Cisco Industrial Ethernet 4000, 4010 and 5000 Switch Software. Configuration Guide (2022)

Configuring PROFINET

Restrictions for Configuring PROFINET

Cisco IE series switches support PROFINET I/O, RT but not IRT (isochronous real-time).

Information About Configuring PROFINET

PROFINET is the PROFIBUS International (PI) open Industrial Ethernet Standard that uses TCP/IP and IT standards for

automation control. PROFINET is particularly useful for industrial automation systems and process control networks,

in which motion control and precision control of instrumentation and test equipment are important. It emphasizes

data exchange and defines communication paths to meet speed requirements. PROFINET communication is scalable on

three levels:

Normal non-real-time communication uses TCP/IP and enables bus cycle times of approximately 100 ms.

Real-time communication enables cycle times of approximately 10 ms.

Isochronous real-time communication enables cycle times of approximately 1 ms.

PROFINET I/O is a modular communication framework for distributed automation applications. PROFINET I/O uses cyclic

data transfer to exchange data, alarms, and diagnostic information with programmable controllers, input/output (I/O)

devices, and other automation controllers (for example, motion controllers).

PROFINET I/O recognizes three classes of devices:

I/O devices

I/O controllers

I/O supervisors

127

Configuring PROFINET

Information About Configuring PROFINET

PROFINET Device Roles

Figure 15

PROFINET Device Roles

I/O supervisor

I/O controller/PLC

(Programming device/PC)

Control and exchange

Commissioning,

data with I/O devices

Plant diagnostics

Ethernet

Read and write

I/O data

I/O device

(Field device)

An I/O controller is a programmable logic controller (PLC) that controls I/O devices and exchanges data such as

configuration, alarms, and I/O data through an automation program. The I/O controller and the I/O supervisor exchange

diagnostic information. The I/O controller shares configuration and input/output information with the I/O device and

receives alarms from the I/O device.

PROFINET is designed to be the sole or primary management system platform. Because the I/O controller detects the

switch with the Discovery and Configuration Protocol (DCP), and sets the device name and IP address, you do not need

to enter Cisco IOS commands for the basic configuration. For advanced configurations (for example, QoS, DHCP, and

similar features) you must use Cisco IOS commands on the switch because these features cannot be configured by using

PROFINET.

An I/O supervisor is an engineering station, such as a human machine interface (HMI) or PC, used for commissioning,

monitoring, and diagnostic analysis. The I/O supervisor exchanges diagnostic, status, control, and parameter information

with the I/O device.

An I/O device is a distributed input/output device such as a sensor, an actuator, or a motion controller.

Note: If Profinet DCP cannot detect the switch/PLC/IO mac addresses, temporarily disable the firewall/virus scan from

the Window PC that installed the Siemens STEP7 or TIA Portal.

In a PROFINET I/O system, all the I/O devices communicate over an Ethernet communication network to meet the

automation industry requirement for bus cycle times of less than 100 ms. The network uses switches and full-duplex

data exchange to avoid data collisions.

PROFINET Device Data Exchange

After PROFINET uses DCP to discover devices, including the switch, they establish application relationships (ARs) and

communication relationships (CRs). After a connection is established and information about device parameters is

exchanged, input and output data is exchanged. The switch uses non-real-time CRs to exchange the data attributes

listed in Table 17 on page 129 and Table 18 on page 129.

128

Configuring PROFINET

Information About Configuring PROFINET

Table 17

PROFINET I/O Switch Attributes

PROFINET I/O Switch Configuration

Value or Action

Attributes

Device name

Configures a name for the device.

TCP/IP

IP address, subnet mask, default gateway, SVI.

Primary temperature alarm

Enables or disables monitoring for the specified alarm.

Secondary temperature alarm

Enables or disables monitoring for the specified alarm.

RPS failed alarm

Enables or disables monitoring for the specified alarm.

Relay major alarm

Enables or disables monitoring for the specified alarm.

Reset to factory defaults

Uses the PROFINET I/O controller to reset the switch to factory defaults.

This action removes the startup configuration and reloads the switch.

Relay major configuration

Specifies the type of port alarm (for example, link fault) that triggers the

major relay. Any port configured with the specified alarm type can trigger

the major relay.

Table 18

PROFINET I/O Port Attributes

PROFINET I/O Port Configuration

Value or Action

Attributes

Speed

10/100/1000/auto,

Duplex

Half/full/auto,

Port mode

Access/trunk,

Link status

Shut down/no shut down,

Configure rate limiting

Broadcast, unicast, multicast threshold exceeds configured levels.

Port link fault alarm

Enables or disables monitoring for specified alarm.

Port not forwarding alarm

Enables or disables monitoring for specified alarm.

Port not operating alarm

Enables or disables monitoring for specified alarm.

Port FCS threshold alarm

Enables or disables monitoring for specified alarm.

PROFINET devices are integrated by using a general station description (GSD) file that contains the data for engineering

and data exchange between the I/O controller, the I/O supervisor, and the I/O devices, including the switch. Each

PROFINET I/O field device must have an associated GSD file that describes the properties of the device and contains all

this information required for configuration:

Device identification information (device ID, vendor ID and name, product family, number of ports)

Number and types of pluggable modules

Error text for diagnostic information

Communication parameters for I/O devices, including the minimum cycle time, the reduction ratio, and the watch

dog time

Configuration data for the I/O device modules, including speed, duplex, VLAN, port security information, alarms, and

broadcast-rate-limiting thresholds

Parameters configured for I/O device modules for the attributes listed in Table 18 on page 129

129

Configuring PROFINET

How to Configure PROFINET

The GSD file is on the switch, but the I/O supervisor uses this file.

Note: You must use the GSD file that is associated with the Cisco IOS release on the switch to manage your PROFINET

network. Both the I/O supervisor and the Cisco IOS software alert you to a mismatch between the GSD file and the switch

Cisco IOS software version.

