Wonders of Telecom

Sunday, January 8, 2012

CCDA 640-864 Official Cert Guide - Chapter 8 Summary

IPv4 Header

IP Header

ToS

IPv4 Fragmentation

IPv4 Addressing

IPv4 Address Classes

IPv4 Address Types

IPv4 Private Addresses

NAT

How NAT Works

IPv4 Address Subnets

Variable-Length Subnet Masks

Address Assignment and Name Resolution

BOOTP

DHCP

DNS

ARP

CCDA 640-864 Official Cert Guide - Chapter 7 Summary

Traditional WAN Technologies

Circuit switched

Leased Line

Packet and cell switching

Hub-and-Spoke Topology

Full-Mesh Topology

Partial-Mesh Topology

Remote-Access Network Design

VPN Network Design

Access VPN

Intranet VPN

Extranet VPN

Enterprise VPN vs. Service Provider VPN

WAN Backup Design

Enterprise WAN Architecture

High Availability

Support for growth

Operational expenses

Cost of implement

Network segmentation support

Support for voice and video

Enterprise WAN Components

Enterprise Branch Architecture

Enterprise Teleworker Design

Wednesday, January 4, 2012

CCDA 640-864 Official Cert Guide - Chapter 6 Summary

WAN Overview

WAN Defined

SLA - Defines theavailability of the network.

Cost and Usage

Enterprise WAN

WAN Connection Modules

WAN Interconnections

WAN Transport Technologies

WAN Comparison

ISDN

Digital Subscriber Line

TDM

WAN Design Methodology

By PPDIOO;

Analyzing the network requirements

Characterizing the existing network

Designing the topology

Application Requirements

Response Time - Response time measures the time between the client user request and the response from the server host.

Throughput - In network communications, throughput is the measure of data transferred from one host to another in a given amount of time.

Reliability - Reliability is the measure of a given application’s availability to its users.

Bandwidth Considerations:

Copper

Fiber

Wireless

WAN Link Categories:

Private

Leased

Shared

Optimizing Bandwidth Using QoS

Queuing, Traffic Shaping, and Policing

Classification - Identifies and marks flow and provides priority to certain flows:

NBAR - Network-Based Application Recognition

CAR - Committed access rate

Congestion management - Mechanism to handle traffic overflow using a queuing algorithm:

The hardware queue uses the strategy of first in, first out (FIFO). The software queue schedules packets first and then places them in the hardware queue. Keep in mind that the software queue is used only during periods of congestion. The software queue uses QoS techniques such as priority queuing, custom queuing, weighted fair queuing, class-based weighted fair queuing, low-latency queuing, and traffic shaping and policing.

Link-efficiency mechanisms - Reduce latency and jitter for network traffic on low-speed links:

Link fragmentation and interleaving (LFI), Multilink PPP (MLP), and Real-Time Transport Protocol (RTP) header compression provide for more efficient use of available bandwidth.

Traffic shaping and policing - Avoids congestion by policing ingress and egress flows:

Traffic shaping and policing are mechanisms that inspect traffic and take an action based on the traffic’s characteristics, such as DSCP or IP precedence its set in the IP header.

Window Size - The window size defines the upper limit of frames that can be transmitted without getting a return acknowledgment (8192).

Flash Cards Apps for Android

Hello world,

For a few of us who time to time "praying" over different material to memorize it for the future project or certification i am proud to present to mobile version of great application that i found: its name StudyDroid.

It is a nice software that helps you to create your own Flash cards, it can be uploaded from the CSV file or created manually, then easy to uploaded to your smartphone.

I am using a while and it is just great !!!

Recommended to all busy boys and girls who is like this kind of preparation (It is very personal approach, but i think the most of us still using the old and good fashion of flash cards) of taking some notes to learn to go.

Tested...Enjoy.

