Cisco Ccie Fundamentals: Network Design 2-12

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Figure 2-8 The Dial-on-demand routing environment.
Using DDR, low-volume, periodic network ccie online trainingconnections can be made over the PSTN. A router activates the DDR feature when it receives a bridged or routed IP packet destined for a location on the other side of the dial-up line. After the router dials the destination phone number and establishes
the connection, packets of any supported protocol can be transmitted. When the transmission is complete, the line is automatically disconnected. By terminating unneeded connections, DDR reduces cost of ownership.
Encapsulation (Tunneling)
Encapsulation takes packets or frames fromone network systemand places theminside frames from another network system. This method is sometimes called tunneling. Tunneling provides a means for encapsulating packets inside a routable protocol via virtual interfaces. Synchronous Data Link
Control (SDLC) transport is also an encapsulation of packets in a routable protocol. In addition,transport provides enhancements to tunneling, such as local data-link layer termination, ...
... broadcast avoidance, media conversion, and other scalability optimizations.
Cisco routers support the following encapsulation and tunneling techniques:
The IBM technology feature set ccie sp online trainingprovides these methods:
Serial tunneling (STUN) or Synchronous Data Link Control (SDLC) Transport
SRB with direct encapsulation
SRB with Fast Sequenced Transport (FST) encapsulation
SRB with Transmission Control Protocol/Internet Protocol (TCP/IP) encapsulation
Data Link Switching Plus (DLSw+) with direct encapsulation
DLSw+ with TCP/IP encapsulation
DLSw+ with Fast Sequenced Transport/Internet Protocol (FST/IP) encapsulation
DLSw+ with DLSw Lite (Logical Link Control Type 2 [LLC2]) encapsulation
Generic Routing Encapsulation (GRE)
Cisco supports encapsulating Novell Internetwork Packet Exchange (IPX), Internet Protocol(IP), Connectionless Network Protocol (CLNP), AppleTalk, DECnet Phase IV, Xerox Network Systems (XNS), Banyan Virtual Network System (VINES), and Apollo packets for transport over IP Single-protocol tunneling techniques: Cayman (AppleTalk over IP), AURP (AppleTalk over IP),EON (CLNP over IP), and NOS (IP over IP)The following discussion focuses on ccie rs online training encapsulations and the multiprotocol GRE tunneling feature.