How to Configure PROFINET

Configuring PROFINET

You can use either the PROFINET software on the I/O supervisor or the Cisco IOS software for basic switch configuration.

After you enable PROFINET, LLDP is automatically enabled on the switch because PROFINET relies on LLDP to fully

function. If you disable PROFINET, you can enable or disable LLDP as needed.

Default Configuration

PROFINET is enabled by default on all the base switch module ports. The default config is enabled on VLAN 1 but can

be changed to another VLAN ID. If PROFINET has been disabled, follow the instructions in the Enabling PROFINET,

page 130.

Enabling PROFINET

Command

Purpose

configure terminal

Enters global configuration mode.

profinet

Enables PROFINET on the switch.

profinet id line

(Optional) Sets the PROFINET device identifier (ID) by using the Cisco IOS

software.

The maximum length is 240 characters. The only special characters allowed are

the period (.) and hyphen (-), and they are allowed only in specific positions

within the ID string. It can have multiple labels within the string. Each label can

be from 1 to 63 characters, and labels must be separated by a period (.). The

final character in the string must not be zero (0).

For more details about configuring the PROFINET ID, see the PROFINET

specification, document number TC2-06-0007a, filename

PN-AL-protocol_2722_V22_Oct07, available from PROFIBUS.

profinet vlan vlan id

(Optional) Changes the VLAN number. The default VLAN number is 1. The VLAN

ID range is 1-4096. Supports one VLAN per switch.

end

Returns to privileged EXEC mode.

show running-config

Verifies your entries.

copy running-config

(Optional) Saves your entries in the configuration file.

startup-config

130

Configuring PROFINET

Monitoring and Maintaining PROFINET

Table 19

Commands for Displaying the PROFINET Configuration

Command

Purpose

show profinet sessions

Displays the currently connected PROFINET sessions.

show profinet status

Displays the status of the PROFINET subsystem.

show lldp neighbor interface x/x detail

Displays information about the adjacent interface.

Example

IE5000#show profinet status

State : Enabled

Vlan : 2

Id : Ie5000

Connected : Yes

ReductRatio : 128

GSD Version: Match

Troubleshooting PROFINET

The PLC has LEDs that display red for alarms, and the I/O supervisor software monitors those alarms.

To troubleshoot PROFINET use the debug profinet privileged EXEC command with the keywords shown in Table 20 on

page 131. Be aware that the output of a debug command might cause a serial link to fail. You should use these

commands only under the guidance of a Cisco Technical Support engineer. When you use this command, use Telnet to

access the Cisco IOS command-line interface (CLI) by using Ethernet rather than a serial port.

Table 20

Commands for Troubleshooting the PROFINET Configuration

Command

Purpose

debug profinet alarm

Displays the alarm status (on or off) and content of PROFINET alarms.

debug profinet cyclic

Displays information about the time-cycle-based PROFINET Ethernet frames.

debug profinet error

Displays the PROFINET session errors.

debug profinet packet ethernet

Displays information about the PROFINET Ethernet packets.

debug profinet packet udp

Displays information about the PROFINET Upper Layer Data Protocol (UDP)

packets.

debug profinet platform

Displays information about the interaction between the Cisco IOS software and

PROFINET.

debug profinet topology

Displays the PROFINET topology packets received.

debug profinet trace

Displays a group of traced debug output logs.

Additional References

The following sections provide references related to switch administration:

131

Configuring PROFINET

Additional References

Related Topic

Document Title

Cisco IOS basic commands

Cisco IOS Configuration Fundamentals Command Reference

Standards

Title

No new or modified standards are supported by this

—

feature, and support for existing standards has not

been modified by this feature.

MIBs

MIBs Link

—

To locate and download MIBs using Cisco IOS XR software, use the

Cisco MIB Locator found at the following URL and choose a platform

under the Cisco Access Products menu:

http://cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

RFCs

Title

No new or modified RFCs are supported by this

—

feature, and support for existing RFCs has not been

modified by this feature.

Technical Assistance

Description

Link

The Cisco Technical Support website contains

http://www.cisco.com/techsupport

thousands of pages of searchable technical content,

including links to products, technologies, solutions,

technical tips, and tools. Registered Cisco.com users

can log in from this page to access even more content.

135

Configuring SDM Templates

Prerequisites for Configuring SDM Templates

You must enter the reload privileged EXEC command to have your configured SDM template take effect.

Restrictions for Configuring SDM Templates

When you select and configure SDM templates, you must reload the switch for the configuration to take effect.

If you try to configure IPv6 features without first selecting a dual IPv4 and IPv6 template, a warning message is

generated.

Using the dual-stack templates results in less TCAM capacity allowed for each resource, so do not use if you plan

to forward only IPv4 traffic.

Information About Configuring SDM Templates

SDM Templates

You can use SDM templates to configure system resources in the switch to optimize support for specific features,

depending on how the switch is used in the network.

You can select a template to provide maximum system usage for some functions or use the default template to balance

resources.

To allocate ternary content addressable memory (TCAM) resources for different usages, the switch SDM templates

prioritize system resources to optimize support for certain features. When running the IPservices license, you can select

SDM templates to optimize these features:

Default—The default template gives balance to all Layer 2 functions.

Dual IPv4 and IPv6—Allows the switch to be used in dual-stack environments (supporting both IPv4 and IPv6).

Routing—The routing template maximizes system resources for IPv4 unicast routing, typically required for a router or

aggregator in the center of a network.

See Dual IPv4 and IPv6 SDM Default Template, page 138.

There are four templates for ip services and one template for lanbase licensing.