CCDA 640-864 Official Cert Guide - Chapter 5 Summary

Wireless LAN Technologies

WLAN Standards

ISM and UNII Frequencies

ISM - Industrial, Scientific and medical - frequencies are set aside by ITU-R radio regulations 5.138 and 5.150. In the U.S., the Federal Communications Commission (15.247) specifies the ISM bands for unlicensed use. Several bands are specified in the following ranges:

900 to 928 MHz

2.4 to 2.5 GHz

5.75 to 5.875 GHz

Of these, channels located in the 2.4-GHz range are used for 802.11b and 802.11g. As shown in Figure above, 11 overlapping channels are available for use. Each channel is 22 MHz wide. It is common to use channels 1, 6, and 11 in the same areas, because these three channels do not overlap.

The UNII - Unlicensed National Information Infrastructure - radio bands were specified for use with 802.11a wireless. UNII operates over three ranges:

UNII 1—5.15 to 5.25 GHz and 5.25 to 5.35 GHz.

UNII 2—5.47 to 5.725 GHz. This range is used by High Performance Radio LAN (HiperLAN) in Europe.

UNII 3—5.725 to 5.875 GHz. This range overlaps with ISM.

UNII provides 12 nonoverlapping channels for 802.11a.

WLAN Standards summary
IEEE Protocol	Release	Frequency	Typical Data rate	Max. Data Rate
Legacy	1997	ISM	1 Mbps	2 Mbps
802.11a	1999	UNII	25 Mbps	54 Mbps
802.11b	1999	ISM	6,5 Mbps	11 Mbps
802.11g	2003	ISM	25 Mbps	54 Mbps
802.11n	2007 (Draft)	ISM or UNII	200 Mbps	540 Mbps

Service Set Identifier

A service set is all the devices associated with a local or enterprise IEEE 802.11 wireless local area network (WLAN). An SSID is the name of a wireless local area network (WLAN). All wireless devices on a WLAN must employ the same SSID in order to communicate with each other.

WLAN Layer 2 Access Method

WLAN Security

Unauthorized Access

WLAN Security Design Approach

IEEE 802.1X-2001 Port-Based Authentication

Dynamic WEP Keys and LEAP

Controlling WLAN Access to Servers

Cisco Unified Wireless Network

Cisco UWN Architecture

Client devices: With more than 90 percent of shipping client devices certified as Cisco Compatible under the CCX program, almost any client device that is selected will support the Cisco UWN advanced features.
Lightweight APs: Dynamically configured APs provide ubiquitous network access in all environments. Enhanced productivity is supported through plug-and-play with the LWAPP used between the APs and the Cisco WLCs. Cisco APs are a proven platform with a large installed base and market share leadership. All Cisco lightweight APs support mobility services, such as fast secure roaming for voice, and location services for real-time network visibility.
Network unification: Integration of wired and wireless networks is critical for unified network control, scalability, security, and reliability. Seamless functionality is provided through wireless integration into all major switching and routing platforms.
Network management: The same level of security, scalability, reliability, ease of deployment, and management for WLANs as wired LANs is provided through network management systems such as the Cisco WCS, which helps visualize and secure the airspace. The Cisco wireless location appliance provides location services.
Mobility services: Unified mobility services include advanced security threat detection and mitigation, voice services, location services, and guest access.

Cisco Unified Wireless Technology and Architecture

http://www.rmcug.org/presentations/prezo0603a%20-%20Unified%20Wireless%20Architecture.pdf

LWAPP

Lightweight Access Point Protocol or LWAPP is the name of a protocol that can control multiple Wi-Fi wireless access points at once. This can reduce the amount of time spent on configuring, monitoring or troubleshooting a large network. The system will also allow network administrators to closely analyze the network.

This system is installed in a central server that gathers data from RF devices from different brands and settings. The server can command a selected group of devices to apply given settings simultaneously.

Note: Layer 2 LWAPP tunnels use EtherType code 0xBBBB. Layer 3 LWAPP uses UDP ports 12222 and 12223.

Layer 3 LWAPP

CAPWAP

CAPWAP - Control and provisioning of wireless access points. The protocol specification is described in RFC5415 and an IEEE 802.11 binding is provided in RFC5416 and is based on LWAPP (Lightweight Access Point Protocol).

CAPWAP is a standard, interoperable protocol that enables a controller to manage a collection of wireless access points, and uses UDP ports 5246 and 5247.

