Avaya ERS 8600 series, Configuration Manual

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Hold-up timer
When both RSMLT peers are active, both peers forward traffic for each other. When a router
detects that its peer is down, it begins terminating IPv6 traffic destined to the peer's IPv6
addresses (including, for example, responding to pings and router solicitations). The router
continues to forward and terminate traffic for its peer for a duration defined by the hold-up timer.
If the peer is not restored and the hold-up timer expires, the router stops forwarding and
terminating traffic for the peer.
You can set the hold-up timer (in the preceding example, the amount of time R2 routes for
R1 in a failure) for a time period greater than the routing protocol convergence. You can also
set it as infinite (that is, the members of the pair always route for each other).
Avaya recommends that you use an infinite (9999) hold-up timer value for applications that
use RSMLT at the edge instead of VRRP.
RSMLT or VRRP
For VLAN 1, VRRP with a backup master can provide the same functionality as RSMLT, as
long as no additional router is connected to IPv6 prefix 2003::/64.
RSMLT provides superior router redundancy in core networks (IPv6 prefix B), where OSPFv3 is
used for the routing protocol. Routers R1 and R2 provide router backup for each other, not
only for the edge IP Prefix 2003::/64, but also for the core IPv6 prefix B. Similarly routers R3
and R4 provide router redundancy for IPv6 prefix C and also for core IPv6 prefix B.
Avaya does not recommend that you both VRRP and RSMLT on the same VLAN. Use one or
the other.
Coexistence with IPv4 RSMLT
The IPv6 RSMLT feature introduces no changes to the existing IPv4 RSMLT state machine
including RSMLT configuration, definitions of events, logic of state transitions, or timer
operations. A single instance of state and configuration parameter set controls both IPv4 and
IPv6 RSMLT logic. With the introduction of this feature, RSMLT is best thought of as a property
of the VLAN layer as opposed to the IP (v4 or v6) layer above it. RSMLT configuration and
states affect IPv4 and IPv6 operation simultaneously.
IPv6 routing fundamentals
72 Configuration — IPv6 Routing November 2010