137

Configuring SDM Templates

Information About Configuring SDM Templates

Table 23

IP Services license SDM Templates

Resource

Default

IPv4 Routing

Dual-Default

Dual-Routing

Unicast MAC addresses

16 K

IPv4 IGMP or IPv6 groups

1K IPv4

1K IPv6

Direct routes

16K IPv4

4K IPv4

4K IPv6

Indirect routes

2K IPv4

8K IPv4

1.25K IPv4

2K IPv4

1.25K IPv6

3K IPv6

IPv4 or IPv6 policy-based routing ACEs

0.125K (IPv4

0.5K (IPv4

0.25K (IPv4 PBR)

0.125K (IPv4 PBR)

PBR)

0.25K (IPv6 PBR)

0.125K (IPv6 PBR)

IPv4 or IPv6 QoSACEs

1.875K (IPv4

0.5K (IPv4

0.5K (IPv4 QoS)

QoS)

0.375K (IPv6

0.125K (IPv6

QoS)

IPv4 or IPv6 port or MAC security ACEs

1.875K (IPv4

1K (IPv4

0.75K (IPv4 ACL)

0.625K (IPv4 ACL)

ACL)

0.375K (IPv6 ACL)

0.125K (IPv6 ACL)

Table 24

Lanbase license SDM Template

Resource

Default

Unicast MAC addresses

16 K

IPv4 IGMP or IPv6 groups

1K IPv4/1K IPv6

Direct routes

4K IPv4/4K IPv6

Indirect routes

1.25K IPv4/1.25K IPv6

IPv4 or IPv6 policy-based routing ACEs

0.25K (IPv4 PBR)/0.25K (IPv6 PBR)

IPv4 or IPv6 QoSACEs

1K (IPv4 QoS)/0.25K (IPv6 QoS)

IPv4 or IPv6 port or MAC security ACEs

1K (IPv4 ACL)/0.25K (IPv6 ACL)

The first eight rows in the tables (unicast MAC addresses through security ACEs) represent approximate hardware

boundaries set when a template is selected. If a section of a hardware resource is full, all processing overflow is sent to

the CPU, seriously impacting switch performance.

Dual IPv4 and IPv6 SDM Default Template

You can select an SDM template to support IP Version 6 (IPv6) switching. The dual IPv4 and IPv6 template allows the

switch to be used in dual-stack environments (supporting both IPv4 and IPv6). Using the dual-stack templates results in

less TCAM capacity allowed for each resource. You should not use this template if you plan to forward only IPv4 traffic.

These SDM templates support IPv4 and IPv6 environments:

Dual IPv4 and IPv6 default template—Supports Layer 2, QoS, and ACLs for IPv4; and Layer 2, IPv6 host, and ACLs

for IPv6.

Dual IPv4 and IPv6 routing template—Supports Layer 2, multicast, routing (including policy-based routing), QoS, and

ACLs for IPv4; and Layer 2, routing, and ACLs for IPv6.

138

Configuring SDM Templates

How to Configure the Switch SDM Templates

Setting the SDM Template

Command

Purpose

configure terminal

Enters global configuration mode.

sdm prefer {default | dual-ipv4-and-ipv6

Specifies the SDM template to be used on the switch:

{default} | routing}

default—Gives balance to all functions.

dual-ipv4-and-ipv6—Selects a template that supports both

IPv4 and IPv6 routing.

— default—Balances IPv4 and IPv6 Layer 2 functionality.

routing—Maximizes IPv4 routing on the switch.

Use the no sdm prefer command to set the switch to the default

template. The default template balances the use of system

resources.

end

Returns to privileged EXEC mode.

reload

Reloads the operating system.

Configuration Examples for Configuring SDM Templates

Configuring IP Services Templates: Examples

This is an example of output from the show sdm prefer default command:

Switch# show sdm prefer default

"IPv4 default" template:

The selected template optimizes the resources in

the switch to support this level of features for

8 routed interfaces and 1024 VLANs.

number of unicast mac addresses:

16K

number of IPv4 IGMP groups + multicast routes:

number of IPv4 unicast routes:

18K

number of directly-connected IPv4 hosts:

16K

number of indirect IPv4 routes:

number of IPv6 multicast groups:

number of IPv6 unicast routes:

number of directly-connected IPv6 addresses:

number of indirect IPv6 unicast routes:

number of IPv4 policy based routing aces:

0.125k

number of IPv4/MAC qos aces:

1.875k

number of IPv4/MAC security aces:

1.875k

number of IPv6 policy based routing aces:

number of IPv6 qos aces:

number of IPv6 security aces:

This is an example of output from the show sdm prefer dual-ipv4-and-ipv6 default command:

139

Configuring SDM Templates

Configuration Examples for Configuring SDM Templates

Switch# show sdm prefer dual-ipv4-and-ipv6 default

"dual IPv4/IPv6 default" template:

The selected template optimizes the resources in

the switch to support this level of features for

8 routed interfaces and 1024 VLANs.

number of unicast mac addresses:

16K

number of IPv4 IGMP groups + multicast routes:

number of IPv4 unicast routes:

5.25K

number of directly-connected IPv4 hosts:

number of indirect IPv4 routes:

1.25K

number of IPv6 multicast groups:

number of IPv6 unicast routes:

5.25K

number of directly-connected IPv6 addresses:

number of indirect IPv6 unicast routes:

1.25K

number of IPv4 policy based routing aces:

0.25K

number of IPv4/MAC qos aces:

0.5K

number of IPv4/MAC security aces:

0.75K

number of IPv6 policy based routing aces:

0.25K

number of IPv6 qos aces:

0.375k

number of IPv6 security aces:

0.375k

This is an example of output from the show sdm prefer dual-ipv4-and-ipv6 routing command:

Switch# show sdm prefer dual-ipv4-and-ipv6 routing

"dual IPv4/IPv6 routing" template:

The selected template optimizes the resources in

the switch to support this level of features for

8 routed interfaces and 1024 VLANs.

number of unicast mac addresses:

16K

number of IPv4 IGMP groups + multicast routes:

number of IPv4 unicast routes:

number of directly-connected IPv4 hosts:

number of indirect IPv4 routes:

number of IPv6 multicast groups:

number of IPv6 unicast routes:

number of directly-connected IPv6 addresses:

number of indirect IPv6 unicast routes:

number of IPv4 policy based routing aces:

