isis padding-hello

Function

The isis padding-hello command configures a P2P interface to send Hello packets with the padding field after the neighbor relationship is established.

The undo isis padding-hello command restores the default configuration.

This command varies in transport and router modes. For detailed differences, see Differences Between Commands in Transport and Router Modes. This topic describes the command configuration in router mode.

By default, a P2P interface sends Hello packets without the padding field after the neighbor relationship is established.

Format

isis padding-hello

undo isis padding-hello

Parameters

None

Views

100GE interface view, 10GE interface view, 25GE sub-interface view, 25GE interface view, 400GE interface view, 40GE interface view, 50GE sub-interface view, 50GE interface view, Eth-Trunk interface view, FlexE interface view, GE optical interface view, GE electrical interface view, GMPLS-UNI interface view, Global VE sub-interface view, Loopback interface view, Tunnel interface view, VBDIF interface view, VE sub-interface view, VE interface view, VLANIF interface view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
isis	write

Usage Guidelines

Usage Scenario

By default, the rules for sending IS-IS Hello packets on P2P interfaces and broadcast interfaces are as follows:

For a P2P interface
- Before the P2P neighbor relationship is established, the P2P interface sends the standard Hello packet with the padding field.
- After the P2P neighbor relationship is established, the P2P interface sends the small-sized Hello packet without the padding field.
  For a P2P interface, the length of padding field is equal to the length of LSP packets originated by local IS.
For a broadcast interface
It sends the standard Hello packet with the padding field.
For a broadcast interface, the length of padding field is equal to the length of MTU.
The isis padding-hello command enables a device to send Hello packets to neighbors according to its interface MTU. If the interfaces of neighbors do not support the interface MTU of the device, neighbor relationships cannot be established. This prevents the LSDB asynchronization when only smaller PDUs are transmitted and larger PDUs are discarded after neighbor relationships are established.

Prerequisites

An IS-IS process has been created on a specified interface.

Configuration Impact

The isis padding-hello command is used to configure an interface to send the standard Hello packets with the padding field. The isis padding-hello command and the isis small-hello command are mutually exclusive. The isis small-hello command is used to configure an interface to send the small-sized Hello packets without the padding field.

Example

# Configure GE 0/1/0 to send the standard IS-IS Hello packets with the padding field.

<HUAWEI> system-view
[~HUAWEI] isis 1
[*HUAWEI-isis-1] quit
[*HUAWEI] interface GigabitEthernet 0/1/0
[*HUAWEI-GigabitEthernet0/1/0] isis enable 1
[*HUAWEI-GigabitEthernet0/1/0] isis padding-hello