Cisco Unified Wireless Network Split-MAC Architecture

In controller software release 5.2 or later, Cisco lightweight access points use the IETF standard Control and Provisioning of Wireless Access Points protocol (CAPWAP) in order to communicate between the controller and other lightweight access points on the network. Controller software releases prior to 5.2 use the Lightweight Access Point Protocol (LWAPP) for these communications.

CAPWAP, which is based on LWAPP, is a standard, interoperable protocol that enables a controller to manage a collection of wireless access points. CAPWAP is being implemented in controller software release 5.2 for these reasons:

To provide an upgrade path from Cisco products that use LWAPP to next-generation Cisco products that use CAPWAP
To manage RFID readers and similar devices
To enable controllers to interoperate with third-party access points in the future

LWAPP-enabled access points can discover and join a CAPWAP controller, and conversion to a CAPWAP controller is seamless. For example, the controller discovery process and the firmware downloading process when you use CAPWAP are the same as when you use LWAPP. The one exception is for Layer 2 deployments, which are not supported by CAPWAP.

You can deploy CAPWAP controllers and LWAPP controllers on the same network. The CAPWAP-enabled software allows access points to join either a controller that runs CAPWAP or LWAPP. The only exception is the Cisco Aironet 1140 Series Access Point, which supports only CAPWAP and therefore joins only controllers that run CAPWAP. For example, an 1130 series access point can join a controller that runs either CAPWAP or LWAPP whereas an 1140 series access point can join only a controller that runs CAPWAP.

Access Point Modes

An LAP can operate in any of these modes:

Local mode—This is the default mode of operation. When an LAP is placed into local mode, the AP will transmit on the normally assigned channel. However, the AP also monitors all other channels in the band over a period of 180 seconds to scan each of the other channels for 60ms during the non-transmit time. During this time, the AP performs noise floor measurements, measures interference, and scans for IDS events.
REAP mode—Remote Edge Access Point (REAP) mode enables an LAP to reside across a WAN link and still be able to communicate with the WLC and provide the functionality of a regular LAP. REAP mode is supported only on the 1030 LAPs.
H-REAP Mode— H-REAP is a wireless solution for branch office and remote office deployments. H-REAP enables customers to configure and control access points (APs) in a branch or remote office from the corporate office through a WAN link without the need to deploy a controller in each office. H-REAPs can switch client data traffic locally and perform client authentication locally when the connection to the controller is lost. When connected to the controller, H-REAPs can also tunnel traffic back to the controller.
Monitor mode—Monitor mode is a feature designed to allow specified LWAPP-enabled APs to exclude themselves from handling data traffic between clients and the infrastructure. They instead act as dedicated sensors for location based services (LBS), rogue access point detection, and intrusion detection (IDS). When APs are in Monitor mode they cannot serve clients and continuously cycle through all configured channels listening to each channel for approximately 60 ms.
Rogue detector mode—LAPs that operate in Rogue Detector mode monitor the rogue APs. They do not transmit or contain rogue APs. The idea is that the rogue detector should be able to see all the VLANs in the network since rogue APs can be connected to any of the VLANs in the network (thus we connect it to a trunk port). The switch sends all the rogue AP/Client MAC address lists to the Rogue Detector (RD). The RD then forwards those up to the WLC in order to compare with the MACs of clients that the WLC APs have heard over the air. If MACs match, then the WLC knows the rogue AP to which those clients are connected is on the wired network.
Sniffer mode—An LWAPP that operates in Sniffer mode functions as a sniffer and captures and forwards all the packets on a particular channel to a remote machine that runs Airopeek. These packets contain information on timestamp, signal strength, packet size and so on. The Sniffer feature can be enabled only if you run Airopeek, which is a third-party network analyzer software that supports decoding of data packets.
Bridge Mode— Bridge mode is used when the access points are setup in a mesh environment and used to bridge between each other.

LWAPP Discovery of WLC

WLAN Authentication

Authentication Options

After the wireless client associates to the AP, the AP blocks the client from gaining access to anything on the network, except the authentication server, until the client has logged in and authenticated. The client (the supplicant) supplies network login credentials such as a user ID and password to the authenticator (the WLC). The supplicant, the authenticator, and the authentication server participate in the authentication process. If the authentication process succeeds, the authenticator allows network access to the supplicant through the appropriate port. The WLC tells the lightweight AP which dynamic interface (as described in the “WLC Interfaces” section later in this chapter) and policies to use for the client.

