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What is a Circuit Switched PSTN (Phone Service, Analog Modems, ISDN)
-dedicated circuit paths established during call
-ISDN combines voice and data and serves as a backup
Packet and Cell Switched
ex. X 25, Frame Relay, SMDS, ATM
-permanent virtual circuits which deliver packets of data between customer sites
ATM uses cells and provides QoS
What are the 4 emerging WAN technologies?
-DSL-ordinary copper lines
-LRE-ethernet over telephone using DSL
-Cable-coaxial and fiber that supports analog and digital video
4 types of WAN Interconnections
-Enterprise edge and ISP Edge modules
-sites across ISP Network
-Enterprise sites across SP network
How do you plan and design the Enterprise Edge WAN?
-Analyze customer requirements
-Characterize customer rewuirements
-Desgin topolgy
Considerations when planning and designing WAN
Application aspect
Technical aspect
Determing Maximum Offered Traffic
- end users require minimum response times
-network managers require maximum link utilizations
Typical Applications on Client Enterprise Edge APplicaitons
Internet Apps (mail, web, public servers)
Ecommerce apps
4 types of network geography
-interbuilding- b/t 2 buildings
-intrabuilding- within buildings
-distant remote building-
-distance remote building over 100km
What is a Leased Line
-physical wire
Intrabuilding Structure
-inside building connections
-access and distribution layers
-UTP (copper) or Optical fiber
Interbuilding Structure
-connection between 2 buildings
-distribution and or core layers
-optical fiber (MM or SM)
Distant Remote Building Structure
-uses company owned fiber (SM)
-through enterprise WAN
What is switching later decicion dictated by?
-network service capabilities (QoS, policing, etc.)
-size of network segments
L2 offer load sharing by?
Distributing VLANs accross different uplinks
How do L3 perform load sharing?
between ports
When designing enterprise campus what do you take in consideration?
-application traffic
-multicast traffic
When designing campus models concentrate on:
-access and distribution
-server farm
-edge distribution
What do network traffic represent?
-organizational application traffic flows
Traditional Network vs. Modern Networks in network traffic
Trad- 80/20 rule (20% into WAN)
-servers in workgroup
-most traffic LOCAL
Modern- 20/80 (80% in WAN)
-servers in server farm
What do IP Multicast deliver?
a traffic stream to mulitple destinations
IGMP- Internet Group Managment Protocol
- hosts that are interested in receiving data flowing to a particular group must join the group by using this
CGMP- Cisco Group Management Protocol
-cisco propriety solution implemented on all Cisco LAN switches
IGMP Snooping
snooper that looks into the L3
What are the L2 QoS catergories ? (4)
-classification and marking
-congestion management
-policing and shaping
input of device
output of device
What are the Building Access Design considerations
-# of users and ports
-VLAN deployment
What is the building distribution design and what are the considerations?
-provides access aggregation to the backbone
-#of ports of neighbhors
-intelligent network devices
What is the campus backbone and what are the considerations?
-provides high speed connectivity to building distribution and server farm
-L2 or L3
-high capacity ports for distribution
What does server farm model connect to and what are its considerations?
-connectivity of servers in enterprise campus network
-considerations- access control, huge traffic demands, switch and link oversubsciptions, server connectivity options
What are servers in the server farm connected via?
-single NIC
-dual NIC
-server load balancing switch
What layers in the OSI model does the WAN cover?
-physical, data link, netowrk
What are WAN technologies?
-leased lines, circuit switching, packet switching, and cell switching
Layers in the Heirarchical Model
Access, Distribution, Core (Backbone) Layers
Why is Design So Important?
Networks are Critical and Complex
According to the OSI Model, where are the Layers in the Heirarchical Model Placed?
Access- Placed in the protocols of the application, presentation, session, and transport
Distribution- core of the transport and network layer interaction
Core- Transport
Access Layer
-Local and Remote Workgroup Access
-Controls traffic by localizing service requests to the access media
-Examples of what is on the Access Layer- routers, Firewalls, PC's, L2 Switches, WAN, Internet, PSTN
Distribution Layer
-Provides policy based connectivity
-QoS, Access Lists, Security
-makes efficient use of bandwidth
-Prioritize traffic
-Ex. Routers, L2/3 Switches
Core Layer
-High Speed Switching
-Send data to network as fast as possible
-Maintain connectivity when circuits connecting them fail
-Ex. Servers, L2 or L3 Switches
Roles of the Access Layer
-Clients Access Network through this layer by using LANs and WANs (shared vs. switched), PSTN (shared vs. switched vs. leased line)
-Access may only be granted by those authenticated
Access Layer Design Options
L2- determines single broadcast domain