0.125k

number of IPv4/MAC qos aces:

0.5K

number of IPv4/MAC security aces:

0.625k

number of IPv6 policy based routing aces:

0.125k

number of IPv6 qos aces:

0.125k

number of IPv6 security aces:

0.125k

This is an example of output from the show sdm prefer routing command:

Switch# show sdm prefer routing

"IPv4 routing" template:

The selected template optimizes the resources in

the switch to support this level of features for

8 routed interfaces and 1024 VLANs.

number of unicast mac addresses:

16K

number of IPv4 IGMP groups + multicast routes:

number of IPv4 unicast routes:

24K

number of directly-connected IPv4 hosts:

16K

number of indirect IPv4 routes:

number of IPv6 multicast groups:

number of IPv6 unicast routes:

number of directly-connected IPv6 addresses:

number of indirect IPv6 unicast routes:

number of IPv4 policy based routing aces:

0.375k

140

Configuring SDM Templates

Configuration Examples for Configuring SDM Templates

number of IPv4/MAC qos aces:

0.5K

number of IPv4/MAC security aces:

number of IPv6 policy based routing aces:

number of IPv6 qos aces:

number of IPv6 security aces:

Configuring Lanbase Templates: Example

This is an example of output from the show sdm prefer command on a Lanbase image:

Switch# show sdm prefer

The current template is "IPv4 default" template.

The selected template optimizes the resources in

the switch to support this level of features for

8 routed interfaces and 1024 VLANs.

number of unicast mac addresses:

16K

number of IPv4 IGMP groups + multicast routes:

number of IPv4 unicast routes:

5.25K

number of directly-connected IPv4 hosts:

number of indirect IPv4 routes:

1.25K

number of IPv6 multicast groups:

number of IPv6 unicast routes:

5.25K

number of directly-connected IPv6 addresses:

number of indirect IPv6 unicast routes:

1.25K

number of IPv4 policy based routing aces:

0.25K

number of IPv4/MAC qos aces:

number of IPv4/MAC security aces:

number of IPv6 policy based routing aces:

0.25K

number of IPv6 qos aces:

0.25K

number of IPv6 security aces:

0.25K

141

Configuring Switch-Based Authentication

Prerequisites for Configuring Switch-Based Authentication

If you configure an SDM template and then perform the show sdm prefer command, the template currently in use

displays.

You must enter the reload privileged EXEC command to have your configured SDM template take effect.

You should have access to and should configure a RADIUS server before configuring RADIUS features on your

switch.

At a minimum, you must identify the host or hosts that run the RADIUS server software and define the method lists

for RADIUS authentication. You can optionally define method lists for RADIUS authorization and accounting.

Restrictions for Configuring Switch-Based Authentication

To use the Radius CoA interface, a session must already exist on the switch. CoA can be used to identify a session

and enforce a disconnect request. The update affects only the specified session.

To use Secure Shell, you must install the cryptographic (encrypted) software image on your switch. You must obtain

authorization to use this feature and to download the cryptographic software files from Cisco.com. For more

information, see the release notes for this release.

Information About Configuring Switch-Based Authentication

Prevention for Unauthorized Switch Access

You can prevent unauthorized users from reconfiguring your switch and viewing configuration information. Typically, you

want network administrators to have access to your switch while you restrict access to users who dial from outside the

network through an asynchronous port, connect from outside the network through a serial port, or connect through a

terminal or workstation from within the local network.

To prevent unauthorized access into your switch, you should configure one or more of these security features:

At a minimum, you should configure passwords and privileges at each switch port. These passwords are locally

stored on the switch. When users attempt to access the switch through a port or line, they must enter the password

specified for the port or line before they can access the switch.

For an additional layer of security, you can also configure username and password pairs, which are locally stored on

the switch. These pairs are assigned to lines or ports and authenticate each user before that user can access the

switch. If you have defined privilege levels, you can also assign a specific privilege level (with associated rights and

privileges) to each username and password pair.

If you want to use username and password pairs, but you want to store them centrally on a server instead of locally,

you can store them in a database on a security server. Multiple networking devices can then use the same database

to obtain user authentication (and, if necessary, authorization) information.

143

Configuring Switch-Based Authentication

Information About Configuring Switch-Based Authentication

You can also enable the login enhancements feature, which logs both failed and unsuccessful login attempts. Login

enhancements can also be configured to block future login attempts after a set number of unsuccessful attempts

are made.

Password Protection

A simple way of providing terminal access control in your network is to use passwords and assign privilege levels.

Password protection restricts access to a network or network device. Privilege levels define what commands users can

enter after they have logged into a network device.

Default Password and Privilege Level Configuration

Table 25

Default Password and Privilege Levels

Feature

Default Setting

Enable password and privilege level

No password is defined. The default is level 15 (privileged EXEC level).

The password is not encrypted in the configuration file.

Enable secret password and privilege level

No password is defined. The default is level 15 (privileged EXEC level).

The password is encrypted before it is written to the configuration file.

Line password

No password is defined.

Enable Secret Passwords with Encryption

To provide an additional layer of security, particularly for passwords that cross the network or that are stored on a Trivial

File Transfer Protocol (TFTP) server, you can use either the enable password or enable secret global configuration

commands. Both commands accomplish the same thing; that is, you can establish an encrypted password that users

must enter to access privileged EXEC mode (the default) or any privilege level you specify.

We recommend that you use the enable secret command because it uses an improved encryption algorithm.

If you configure the enable secret command, it takes precedence over the enable password command; the two

commands cannot be in effect simultaneously.

Use the level keyword to define a password for a specific privilege level. After you specify the level and set a password,

give the password only to users who need to have access at this level. Use the privilege level global configuration

command to specify commands accessible at various levels.

If you enable password encryption, it applies to all passwords including username passwords, authentication key

passwords, the privileged command password, and console and virtual terminal line passwords.

