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Posts with #cisco routers tag

What are Ethernet and Ethernet Switches?

February 14 2012 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Routers

Ethernet is the most common LAN (Local Area Network) technology in use today. Xerox developed Ethernet in the 1970s, and became popular after Digital Equipment Corporation and Intel joined Xerox in developing the Ethernet standard in 1980. Ethernet was officially accepted as IEEE standard 802.3 in 1985. The original Xerox Ethernet operated at 3Mbps. Ethernet networks up to 10Gbps now exist.

Erternet Switches

 

Ethernet Cabling

The first Ethernet standard, 10Base-5, ran over thick coaxial cable. A later standard, Ethernet 10Base-2, ran over a much thinner coaxial cable. These two versions of Ethernet were colloquially known as thicknet and thinnet.

 

Modern Ethernet standards run on UTP (Unshielded Twisted Pair) or fiber-optic cabling.

Ethernet Standard

Cable Specification

10Base-T

Category 3 UTP

100Base-TX

Category 5 UTP

1000Base-T

Cat 5e UTP

1000Base-SX

Optical Fiber

 

Ethernet Topologies

Ethernet 10Base-5 and 10Base-2 used a bus topology. Bus topologies were difficult to maintain and troubleshoot.

Modern Ethernet networks use a star topology with an Ethernet hub, switch, or router at the center of the star.

It is still possible to create a two-node Ethernet network in a bus topology using a null-Ethernet cable between the two devices.

 

Ethernet DTE and DCE

All nodes on an Ethernet network are either DTE (Data Terminal Equipment) or DCE (Data Communications Equipment).

Ethernet DTE are devices such as computers and printers that are trying to communicate on the Ethernet network.

Ethernet DCE are devices such as switches and routers that are trying to help other devices communicate on the Ethernet network.

 

Ethernet CSMA/CD

Like any network, Ethernet must have an algorithm for determining when each network node is allowed to communicate.

In Ethernet, this algorithm is known as CSMA/CD (Carrier Sense Multiple Access / Collision Detection).

CSMA/CD has proven to be a very capable, if highly anarchistic, algorithm.

 

Ethernet Switch

A switch is something that is used to turn various electronic devices on or off. However, in computer networking, a switch is used to connect multiple computers with each other. Since it is an external device it becomes part of the hardware peripherals used in the operation of a computer system. This connection is done within an existing Local Area network (LAN) only and is identical to an Ethernet hub in terms of appearance except with more intelligence. These switches not only receive data packets, but also have the ability to inspect them before passing them on to the next computer. That is, they can figure out the source, the contents of the data, and identify the destination as well. As a result of this uniqueness, it sends the data to the relevant connected system only, thereby using less bandwidth at high performance rates.

 

More Ethernet and Ethernet Switches Tips: Ethernet & Ethernet Switch

 

 

Ethernet Switches and Crossover Cables

The wires in a crossover cable are “crossed” so that output signals from the transmitting device are properly sent as input signals to the receiving end. An Ethernet switch can be thought of as a device that makes temporary crossover cable connections between computers that want to communicate. Just like crossover cables, switches do not suffer from collision problems.

 

However, it should be noted that the actual cables used are “straight through.” The crossover function is done inside of the switch.

 

Since separate wires are used for sending and receiving, switches support operation in full duplex mode. This mode allows devices to send and receive data at the same time.

 

Advantages over Hubs

As mentioned above, switches are intelligent devices that can read the data packets that pass through them. By storing each host’s MAC address and its corresponding port in a table, switches ensure that bandwidth is not wasted by intelligently directing traffic. Hubs are dumb devices that do not do any processing.

 

Unlike hubs, switches are modern, fast, and support full duplex operation. In short, they are much better. 

 

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General Info Helps You Understand Networking Fundamentals

February 8 2012 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Routers

Computer Networking is any set of computers or devices connected to each other so as to communicate or exchange data. For a network to function, the devices must be interconnected. Network connections can be wired or wireless.

 

All networks are connected to enable communication with different kinds of media (wire or cables), which includes, twisted-pair copper wire cable, coaxial cable, optical fiber, power lines and various wireless technologies.

 

The devices can be separated by a few meters (e.g. via Bluetooth) or nearly unlimited distances (e.g. via the interconnections of the Internet).

 

In Wired networks, the medium is either copper, which carries electrical signals, or optical fibre, which carries light signals.

 

In Wireless networks, the medium of connection or mode of transmitting is radio waves, space, or microwaves. Wireless networks may include the home wireless connection between a wireless router and a computer with a wireless network card, the global wireless connection between two ground stations, or the communication between devices on earth and satellites then received via the internet.

