The lsp-fragments-extend command enables LSP fragment extension on an IS-IS device in a specified mode and at a specified level. To enable the device to generate extended LSP fragments, at least one virtual system ID must be configured.
The undo lsp-fragments-extend command disables the function.
By default, the LSP fragment extension on an IS-IS device is disabled.
| Parameter | Description | Value |
|---|---|---|
| level-1 |
Enables LSP fragment extension at Level-1. |
- |
| level-2 |
Enables LSP fragment extension at Level-2. |
- |
| level-1-2 |
Enables LSP fragment extension at Level-1-2. |
- |
| mode-1 |
Enables the device to be compatible with a device that does not support LSP fragment extension. |
- |
| mode-2 |
Indicates a fragment extension mode that requires LSP fragment extension on all devices. By default, mode-1 and level-1-2 are used. |
- |
Usage Scenario
The lsp-fragment-extend command enables LSP fragment extension on an IS-IS device in a specified mode and at a specified level. One LSP fragment occupies only one byte and therefore a maximum of 256 fragments are supported. If there are a great number of LSPs and the number of fragments exceeds 256, some information is lost. Therefore, the fragment extension function is introduced. You can run the virtual-system command to configure one or more virtual system nodes for the IS-IS process on the local system so that the number of LSPs exceeds 256.
Prerequisites
Virtual systems have been configured using the virtual-system command.
Configuration Impact
After LSP fragment extension is configured, if the number of LSP fragments exceeds 256, the excessive LSP fragments are forwarded by virtual systems.