To remove a password and level, use the no enable password [level level] or no enable secret [level level] global

configuration command. To disable password encryption, use the no service password-encryption global configuration

command.

Password Recovery

Any end user with physical access to the switch can recover from a lost password by interrupting the boot process while

the switch is powering on and manually deleting the configuration of the switch.

Press and hold the factory default button when power is applied to the switch. You can release the button once you see

the password-recovery mechanism is enabled message. You will be at the boot loader prompt at this point and will be

able to delete the configuration file (which contains the forgotten password).

144

Configuring Switch-Based Authentication

Information About Configuring Switch-Based Authentication

Telnet Password for a Terminal Line

When you power-up your switch for the first time, an automatic setup program runs to assign IP information and to create

a default configuration for continued use. The setup program also prompts you to configure your switch for Telnet access

through a password. If you did not configure this password during the setup program, you can configure it now through

the command-line interface (CLI).

Username and Password Pairs

You can configure username and password pairs, which are locally stored on the switch. These pairs are assigned to

lines or ports and authenticate each user before that user can access the switch. If you have defined privilege levels, you

can also assign a specific privilege level (with associated rights and privileges) to each username and password pair.

Multiple Privilege Levels

By default, the Cisco IOS software has two modes of password security: user EXEC and privileged EXEC. You can

configure up to 16 hierarchical levels of commands for each mode. By configuring multiple passwords, you can allow

different sets of users to have access to specified commands.

For example, if you want many users to have access to the clear line command, you can assign it level 2 security and

distribute the level 2 password fairly widely. But if you want more restricted access to the configure command, you can

assign it level 3 security and distribute that password to a more restricted group of users.

When you set a command to a privilege level, all commands whose syntax is a subset of that command are also set to

that level. For example, if you set the show ip traffic command to level 15, the show commands and show ip commands

are automatically set to privilege level 15 unless you set them individually to different levels.

To return to the default privilege for a given command, use the no privilege mode level level command global

configuration command.

Users can override the privilege level you set using the privilege level line configuration command by logging in to the

line and enabling a different privilege level. They can lower the privilege level by using the disable command. If users

know the password to a higher privilege level, they can use that password to enable the higher privilege level. You might

specify a high level or privilege level for your console line to restrict line usage.

To return to the default line privilege level, use the no privilege level line configuration command.

Switch Access with TACACS+

This section describes how to enable and configure Terminal Access Controller Access Control System Plus (TACACS+),

which provides detailed accounting information and flexible administrative control over authentication and authorization

processes. TACACS+ is facilitated through authentication, authorization, accounting (AAA) and can be enabled only

through AAA commands.

TACACS+

TACACS+ is a security application that provides centralized validation of users attempting to gain access to your switch.

TACACS+ services are maintained in a database on a TACACS+ daemon typically running on a UNIX or Windows NT

workstation. You should have access to and should configure a TACACS+ server before the configuring TACACS+

features on your switch.

TACACS+ provides for separate and modular authentication, authorization, and accounting facilities. TACACS+ allows

for a single access control server (the TACACS+ daemon) to provide each service—authentication, authorization, and

accounting—independently. Each service can be tied into its own database to take advantage of other services available

on that server or on the network, depending on the capabilities of the daemon.

145

Configuring Switch-Based Authentication

Information About Configuring Switch-Based Authentication

The goal of TACACS+ is to provide a method for managing multiple network access points from a single management

service. Your switch can be a network access server along with other Cisco routers and access servers. A network

access server provides connections to a single user, to a network or subnetwork, and to interconnected networks as

shown in Figure 16 on page 146.

Figure 16

Typical TACACS+ Network Configuration

UNIX workstation

(TACACS+

Catalyst 6500

server 1)

series switch

171.20.10.7

UNIX workstation

(TACACS+

server 2)

171.20.10.8

Configure the switches with the

TACACS+ server addresses.

Set an authentication key

(also configure the same key on

the TACACS+ servers).

Enable AAA.

Create a login authentication method list.

Apply the list to the terminal lines.

Create an authorization and accounting

Workstations

method list as required.

Workstations

TACACS+, administered through the AAA security services, can provide these services:

Authentication—Provides complete control of authentication through login and password dialog, challenge and

response, and messaging support.

The authentication facility can conduct a dialog with the user (for example, after a username and password are

provided, to challenge a user with several questions, such as home address, mother’s maiden name, service type,

and social security number). The TACACS+ authentication service can also send messages to user screens. For

example, a message could notify users that their passwords must be changed because of the company’s password

aging policy.

Authorization—Provides fine-grained control over user capabilities for the duration of the user’s session, including

but not limited to setting autocommands, access control, session duration, or protocol support. You can also enforce

restrictions on what commands a user can execute with the TACACS+ authorization feature.

Accounting—Collects and sends information used for billing, auditing, and reporting to the TACACS+ daemon.

Network managers can use the accounting facility to track user activity for a security audit or to provide information

for user billing. Accounting records include user identities, start and stop times, executed commands (such as PPP),

number of packets, and number of bytes.

The TACACS+ protocol provides authentication between the switch and the TACACS+ daemon, and it ensures

confidentiality because all protocol exchanges between the switch and the TACACS+ daemon are encrypted.

You need a system running the TACACS+ daemon software to use TACACS+ on your switch.

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TACACS+ Operation

When a user attempts a simple ASCII login by authenticating to a switch using TACACS+, this process occurs:

When the connection is established, the switch contacts the TACACS+ daemon to obtain a username prompt to

show to the user. The user enters a username, and the switch then contacts the TACACS+ daemon to obtain a

password prompt. The switch displays the password prompt to the user, the user enters a password, and the

password is then sent to the TACACS+ daemon.

TACACS+ allows a dialog between the daemon and the user until the daemon receives enough information to

authenticate the user. The daemon prompts for a username and password combination, but can include other items,

such as the user’s mother’s maiden name.