 

Examples of Networks are:

Local Area Network. (LAN)

A LAN (Local Area Network) is an individual network that covers a single geographical area, providing networking services and applications to people within a common managerial structure, such as a single business, campus or region.

 

A LAN is usually administered by a single organization. The administrative control that governs the security and access control policies are enforced on the network level. LANs and WANs are very useful to individual organizations. They connect the users within the organization. They allow many forms of communication including exchange e-mails, corporate training, and other resource sharing. 

 

Wide Area Network. (WAN)

WAN that is usually a larger network that covers a large geographic area. An example of this is an organization that uses a WAN to interconnect their offices in different countries. The largest and best example of a WAN is the Internet, which is a network of networks, composed of many smaller networks. The Internet is considered the largest network in the world.

 

Main Features of WANs:

  • WANs generally connect devices that are separated by a broader geographical area than can be served by a LAN.
  • WANs use the services of carriers, such as telephone companies, cable companies, satellite systems, and network providers.
  • WANs use serial connections of various types to provide access to bandwidth over large geographic areas.

 

Wireless LANs and WANs. (WLAN & WWAN)

WLAN & WWAN are the wireless equivalent of the LAN and WAN. But there are no wires between end devices and servers. Communication or data is transferred over sets of radio transceivers or waves. These types of networks are beneficial when it is too costly or inconvenient to run the necessary cables.. The media access protocols for LANs come from the IEEE.

 

Components of the Network
The path that a message takes from source to destination can be as simple as a single cable connecting one computer to another or as complex as a network that literally spans the globe. This network infrastructure is the platform that supports our human network. It provides the stable and reliable channel over which our communications can occur.

 

Devices and Media

Devices and media are the physical elements or hardware of the network. Hardware is often the visible components of the network platform such as a laptop, a PC, a Switch, Router or the cabling used to connect the devices. Occasionally, some components may not be so visible. In the case of wireless media, messages are transmitted through the air using invisible radio frequency or infrared waves.

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Focus on CCNA Exam, Two Important Topics

February 6 2012 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Routers

The CCNA might be intimidating at first, especially since Cisco has expanded the scope of the exam to include more advanced topics such as Open Shortest Path First (OSPF) routing which is traditionally only tested in the CCNP and other professional level exams.  Time management during the exam is the number 1 most important thing to do well.  This means scoring easy points when possible and to spend more time focusing on those questions which are harder. 

 

To maximize the chance of passing the CCNA exam, here are 2 most important (in my opinion) topics to focus on for the CCNA:

Subnetting

Learning how to subnet effectively is the most important thing for the CCNA.  It’s also important to be able to size subnets quickly in the real world for network planning and troubleshooting purposes.  Because the CCNA (and any other certification exam) is a test of your time management skills during the test, and subnetting can be done quickly (and 100% correctly) if you know the right technique, it’s a quick way to score easy points.

 

Common subnetting questions include calculating the number of hosts in a subnet, finding if 2 hosts are in the same subnet, and deciding on the correct hostmasks, among others.  Being able so solve such questions quickly means that you will be able to free up valuable exam time to solve other questions.  Answering such calculation questions are a matter of simple calculations and it’s hard to get them wrong once you know how.  Again, the key is speed and you will definitely want to get subnetting questions out of the way as quickly as possible. 

 

Simulation Questions

Simulation questions (commonly now referred to as “sims”) are designed by Cisco to test the practical aspect of Cisco networking.  A simulation of a real Cisco IOS command-line is provided to you and you are expected to troubleshoot or otherwise configure the network to the required specification.

 

These questions are more time consuming but very important.  Only Cisco knows for sure how these are actually scored but it’s very likely that you won’t get enough points to pass the CCNA if you cannot answer all the simulation questions to a satisfactory level.  The CCNA passing score gets higher all the time, which makes scoring high on the simulation questions a priority.

 

One good thing about using simulation questions is that you’ll be able to gauge roughly how well you’ve done by showing the running configuration and running other tests such as ping and using other show commands.  A good way to prepare for the exam is to use a Cisco router simulator.

 

More guide and tips about CCNA: Best Path for Getting Your CCNA Certification

 


 

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Cisco 1941W Enables Borderless Networks at the Branch

February 2 2012 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Routers

The Cisco 1941W Integrated Services Router (ISR) delivers highly secure data, mobility, and application services.

Cisco-1941w.jpg

 

Cisco 1941W is a true solution in terms of delivering pure security for your transmitted data, application as well as for security of your mobility over wired or especially designed wireless network whether it is at home or the network is prepared for your small office. This ISR router of 1900 series has Ethernet ports (2 same ports) of 10Mbps, 100Mbps and 1000Mbps speed.