After mutual authentication has been successfully completed, the client and RADIUS server each derive the same encryption key, which is used to encrypt all data exchanged between the client and the WLC. Using a secure channel on the wired LAN, the RADIUS server sends the key to WLC, which stores and uses it when communicating with the client. The result is per-user, per-session encryption keys, with the length of a session determined by a policy defined on the RADIUS server. When a session expires or the client roams from one AP to another, a reauthentication occurs and generates a new session key. The reauthentication is transparent to the user.

Several 802.1X authentication types exist, each providing a different approach to authentication while relying on the same framework and EAP for communication between a client and the authentication server. Cisco UWN EAP support includes the following types:

EAP-Transport Layer Security (EAP-TLS): EAP-TLS is an Internet Engineering Task Force (IETF) open standard that is well supported among wireless vendors but rarely deployed. It uses PKI to secure communications to the RADIUS server using TLS and digital certificates; it requires certificates on both the server and client.
EAP-Tunneled TLS (EAP-TTLS): EAP-TTLS was codeveloped by Funk Software and Certicom. It is widely supported across platforms and offers very good security. EAP-TTLS uses PKI certificates only on the RADIUS authentication server. The authentication of the client is done with a username and password.
Protected Extensible Authentication Protocol (PEAP): PEAP was a joint proposal by Cisco Systems, Microsoft, and RSA Security as an open standard. Authentication of the client is done using PEAP-Generic Token Card (GTC) or PEAP-Microsoft Challenge Handshake Authentication Protocol version 2 (MSCHAPv2). PEAP-MSCHAPv2 is the most common version and is widely available in products and widely deployed. It is similar in design to EAP-TTLS but requires a PKI certificate only on the server to create a secure TLS tunnel to protect user authentication. PEAP-GTC allows more generic authentication to a number of databases, such as Novell Directory Services.
Cisco Lightweight Extensible Authentication Protocol (LEAP): LEAP is an early proprietary EAP method and is supported in the CCX program. It is vulnerable to dictionary attack.
Cisco EAP-Flexible Authentication via Secure Tunneling (EAP-FAST): EAP-FAST is a proposal by Cisco Systems to fix the weaknesses of LEAP; it is supported in the CCX program. EAP-FAST uses a protected access credential (PAC) and optionally uses server certificates. EAP-FAST has three phases. Phase 0 is an optional phase where the PAC can be provisioned manually or dynamically. In Phase 1, the client and the AAA server use the PAC to establish TLS tunnel. In Phase 2, the client sends user information across the tunnel.

Each EAP type has advantages and disadvantages. Trade-offs exist between the security provided, manageability, operating systems supported, client devices supported, client software and authentication messaging overhead, certificate requirements, user ease of use, and WLAN infrastructure device support. When selecting an EAP type to use, considerations include the type of security mechanism used for the security credentials, the user authentication database, the client operating systems in use, the available client supplicants, the type of user login needed, and whether RADIUS or AAA servers are used.

WLAN Controller Components

WLAN - Identified by a unique SSID and assigned to an interface

Interface - A logical connection that maps to a VLAN in the wired network

Port - A physical connection to the wired LAN

WLC Interface Types

Roaming and Mobility Groups

WLAN Design

Controller Redundancy Design: Deterministic vs. Dynamic

N+1 WLC Redundancy

N+N WLCRedundancy

N+N+1 WLC Redundancy

Radio Management and Radio Groups

RF Groups

RF Site Survey

Using EoIP Tunnels for Guest Services

Wireless Mesh for Outdoor Wireless

Outdoor wireless networks deliver real-time access to people, applications, and network resources, transforming down-time into productive time.

Whether you're a mobile worker e-mailing a customer from the airport, a student at a coffee shop downloading a homework assignment on your PDA, or a police officer viewing a video surveillance camera from a patrol car, mobility is letting you stay connected, anytime, anywhere.

Cisco outdoor wireless solutions come as small as a single hot spot for a home office and can grow to high-speed wireless connectivity across entire cities and counties.

