snapshot routing, the routing table is placed in an update restricted (that is, frozen) state. This
implementation of DDR utilizes a quiet period and an active period. The routing table is not
updated during the quiet period, which is the amount of time that the routing table remains
frozen. When the quiet period expires, a dialer interface initiates a call to a remote router. The
active period is the amount of time the call remains up in order for the two routers to exchange
routing updates.
protocols. In addition, you can configure the router to exchange routing updates each time the
line protocol goes from "down" to "up" or from "dialer spoofing" to "fully up."
is in charge of the quiet timer countdown. Once the counter reaches zero, the client router dials
the server router. Snapshot routing enables dynamic distance vector routing protocols to run
over DDR lines.
DDR interfaces and static definitions are configured instead. With snapshot routing
implementations, normal updates are sent across the DDR interface for the short duration of the
active period. After this, routers enter the quiet period, during which time the routing tables at
both ends of the link remain unchanged. Snapshot routing is therefore a triggering mechanism
that controls routing update exchange in DDR scenarios. Only during the active period are the
neighboring routers exchanging routing protocol updates. During the quiet period, no updates
traverse the link (even if the link is up to enable interesting traffic to cross) and the routing
information previously collected is kept in an isolated state in the routing tables.
offices over a dedicated serial line