being replicated back to the WAN by using a common ring number because the explorer
cannot travel through the same ring twice.
address destination to be sent across the WAN at a time. All other explorers trying to reach
the same destination must wait until a response is received from the first explorer. This
prevents the start-of-day explorer storm that many networks experience.
DLSw+ reduces broadcasts and improves scalability by supporting local, remote, and peer
group caching.
topologies that also help limit explorer traffic. Full-mesh networks are difficult to support and
troubleshoot because all routers must have a physical connection using a static configuration to
all other routers on the network. To find the number of links, use the formula from previous
chapters, n(n 1) / 2, where n is the number of routers. For example, 10 routers means 45
connections. DLSw+ solves this problem by providing a hierarchical structure using border
peers.
router E sends only a single CANUREACH broadcast to its border peer, as shown in Figure 14-
13. Before the border peer forwards the explorer from Router E, it checks its local, remote, and
group cache. If the destination resource is not found, the border peer propagates the broadcast
within its group and to other border peers. The other border peers in turn flood the broadcast
within their group. In this case, Border Peer A must make five broadcasts to its neighbors if the
address is not located in the cache.