With snapshot routing, the router is
configured for dynamic routing. Snapshot routing controls the update
interval of the routing protocols. Snapshot routing works with the
following distance vector protocols:
- Routing Information Protocol (RIP)
for IP
- Interior Gateway Routing Protocol
(IGRP) for IP
- Routing Information Protocol (RIP)
and Service Advertisement Protocol (SAP) for Novell Internet
Packet Exchange (IPX)
- Routing Table Maintenance Protocol
(RTMP) for AppleTalk
- Routing Table Protocol (RTP) for
Banyan VINES
Under normal circumstances, these
routing protocols broadcast updates every 10 to 60 seconds, so an
ISDN link would be made every 10 to 60 seconds simply to exchange
routing information. From a cost perspective, this frequency is
prohibitive. Snapshot routing solves this problem.
The goal of snapshot routing is to
allow routing protocols to exchange updates as they normally would.
Because Enhanced IGRP and link-state routing protocols, such as
Novell Link Services Protocol (NLSP), Open Shortest Path First (OSPF),
and Intermediate System-to-Intermediate System (IS-IS) depend on the
frequent sending of hello messages to neighboring routers in order
to discover and maintain routes, they are incompatible with snapshot
routing.
Note: Snapshot routing is
available in Cisco IOS Software Release 10.2 or later.
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