Cisco Router 800 Series Software Configuration Guide

 
1-9
Cisco 800 Series Software Configuration Guide
78-5372-06
Chapter 1      Concepts
PPP Authentication Protocols
RIP, refer to the Cisco IOS 12.0(1)T documentation set. For information on 
accessing the documentation, see the “References to Cisco IOS Documentation 
Set” on page xxi.
EIGRP
EIGRP is an advanced Cisco proprietary distance-vector and link state routing 
protocol, which means it uses a metric more sophisticated than distance (hop 
count) for route selection. Enhanced IGRP uses a metric...

 
Chapter 1      Concepts
PPP Authentication Protocols
1-10
Cisco 800 Series Software Configuration Guide
78-5372-06
The current implementation of PPP supports two security authentication protocols 
to authenticate a PPP session:
Password Authentication Protocol (PAP)
Challenge Handshake Authentication Protocol (CHAP)
PPP with PAP or CHAP authentication is often used to inform the central site 
which remote routers are connected to it. 
PAP
PAP uses a two-way handshake to verify the passwords between...

 
1-11
Cisco 800 Series Software Configuration Guide
78-5372-06
Chapter 1      Concepts
TACACS+
CHAP has the following characteristics:
The authentication process uses a variable challenge value rather than a 
password.
CHAP protects against playback attack through the use of the variable 
challenge value, which is unique and unpredictable. Repeated challenges 
limit the time of exposure to any single attack.
The corporate office router controls the frequency and timing of the 
authentication...

 
Chapter 1      Concepts
Network Interfaces
1-12
Cisco 800 Series Software Configuration Guide
78-5372-06
Ethernet 
Ethernet is a baseband LAN protocol that transports data and voice packets to the 
WAN interface using carrier sense multiple access collision detect (CSMA/CD). 
The term Ethernet is now often used to refer to all CSMA/CD LANs. Ethernet was 
designed to serve in networks with sporadic, occasionally heavy traffic 
requirements, and the IEEE 802.3 specification was developed in 1980 based on...

 
1-13
Cisco 800 Series Software Configuration Guide
78-5372-06
Chapter 1      Concepts
Network Interfaces
layer (AAL) and the encapsulation type. An AAL defines the conversion of user 
information into cells. An AAL segments upper-layer information into cells at the 
transmitter and reassembles the cells at the receiver. 
Cisco routers support the AAL5 format, which provides a streamlined data 
transport service that functions with less overhead and affords better error 
detection and correction...

 
Chapter 1      Concepts
Dial Backup
1-14
Cisco 800 Series Software Configuration Guide
78-5372-06
Dial Backup
Dial backup provides protection against WAN downtime by allowing user to 
configure a backup modem line connection. The following can be used to bring 
up the dial backup feature in the Cisco IOS software: 
Backup Interface
Floating Static Routers
Dialer Watch
Backup Interface
A backup interface is an interface that stays idle until certain circumstances occur, 
such as WAN downtime, at...

 
1-15
Cisco 800 Series Software Configuration Guide
78-5372-06
Chapter 1      Concepts
NAT
Dialer Watch
Dialer watch is a backup feature that integrates dial backup with routing 
capabilities. Dialer watch provides reliable connectivity without having to define 
traffic of interest to trigger outgoing calls at the central router. Hence, dialer 
watch can be considered regular DDR with no requirement for traffic of interest. 
By configuring a set of watched routes that define the primary interface, you...

 
Chapter 1      Concepts
Easy IP (Phase 1)
1-16
Cisco 800 Series Software Configuration Guide
78-5372-06
Translations can be static or dynamic. A static address translation establishes a 
one-to-one mapping between the inside network and the outside domain. 
Dynamic address translations are defined by describing the local addresses to be 
translated and the pool of addresses from which to allocate outside addresses. 
Allocation occurs in numeric order and multiple pools of contiguous address 
blocks can...

 
1-17
Cisco 800 Series Software Configuration Guide
78-5372-06
Chapter 1      Concepts
Easy IP (Phase 2)
Easy IP (Phase 2)
The Easy IP (Phase 2) feature combines Dynamic Host Configuration Protocol 
(DHCP) server and relay. DHCP is a client-server protocol that enables devices 
on an IP network (the DHCP clients) to request configuration information from a 
DHCP server. DHCP allocates network addresses from a central pool on an 
as-needed basis. DHCP is useful for assigning IP addresses to hosts...

 
Chapter 1      Concepts
VoIP
1-18
Cisco 800 Series Software Configuration Guide
78-5372-06
After the IPSec server has been configured, a VPN connection can be created with 
minimal configuration on an IPSec client, such as a supported Cisco 800 series 
router. When the IPSec client then initiates the VPN tunnel connection, the IPSec 
server pushes the IPSec policies to the IPSec client and creates the corresponding 
VPN tunnel connection.
VoIP
The Cisco 827-4V router is a voice-and-data-capable router...