Ch 1 Routing Services Review

Question 1

Converged Networks

Answer 1

• Contains a variety of different types of traffic, including the following:
  
  • Voice & Video traffic - IP telephony, video broadcase and conferencing.
  • Voice Apps traffic - Generated by voice-related apps such as contact centers.
  • Mission-Critical traffic - Generated by apps critical to an org such as info generated by a stock exchange app at a finance company, or patient records at a hospital.
  • Transactional traffic - Generated by apps such as those for e-commerce.
  • Routing Protocol traffic - data from whichever routing protocols are running in the network, such as RIP, EIGRP, OSPF.
  • Network management traffic - including info about the status of the network and its devices.

Question 2

Cisco IIN

Answer 2

A strategy that addresses how the network is integrated with businesses and business priorities.

Question 3

Cisco IIN

Three PHASES

Answer 3

Phase 1: Integrated Transport- Everything (data, voice, video) consolidated into one IP network for a secure network convergence.

Phase 2: Integrated Services- When the network infrastructur is converged, IT resources can be pooled and shared, or virtualized, to flexibly address the changing needs of the org. Integrated services help to unify common elements, such as storage, and data center server capacity.

Phase 3: Integrated Application- This phase focuses on making the network application-aware so that it can optimize application performance and more efficiently. Caching, load-balancing, application-level security.

Question 4

Cisco Enterprise Architecture

Answer 4

Cisco provides an enterprisewide systems architecture that helps companies to protect, optimize, and grow.

Question 5

Cisco Enterprise Architecture - Components

Answer 5

• Cisco Enterprise Campus
  
  • Intelligent switching - high availability with multilayer design, redundant hardware/software.
  • IP communications, mobility and advanced security.
  • employs 802.1x, EAP, IPsec, MPLS VPNs, and VLANS.
• Cisco Enterprise Data Center
  
  • Supports requirements for consolidation, business continuanace and security.
  • Redundant data centers provide backup using synchronous and asynchronous data and application replication.
• Cisco Enterprice Branch
  
  • Allows enterprises to extend head-office applications and services to remote locations.
  • Advanced routing, VPNs redundant WAN links, app content caching and local IP telephony features are all available with high levels of resilience for all branch offices.
• Cisco Enterprise Teleworker
  
  • Allows enterprises to securely deliver voice & data services to remote offices over a standard broadband access services, providing a business-resiliency solution for the enterprise.
  • Centralized management minimizes the IP support costs.
    *

Question 6

Cisco Hierarchical Network Model

The 3-layered hierarchical network model framework is designed for flexibility and facilitates implementation and troubleshooting.

Answer 6

1. Access layer - this layer is used to grant users access to network devices. (Switches with ports that provide connectivity to PCs and servers.)
2. Distribution layer - This layer aggregates the wiring closet connections and uses switches to segment workgroups and isolate netowrk problems in a campus environment. (Aggregates WAN connections at the Edge of the campus and provides policy-based connectivity - implements the org’s policies.)
3. Core layer - Also referred to as the Backbone, this layer is a high-speed backbone and is designed to switch packets as fast as possible. (must provide a high level of availablity and adapt to changes quickly)

Question 7

Cisco Enterprise Composite Network Model

Answer 7

Cisco as developed a set of best practices for security, comprising a blueprint for network designers and admins for the proper deployment of security solutions to support network apps and the existing network infrastructure.

This blueprint is called “SAFE”

SAFE includes the Enterprise Composite Network Model, which can be used to describe and analyze any enterprise network.

Question 8

Cisco Enterprise Composite Network Model

Three Functional Areas

Answer 8

1. Enterprise Campus- this functional area contains the modules required to build hierarchical, highly robust campus network. Access, Distribution, and Core principles are applied to these modules.
2. Enterprise Edge- This functional area aggregates connectivity from the various elements at the edge of the enterprise network, connectivity including to remote locations, the Internet, and remote users.
3. Service Provider Edge - this area is not implemented by the org; instead, it is included to represent connectivity to ISPs, WAN providers,a nd PSTN (public switched telephone networks)

Question 9

Cisco Enterprise Composite Network Model

Functional Area - Enterprise Campus

Answer 9

The Enterprise Campus comprises the following modules:

• Building - contains access switches and end-user devices.
• Building Distribution - includes distribution multilayer switches to provide access between workgroups and to the CORE.
• Core - the backbone provides high-speed connection between buildings themselves, and between buildings and the Server Farm and Edge Distribution.
• Edge Distribution - the interface between the Enterprise Campus and the The Enterprise Edge. This module concentrtes connectivity to and from all branches and teleworkers accessing the campus via a WAN or the Internet.
• Server Farm - represents the campus’s data center.
• Management - represents the network management functionality, including monitoring, logging, security, and other management features within the enterprise.

Question 10

Cisco Enterprise Composite Network Model

Functional Area - Enterprise Edge

Answer 10

The Enterprise Edge comprises the following modules:

• ISP - represents Internet connection.
• PSTN - reprsents all nonpermanent connections, including analog phones, celluar phones, and ISDN.
• Frame Relay/ATM - represents all permenent connections to remote locations, including Frame Relay, ATM, leased-lines, cable, DSL, and wireless bridging.