Wireless Mesh Access Points

The Cisco wireless mesh networking solution lets you deploy cost-effective, scalable outdoor wireless LANs. It doesn't matter whether you're an individual or a government agency IT manager. There's a solution for you.

Wireless Bridges

Wireless bridges offer high-speed, building-to-building or campus connectivity for line-of-sight applications. Wi-Fi bridging solutions offer an affordable alternative to leased-line services and operate by sharing LAN/Internet access between two or more sites.

Mobile Networks

The Cisco Mobile Network forms a wireless network in and around a vehicle. This allows users to roam across different networks in a metropolitan area while maintaining a secure broadband connection in motion. It's specifically designed for the secure delivery of data for public safety and transportation applications.

MeshDesign Recommendations

Campus Design Considerations

Branch Design Considerations

Local MAC

REAP

Hybrid REAP

Branch Office Controller Options

FAQ

Monday, January 2, 2012

CCDA 640-864 Official Cert Guide - Chapter 4 Summary

Enterprise DC Architectures

From DC 1.0 to DC 3.0

Virtualization

· Virtual local-area network (VLAN), virtual storage-area network (VSAN), and virtual device contexts (VDC) help to segment the LAN, SAN, and network devices instances.

· Cisco Nexus 1000V virtual switch for VMware ESX and ESXi help to deliver visibility and policy control for virtual machines (VM).

· Flexible networking options with support for all server form factors and vendors, including support for blade servers from Cisco, Dell, IBM, and HP with integrated Ethernet and Fibre Channel switches.

Unified Fabric

· Fibre Channel over Ethernet (FCoE) and Internet Small Computer Systems Interface (iSCSI) are two methods for implementing unified fabric in the data center over 10 Gigabit Ethernet networks.

· FCoE is supported on VMware ESX/ESXi vSphere 4.0 and later.

· The Cisco Catalyst, Cisco Nexus, and Cisco MDS family of switches all support iSCSI. The Cisco Nexus 5000 support unified fabric lossless operation, which improves the performance of iSCSI traffic using 10 Gigabit Ethernet.

· The Cisco Nexus family of switches was designed to support unified fabric. Currently, the Cisco Nexus 5000 and the Nexus 4000 supports data center bridging (DCB) and FCoE. However, there are future plans for the Cisco Nexus 7000 series and the Cisco MDS family of switches to support FCoE, as well.

· Converged network adapters (CNA) run at 10GE and support FCoE. CNAs are available from both Emulex and QLogic. Additionally, a software stack is available for certain 10GE network interfaces from Intel.

Unified Computing

· Cisco Unified Computing System (UCS) is an innovative next-generation data center platform that converges computing, network, storage, and virtualization together into one system.

· Integrates lossless 10GE unified network fabric with x86 architecture-based servers.

· Allows for Cisco Virtual Interface Card to virtualize your network interfaces on your server.

· Offers Cisco VN-Link virtualization.

· Supports Extended Memory Technology patented by Cisco.

· Increases productivity with just-in-time provisioning using service profiles.

Data Center 3.0 Components

Summary of Data Center Facility Considerations

Data Center Space

Data Center Power - The power in the data center facility is used to power cooling devices, servers, storage equipment, the network, and some lighting equipment. Cooling down the data center requires the most power, next to servers and storage.

Data Center Cooling

Note: 1 watt = 3.41214 British thermal units (BTU). Many manufacturers publish kW, kilovolt ampere (kWA), and BTU in their equipment specifications. Sometimes dividing the BTU value by 3.413 does not equal the published wattage. Use the manufacturer information if available, if not this can be a helpful conversion formula to use.

