cisco 3600 series router installation and configuration guides is very helpful.

Configuration Tasks

To configure an asynchronous serial interface on a Cisco 3600 series router, you must set up the interface to send Serial Line Internet Protocol (SLIP) or Point-to-Point Protocol (PPP) packets. PPP and SLIP define methods of sending Internet packets over a standard EIA-232 asynchronous serial line. PPP also defines methods for sending Internetwork Packet Exchange (IPX) and AppleTalk Remote Access (ARA) packets during PPP sessions.

Asynchronous Serial Task List

To configure an asynchronous interface so you can connect to an asynchronous device on the network, complete the tasks in the following sections:

Note You can also configure support for SLIP and PPP using extended BOOTP requests.

Specify an Asynchronous Serial Interface

On Cisco 3600 series routers, you can configure up to 32 asynchronous interfaces per card. The auxiliary (labeled AUX on the back of the product) port can also be configured as an asynchronous serial interface, although performance on the AUX port is much slower than on standard asynchronous interfaces and does not support some features. Table 33 illustrates why asynchronous interfaces permit substantially better performance than AUX ports configured as asynchronous interfaces.

Table 33: Differences between Auxiliary (AUX) Port and Asynchronous Port

Feature	Asynchronous Interface	Auxiliary Port
Maximum speed	134400 bps	38400 bps
Supported Platforms	Cisco 3640 and 3620	All Cisco routers
Supports DMA buffering¹	Yes	No
PPP framing on chip²	Yes	No
IP fast switching³	Yes	No

¹ Direct Memory Access (DMA) buffering moves data packets directly to and from system memory without interrupting the main central processing unit (CPU). This process removes overhead from the CPU and increases overall system performance.
² PPP framing on a hardware chip removes overhead from the router's CPU, which enables the router to sustain 115.2-kbps throughput on all asynchronous ports simultaneously.
³ After the destination of the first IP packet is added to the fast switching cache, it is fast-switched to and from other interfaces with minimal involvement from the main processor.

Use the line command with the appropriate line configuration commands for modem control, such as speed. Perform the following task in global configuration mode to specify a port as an asynchronous interface to configure:

Task	Command
Specify an asynchronous serial interface.	interface async port-number

Configure Asynchronous Serial Encapsulation

There are two asynchronous serial encapsulation methods:

SLIP
PPP

Only IP packets can be sent across lines configured for SLIP. PPP supports transmission of IP, IPX, and ARA packets on an asynchronous serial interface.

For information about configuring SLIP and PPP, refer to the chapter "Configuring SLIP and PPP" in the Access Services Configuration Guide.

Configure Dedicated or Interactive Mode

You can configure the asynchronous interface to be in dedicated network or interactive mode.

In dedicated mode, there is no user prompt or EXEC level, so no end-user commands are required to place the line into interface mode. When the interface is configured for dedicated mode, the user cannot change the encapsulation method, address, or other parameters.

To configure an asynchronous interface to be in dedicated network mode, perform the following task in interface configuration mode:

Task	Command
Place the asynchronous line into dedicated network mode.	async mode dedicated

Alternatively, you can configure an asynchronous line for interactive mode. In interactive mode, the line can be used to make any type of connection, depending on the EXEC command entered by the user. For example, depending on its configuration, the line could be used for Telnet connections, or SLIP or PPP encapsulation. Perform the following task in interface configuration mode to configure an asynchronous line for interactive mode:

Task	Command
Place the asynchronous line in interactive mode.	async mode interactive

Enable Routing on the Asynchronous Interface

To enable dynamic routing protocols on asynchronous interfaces, perform the following task in interface configuration mode:

Task	Command
Configure an asynchronous interface for routing.	async dynamic routing

Configure Group and Member Asynchronous Interfaces

You can create an asynchronous interface to be used as a group interface, which can be associated with other, member asynchronous interfaces.

This association allows you to configure the group interface and all of its member interfaces with a single command entered at the asynchronous group interface command line. You can have more than one group interface on a device; however, a member interface can be associated with only one group.

Figure 12 illustrates the group-member interface concept.

