Nokia 7705 - Page 415

MPLS Guide Label Distribution Protocol
3HE 18686 AAAB TQZZA © 2022 Nokia.
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415
Like the LDP session-level FEC-type capability, the adjacency FEC-type capability
is negotiated for both directions of the adjacency. If one or both peers advertise the
disabling of a capability in the LDP Hello message, no FECs of the corresponding
FEC type will be resolved by either peer over the link of this adjacency for the lifetime
of the LDP Hello adjacency, unless one or both peers sends the LDP adjacency
capability TLV subsequently to explicitly enable it.
The user can enable or disable a specific FEC type for a given LDP interface to a
peer by using the following CLI commands:
• config>router>ldp>if-params>if>ipv4>fec-type-capability>p2mp-ipv4
• config>router>ldp>if-params>if>ipv4/ipv6>fec-type-capability>prefix-ipv4
• config>router>ldp>if-params>if> ipv4/ipv6>fec-type-capability>prefix-
ipv6
These commands, when applied to the IPv4 P2MP FEC, deprecate the existing
multicast-traffic command under the interface. Unlike the session-level capability,
these commands can disable multicast FEC for IPv4.
The encoding of the adjacency capability TLV uses a PRIVATE Vendor TLV. It is
used only in a Hello message to negotiate a set of capabilities for a specific LDP IPv4
or IPv6 hello adjacency.
0123
01234567890123456789012345678901
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|0| ADJ_CAPABILITY_TLV | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VENDOR_OUI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|S| Reserved | |
+-+-+-+-+-+-+-+-+ +
| Adjacency capability elements |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The value of the U-bit for the TLV is set to 1 so that a receiver must silently ignore if
the TLV is deemed unknown.
The value of the F-bit is 0. After being advertised, this capability cannot be
withdrawn; therefore, the S-bit is set to 1 in a Hello message.