 

Cisco 1941W router also comes with (e)HWIC’s 2 slots that are able of supporting or hosting 1 single wide Enhanced High-Speed WAN Interface Card as well as of 2 single wide or you may say 1 double wide card. Wireless Access Point is also supported by 1941W router through built-in 802.11n technology. Power distribution is also fully integrated to this router just to support Cisco Enhanced Power of Ethernet as well as 802.3a PoE.

 

VPN encryption through accelerated hardware (embedded hardware rather) is also supported by Cisco 1941W Integrated Services Router and this 1900 series’ router has identity management support as well which is normally done through public key infrastructure’s usage as well as through the usage of authorization, authentication and accounting method i.e. “AAA”.

 

Integrated threat control functionality of Cisco 1941W is as same as it is seen in 1941 router of 1900 series who provides it (threat control functionality) through IOS IPS of Cisco, IOS Zone-Based Firewall of Cisco, IOS Content Filtering of Cisco and finally IOS Firewall of Cisco. Mobility in this router is supported through 5 GHz mode of 802.11a/n as well as through 2.4 GHz mode of 801.11/b/g/n of radio signals.

 

Quick View: Key features of Cisco 1941W include:

  • 2 integrated 10/100/1000 Ethernet ports
  • 2 Enhanced High-Speed WAN Interface Card slots that can host 2 single wide or 1 double wide and 1 single wide (e)HWIC
  • 1 integrated 802.11n Wireless Access Point
  • Fully integrated power distribution to modules supporting 802.3af Power over Ethernet (PoE) and Cisco Enhanced PoE
  • Security
    • Embedded hardware-accelerated encryption for VPN
    • Secure collaborative communications with Group Encrypted Transport VPN, Dynamic Multipoint VPN, or Enhanced Easy VPN
    • Integrated threat control using Cisco IOS Firewall, Cisco IOS Zone-Based Firewall, Cisco IOS IPS, and Cisco IOS Content Filtering
    • Identity management that uses authentication, authorization and accounting (AAA), and public key infrastructure
  • Mobility
    • The integrated access point offers IEEE 802.11n draft 2.0 support for mobile access to high-bandwidth data, voice, and video
    • The access point supports both unified and autonomous deployments and is supported by a wireless LAN controller and the Cisco Wireless Controller System
    • IEEE 802.11n technology delivers outstanding reliability and up to nine times the throughput of current IEEE 802.11 a/b/g networks
    • Dual radios for 2.4-Ghz 802.11b/g/n. and 5-GHz 802.11a/n modes
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From Technical User: Open Port 873 on Cisco 1921