Figure 12: Group-Member Association on Asynchronous Interfaces

Create the Group Interface and the Member Interfaces

To create an asynchronous group interface and associate member interfaces to this group interface, perform the following commands starting in global configuration mode:

Task	Command
Create an asynchronous group interface.	interface group-async unit-number
Associate one or more asynchronous interfaces (members) to the group interface so that all associated interfaces can be configured through the group interface.	group-range low-end-of-range high-end-of-range

Define Member Asynchronous Interface Characteristics

Member interfaces can have certain interface configurations that differ from their group. The following are valid interface configuration commands:

async default ip address
description

To configure a member with two or more interface configurations that are different from its group, enter the following command in interface configuration mode, where interface-command is one of the commands listed in the preceding list:

Task	Command
Configure a member to have specific differences from its group.	member interface-number interface-command

Configuration Examples

This section shows the configuration output for one 32-port module.This configuration output shows only the group async, dialer, and line interfaces for the module.

!
interface Group-Async1
 no ip address
 encapsulation ppp
 bandwidth 132
 load-interval 30
 async default routing
 async dynamic routing
 async mode interactive
 dialer in-band
 dialer rotary-group 1
 no fair-queue
 no cdp enable
 group-range 33 56
!
interface Group-Async2
 no ip address
 encapsulation ppp
 bandwidth 134
 load-interval 30
 async default routing
 async dynamic routing
 async mode interactive
 dialer in-band
 dialer rotary-group 2
 no fair-queue
 no cdp enable
 group-range 57 80
!
interface Group-Async3
 no ip address
 encapsulation ppp
 bandwidth 134
 load-interval 30
 async default routing
 async dynamic routing
 async mode interactive
 dialer in-band
 dialer rotary-group 3
 no fair-queue
 no cdp enable
 group-range 81 104
!
interface Group-Async4
 no ip address
 encapsulation ppp
 bandwidth 134
 load-interval 30
 async default routing
 async dynamic routing
 async mode interactive
 dialer in-band
 dialer rotary-group 4
 no fair-queue
 no cdp enable
 group-range 105 128
!
interface Dialer1
 ip address 1.0.3.1 255.255.255.0
 ip accounting access-violations
 encapsulation ppp
 bandwidth 3350
 load-interval 30
 appletalk cable-range 200-200 200.1
 appletalk zone bh-galaxy
 ipx network 10003
 ipx accounting
 no peer default ip address
 dialer in-band
 dialer enable-timeout 2000000
 dialer map ip 1.0.3.2 name galaxy modem-script login-ppp-neg broadcast 5550002
 dialer map appletalk 200.2 name galaxy modem-script login-ppp-neg broadcast 5550002
 dialer map ipx 10003.000c.000c.0002 name galaxy modem-script login-ppp-neg broadcast 5550002
 dialer load-threshold 1
 dialer-group 1
 no cdp enable
 ppp authentication chap
 pulse-time 3
!
interface Dialer2
 ip address 1.0.6.1 255.255.255.0
 ip accounting access-violations
 encapsulation ppp
 bandwidth 3350
 load-interval 30
 appletalk cable-range 300-300 300.1
 appletalk zone bh-quasar
 ipx network 10006
 ipx accounting
 no peer default ip address
 dialer in-band
 dialer enable-timeout 2000000
 dialer map ip 1.0.6.2 name quasar modem-script login-ppp-neg broadcast 5550003
 dialer map ipx 10006.000c.000c.0003 name quasar modem-script login-ppp-neg broadcast 5550003
 dialer map appletalk 300.2 name quasar modem-script login-ppp-neg broadcast 5550003
 dialer load-threshold 1
 dialer-group 2
 no cdp enable
 ppp authentication chap
 pulse-time 3
!
interface Dialer3
 ip address 1.0.7.1 255.255.255.0
 ip accounting access-violations
 encapsulation ppp
 bandwidth 3350
 load-interval 30
 appletalk cable-range 400-400 400.1
 appletalk zone bh-nebula
 ipx network 10007
 ipx accounting
 no peer default ip address
 dialer in-band
 dialer enable-timeout 2000000
 dialer map ip 1.0.7.2 name nebula modem-script login-ppp-neg broadcast 5550005
 dialer map appletalk 400.2 name nebula modem-script login-ppp-neg broadcast 5550005
 dialer map ipx 10007.000c.000c.0004 name nebula modem-script login-ppp-neg broadcast 5550005
 dialer load-threshold 1
 dialer-group 3
 no cdp enable
 ppp authentication chap
 pulse-time 3
!
interface Dialer4
 mtu 4500
 ip address 1.0.9.1 255.255.255.0
 ip accounting access-violations
 encapsulation ppp
 bandwidth 3350
 load-interval 30
 appletalk cable-range 500-500 500.1
 appletalk zone bh-starburst
 ipx network 10002
 ipx accounting
 no peer default ip address
 dialer in-band
 dialer enable-timeout 2000000
 dialer map ip 1.0.9.2 name starburst modem-script login-ppp-neg broadcast 5550008
 dialer map ipx 10002.000c.000c.0005 name starburst modem-script login-ppp-neg broadcast 5550008
 dialer map appletalk 500.2 name starburst modem-script login-ppp-neg broadcast 5550008
 dialer load-threshold 1
 dialer-group 4
 no cdp enable
 ppp authentication chap
 pulse-time 3
!         
line con 0
line 33 128
 exec-timeout 0 0
 login
 transport input all
 escape-character NONE
 telnet transparent
 speed 113400
 flowcontrol hardware
line aux 0
line vty 0 4
 login
!
end

