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Hierarchy Level


Specify the prefix address of the aggregated group of LDP neighbors for the remote end of the LDP session.

The session-group statement is useful when an LDP neighbor is dynamic; for instance, in the case of remote loop free alternate (LFA), a targeted or indirect LDP neighbor is automatically picked from any of the nodes in the network.

The session-group statement can also be used for configuring authentication for a prefix group, as LDP authentication for all sessions or authentication at the interface level is not supported.

The remaining statements are explained separately. See CLI Explorer.



Session destination address or prefix length.


Authentication algorithm name.

  • Values:

    • aes-128-cmac-96—Cipher-based Message Authentication Code (AES128) (96 bits)

    • hmac-sha-1-96—Hash-based Message Authentication Code (SHA1) (96 bits)

    • md5—Message Digest 5


      MD5 authentication algorithm is supported in both Junos OS and Junos OS Evolved Releases. Whereas, aes-128-cmac-96 and hmac-sha-1-96 algorithms are not supported in Junos OS Evolved Releases


MD5 authentication key.


Authentication key chain name. Authentication key chain option is not supported in Junos OS Evolved Releases.


Configure downstream on demand label distribution mode.

mtu-discovery | no-mtu-discovery

Enable and disable TCP path MTU discovery, respectively.

transport-address transport-address

IP address used for TCP sessions to the LDP neighbors that have targeted-LDP adjacencies, and fall under the same IP subnet.

You cannot configure this statement for LDP sessions that have discovered adjacencies.

The transport-address configuration can be rejected at the time of validation, if there is no interface with the configured IP address.

Required Privilege Level

routing—To view this statement in the configuration.

routing-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 16.1.

transport-address option introduced in Junos OS Releasse 19.1R1 for all platforms.

Starting in Junos OS Evolved 22.1R1 Release, MD5 authentication algorithm is supported for all platforms.