Easy Virtual Network Management and Troubleshooting

This module describes how to manage and troubleshoot Easy Virtual Network (EVN).

Prerequisites for EVN Management and Troubleshooting

  • Read the "Overview of Easy Virtual Network" section and the "Configuring Easy Virtual Network" section, and implement EVN.

Information About EVN Management and Troubleshooting

Routing Context for EXEC Mode Reduces Repetitive VRF Specification

There may be occasions when you want to issue several EXEC commands to apply to a single virtual network. In order to reduce the repetitive entering of virtual routing and forwarding (VRF) names for multiple EXEC commands, the routing-context vrf command allows you to set the VRF context of such EXEC commands once, and then proceed using EXEC commands.

The table below shows four EXEC commands in Cisco IOS XE software without routing context and in routing context. Note that in the left column, each EXEC command must specify the VRF. In the right column, the VRF context is specified once and the prompt changes to reflect that VRF; there is no need to specify the VRF in each command.

Table 1. EXEC Commands Routing Context
EXEC Commands CLI without Routing Context EXEC Routing Context

—

 

Router# routing-context vrf red
Router%red#
 

Router# show ip route vrf red
[Routing table output for VRF red] 

Router%red# show ip route
[Routing table output for VRF red] 

Router# ping vrf red 10.1.1.1
[Ping result using VRF red] 

Router%red# ping 10.1.1.1
[Ping result using VRF red] 

Router# telnet 10.1.1.1 /vrf red
[Telnet to 10.1.1.1 in VRF red] 

Router%red# telnet 10.1.1.1
[Telnet to 10.1.1.1 in VRF red] 

Router# traceroute vrf red 10.1.1.1
[Traceroute output in VRF red] 

Router%red# traceroute 10.1.1.1
[Traceroute output in VRF red]

Output of traceroute Command Indicates VRF Name and VRF Tag

Output of the traceroute command is enhanced to make troubleshooting easier by displaying the incoming VRF name/tag and the outgoing VRF name/tag, as shown in the following example: 


Router# traceroute vrf red 10.0.10.12 
Type escape sequence to abort.
Tracing the route to 10.0.10.12
VRF info: (vrf in name/id, vrf out name/id)
  1 10.1.13.15 (red/13,red/13) 0 msec
    10.1.16.16 (red/13,red/13) 0 msec
    10.1.13.15 (red/13,red/13) 1 msec
  2 10.1.8.13 (red/13,red/13) 0 msec
    10.1.7.13 (red/13,red/13) 0 msec
    10.1.8.13 (red/13,red/13) 0 msec
  3 10.1.2.11 (red/13,blue/10) 1 msec 0 msec 0 msec
  4  *  *  *

Debug Output Filtering Per VRF

Using EVN, you can filter debug output per VRF by using the debug condition vrf command. The following is sample output from the debug condition vrf command: 


Router# debug condition vrf red

Condition 1 set
CEF filter table debugging is on
CEF filter table debugging is on
R1#
*Aug 19 23:06:38.178: vrfmgr(0) Debug: Condition 1, vrf red triggered, count 1
R1#

CISCO-VRF-MIB

EVN provides a CISCO-VRF-MIB for VRF discovery and management.

How to Manage and Troubleshoot EVN

Setting the Routing Context for EXEC Mode to a Specific VRF

To reduce the repeated entering of virtual routing and forwarding (VRF) names when you are issuing EXEC commands on a router, set the routing context of the EXEC commands once, and then proceed with entering them in any order. Perform this task to set the routing context for EXEC mode to a specific VRF, issue EXEC commands, and then restore the system to the global EXEC context.

SUMMARY STEPS

  1. enable
  2. routing-context vrf vrf-name
  3. show ip route [ip-address [mask ] [longer-prefixes ] | protocol [process-id ] | static download ]
  4. ping [protocol [tag ] {host-name | system-address }]
  5. telnet host [port ]
  6. traceroute [vrf vrf-name | topology topology-name ] [protocol ] destination
  7. routing-context vrf global

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

routing-context vrf vrf-name

Example:


Router# routing-context vrf red

Enters the routing context for EXEC mode to a specified VRF.

Step 3

show ip route [ip-address [mask ] [longer-prefixes ] | protocol [process-id ] | static download ]

Example:


Router%red# show ip route

(Optional) Displays the current state of the routing table.

  • The system prompt changes to reflect the target VRF.

  • This example shows the show ip route command issued within the context of vNET red. The routing table for vNET red would be displayed.

Step 4

ping [protocol [tag ] {host-name | system-address }]

Example:


Router%red# ping 10.1.1.1

(Optional) Sends an echo request packet to an address.

  • This example shows the ping command issued within the context of vNET red. Ping results using vNET red would be displayed.