The switch eventually receives one of these responses from the TACACS+ daemon:

• ACCEPT—The user is authenticated and service can begin. If the switch is configured to require authorization,

authorization begins at this time.

• REJECT—The user is not authenticated. The user can be denied access or is prompted to retry the login

sequence, depending on the TACACS+ daemon.

• ERROR—An error occurred at some time during authentication with the daemon or in the network connection

between the daemon and the switch. If an ERROR response is received, the switch typically tries to use an

alternative method for authenticating the user.

• CONTINUE—The user is prompted for additional authentication information.

After authentication, the user undergoes an additional authorization phase if authorization has been enabled on the

switch. Users must first successfully complete TACACS+ authentication before proceeding to TACACS+

authorization.

If TACACS+ authorization is required, the TACACS+ daemon is again contacted, and it returns an ACCEPT or REJECT

authorization response. If an ACCEPT response is returned, the response contains data in the form of attributes that

direct the EXEC or NETWORK session for that user and the services that the user can access:

• Telnet, Secure Shell (SSH), rlogin, or privileged EXEC services

• Connection parameters, including the host or client IP address, access list, and user timeouts

Default TACACS+ Configuration

TACACS+ and AAA are disabled by default.

To prevent a lapse in security, you cannot configure TACACS+ through a network management application. When

enabled, TACACS+ can authenticate users accessing the switch through the CLI.

Note: Although TACACS+ configuration is performed through the CLI, the TACACS+ server authenticates HTTP

connections that have been configured with a privilege level of 15.

TACACS+ Server Host and the Authentication Key

You can configure the switch to use a single server or AAA server groups to group existing server hosts for

authentication. You can group servers to select a subset of the configured server hosts and use them for a particular

service. The server group is used with a global server-host list and contains the list of IP addresses of the selected server

hosts.

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TACACS+ Login Authentication

To configure AAA authentication, you define a named list of authentication methods and then apply that list to various

ports. The method list defines the types of authentication to be performed and the sequence in which they are performed;

it must be applied to a specific port before any of the defined authentication methods are performed. The only exception

is the default method list (which, by coincidence, is named default). The default method list is automatically applied to

all ports except those that have a named method list explicitly defined. A defined method list overrides the default

method list.

A method list describes the sequence and authentication methods to be queried to authenticate a user. You can

designate one or more security protocols to be used for authentication, thus ensuring a backup system for authentication

in case the initial method fails. The software uses the first method listed to authenticate users; if that method fails to

respond, the software selects the next authentication method in the method list. This process continues until there is

successful communication with a listed authentication method or until all defined methods are exhausted. If

authentication fails at any point in this cycle—meaning that the security server or local username database responds by

denying the user access—the authentication process stops, and no other authentication methods are attempted.

TACACS+ Authorization for Privileged EXEC Access and Network Services

AAA authorization limits the services available to a user. When AAA authorization is enabled, the switch uses information

retrieved from the user’s profile, which is located either in the local user database or on the security server, to configure

the user’s session. The user is granted access to a requested service only if the information in the user profile allows it.

You can use the aaa authorization global configuration command with the tacacs+ keyword to set parameters that

restrict a user’s network access to privileged EXEC mode.

The aaa authorization exec tacacs+ local command sets these authorization parameters:

Use TACACS+ for privileged EXEC access authorization if authentication was performed by using TACACS+.

Use the local database if authentication was not performed by using TACACS+.

Note: Authorization is bypassed for authenticated users who log in through the CLI even if authorization has been

configured.

TACACS+ Accounting

The AAA accounting feature tracks the services that users are accessing and the amount of network resources that they

are consuming. When AAA accounting is enabled, the switch reports user activity to the TACACS+ security server in the

form of accounting records. Each accounting record contains accounting attribute-value (AV) pairs and is stored on the

security server. This data can then be analyzed for network management, client billing, or auditing.

Switch Access with RADIUS

This section describes how to enable and configure the RADIUS, which provides detailed accounting information and

flexible administrative control over authentication and authorization processes. RADIUS is facilitated through AAA and

can be enabled only through AAA commands.

RADIUS

RADIUS is a distributed client/server system that secures networks against unauthorized access. RADIUS clients run on

supported Cisco routers and switches. Clients send authentication requests to a central RADIUS server, which contains

all user authentication and network service access information. The RADIUS host is normally a multiuser system running

RADIUS server software from Cisco (Cisco Secure Access Control Server Version 3.0), Livingston, Merit, Microsoft, or

another software provider. For more information, see the RADIUS server documentation.

Use RADIUS in these network environments that require access security:

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Networks with multiple-vendor access servers, each supporting RADIUS. For example, access servers from several

vendors use a single RADIUS server-based security database. In an IP-based network with multiple vendors’ access

servers, dial-in users are authenticated through a RADIUS server that has been customized to work with the Kerberos

security system.

Turnkey network security environments in which applications support the RADIUS protocol, such as in an access

environment that uses a smart card access control system. In one case, RADIUS has been used with Enigma’s

security cards to validates users and to grant access to network resources.

Networks already using RADIUS. You can add a Cisco switch containing a RADIUS client to the network. This might

be the first step when you make a transition to a TACACS+ server.

Network in which the user must only access a single service. Using RADIUS, you can control user access to a single

host, to a single utility such as Telnet, or to the network through a protocol such as IEEE 802.1x. For more information

about this protocol, see Configuring IEEE 802.1x Port-Based Authentication, page 189

Networks that require resource accounting. You can use RADIUS accounting independently of RADIUS

authentication or authorization. The RADIUS accounting functions allow data to be sent at the start and end of

services, showing the amount of resources (such as time, packets, bytes, and so forth) used during the session. An

Internet service provider might use a freeware-based version of RADIUS access control and accounting software to

meet special security and billing needs.

