Enabling Protocol Discovery

Network-Based Application Recognition (NBAR) includes a feature called Protocol Discovery. Protocol discovery provides an easy way to discover the application protocol packets that are passing through an interface. When you configure NBAR, the first task is to enable protocol discovery.

This module contains concepts and tasks for enabling the Protocol Discovery feature.

Prerequisites for Enabling Protocol Discovery

Before enabling Protocol Discovery, read the information in the "Classifying Network Traffic Using NBAR" module.

Restrictions for Enabling Protocol Discovery

NBAR protocol discovery does not support the following:

  • Asymmetric flows with stateful protocols.


Note

In the NBAR context, asymmetric flows are the flows in which different packets of the flow go through different routers, for reasons such as load balancing implementation or asymmetric routing where packets flow through different routes to different directions.

  • NBAR processing. By design, NBAR processing is temporarily disabled during the In-Service Software Upgrade (ISSU). The following syslog message indicates restart of NBAR classification once ISSU is complete.

"%NBAR_HA-5-NBAR_INFO: NBAR sync DONE!"

  • Multicast packet classification.

  • Multiprotocol Label Switching (MPLS)-labeled packets. NBAR classifies IP packets only. You can, however, use NBAR to classify IP traffic before the traffic is handed over to MPLS. Use the modular quality of service (QoS) CLI (MQC) to set the IP differentiated services code point (DSCP) field on the NBAR-classified packets and make MPLS map the DSCP setting to the MPLS experimental (EXP) setting inside the MPLS header.

  • Non-IP traffic.

  • Packets that originate from or that are destined to the router running NBAR.

NBAR is not supported on the following logical interfaces:

  • Dialer interfaces

  • Dynamic tunnels such as Dynamic Virtual Tunnel Interface (DVTI)

  • IPv6 tunnels that terminate on the device

  • MPLS

  • Overlay Transport Virtualization (OTV) overlay interfaces


Note
In cases where encapsulation is not supported by NBAR on some links, you can apply NBAR on other interfaces of the device to perform input classification. For example, you can configure NBAR on LAN interfaces to classify output traffic on the WAN link.
The following virtual interfaces are supported depending on the image of your Cisco IOS:

  • Generic routing encapsulation (GRE)

  • IPsec IPv4 tunnel (including tunneled IPv6) in protocol discovery mode and MQC mode

  • IPsec IPv6 tunnel in protocol discovery mode but not in MQC mode

  • Multipoint GRE/Dynamic Multipoint VPN (DMVPN) in protocol discovery mode


Note
NBAR requires more CPU power when NBAR is enabled on tunneled interfaces.

If protocol discovery is enabled on both the tunnel interface and the physical interface on which the tunnel interface is configured, the packets that are designated to the tunnel interface are counted on both interfaces. On the physical interface, the packets are classified and are counted based on the encapsulation. On the tunnel interface, packets are classified and are counted based on the Layer 7 protocol.


Note

You cannot use NBAR to classify output traffic on a WAN link where tunneling or encryption is used. Therefore, you should configure NBAR on other interfaces of the router (such as a LAN link) to perform input classification before the traffic is switched to the WAN link.

Information About Protocol Discovery

Protocol Discovery Overview

The Protocol Discovery feature of NBAR provides an easy way of discovering the application protocols passing through an interface so that appropriate QoS features can be applied.

NBAR determines which protocols and applications are currently running on your network. Protocol discovery provides an easy way of discovering the application protocols that are operating on an interface so that appropriate QoS features can be applied. With protocol discovery, you can discover any protocol traffic that is supported by NBAR and obtain statistics that are associated with that protocol.

Protocol discovery maintains the following per-protocol statistics for enabled interfaces:

  • Total number of input packets and bytes

  • Total number of output packets and bytes

  • Input bit rates

  • Output bit rates

These statistics can be used when you define classes and traffic policies (sometimes known as policy maps) for each traffic class. The traffic policies (policy maps) are used to apply specific QoS features and functionality to the traffic classes.

How to Enable Protocol Discovery

Enabling Protocol Discovery on an Interface

Perform this task to enable protocol discovery on an interface.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. interface type number [name-tag ]
  4. ip nbar protocol-discovery
  5. end

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

interface type number [name-tag ]

Example:


Router(config)# interface fastethernet1/1/1

Configures an interface type and enters interface configuration mode.

  • Enter the interface type and the interface number.

Step 4

ip nbar protocol-discovery

Example:


Router(config-if)# ip nbar protocol-discovery

Configures NBAR to discover traffic for all protocols that are known to NBAR on a particular interface.

