Users Guide

Sample Configuration of IPv6 Peer Routing in a
VLT Domain
Consider a sample scenario as shown in the following figure in which two VLT nodes, Unit1 and Unit2, are
connected in a VLT domain using an ICL or VLTi link. To the south of the VLT domain, Unit1 and Unit2 are
connected to a ToR switch named Node B. Also, Unit1 is connected to another node, Node A, and Unit2 is
linked to a node, Node C. The network between the ToR and the VLT nodes is Layer 2. Servers or hosts that
are connected to the ToR (Node B) generate Layer 3 control/data traffic from the South or lower-end of the
vertically-aligned network.
Figure 151. Sample Configuration of IPv6 Peer Routing in a VLT Domain
Neighbor Solicitation from VLT Hosts
Consider a case in which NS for VLT node1 IP reaches VLT node1 on the VLT interface and NS for VLT node1
IP reaches VLT node2 due to LAG level hashing in the ToR. When VLT node1 receives NS from VLT VLAN
interface, it unicasts the NA packet on the VLT interface. When NS reaches VLT node2, it is flooded on all
interfaces including ICL. When VLT node 1 receives NS on ICL, it floods the NA packet on the VLAN. If NS is
unicast and if it reaches the wrong VLT peer, it is lifted to the CPU using ACL entry. Then wrong peer adds a
tunnel header and forwards the packet over ICL.
Neighbor Advertisement from VLT Hosts
Virtual Link Trunking (VLT) 1179