Step 5

telnet host [port ]

Example:


Router%red# telnet 10.1.1.1

(Optional) Logs in to a host that supports Telnet.

Step 6

traceroute [vrf vrf-name | topology topology-name ] [protocol ] destination

Example:


Router%red# traceroute 10.1.1.1

(Optional) Displays the route that packets will take to the destination.

Step 7

routing-context vrf global

Example:


Router%red# routing-context vrf global

Example:


Router>

(Optional) Restores the system to the global EXEC context.

  • The prompt returns to the user EXEC prompt.

Enabling Debug Output for VRFs

SUMMARY STEPS

  1. enable
  2. debug vrf {create | delete | error | ha | initialization | interface | ipv4 | ipv6 | issu | lock | lookup | mpls | selection }

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

debug vrf {create | delete | error | ha | initialization | interface | ipv4 | ipv6 | issu | lock | lookup | mpls | selection }

Example:


Router# debug vrf ipv4

Displays VRF debugging information.

Setting SNMP v2c Context for Virtual Networks

Perform this task to map an SNMP v2c context to a VRF. The following SNMP v2c configurations will then be done by the system automatically:

  • Context creation (instead of the snmp-server context command), using the same name as the context-name entered in the snmp context command.

  • Group creation (instead of the snmp-server group command), using the same name as the community-name entered in the snmp context command.

  • Community creation (instead of the snmp-server community command), using the same name as the community-name entered in the snmp context command. The default permission is ro (read-only).

  • Community context mapping (instead of the snmp mib community-map command).

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. vrf definition vrf-name
  4. address-family ipv4
  5. snmp context context-name [community community-name [rw | ro ]]

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

vrf definition vrf-name

Example:


Router(config)# vrf definition vrf1

Defines a virtual routing and forwarding instance (VRF) and enters VRF configuration mode.

Step 4

address-family ipv4

Example:

Device(config-vrf)# address-family ipv4

Enters address family configuration mode to configure a routing session using standard IPv4 address prefixes.

Step 5

snmp context context-name [community community-name [rw | ro ]]

Example:


Router(config-vrf)# snmp context xxx community yyy

Sets the SNMP v2c context for the VRF.

  • The default is read-only (ro ).

Setting SNMP v3 Context for Virtual Networks

Perform this task to map an SNMP v3 context to a virtual routing and forwarding (VRF). The following SNMP v3 configurations will then be done by the system automatically:

  • Context creation (instead of the snmp-server context command), using the same name as the context-name entered in the snmp context command.

  • Group creation (instead of the snmp-server group command). The group name will be generated by appending “_acnf” to the context-name entered in the snmp context command.

  • User creation (instead of the snmp-server user command). The user will be created using the details configured in the snmp context command.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. vrf definition vrf-name
  4. address-family ipv4
  5. snmp context context-name [user username [credential | [encrypted ] [auth {md5 password | sha password }] [access {access-list-number | access-list-name | ipv6 access-list-name }]]]

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

vrf definition vrf-name

Example:


Router(config)# vrf definition vrf1

Defines a VRF and enters VRF configuration mode.

Step 4

address-family ipv4

Example:

Device(config-vrf)# address-family ipv4

Enters address family configuration mode to configure a routing session using standard IPv4 address prefixes.

Step 5

snmp context context-name [user username [credential | [encrypted ] [auth {md5 password | sha password }] [access {access-list-number | access-list-name | ipv6 access-list-name }]]]

Example:


Router(config-vrf)# snmp context green_ctx user green_comm encyrpted

Sets the SNMP v3 context for the VRF.

Additional References

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

Easy Virtual Network commands

Easy Virtual Network Command Reference

Overview of Easy Virtual Network

“Overview of Easy Virtual Network” module in the Easy Virtual Network Configuration Guide

Configuring Easy Virtual Network

“Configuring Easy Virtual Network” module in the Easy Virtual Network Configuration Guide

Easy Virtual Network shared services and route replication

“Easy Virtual Network Shared Services” module in the Easy Virtual Network Configuration Guide

MIBs

MIB

MIBs Link

Any MIB that gives VRF information will continue to work with Easy Virtual Network. VRF-independent MIBs report information on every VRF in a system:

  • CISCO-MVPN-MIB

  • MPLS-VPN-MIB

  • CISCO-VRF-MIB

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 EVN Management and Troubleshooting

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 2. Feature Information for EVN Management and Troubleshooting

Feature Name

Releases

Feature Information

EVN Cisco EVN MIB

EVN Cisco EVN MIB simplifies SNMP configuration.

The following command was modified: snmp context . .

EVN Traceroute

EVN Traceroute enhances output of the traceroute command to display the VRF name and tag.

The following command was modified: traceroute . .

EVN VNET Trunk

Users can filter debug output per VRF by using the debug condition vrf command.

The following commands were introduced: debug condition vrf , debug vrf .