L3- optimized to satisfy the needs of a particular user, static routing, Dial-on-demand (cuts WAN costs)
Layer 2 VLANs Example
-for traffic management
-workstations connected to VLANs with L2 switches
-switches are connected via VLAN Trunk
-Switch sends appropriate VLAN to trunk
Roles of Distribution Layer
-Separation between access and core
-aggregates all users
-L2 or L2/3 Switching
-determines department or workgroup access
-provides redudandant connections
What are the benefits of swtiched vs. shared technology?
-high bandwidth support
-larger network diameter
-addition L2 L3 devices
-high availability
Distribution Layer Design Options
-L3 between access and core
-route aggregation, redistribution, and filtering
-redudundancy, load balancing
-Policy based decisions
-filtering by source and destination address
-filtering by input/output ports
-static routing
-security, QoS
-hiding internal network #'s by route filtering
Distribution Layer in Routed Campus Network (2-16)
-high redundant connectivity- towards access and core
-L3- access and distribution and extended towards core
-2-way redistribution to exchange routes between routing processes
-route filtering configured towards access layer
-route summarization configured toward core layer
List 3 key distribution layer features
1.distribution layer aggregates access layer links
2.represents a routing boundary between access and core
3.provides policy based connectivity
Role of Core Layer
-provide fast and efficient data transport
-high speed backbone, redundancy and fault tolerance
-design options- L2 or L3
What are 3 roles of core layer in LAN design
-high speed data transport
-fast convergent infrastructure with high level of redundancy
-avoids data manipulation
Drawbacks of Enterprise Networks (3)
1.diffuclt to manage
2.difficult to scale
3.difficult to evaluate end to end
Enterprise Composite Network Model Goals (3)
1.more deterministic networks
2.small modules ease design and improve scalabilty
3.easier to add modules
Benefits of Enterprise Composite Network Model
-concentrate on each module and on relationships between modules
-additional integrity in network design
-ease in evaluating network solution (IP Telephony, etc.) and any intelligent network service (security, QoS)
3 Functional Areas of ECNM (2-31)
1.Enterprise Campus- all network elements for independent operation within one campus location
-no remote connections or internet access
2.Enterprise Edge- aggregates connectivity from various elements at edge of enterprise campus network-
-routes traffic from edge to enterprise campus
-includes remote locations, business partners, mobile users, and Internet
3.Service Provider Edge-enable communication with other networks using different WAN technologies and Internet Service Providers (ISPs)
ECNM Functional Detail (2-33)
Network Management connects to Enterprise Campus which connects to Enterprise Edge which connects to Service Provider Edge
Name 3 modules part of the Enterprise Campus.
1.Network Management Module
2.Edge Distribution Module
3.Server Farm Module
Enterprise Campus Functional Area- name all components- be able to draw this out- (2-36)
Network Management-
Campus Infrastructure
Server Farm
Edge Distribution
Campus Infrastructure Module (2-38)
-connects users with Server Farm and Edge Distribution Modules
-Building Block- Building Access, Building Distribution
-Campus Backbone
-Server Farm- Internal Email, Corporate Server, CallManager
-Edge Distribution
Campus Infrastructure- Building Block (2-39)
-Contains Building Access- end user workstations, printers, IP phones, etc
-Building Distribution- uses L3 switches- provides aggregation of access networks- performs routing, QoS, access control
Campus Infrastructure- Campus Backbone (2-40)
-high speed switching
Network Management Module (2-41)
-performs intrusion detection, system logging, and Terminal Access Control Sytem Plus (TACACS+), OTP
-Examples- OTP, Access Control Server, IDS detector, Syslog, System Admin, Out of Band Management
-Cisco IOS routers act as terminal servers
Server Farm Module (2-42)
-contains internal email and corporate servers
-switches are cross connected to 2 different switches for redundancy and load sharing
-include Internal Email, Corporate Server, Call Manager
Edge Distribution Module (2-43)
-routes traffic into Campus Backbone Submodule
-uses access control to filter traffic
-L3 switching
Network Solution in the Enterprise Campus (2-44)- example of how IP telephones are used to call each other
check out description-
What module connects Server Farm to Edge Distribution Module?
Campus Backbone Submodule
Enterprise Edge Functional Area- 4 modules
-going out from enterprise into the world
2.Internet Connectivity M
3.Remote Access and VPN
4.WAN module
E-Commerce Module (2-48)- to build a successful interface for e-commerce navigation
-web servers
-application servers
-database servers
-firewall or firewall routers
-network intrustion detection system (NIDS)
-L3 switch with IDS modules
Internet Connectivity Module (2-49)
ex. corporate website without people connecting intranet-
-SMTP mail servers
-DNS Servers
-Firewall routers
-L2 switches
-Edge Routers
Remote Access and VPN Module
-dial in access concentrators
-VPN concentrators
-L2 switches
-NIDS appliances
WAN module
-connects to Frame Relay/ATM
-uses different WAN technologies for routing traffic between remote sites and central site
What are servers on the Internet Connectivity Module?
public servers
What 3 servers to E-commerce modules use for web communication with users who are running apps and storing data?
Service Provider Edge Functional Area
-implemented by enterprise itself
-contain ISP and PSTN and Frame Relay/ATM (L2 and encapsulation)
Name 2 modules that connect to Remote Access and VPN module
PSTN and Internet Connectivity Module
Name the types of security for Enterprise Campus and Enterprise Edge.
EC- internal security
EE- from external threats
Internal Security- where is packet manipulation? in campus infrastructure
Building Distribution
Is there packet manipulation in campus backbone?
go over slide 2-70
do we need to memorize this?
External Threats types (2-73)
IP spoofing, password attacks, DoS, application layer attacks
Where is the first front protection against external threats?
Enterprise Edge
Which module of ECNM is responsible for AAA and stores OTP?
Network Management Module
Importance of High Availabilty
-no down time
-route redundancy, link redundancy
-redundant connections to critical workstations and servers
How to design high availability.
-anaylze business and tech goals
-identify critcal apps
-document tradeoffs between costs and redudancy
-duplicate vital links and connect them to different devices
High Availabilty in Server Farms- what type? (2-78)
-dual attachement- increase availabilty and prevent session loss-
-attachemnt through redundant transceiver
-redundant NIC
-Fast EtherChannel and Gigabit EtherChannel port bundles
Physical Redundancy- Redundant Transceiver Attachment (2-79)
-activates back up link if primary fails
-cannot detect failures beyone physical link- it can;t tell if server is down
-implemented on servers
Physical Redundancy- Redundant NIC Attachment (2-80)
-2 NIC cards as single logical interface
-uses one MAC address for both interfaces
-backup activated when primary gone
Designing Route Redundancy Purposes (2)
1. minimize link failures
2. minimize interneteworking device failure
Designing Route Redundancy- how to make connection redundant:
- parallel physical links between switches and routers
-backup LAN and WAN links
How to make network redundant
-full mesh
-partial mesh
How can enterprise edge create redundancy?
using an ISDN backup interface
What protects a primary leased line?
What is ideal for a campus backbone?
What is ideal for a distributed network?
CB- full mesh
DN- partial mesh
What is a network solution?
-network based application that runs over the network infrastructure
ex. IP Telephony, IP VC, conent and Storage networking
Difference between IP Telephony and IP VC?
IP T- phone and call manager, originates from phone, voice in- IP out