Command Reference

This section provides command reference documentation for the show controllers async command.

show controllers async

Use the show controllers async EXEC command to display asynchronous controller information.

show controllers async

Command Mode

Privileged EXEC

Sample Display

The following is sample output from the show controllers async command:

Router# show controllers async 
 
Cirrus CD2430 Quadart 16, Chip Revision 00, Microcode 53
Global registers
  rpilr 0x2, rir 0x3, risr 0x0, rfoc 0x0, rdr 0x0
  tpilr 0x1, tir 0x0, tisr 0x68, tftc 0x0, tdr 0x4
  mpilr 0x3, mir 0x3, misr 0xA0
  bercnt 0xFF, stk 0x0
TTY line 65
Per-channel registers for channel 0
  Option registers
  0x00 0x02 0x70 0x87 0x8C 0x00 0x00
  Command and status registers
  cmr 0xC4, ccr 0x00, csr 0x99, msvr-rts 0xA3, msvr-dtr 0xA3
  Clock option registers
  rcor 0x80, rbpr 0x25, tcor 0x00, tbpr 0x25
  Interrupt registers
  ier 0xA9, livr 0x00, licr 0x00
  DMA buffer status 0x22
  DMA receive registers
  arbaddr 0x1F329F4, arbcnt 1508, arbsts 0x1
  brbaddr 0x1F32334, brbcnt 1508, brbsts 0x1
  rcbaddr 0x1F330DE
  DMA transmit registers
  atbaddr 0x1EE1E2E, atbcnt 38, atbsts 0x62
  btbaddr 0x1EC78F0, btbcnt 40, btbsts 0x62
  tcbaddr 0x1EC7918
  Special character registers
  schr1 0x00, schr2 0x00, schr3 0x0A, schr4 0x00
  scrl 0x0, scrh 0x0, lnxt 0x0
Buffer information
  Rx ttycnt 0, sysbuf 0 0
  Tx ttycnt 0
  Rx Buffs: inpk 60CC7DF0/60CC7C10 inheadpk 0 dataq 0 0 0
            pakq 60B49304 60B48F44 3
  Tx Buffs: outpk 0  txpkq 60B48B84 60B48D64 2
  Priv Flags: 18      
Error Counters
  Nested interrupts: transmit 0, receive 0, modem 0

Table 34 describes the significant fields in the command's output.

Table 34: Show Controllers Async Display Descriptions

Field	Description
Cirrus CD2430 Quadart	Controller used as the asynchronous controller in the network module.
Global registers	Global registers of the logic controller. The first three lines stand for receive, transmit, and modem respectively.
TTY line 33	TTY line number associated with the current channel of the current controller.
Per-channel registers for channel 0	Unique registers for each channel of the controller. There are four channels per controller, each of which is used for a separate async line.
Buffer information	The receive and transmit related buffer information for the specific channel.
Error Counters	A counter that keeps track of how many times nested interrupts were encountered. Since the Cisco 3600 series platforms are MIPS processor based platforms, only zeros should appear.

What to Do Next

Refer to the following publications for additional software configuration information:

16-port and 32-Port Asynchronous Network Module Configuration Note
Cisco 3640 Router Installation and Configuration Guide
Cisco 3620 Router Installation and Configuration Guide

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