The following describes feature interactions.
LSR A (LSR B) do not originate both IPv6 and IPv4 Hello messages with the configured 32-bit LSR-ID value when both IPv4 and IPv6 contexts are enabled on the same LDP interface (dual-stack LDP IPv4/IPv6). This behavior is allowed in RFC 7552 for migration purposes but SR OS implements separate IPv4 and IPv6 Hello adjacencies and LDP sessions with different LSR-ID values. Therefore, an IPv6 context that uses a 32-bit LSR-ID address matching that of the IPv4 context on the same interface is not allowed to be brought up (no shutdown fails) and the other way around.
Furthermore, an IPv6 context of any interface or targeted peer that uses a 32-bit LSR-ID address matching that of an IPv4 context of any other interface, an IPv6 context of any other interface using 32-bit LSR-ID, a targeted IPv4 peer, a targeted IPv6 peer using 32-bit LSR-ID, or an auto T-LDP IPv4 template on the same router is not allowed to be brought up (no shutdown fails) and the other way around.
With the introduction of a 32-bit LSR-ID for a IPv6 LDP interface or peer, it is possible to configure the same IPv6 transport address for an IPv4 LSR-ID and an IPv6 LSR-ID on the same node. For instance, assume the following configuration:
Interface I/F1:
local-lsr-id (config>router>ldp>interface-parameters>interface>ipv6) = interface LoA1; option 32bit-format enabled.
LDP identifier = {<LSR Id=A1/32> : <label space id=0>}; transport address = <A2/128>
Interface I/F2:
local-lsr-id (config>router>ldp>interface-parameters>interface>ipv6) = interface LoA1
LDP identifier = {<LSR Id=A2/128> : <label space id=0>}; transport address = <A2/128>
Targeted Session:
local-lsr-id (config>router>ldp> targeted-session>peer) = interface LoA1
LDP identifier = {<LSR Id=A2/128> : <label space id=0>}; transport address = <A2/128>
The above configuration results in two interfaces and a targeted session with the same local end transport IPv6 address but the local LSR-ID for interface I/F1 is different.
If an IPv6 Hello adjacency over interface I/F1 toward a specified peer comes up first and initiates an IPv6 LDP session, then the other two Hello adjacencies to the same peer do not come up.
If one of the IPv6 Hello adjacencies of interface I/F2 or Targeted Session 1 comes up first to a peer, it triggers an IPv6 LDP session shared by both these adjacencies and the Hello adjacency over interface I/F1 to the same peer does not come up.