IP VC- phones take analog voice and convert into packets by voice-enabled routers
4 main IP Telephony Components
1.IP phones
2.Swtiches with inline power
3.Cisco CallManager
4.Voice gateway
In ECNM how does the Voice Network Design correlate to all the components?
-Building Access- connectivity, packet classification, power to IP phones
-Building Distribution- wiring closets, packet reclassification
-Campus Backbone- fast packet switching between modules
-Server Farm- enables connection to Call Manager
-Enterprise Edge- extend IP Telephony to PSTN, IP WAN, and Internet
3 Content Delivery Functions
and where are they present in the network modules?
1.Caching- presnt in any network module
2.Content Routing- present in any network module
3.Content Swtiching- Campus backbone, server farm, internet connectivity, and E-commerce
Describe the route of Content Caching
1.Client request to origin
2.router intercepts traffic and forwards to cache
3.cahce miss
4.content request to origin
5.origin returns content
6.content stored in cache
7.content sent to client
Route of Content Routing
What 3 components do design documents usually contain?
1.desgin requirements
3.implementation plan
Detailed Structure of a Design Document (1-151)
1.intro requirements
3.exisiting network infrastructure
5.proof of concept (pilot or prototype)
6.implementation plan
Pilot vs. Prototype Network
Pilot- tests and verifies design before network is launched