February 1 2012 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Routers

Caskibum’s Problem of Opening Port 873 on Cisco 1921

I have a Cisco 1921 and need to open ports 22 (SSH) and 873 (rsync) to run an rsync server on my network and the rest of the network needs standard "internet" access.  I am fairly new to Cisco ACLs and so I expect I'm doing something stupid but not sure what. When I add the ip access-group XXX in / out to the gig0/0 interface, I lose all www functionality at that point. Here is my current (working) config with the ACLs listed (101 and 102) but not enabled on the gig0/0 interface. I have tried the "established" statement at the start and end of the 101 list, no difference. Thanks for any help!
Router#show run
Building configuration...
Current configuration : 2675 bytes
!
! Last configuration change at 15:03:45 UTC Sun Dec 18 2011 by
!
version 15.0
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$Sx2k$wiHT8Af585IB/HsSZkwC61
enable password 7 073E325F19190C1D47
!
no aaa new-model
!
no ipv6 cef
ip source-route
ip cef
!
!
no ip dhcp use vrf connected
ip dhcp excluded-address 10.1.0.1 10.1.0.149
ip dhcp excluded-address 10.1.0.200 10.1.0.254
!
ip dhcp pool net_dhcp
   import all
   network 10.1.0.0 255.255.255.0
   default-router 10.1.0.1
   lease 0 0 5
!
!
no ip domain lookup
ip domain name treeskier.ca
multilink bundle-name authenticated
!
!
!
license udi pid CISCO1921/K9 sn FGL15092836
!
!
username blah password blahblah
!
!         
ip ssh version 2
!
!
!
!
interface GigabitEthernet0/0
 description Internet
 ip dhcp client update dns
 ip address dhcp
 ip nat outside
! ip access-group 101 in
! ip access-group 102 out
! once I turn these on, it all dies.
 ip virtual-reassembly
 duplex auto
 speed auto
 no cdp enable
 no mop enabled
!
interface GigabitEthernet0/1
 description internal
 ip address 10.1.0.1 255.255.255.0
 ip nat inside
 ip virtual-reassembly
 duplex auto
 speed auto
 no mop enabled
!
ip forward-protocol nd
!
ip http server
ip http authentication local
no ip http secure-server
!
ip nat inside source list 1 interface GigabitEthernet0/0 overload
ip nat inside source static tcp 10.1.0.102 873 interface GigabitEthernet0/0 873
ip nat inside source static tcp 10.1.0.102 22 interface GigabitEthernet0/0 22
!
access-list 1 permit 10.1.0.0 0.0.0.255
access-list 1 remark INSIDE_IF=gig0/1
access-list 101 permit tcp any 10.1.0.0 0.0.0.255 established
access-list 101 permit tcp any host 10.1.0.102 eq 22
access-list 101 permit udp any host 10.1.0.102 eq 22
access-list 101 permit tcp any host 10.1.0.102 eq 873
access-list 101 permit udp any host 10.1.0.102 eq 873
access-list 102 permit tcp 10.1.0.0 0.0.0.255 any
access-list 102 permit udp 10.1.0.0 0.0.0.255 any
dialer-list 1 protocol ip permit
!
!         
!
control-plane
!
banner login ^C**************************^C
!
CON and VTY setup
!
scheduler allocate 20000 1000
end
A bit of really basic troubleshooting:
Router#sh access-lists
Standard IP access list 1
    10 permit 10.1.0.0, wildcard bits 0.0.0.255 (9854736 matches)
Extended IP access list 101
    10 permit tcp any 10.1.0.0 0.0.0.255 established
    20 permit tcp any host 10.1.0.102 eq 22
    30 permit udp any host 10.1.0.102 eq 22
    40 permit tcp any host 10.1.0.102 eq 873
    50 permit udp any host 10.1.0.102 eq 873
Extended IP access list 102
    10 permit tcp 10.1.0.0 0.0.0.255 any
    20 permit udp 10.1.0.0 0.0.0.255 any

Router#sh ip nat translations
Pro Inside global         Inside local          Outside local         Outside global
tcp 192.168.0.10:22       10.1.0.102:22         ---                   ---
tcp 192.168.0.10:873      10.1.0.102:873        ---                   ---
tcp 192.168.0.10:54693    10.1.0.150:54693      208.88.180.96:80      208.88.180.96:80
tcp 192.168.0.10:54695    10.1.0.150:54695      208.88.180.96:80      208.88.180.96:80
tcp 192.168.0.10:54696    10.1.0.150:54696      208.88.180.106:5222   208.88.180.106:5222
tcp 192.168.0.10:54699    10.1.0.150:54699      208.88.181.46:1935    208.88.181.46:1935
tcp 192.168.0.10:54700    10.1.0.150:54700      208.88.180.96:80      208.88.180.96:80
... (more dynamic NAT at work)

 

Reply to Caskibum from Imbadatthis

You aren't allowing DNS in .

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_configuration_example09186a0080100548.shtml#allowdns 

also a nice to know:

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_configuration_example09186a0080100548.shtml#debugtraffic

 

After Imbadatthis ‘s Reply

Caskibum solved problems like this:

Thanks for the response. 

I actually sorted it out last night, my "new" cable modem was blocking the port forwarding before it got to the router.  So once I set up the NAT port forwarding on the cable modem, all good now.

Just FYI, I've ended up with a much simpler ACL and NAT setup:

!

ip nat inside source list nat-acl interface GigabitEthernet0/0 overload

ip nat inside source static tcp 10.1.0.101 873 interface GigabitEthernet0/0 873

ip nat inside source static tcp 10.1.0.101 22 interface GigabitEthernet0/0 22

!

ip access-list extended nat-acl

 permit ip 10.1.0.0 0.0.0.255 any

 permit tcp any host 10.1.0.101 eq 22

 permit tcp any host 10.1.0.101 eq 873

!

!

Best Regards

 

More discussion between these two buddies to talk about Opening port 873 on Cisco 1921

Imbadatthis: So you've removed both acl 101 and 102?

 

Caskibum:

Yep, the only ACL is the named extended list, which is applied on the outside interface in the overload command. I could have probably left them in place, I found this "alternate" solution with the named extended list as it is now, and then after that didn't work either I went to the cable modem and found the source of the problem.  I expect the 101 / 102 acls are fine if I were to use them. Then the two static NAT commands to handle the traffic direction. Seems to be working. I'm no security expert so if this leaves some gaping hole please let me know and I'll rework it.

Cheers!

