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.
Verify IS-IS hello padding status:
Switch:1>show isis
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ISIS General Info
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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