Prototype- tests and verifies design in an isolated network (to an exisiting network)
Planning a Design Implementation
-implement each step separately
-incremental implementation
Which 2 tools should be used during network design process?
-network modeling tools
-simulate and test tools
Network Design Tools (4)
1.Network modeling tools- takes parameters and puts it into a software
2.Strategic Analysis Tools- what if tools
3.Simulation and Verification- run tests
4.Deciscion Tables- manual tables, helps in network designs
After examining exisiting network what kind of document do you create?
Draft Design Document
Describe the different sections in Draft Design Document.
1. Design Requirements
2.Existing Network Infra
2.1 Network Topolgy (physical and logical- L1 and L3)
2.2 Network Audit
2.3 Apps used in network
2.4 Network health
2.5 Recommendations of changes
How should you characterize the exisiting network? (3)
1. customer input
2. network audit
3. network analysis
What 3 sources can be used to produce a detailed description of design requirements?
2.Direct customer input
3.existing documentation describing the network
How do you create the design requirements document?
-extract customer requirements (RFP, RFI)
-query customer for raw requirements
-produce draft document
-verify desgin requirements
-revise if necessary
What are customer requirements extracted from? (3)
RFP- request for proposal
RFI- request for information
Direct Customer Input
List the 8 steps in the Design Methodolgy Process Review.
1.Identify customer requirements
2.Characterize exisiting network
3.Design topolgy and network solutions
4.PLan implementation
5.Build pilot (optional)
6.Document the design
7.Implement and very design
8.Monitor and revise if necessary
What is the physical address that every node is connected to called?
MAC address
What must all computers connected to the Internet must have in order to communicate with other Internet nodes/hosts?
IP address or logical address
What is the connectionless protocol that operates at the transport layer?
User Datagram Protocol (UDP)
What is the format required for delivery to the Network Layer?
Ethernet half-duplex communications
two way transmissions but only one direction at a time- nodes must agree to only talk one at a time
OSI Model
OSI Summary- Applications Layer- name the protocols and devices/services
-FTP, HTTP, Telnet, DNS
-devcice/services- Web browser
Examples of Presentation Layer
Examples of Session Layer
RPC, NFS, SQL, X-Windows
Examples of Transport Layer
Examples of Network Layer and devices at this layer
devices- router
Examples of Data Link and devices
ex- Ethernet, Frame Relay, HDLC
devices- bridge, switch, NIC
Examples of Physical and devices
ex- T1, leased line, 56Kbps services
devices- cabling, repeater
Data formatting handled by which layer?
Presentation layer
3 phases of establishing communication are:
-negotiate duplex, transfer data, connection release
Which layer that ensures that the proper formats are used for a variety of mulitmedia formats?
presentation layer
DNS is what type of protocol?
What are the TCP/IP primary transport layer protocols?
Port #'s for the following:
IP address class characteristics
A- network.node.node.node


Switched vs. Shared numbers
intelligent devices (Y o N)
High Avalalability (Y o N)
-sw- > 10 Mbps sh- < 100 Mbps

