Network

Access Controls   Lists(ACL): ACL is a set of rules which will allow or deny the traffic moving through the router. It is a layer 3 security which controls the flow of traffic from one router to another. It is also called as packet filtering firewall. ACL is two type: 1.Standard ACL: standard access controls   Lists(ACLs) are the oldest type of access control lists. Standard IP access lists are used to permit/deny traffic only based on source IP address of the IP datagram packets. Standard Access Control list can be created by using the access-list IOS command. Function: The access list number range is 1 -99 Can block a network, host and subnet Two way communication is stopped All services are blocked. Implemented closest to the destination. Filtering is done based on only source IP address. 2.Extended ACL: Extended Access Control Lists allow you to permit or deny traffic from specific IP addresses to a specific destination IP address and por...

Compare and contrast OSI and TCP/IP models : 1.Physical Layer:      it is responsible for moving data form one node to the next.  Function: I. Transmission media II. Types of encoding III. Data rate{no of bits sent each sec} IV. Synchronization of bits. V. Line configuration (Example: point to point , multipoint) VI. Topology (Bus,Star,Ring,Mesh) VII. Transmission (simplex ,half duplex, full duplex) 2.Data like Layer:      it transforms the physical layer into a reliable link. Function: I.Framing: conversion of bits to frames. framing are working in four methods can be used to mark the start to end of frame. i) Character Count: ii) Flag bytes with byte/character staffing iii) Starting and ending flags, with bits staffing iv) Physical bye coding valuations. II.  Physical addressing : header is adding to frame. III. Flow control IV. Error control V. Access control 3.Network Layer:      Re...