Configure IS-IS Hello Padding

Perform this procedure to dynamically configure IS-IS hello padding on all IS-IS NNI links. IS-IS hello padding is enabled by default.

About this task

Disable hello padding if the WAN-line MTU is less than 1596 bytes and fragmentation and reassembly functionality is enabled.

Procedure

  1. Enter IS-IS Router Configuration mode:

    enable

    configure terminal

    router isis

  2. Perform one of the following actions:
    • Disable hello padding: no hello-padding
    • Enable hello padding, if previously disabled: hello-padding
  3. Verify the configuration:
    show isis

Example

Verify IS-IS hello padding status:

Switch:1>show isis
================================================================================
                               ISIS General Info
================================================================================
                            AdminState : enabled
                            RouterType : Level 1
                             System ID : 0014.c7e1.33df
                  Max LSP Gen Interval : 900
                                Metric : wide
                   Overload-on-startup : 20
                              Overload : false
                         Csnp Interval : 10
                         PSNP Interval : 2
                     Rxmt LSP Interval : 5
                             spf-delay : 100
                           Router Name : Switch1
                     ip source-address : 41.41.41.100
                   ipv6 source-address : 41:0:0:0:0:0:0:100
              ip tunnel source-address : 11.11.12.11
                            Tunnel vrf : spboip
                         ip tunnel mtu : 1950
                     Num of Interfaces : 2
                 Num of Area Addresses : 1
                        inband-mgmt-ip : 
                              backbone : disabled
              Dynamically Learned Area : 00.0000.0000
                            FAN Member : No
                         Hello Padding : enabled
                  Multi-Area OperState : disabled
                      Multi-Area Flags : home-always-up