-sw- 1km<< sh- < 500m

switched have intelligent devices and high availabilty
Why is LAN switching technology better than shared LAN technology?
- LAN switching allows more than one port to communicate simultaneously
What is application characterization?
-provides information on the network usage and response times
-influences the tranmission medium selection
Name 4 types of applications
peer to peer
client distributed servers
client server farm
client enterprise edge servers
typical applications on peer to peer
ip telephony
file sharing
videoconferencing systems
client distributed server applications examples
servers located close to clients
-servers in clients in same VLAN
-each VLAN has own server
CLient Server Farm Applications Example
-mail servers, file servers, database servers
What are the 5 campus design decisions?
-transmission media
-swtiched or shared (switches or hubs)
-L2 or L3 switching
What does physical media in the network design determine?
-connection speeds
-device to device distance
What are the 2 types of physical connection used?
-optical fiber
Copper vs. Fiber-
deployment area
c- ethernet: <1 Gpbs LRE- 15 Mbps
F- <10 Gbps

c-ehternet <100m LRE- < 1.5 km
f- MM<550m SM <100km

c-wiring closet
f- internode/interbuilding
Summary Report- what is it used for?
(do this after the characterization of the network)
-describe software features required by customer
-describe possible problems (network health)
-influence on customer requirements
Cisco Manual Analysis Tools (2)
Cisco Software or hardware based network analyzers (2)
-Cisco FlowCollector
-Cisco Data Analyzer
3rd party network analyzers (4)
-Network Monitor
Network Application Discovery
-describing requirements of discovered applications
-Scope (in which network modules an application is present)
What are the 3 address assignment strategies available in IPv6?
address assignment with DHCP
statless autoconfiguration
Magic Number
Differences between IPv4 and IPv6
-IPv6 address longer
-6 header changed
-6 uses multicast addresses instead of broadcast addresses
-6 requires adaption of routing protocols
3 major transition strategies

look at pages 5-76 to 5-79 for more information on each strategy
-dual stack


What does the network architecture include? (4)
-enabling network solutions
-pre-requisite systems
-network infrastructure with intelligent systems
If don't use site or link-locad address for IPv6 what do you use?and whats its header?
global aggregatable address-
header- 001
What is the investment and running costs of private WAN?
-owner must buy, configure, and maintain the physical layer connectivity and terminal equipment required to connect the locations
What is the investment and costs of Leased?
-bandwidth is leased from a carrier company with either private or leased terminal equipment
-company pays for allocated bandwidth where oir not it is used
What is the investment and running costs of shared?
-carriers offer a variety of switching transports for user traffic- physical resources in core are shared with many users
example: switching technologies
What does hardware selection incorporate according to WAN technologies and what are the considerations?
-selection of L2 functions
-considerations- port density, packet throughput, future expandabilty, redundancy
What are the Software features when building a WAN and what are the considerations?
-L3 performance
-considerations- forwarding decisions, optimization of bandwidth usage, security
T or F are redunandant links necessary in WANs?
Name 4 ways to optimize bandwidth usage on WAN links?
-data compression
-window size
-traffic shaping and policing
Define Data Compression
-what does it do?
-where does it take place?
-two types of implementation
-can compress header and or data
-reduces size frame of data to be transmitted over a network link
-takes place on an entire-packet, header only, payload only basis
-implementation- software or hardware based
Name 2 products of Data Compression
-Link Access Procedure Balanced (LAPB) payload compression using Lempel-Ziv Stack or Stack Predictor (Payload)

-Van Jacobson Header Compression for TCP/IP
What does window size do?
what is it important for?
-specifies maximum number of frames that may be transmitted without recieving an acknowledgement
-the smaller the window size the more acknowledgement
-important for long and fast transmissions
What does queuing do?
-allows network administrators to manage varying demands of applications on networks and routers
Name the 3 basic types of queuing.
-weighted fair queuing
-priority queuing
-custom queuing
Weight fair queuing-
-bulk queuing
-FIFO basis
-assess size of each packets
-makes sure big guy doesnt push little guy
Priorty Queuing
-sets up 4 interface queues
-always empties first bucket first (first bucket has the highest priorty)
Custom Queuing
-16 buckets
-sets priorities for each bucket, but goes to next bucket once emptied
-fairer solution
What are 2 mechanisms used to rate limit traffic classes and explain each.
-traffic shaping- delays excess packets to stay within rate limit
-traffic policing- drops excess traffic to stay within rate limit
Where is data compression, queuing, policing, shaping found?(on SP edge)
data compression- ISP into e-commerce
queuing- ISP into internet connectivity
-policing- SP into WAN
-shaping - SP into WAN
What is a benefit of ISDN over analog PSTN connectivity?
-increased bandwidth, reduced call set up time, reduced latency, and lower signal to noise ratios
TDM vs. Packet Switching
-TDM- point to point connections reserved for transmissions