Question 11

Review IP Routing Principles

Answer 11

The primary responsibility of a router is to direct packets destined for local or remote networks by:

• Determining the best path to send packets.
• Forwarding packets toward their destination.

To forward the packets, routers must know abou the networks directly connected to its interfaces; it calculates the subnet of the interface by using the address and subnet mask configured on that interface.

For networks not directly connected to one of its interfaces, however, the router must rely on outside information. A router can be made aware of remote networks in two ways:

1. Static routing
2. Dynamic routing

Question 12

Static routing

Answer 12

Static routing

• an admin can manually configure the information.
• are commonly used when routing from a network to a stub network.
  
  • A stub network - a network accessed by a single route -only one-way in and out.
• Static route out next-hop addrss has Default Admin Distance of 1
• Static router out exit interface has Default Admin Distance of 1* however, since it is using the local router interface as exit, it is considering it a directly connected route; and the Default Admin Distance will be between 0 and 1.

* Admin Distance - a routing protocols trustworthiness.

Question 13

When to use Static Routing

Answer 13

• When it is undesirable to have dynamic routing updates forwarded across slow bandwidth links, such as a dialup link.
• When the admin needs total control over the routes used by the router, such as in troubleshooting.
• When a backup to a dynamically recognized route is necessary.
• When it is necessary to reach a network accessible by only one path (ie stub network)
• When router connects to ISP - it only needs to have a default route pointing toward the ISP router, rather than learning many routers from the ISP.
• When a router is underpowered and does not have the CPU or memory resources necessary to handle a dynamic routing protocol.
• Hub to spoke design.

Question 14

Configure a Static Route

Answer 14

Syntax to configure a static route at the global config command.

R(config)#ip route prefix mask {addrs | interface} [dhcp] [distance] [name next-hop-name] [permanent | track number] [tag tag]

• Prefix mask - The IP network and subnet mask for the remote network to be entered into the IP routing table - the IP address of where you want to go to that is not directly connected to you.
• Address as exit - The IP address of the next hop that can be used to reach the destination network - the IP address of the neighboring router that is directy connected to you to get to the desired network.
• Interface as exit - The local router outbound interface to be used to reach the destination network.
• DHCP - optional
• Distance - optional

Question 15

Example Static Route

Answer 15

Enter a static route on R3 to reach R1’s LAN

R3#conf t

R3(conf)#ip route 192.168.1.0 255.255.255.0 192.168.3.1

R3(conf)#exit

R3#show ip route

S 192.168.1.0/24 [1/0] via 192.168.3.1

Question 16

Disadvantages of using Static Routes

Answer 16

• A static router cannot respond dynamically to changes in the network, if a link fails, the static router is not longer valid if it is configured to use that failed link, so a new static route must be configured.
• If a new router or new link is added, that info must also be configured on every router in the network.

Question 17

Dynamic Routing

Answer 17

Dynamic routing allows the network to adjust to changes in the topology automatically, without admin involvment.

Some Dynamic Routing Protocols:

• RIP v1 - classful, distance vector, hops, AD 120
• RIP v2 - classless, distance vector, hops, AD 120
• EIGRP - classless, distance vector, composite metric (*bandwidth, *delay, reliability, loading, MTU – uses two * be default), AD summary route 5, Internal 90, External 170.
• OSPF - classless, link state, cost, AD 110
• IS-IS - classless, link state, metric, AD 115
• BGP - classess, distance vector, path attributes, AD External 20, Internal 200.

Question 18

When using a Dynamic Routing Protocol

Answer 18

• The admin configs the routing protocol on each router.
• The routers then exchange info about the reachable networks and the state of each network.
• Routers exchange info only with other routers running the same routing protocols.
• When the network topology changes, the new info is dynamically propagated throughout the network and each router updates its routing table.

Question 19

Configure a Dynamic Routing Protocol

Answer 19

To configure a Dynamic Routing Protocol

• First use the router command followed by the routing protocol at global config to enable the routing protocol.
• Next use the network command to
  tell the router which interfaces are participating in that routing protocol so that it can advertise it’s directly connected networks to its neighbors.
  • The network command is only used for RIP, EIGRP, and OSPF: IS-ISand BGP does not use the network command.

Question 20

The router command

Answer 20

• R(config)#router rip
• R(config)#router eigrp 100 (Process ID significant)
  
  • In order to establish neighbor adjacencies, EIGRP requires all routers in the same routing domain to be conigured with the same process ID.
• R(config)#router ospf 200 (Process ID not significant)
  
  • The Process ID is locally significant, which means that it does not have to match other OSPF routers in order to establish adjacencies with those neighbors.
• R(config)#router bgp 65101 (AS ID significant)
  
  • AS (autonomous-system) identifies the local autonomous system. The BGP process needs to be informed of its autonomous system so that when BGP neighbors are configured it can determine whether they are IBGP or EBGP neighbors.

Question 21

The network command