Note

 

The ipv4 and ipv6 keywords are deprecated from the Cisco IOS XE Cupertino 17.10.1 release onwards.

  • Enables the protocol discovery statistics collection for both IPv4 and IPv6.

  • The no form of this command is not required to disable a keyword because the statistics collection is enabled for the specified keyword only.

Step 5

end

Example:


Router(config-if)# end

(Optional) Exits interface configuration mode.

Reporting Protocol Discovery Statistics

Perform this task to display a report of the protocol discovery statistics per interface.

SUMMARY STEPS

  1. enable
  2. show policy-map interface type number
  3. show ip nbar protocol-discovery [interface type number ] [stats {byte-count | bit-rate | packet-count | max-bit-rate }] [protocol protocol-name | top-n number ]
  4. exit

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

show policy-map interface type number

Example:


Router# show policy-map interface FastEthernet 1/1/1

(Optional) Displays the packet and class statistics for all policy maps on the specified interface.

  • Enter the interface type and interface number.

Step 3

show ip nbar protocol-discovery [interface type number ] [stats {byte-count | bit-rate | packet-count | max-bit-rate }] [protocol protocol-name | top-n number ]

Example:


Router# show ip nbar protocol-discovery interface Fastethernet1/1/1

Displays the statistics gathered by the NBAR Protocol Discovery feature.

  • (Optional) Enter keywords and arguments to fine-tune the statistics displayed. For more information on each of the keywords, refer to the show ip nbar protocol-discovery command in Cisco IOS Quality of Service Solutions Command Reference.

Step 4

exit

Example:


Router# exit

(Optional) Exits privileged EXEC mode.

Configuration Examples for Protocol Discovery

Example: Enabling Protocol Discovery on an Interface

In the following sample configuration, protocol discovery is enabled on Fast Ethernet interface 1/1/1: 


Router> enable 

Router# configure terminal 

Router(config)# interface fastethernet1/1/1 

Router(config-if)# ip nbar protocol-discovery 

Router(config-if)# end

In the following sample configuration, protocol discovery is enabled on Fast Ethernet interface 1/1/2 for IPv6 packets: 


Router> enable 

Router# configure terminal 

Router(config)# interface fastethernet1/1/2 

Router(config-if)# ip nbar protocol-discovery  

Router(config-if)# end

Example: Reporting Protocol Discovery Statistics

The following sample output from the show ip nbar protocol-discovery command displays the five most active protocols on the Fast Ethernet interface 2/0/1: 


Router# show ip nbar protocol-discovery top-n 5
 
 FastEthernet2/0/1
                            Input                    Output                  
                            -----                    ------                  
  Protocol                  Packet Count             Packet Count            
                            Byte Count               Byte Count              
                            30sec Bit Rate (bps)     30sec Bit Rate (bps)    
                            30sec Max Bit Rate (bps) 30sec Max Bit Rate (bps)
--------------------------- ------------------------ ------------------------
   rtp                      3272685                  3272685                           
                            242050604                242050604                         
                            768000                   768000                            
                            2002000                  2002000                           
   gnutella                 513574                   513574                            
                            118779716                118779716                         
                            383000                   383000                            
                            987000                   987000                            
   ftp                      482183                   482183                            
                            37606237                 37606237                          
                            121000                   121000                            
                            312000                   312000                            
   http                     144709                   144709                            
                            32351383                 32351383                          
                            105000                   105000                            
                            269000                   269000                            
   netbios                  96606                    96606                             
                            10627650                 10627650                          
                            36000                    36000                             
                            88000                    88000                             
   unknown                  1724428                  1724428                           
                            534038683                534038683                         
                            2754000                  2754000                           
                            4405000                  4405000                           
   Total                    6298724                  6298724                           
                            989303872                989303872                         
                            4213000                  4213000                           
                            8177000                  8177000

Additional References

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

QoS commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

Cisco IOS Quality of Service Solutions Command Reference

Concepts and information about NBAR

"Classifying Network Traffic Using NBAR" module

MQC

"Applying QoS Features Using the MQC" module

Standards

Standard

Title

No new or modified standards are supported, and support for existing standards has not been modified.

--

MIBs

MIB

MIBs Link

No new or modified MIBs are supported, and support for existing MIBs has not been modified.

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for Enabling Protocol Discovery

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 1. Feature Information for Enabling Protocol Discovery

Feature Name

Releases

Feature Information

Protocol Discovery

Cisco IOS XE 2.1 Cisco IOS XE 3.3S

This feature was introduced on Cisco ASR 1000 Series Routers.

The following sections provide information about this feature:

The following commands were introduced: ip nbar protocol discovery, show ip nbar protocol discovery.