Perform this procedure to dynamically configure IS-IS hello padding on all IS-IS network-to-network interface (NNI) links. IS-IS hello padding is enabled by default.
Disable hello padding if the WAN-line MTU is less than 1596 bytes and fragmentation and reassembly functionality is enabled.
IS-IS logical-interfaces with a configured IS-IS MTU do not perform IS-IS Hello Padding, regardless of the global IS-IS Hello Padding configuration.
enable
configure terminal
router isis
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 Designated BN Hostname : BN4435 Designated BN Home System ID : 0010.7400.4435 Designated BN Remote System ID : 0020.7400.4435