-Packet Switching- share SP network resources dynamically- subscriber charged on per packet basis- QoS needed
What are the on-demand connections?
-Analog Modem Access
What are the always on connections?
-Packet Switching
-Frame Relay
-X 25
IGP- Interior Gateway Protocols- for inside autonomous systems- list the different types of them
-Integrated IS-IS
Frame Relay vs. X.25
-FR- operates at L2 protocol suite, more reliable connection services and a higher degree of reliabilty and higher performance and greater transmission efficiency

-X.25 operates at L3
Name 3 Network Topologies
-hub and spoke-
-partial meshed
What is a solution for minimum down time?
-load sharing
Name 3 WAN backup technologies
-dial back up routing (ISDN)
-permanent secondary WAN link
-Shadow permanant virtual circut
IPv6 routing protocol considerations
RIPing, IS-ISv6, BGP+
EGP- exterior gateway protocols example
OSPF - open shortest path first
-similiar to IPv4
-carry IPv6 addresses
-link-local addresses used as source
-IPv6 transport
Integrated Intermediate System-to-Intermediate Systems (IS-IS)
-same as IPv4 woth some extensions
-two new types, lengths, values (TLVs)
-IPv6 reachability
-IPv6 interface address
-new protocol identifier
BGP4+ (Multiprotocol Extensions to BGP, RFC 2283), RFC 2545
-mulitprotocol extensions for BGP4 enable other protocols besides IPv4
-new identifier for the IPv6 address family
-IPv6 specific extensions
What are the address assignment strategies for static?
same as IPv4
What are the address assignment strategies for dynamic?
stateful using DHCPv6
What are the two IGP IPv6 routing protocols supported by Cisco?
Private and Public Translation Options (3)
-one to one
-many to one
What is the translation criteria in the private and public translation?
-access to public network
-public visibilty
Examples of three translation options
one private address to one public address- private to public (addresses visible from public network)when servers must be visible

many private addresses to one public addresses: systems that need to access public network but do not need ot be seen by outside world

combination- combination of both techniques
Where are public addresses used in the enterprise network?
-internet connectivity module
-e commerce module
-remote access and VPN module
Classful Routing Protocol

does it send subnet?
-does not send subnet
-address sent either way
Classeless Routing Protocol

does it send subnet?
-sends subnet
How do you reduce routing overhead?
-route summarization
What is the static IP address assignement?
management overhead
What are the 2 ways dynamic IP address assignment?
-easy renumbering
-servers assign addresses
Static Address criterias
-up to 30 users
-manual recofig of hosts
-easy address tracking
-IP addresses available at any time
-minor secuirty risk
dynamic address criteria
-more than 30 hosts
-only DHCP server reconfig is needed
-redundant DCHP required
-any device gets IP address
Where are static IP addresses located? On enterprise module...
-network management
-server farm
-maybe pc's
-internet connectivity
-maybe remote access VPN
Where are dynamic addresses located?
-remote access and VPN
What are the 3 possible DHCP address allocation mechanisms?
Describe the three possible address allocation mechanisms
-manual- network administrator manually assigns MAC/IP address, DHCP used

