Cisco® CCENT Exam Cram Notes : Floating Static Route, Ip Routing And Ppp

3.Routing Fundamentals

5. Floating static route

A Floating static route is a route that has a higher administrative distance than the current route in a routing table. The routes that have a lower administrative distance number will be the ones installed into the routing table whereas higher AD numbers will not. Static floating route is static route like any other but with added administrative distance in the configuration

The Administrative Distance of a static route can be changed to form a floating static route, which will only be used if there are no other routes with a lesser AD in the routing table. A floating static route is often used as a backup route to a dynamic routing protocol.

To create a floating static route, we need to use the distance option at the end of the ip route command. We really just need to set an AD for the static route.

6. IP routing and PPP

IP Packets are transported from source network to the destination network by what is known as routing. Hop-by-hop routing model is used by the Internet for delivery of packets. At each hop, the destination IP address is examined, the best next hop is determined by the routing protocol (such as RIP, OSPF or BGP) and the packet is forwarded by one more hop through this route. The same process takes place at the next hop. During this process, the logical addresses remain same. In an IP network, the logical addresses are IP addresses. The hardware interface addresses, such as MAC address change with each hop.

Point-to-Point Protocol (PPP) is a type of Layer 2 protocol (Data-link layer) used on serial links in a Wide Area Network (WAN). PPP features two methods of authentication PAP (Password Authentication Protocol) and CHAP (Challenge Handshake Authentication Protocol) . A connection is established between two peers only after authentication succeeds. PAP sends the password in clear text where as CHAP encrypts the password while sending over the network for authentication. PPP encapsulation is possible only over a serial link.

Typical configuration steps are as given below:

router#configure terminal
serial 0

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