I
NTRODUCTION
1-6
Routing
If ATM Protocol Encapsulation is set for PPP/ATM or IP/ATM, the
router will forward incoming IP packets and use RIP 2 for routing path
management if enabled. The router supports both static routing and
dynamic routing.
• Static routing requires routing information to be stored in the router,
either manually or when a connection is set up, by an application
outside the router.
• Dynamic routing uses a routing protocol to exchange routing
information, calculate routing tables, and respond to changes in the
status or traffic on the network.
Dynamic Routing Protocols - The Barricade supports RIP 2 dynamic
routing protocol. Routing Information Protocol (RIP) is the most widely
used method for dynamically maintaining routing tables. RIP uses a
distance vector-based approach to routing. Routes are chosen to minimize
the distance vector, or hop count, which serves as a rough estimate of
transmission cost. Each router broadcasts its advertisement every 30
seconds, together with any updates to its routing table. This allows all
routers on the network to build consistent tables of next hop links which
lead to relevant subnets.
RIP 2 is a compatible upgrade to RIP. However, RIP 2 adds useful
capabilities for plain text authentication, multiple independent RIP
domains, variable length subnet masks, and multicast transmissions for
route advertising (see RFC 1723).
Note: If the destination route is not found in the routing table, the router simply
transmits the packet to a default router for resolution.