RADIUS is not suitable in these network security situations:

Multiprotocol access environments. RADIUS does not support AppleTalk Remote Access (ARA), NetBIOS Frame

Control Protocol (NBFCP), NetWare Asynchronous Services Interface (NASI), or X.25 PAD connections.

Switch-to-switch or router-to-router situations. RADIUS does not provide two-way authentication. RADIUS can be

used to authenticate from one device to a non-Cisco device if the non-Cisco device requires authentication.

Networks using a variety of services. RADIUS generally binds a user to one service model.

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Figure 17

Transitioning from RADIUS to TACACS+ Services

RADIUS

server

RADIUS

server

TACACS+

server

Remote

TACACS+

server

Workstation

RADIUS Operation

When a user attempts to log in and authenticate to a switch that is access controlled by a RADIUS server, these events

occur:

1. The user is prompted to enter a username and password.

2. The username and encrypted password are sent over the network to the RADIUS server.

3. The user receives one of these responses from the RADIUS server:

a. ACCEPT—The user is authenticated.

b. REJECT—The user is either not authenticated and is prompted to re-enter the username and password, or access

is denied.

c. CHALLENGE—A challenge requires additional data from the user.

d. CHALLENGE PASSWORD—A response requests the user to select a new password.

The ACCEPT or REJECT response is bundled with additional data that is used for privileged EXEC or network

authorization. Users must first successfully complete RADIUS authentication before proceeding to RADIUS authorization,

if it is enabled. The additional data included with the ACCEPT or REJECT packets includes these items:

Telnet, SSH, rlogin, or privileged EXEC services

Connection parameters, including the host or client IP address, access list, and user timeouts

Default RADIUS Configuration

RADIUS and AAA are disabled by default.

To prevent a lapse in security, you cannot configure RADIUS through a network management application. When enabled,

RADIUS can authenticate users accessing the switch through the CLI.

RADIUS Change of Authorization

This section provides an overview of the RADIUS interface including available primitives and how they are used during a

Change of Authorization (CoA).

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Radius COA Overview

A standard RADIUS interface is typically used in a pulled model where the request originates from a network attached

device and the response come from the queried servers. Catalyst switches support the RADIUS Change of Authorization

(CoA) extensions defined in RFC 5176 that are typically used in a pushed model and allow for the dynamic reconfiguring

of sessions from external authentication, authorization, and accounting (AAA) or policy servers.

The switch supports these per-session CoA requests:

Session reauthentication

Session termination

Session termination with port shutdown

Session termination with port bounce

Change-of-Authorization Requests

Change of Authorization (CoA) requests, as described in RFC 5176, are used in a push model to allow for session

identification, host reauthentication, and session termination. The model is comprised of one request (CoA-Request) and

two possible response codes:

CoA acknowledgement (ACK) [CoA-ACK]

CoA non-acknowledgement (NAK) [CoA-NAK]

The request is initiated from a CoA client (typically a RADIUS or policy server) and directed to the switch that acts as a

listener.

RFC 5176 Compliance

The Disconnect Request message, which is also referred to as Packet of Disconnect (POD), is supported by the switch

for session termination.

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Attribute Number

Attribute Name

State

Calling-Station-ID

Acct-Session-ID

Message-Authenticator

101

Error-Cause

Value

Explanation

201

Residual Session Context Removed

202

Invalid EAP Packet (Ignored)

401

Unsupported Attribute

402

Missing Attribute

403

NAS Identification Mismatch

404

Invalid Request

405

Unsupported Service

406

Unsupported Extension

407

Invalid Attribute Value

501

Administratively Prohibited

502

Request Not Routable (Proxy)

503

Session Context Not Found

504

Session Context Not Removable

505

Other Proxy Processing Error

506

Resources Unavailable

507

Request Initiated

508

Multiple Session Selection Unsupported

CoA Request Response Code

The CoA Request response code can be used to convey a command to the switch. The supported commands are listed

in Table 26 on page 153.

CoA Session Identification

For disconnect and CoA requests targeted at a particular session, the switch locates the session based on one or more

of the following attributes:

Calling-Station-Id (IETF attribute 31 which contains the host MAC address)

Audit-Session-Id (Cisco VSA)

Acct-Session-Id (IETF attribute 44)

Unless all session identification attributes included in the CoA message match the session, the switch returns a

Disconnect-NAK or CoA-NAK with the Invalid Attribute Value error-code attribute.

For disconnect and CoA requests targeted to a particular session, any one of these session identifiers can be used:

Calling-Station-ID (IETF attribute 31, which should contain the MAC address)

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Audit-Session-ID (Cisco vendor-specific attribute)

Accounting-Session-ID (IETF attribute 44).

If more than one session identification attribute is included in the message, all the attributes must match the session or

the switch returns a Disconnect- negative acknowledgement (NAK) or CoA-NAK with the error code Invalid Attribute

Value.

The packet format for a CoA Request code as defined in RFC 5176 consists of the fields: Code, Identifier, Length,

Authenticator, and Attributes in Type:Length:Value (TLV) format.

0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Code

| Identifier

Length

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Authenticator

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

| Attributes ...

+-+-+-+-+-+-+-+-+-+-+-+-+-

The attributes field is used to carry Cisco VSAs.

CoA ACK Response Code

If the authorization state is changed successfully, a positive acknowledgement (ACK) is sent. The attributes returned

within CoA ACK will vary based on the CoA Request and are discussed in individual CoA Commands.

CoA NAK Response Code

A negative acknowledgement (NAK) indicates a failure to change the authorization state and can include attributes that

indicate the reason for the failure. Use show commands to verify a successful CoA.

CoA Request Commands

Table 26

CoA Commands Supported on the Switch

Command¹

Cisco VSA

Reauthenticate host

Cisco:Avpair=“subscriber:command=reauthenticate”

Terminate session

This is a standard disconnect request that does not require a VSA.

