Avaya ERS 8600 series, Configuration Manual

Page: 68 / 420

cases requires faster network convergence, which means network problems must be detected
within hundreds of milliseconds.
To meet these requirements, Avaya provides the fast advertisement interval.
The fast advertisement interval is similar to the advertisement interval parameter except for
the unit of measure and the range. The fast advertisement interval is expressed in milliseconds
and the range is from 200 to 1000 milliseconds. (This unit of measure must be in multiples of
200 milliseconds.)
To configure fast advertisement, you must specify a fast advertisement interval and explicitly
enable the fast advertisement feature. When the fast advertisement feature is enabled, the
fast advertisement interval is used instead of the advertisement interval.
When the fast advertisement feature is enabled, VRRP can only communicate with other
Ethernet Routing Switches with the same settings.
VRRP considerations with IPv6
In an IPv6 VRRP network with SMLT, if you delete the VRRP peers on the aggregation
switches, the VRRP addresses on the access switch are not immediately removed from the
IPv6 neighbor table. Instead, the access switch initially displays the IPv6 neighbor states as
Incomplete.
In accordance with the ND RFC, neighbor addresses are aged out 30 minutes after the traffic is
stopped from a neighbor. In this case, the access switch removes the virtual addresses 30
minutes after the VRRP virtual routers are deleted from the two aggregation switches.
IPv6 VRRP and ICMP redirects
In IPv6 networks, do not enable ICMP redirects on VRRP VLANs. If you enable this option
(using the
config ipv6 icmp redirect-msg
command), VRRP cannot function. The
option is disabled by default.
IPv6 RSMLT
In many cases, core network convergence time depends on the length of time a routing protocol
requires to successfully converge. Depending on the specific routing protocol, this
convergence time can cause network interruptions ranging from seconds to minutes.
Avaya Routed Split MultiLink Trunking (RSMLT) permits rapid failover for core topologies by
providing an active-active router concept to core Split MultiLink Trunking (SMLT) networks. In
the event of core router failures, RSMLT manages packet forwarding, thus minimizing dropped
packets during the routing protocol convergence.
IPv6 routing fundamentals
68 Configuration — IPv6 Routing November 2010