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Computer Networking

Below mentioned presentations covers various important topics in Computer Networking viz. OSI reference model, topology design, maccess control level, LAN design, IEEE LAN standards, Logical link control protocols, HDLC, ALOHA, Slotted ALOHA, FDDI, client server model, network layer level, WAN, MAN, TCP/IP, Novel Netware, Routers, Bridges, Gateways. X.25, NETSCAPE, MOSAIC, Transport layer, upper layers, e-mail and other applications

Wildcard Bits

How to Check the Corresponding Address Bits
–0 means check value of corresponding address bit.
–1 means ignore value of corresponding address bit.

Wildcard Bits to Match a Specific IP Host Address

–For example, 172.30.16.29 0.0.0.0 checks all the address bits.
–Abbreviate this wildcard mask using the IP address preceded by the keyword host (host 172.30.16.29).

Wildcard Bits to Match Any IP Address

–Accept any address: 0.0.0.0 255.255.255.255.
–Abbreviate the expression using the keyword any.


Wildcard Bits to Match IP Subnets

Access Lists

What Are Access Lists?
–Standard
- Checks source address
- Generally permits or denies entire protocol suite
–Extended
- Checks source and destination address
- Generally permits or denies specific protocols

• Inbound or outbound
Why Use Access Lists?
– Manage IP traffic as network access grows.
– Filter packets as they pass through the router
Access List Applications
– Permit or deny packets moving through the router.
– Permit or deny vty access to or from the router.
– Without access lists, all packets could be transmitted onto all parts of your network.
Other Access List Uses

- Special handling for traffic based on packet tests
Outbound Access Lists
• If no access list statement matches, then discard the packet.

Interior Gateway Routing Protocol (IGRP)

Interior Gateway Routing Protocol (IGRP) is a kind of IGP which is a distance-vector routing protocol invented by Cisco, used by routers to exchange routing data within an autonomous system.

IGRP– More scalable than RIP
– Sophisticated metric
– Multiple-path support

IGRP Composite Metric

IGRP– Bandwidth
– Delay
– Reliability
– Loading
– MTU

IGRP Unequal Multiple Paths
IGRP
– Maximum 6 paths (default = 4)
– Within metric variance
– Next-hop router closer to destination

Configuring IGRP

IGRP
IGRP Configuration Example

IGRP
debug ip igrp transaction Command
IGRP

Routing Information Protocol (RIP)

The Routing Information Protocol (RIP) is a dynamic routing protocol used in local area networks. As such it is classified as an interior gateway protocol (IGP) using the distance-vector routing algorithm

- Maximum is 6 paths (default = 4).
- Hop-count metric selects the path.
- Routes update every 30 seconds.

RIP Configuration

- Selects participating attached networks.
- Requires a major classful network number


RIP Configuration Example



Verifying the Routing Protocol—RIP


Displaying the IP Routing Table

debug ip rip Command