Bounce host port

Cisco:Avpair=“subscriber:command=bounce-host-port”

Disable host port

Cisco:Avpair=“subscriber:command=disable-host-port”

1. All CoA commands must include the session identifier between the switch and the CoA client.

CoA Session Reauthentication

The AAA server typically generates a session reauthentication request when a host with an unknown identity or posture

joins the network and is associated with a restricted access authorization profile (such as a guest VLAN). A

reauthentication request allows the host to be placed in the appropriate authorization group when its credentials are

known.

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To initiate session authentication, the AAA server sends a standard CoA-Request message which contains a Cisco

vendor-specific attribute (VSA) in this form: Cisco:Avpair=“subscriber:command=reauthenticate” and one or more

session identification attributes.

The current session state determines the switch response to the message. If the session is currently authenticated by

IEEE 802.1x, the switch responds by sending an Extensible Authentication Protocol over LAN (EAPoL) RequestId

message to the server.

If the session is currently authenticated by MAC authentication bypass (MAB), the switch sends an access-request to

the server, passing the same identity attributes used for the initial successful authentication.

If session authentication is in progress when the switch receives the command, the switch terminates the process, and

restarts the authentication sequence, starting with the method configured to be attempted first.

If the session is not yet authorized, or is authorized via guest VLAN, or critical VLAN, or similar policies, the

reauthentication message restarts the access control methods, beginning with the method configured to be attempted

first. The current authorization of the session is maintained until the reauthentication leads to a different authorization

result.

CoA Session Termination

There are three types of CoA requests that can trigger session termination. A CoA Disconnect-Request terminates the

session, without disabling the host port. This command causes reinitialization of the authenticator state machine for the

specified host, but does not restrict that host’s access to the network.

To restrict a host’s access to the network, use a CoA Request with the

Cisco:Avpair="subscriber:command=disable-host-port" VSA. This command is useful when a host is known to be

causing problems on the network, and you need to immediately block network access for the host. When you want to

restore network access on the port, reenable it using a non-RADIUS mechanism.

When a device with no supplicant, such as a printer, needs to acquire a new IP address (for example, after a VLAN

change), terminate the session on the host port with port-bounce (temporarily disable and then reenable the port).

CoA Disconnect-Request

This command is a standard Disconnect-Request. Because this command is session-oriented, it must be accompanied

by one or more of the session identification attributes described in the CoA Session Identification, page 152. If the

session cannot be located, the switch returns a Disconnect-NAK message with the “Session Context Not Found”

error-code attribute. If the session is located, the switch terminates the session. After the session has been completely

removed, the switch returns a Disconnect-ACK.

If the switch fails-over to a standby switch before returning a Disconnect-ACK to the client, the process is repeated on

the new active switch when the request is resent from the client. If the session is not found following resend, a

Disconnect-ACK is sent with the “Session Context Not Found” error-code attribute.

CoA Request: Disable Host Port

This command is carried in a standard CoA-Request message that has this new VSA:

Cisco:Avpair="subscriber:command=disable-host-port"

Because this command is session-oriented, it must be accompanied by one or more of the session identification

attributes described in the CoA Session Identification, page 152. If the session cannot be located, the switch returns a

CoA-NAK message with the “Session Context Not Found” error-code attribute. If the session is located, the switch

disables the hosting port and returns a CoA-ACK message.

If the switch fails before returning a CoA-ACK to the client, the process is repeated on the new active switch when the

request is resent from the client. If the switch fails after returning a CoA-ACK message to the client but before the

operation has completed, the operation is restarted on the new active switch.

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Note: A Disconnect-Request failure following command resend could be the result of either a successful session

termination before change-over (if the Disconnect-ACK was not sent) or a session termination by other means (for

example, a link failure) that occurred after the original command was issued and before the standby switch became

active.

CoA Request: Bounce-Port

This command is carried in a standard CoA-Request message that contains this VSA:

Cisco:Avpair="subscriber:command=bounce-host-port"

Because this command is session-oriented, it must be accompanied by one or more of the session identification

attributes described in the CoA Session Identification, page 152. If the session cannot be located, the switch returns a

CoA-NAK message with the “Session Context Not Found” error-code attribute. If the session is located, the switch

disables the hosting port for a period of 10 seconds, reenables it (port-bounce), and returns a CoA-ACK.

If the switch fails before returning a CoA-ACK to the client, the process is repeated on the new active switch when the

request is resent from the client. If the switch fails after returning a CoA-ACK message to the client but before the

operation has completed, the operation is restarted on the new active switch.

RADIUS Server Host

Switch-to-RADIUS-server communication involves several components:

Hostname or IP address

Authentication destination port

Accounting destination port

Key string

Timeout period

Retransmission value

You identify RADIUS security servers by their hostname or IP address, hostname and specific UDP port numbers, or their

IP address and specific UDP port numbers. The combination of the IP address and the UDP port number creates a unique

identifier, allowing different ports to be individually defined as RADIUS hosts providing a specific AAA service. This

unique identifier enables RADIUS requests to be sent to multiple UDP ports on a server at the same IP address.

If two different host entries on the same RADIUS server are configured for the same service—for example,

accounting—the second host entry configured acts as a fail-over backup to the first one. Using this example, if the first

host entry fails to provide accounting services, the %RADIUS-4-RADIUS_DEAD message appears, and then the switch tries

the second host entry configured on the same device for accounting services. (The RADIUS host entries are tried in the

order that they are configured.)

A RADIUS server and the switch use a shared secret text string to encrypt passwords and exchange responses. To

configure RADIUS to use the AAA security commands, you must specify the host running the RADIUS server daemon

and a secret text (key) string that it shares with the switch.

The timeout, retransmission, and encryption key values can be configured globally for all RADIUS servers, on a per-server

basis, or in some combination of global and per-server settings. To apply these settings globally to all RADIUS servers

communicating with the switch, use the three unique global configuration commands: radius-server timeout,

radius-server retransmit, and radius-server key. To apply these values on a specific RADIUS server, use the

radius-server host global configuration command.

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