Ipv6 Vrrp - Avaya 8800 Planning And Engineering, Network Design

packet received, Routing switch 1 sends an ICMP redirect message to the client to inform it of a
shorter path to the destination through routing switch 2.
Figure 42: ICMP redirect messages diagram
To avoid excessive ICMP redirect messages if network clients do not recognize ICMP redirect
messages, Avaya recommends the network design shown in the following figure. Ensure that the
routing path to the destination through both routing switches has the same metric to the destination.
One hop goes from 30.30.30.0 to 10.10.10.0 through routing switch 1 and routing switch 2. Do this
by building symmetrical networks based on the network design examples presented in
network design on page 55.
Figure 43: Avoiding excessive ICMP redirect messages

IPv6 VRRP

For IPv6 hosts on a LAN to learn about one or more default routers, IPv6-enabled routers send
Router Advertisements using the IPv6 Neighbor Discovery (ND) protocol. The routers multicast
these Router Advertisements every few minutes.
The ND protocol includes a mechanism called Neighbor Unreachability Detection to detect the
failure of a neighbor node (router or host) or the failure of the forwarding path to a neighbor. Nodes
can monitor the health of a forwarding path by sending unicast ND Neighbor Solicitation messages
to the neighbor node. To reduce traffic, nodes only send Neighbor Solicitations to neighbors to
June 2016 Planning and Engineering — Network Design
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Virtual Router Redundancy Protocol
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