-automatic- IP address is permanently assigned to host

-dynamic- pool of IP addresses that server gives to device
Do Dynamic Host Configuration Protocols need servers?
Describe what happens when link disconnected using ISDN as backup?
-backup connection from remote site router to enterprise edge router established
-server in remote acces and VPN is preconfigured to honor an alternative path
Describe a Permanent Secondary WAN link
this is a new link that provides a backup link that can be used if a primary link fails
What determines link failure?
-routing protocols
What do load balancing do?
-increases overall bandwidth availabilty
Descibe Shadow PVC
-used only if primary PVC is unavailable
-gets two connections for the price of one
-bandwidth alternative
-establishes p2p circuits using TDM frames in ring topoligies- guarnateed bandwidth
-automatic recoveries
DWDM- dense wavelength division multiplexing
-improved signaling mechanisms to optimize bandwidth usage
-used inside SONET/SDH ring
Dark Fiber
-edge devices directly connected to regenerators or DWDM concentrators
-use L2 encapsulation
What 2 encapsulations are supported in SONET/SDH network?
-IP over ATM
What type of connection in Sonnet?
point to point
-mature T1 technology that provides symmetric communications up to 1.54 mbps
-data travels over two pairs of wires instead of one
-does not support PSTN
-CPE acts as a ethernet-to-wan router
-PPP session established between CPE and L3 access concetrator
ask about PPPoE/ PPPoA and Chap/PAP
LRE what does it use?
-existing ethernet, DSL and digital modulation techniques with ethernet
-p2p transmissions - full duplex with 15Mbps
-can connect to ISDN, PBX
Cable Modem Termination System
also called uBR
-high speed connectivity and deployed at company's headend
-forwards data upstream to connect to either the PSTN or Internt
3 types of Wireless Technologies
-broadband fixed- building to building
-mobile- cell, GSM, GPRS, UMTS
-wireless LAN- intrabuilding CMN
p2p- how do they communicate with?
-allocates separate sectors in channel
-advantage is speed, not sharing bandwidth
VPN definition
-connectivity deployed on a shared infrastructure with the same policies and performance as private network with lower cost
VPNs are grouped according to what 3?
-access- access to customers intranet or extranet over shared infrastructure

intranet VPNs- extends corporate network across a shared infrastructure

extranet VPN- extends connectivity to business partners, suppliers, and customers
Connectivity options for VPNs are (3)
-peer to peer
Overlay Option
-permanent circuit
-like buying a pipe, won't knows what goes in (runs along provider's backbone)
VPDN example
use dial in infrastructure - use ISDN, DSL, or cable to connect to SP edge
Peer to Peer VPN
-utilizes MPLS/VPN technology
-enables customers to use any IP address space
-no overlapping IP address space problems
Name 3 Benefits of VPNs
-flexibilty-extends networks to users
-network cost- dedicated bandwidth and dial up cost savings
-scalabilty-improve geographic coverage
Which VPN model is not supported by ISP infrastructure?
-L3 overlay model
3 methods for connecting noncontiguous private network over a public IP network
-IP routing without contraints
-GRE tunnels
-IPSec tunnels
GRE tunnels
-user initiated
-doesn't encrypt or gurantee integrity
-standard L3 encapsulation
IPSec Tunnels
-user initiated
-flexible and secure
IPSec compared to GRE (4-90)
-IPSec are secure and can be combined with GRE, have encryption
IP address stucture
-network, host
What part of the IP address does the router care about?
Class A
always starts 0
first octet
has 16,777,214 hosts available
Is 127 used?
No it is used for loop testing
Class B
starts with 10
has 65534 hosts
Class C
starts with 110
254 hosts
Class D
multi cast addresses cannt be used to address hosts
Class E
Private addresses
Memorize Charts on 5-24
Private and Public IPv4 Address Decision Table
-private needs no internet connectivity
-public- all end systems are accessible
IPv6 Datagram Structure
-version- 4 bit field
-traffic class- 8 bit, QoS
-flow label- 20 bit field, that labels the sequence of packets for which source requests special handling by IPv6 routers
-payload length- 16 bit, total length of data portion of the packet
-next header- 8 bit
-hop limit-8 bit field
-source address-16 octets
-destination address- 16 octets
IPv6 address scopt types
one to one
anycast (one to nearest)
multicast (one to many)
IPv6 address types-
-link local address- cannot leave link, V6 will not route link address similar to private addresses in V4

-site local address-used for sites that dont have global prefix- private interior set of V4 addresses, cant be sent out to internet
Link Local Address Header
Site Local Address Header

Deck Info