Data Center Heat

Data Center Cabling - Keep it straight and ordered !!! :)

Enterprise DC Infrastructure

Enterprise Data Center Infrastructure Overview:

Defining the DC Access Layer

Defining the DC Aggregation Layer

Defining the DC Core Layer

Virtualization Overview

Virtualization Key Drivers:

Network virtualization:

VLAN: Virtual local-area network

VSAN: Virtual storage-area network

VRF: Virtual routing and forwarding

VPN: Virtual private network

vPC: Virtual Port Channel

Device virtualization:

Server virtualization: Virtual machines (VM)

Cisco Application Control Engine (ACE) context

Virtual Switching System (VSS)

Cisco Adaptive Security Appliance (ASA) firewall context

Virtual device contexts (VDC)

Virtualization Technologies

VSS

VRF

vPC

Device Contexts

Cisco Nexus 7000 series switches (VDC)

Cisco Adaptive Security Appliance (ASA) firewall

Cisco Catalyst 6500 Firewall Services Module (FWSM)

Cisco Application Control Engine Appliance

Cisco Catalyst 6500 Application Control Engine Module

Cisco Intrusion Prevention System (IPS)

Server Virtualization

VMware ESX Server

Citrix XenServer

Microsoft Hyper-V

Network Virtualization Design Considerations

Access Control - Ensures users and devices are recognized, classified, and authorized for entry to their assigned network segments

Path Isolation - Provides independent logical traffic paths over shared network.(VRF)

Service Edge - Ensures the right services are accessible the intended users, groups, or devices (FWSM)

Additional Info:

Data Center Services System

Data Center Networking Best Practices

Monday, December 26, 2011

Carrier Ethernet

Overview:

The Metro Ethernet Forum (MEF) is an industry organization dedicated to furthering the deployment of carrier Ethernet services. Ethernet began life as a LAN then expanded to the MAN and is now truly a WAN with many carriers offering services that span the globe. The MEF specifies the Ethernet user network interface (E-UNI) and the network services (E-Line, E-LAN and E-Tree). The E-UNI is the service demarc and is defined to be a standard Ethernet interface. The access technology and core network technology is not defined by the MEF, allowing the carrier to select the right technology for its network. Service attributes are defined for each service, so carrier offerings can be compared even though different technology may be used to implement the service.

Carrier Ethernet is a marketing term for extensions to Ethernet to enable telecommunications network providers ("common carriers" in US industry jargon) to provide Ethernet services to customers and to utilize Ethernet technology in their networks.

Network Implementations:

Access	Aggregation	Core
Ethernet LAN	Metro Ethernet	Carrier Ethernet

Carrier Ethernet is equipment that leverages the heritage of Ethernet while extending it with features that make Ethernet useful in mission-critical transport networks. These extensions, predominantly covered in the IEEE 802.1a set of standards, include enhanced scalability and OAM capabilities. Carrier Ethernet supports features needed in a transport network such as connectivity verification, rapid recovery, and performance measurement.

The key features and benefits of Carrier Ethernet include:

Well Known Technology – Carrier Ethernet leverages and extends all the features, including low cost, of traditional Ethernet
LAN Services in the WAN – emulates popular LAN and point-to-point Ethernet services
Scalability – scales to 1000s of endpoints
Convergence – a common platform for IP-based voice, data and video services

There’s no doubt that Ethernet is the service interface of the future. The native protocol for all new devices is moving toward Ethernet – voice, video and data. Until now, the only challenge in deploying a pure Ethernet infrastructure was quality of service.

Carrier Ethernet has finally met that challenge. It offers a great user experience for triple play services, promises new service revenues with user bandwidth profiles and provides carrier class reliability.

On top of that Carrier Ethernet is simple and inexpensive, making it a perfect platform for delivering the triple play.

Networks must support carrier class QoS

Carrier Ethernet has the ability to prioritize data, voice and video to provide a superior user experience, flexible mapping service queues
Carrier Ethernet can segregate users and provide bandwidth profiles, multistage hierarchical scheduling/shaping
Carrier Ethernet provides 50 msec resiliency

Network must provide circuit-based visibility

Carrier Ethernet allows per-circuit performance monitoring
Carrier Ethernet provides Service Based OAM

Networks must be flexible

Carrier Ethernet offers MPLS
Carrier Ethernet allows topology independent
Carrier Ethernet allows technology and protocol independent

Services:

E-Line – Ethernet Line. A service connecting two customer Ethernet ports over a WAN.

E-LAN – Ethernet LAN. A multipoint service connecting a set of customer endpoints, giving the appearance to the customer of a bridged Ethernet network connecting the sites.