 

 

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Cisco 7600 Series Router, Ideal for Enterprise WAN Aggregation

January 19 2012 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Routers

Ideal for Enterprise WAN aggregation or service provider environments, Cisco 7600 series is the industry's first carrier-class edge router to offer integrated, high-density Ethernet switching, carrier-class IP/MPLS routing, and 10-Gbps interfaces, benefiting enterprises and helping enable service providers to deliver both consumer and business services over a single converged Carrier Ethernet network.

Cisco-7600.jpg

 

The Cisco 7600 Internet Router delivers optical wide- and metropolitan-area network (WAN and MAN) services with high-touch IP services at the network edge. Now, service providers (SPs) and enterprises can "service enable" their networks at optical speeds, providing competitive advantage and service differentiation to the SP and high-speed connectivity and link usage efficiency to the enterprise.

 

 

Cisco 7600 Router’s Key Features

High performance, with up to 720 Gbps in a single chassis, or 40 Gbps capacity per slot

A choice of form factors purpose-built for high availability

Cisco I-Flex design: A portfolio of shared port adapters (SPAs) and SPA interface processors (SIPs) that controls voice, video, and data experiences

Scalable and extensible suite of hardware and software capabilities to enable intelligent Carrier Ethernet services

Integrated Video Call Admission Control with innovative visual quality of experience for both broadcast and video on demand (VoD)

Intelligent Services Gateway, providing scalable subscriber and application awareness with multidimensional identity capabilities and policy controls

Integrated Session Border Control with quality of experience in both Session Initiated Protocol (SIP) and non-SIP applications

 

What Cisco 7600 series Supports

Supports Services modules such as IPsec, firewall, SSL VPN

Intrusion Prevention System (IPS) Modularity

Chassis supports up to 4-, 6-, 9-, and 13-slot chassis for redundant supervisors and line cards

Supervisor engines supporting up to 15 Mpps with broad range of edge services

Support for Shared Port Adapter (SPA) and SPA Interface Processors (SIP), which offers intelligent services.

Supports up to 12 SPA bays

Support for the Enhanced FlexWAN module, which offers Port Adapter investment protection

 

Cisco 7600 Router’s Price & Availability

Cisco 7600 series ranges from US$5000 to US$20000, not all the types are required by enterprise head offices. There are some 7600 series items such as Cisco 7606, Cisco 7609, Cisco 7609-S, Cisco 7606-S; these are popular among large enterprises. Prices of Cisco 7606 and Cisco 7609 are available here:

CISCO7606: List price: US$6,000.00 / Wholesale Price: US$2,940.00

CISCO7609: List price: US$10,500.00 / Wholesale Price: US$5,145.00

CISCO7606-S: List price: US$6,000.00 / Wholesale Price: US$2,940.00

CISCO7609-S: List price:  US$10,500.00 / Wholesale Price: US$5,145.00

 

If you want to know more pricing and purchasing information of Cisco router and other Cisco IT equipments, you can visit Cisco router at Router-switch.com…

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How to Use the Cisco Aironet 1242?

January 18 2012 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Routers

The Cisco Aironet 1242 is a wireless access point created by Cisco. The main difference between this device and most other Cisco products is that the Aironet1242 provides support for mesh wireless networks. Mesh networks extend wireless network range by relaying information from an access point to other access points, instead of requiring that each access point have its own wired backbone connection.

Cisco Aironet 1240 Series

 

Ethernet cable you first need

 

Instructions to Use the Cisco Aironet 1242

1. Power on the 1242.

 

2. Connect your network switch to the "Ethernet" port on the back of the 1242, using the Ethernet cable.

 

3. Log in to any computer connected to the same network switch. Click "Start," then "Programs." Select "Accessories" and "Telnet." A new Telnet window will come up.

 

4. Click "Connect," then "Remote system" on the Telnet window. Type the Internet Protocol (IP) of the 1242; the default is 192.168.1.1. Click "Connect."

 

5. Type the following commands into the Telnet session to configure an IP address for the 1242:

configure terminal

interface bvi1

IP address 192.168.40.9 255.255.0.0

Replace "192.168.40.9" and "255.255.0.0" with the IP address and network mask, respectively, assigned to the 1242 by your network's administrator. Press "Enter" after each command.

 

6. Launch a Web browser on the computer and navigate to the Web address "http://192.168.40.9" (replace the IP address with the one assigned in Step 5). Type "Cisco" as the user name and "Cisco" as the password, then press "Enter." The 1242's configuration utility will come up on the browser.

 

7. Click "Express Set-up." Type a host name of your choice if the default value is already being used by another 1242 on the same network. Select "Enable" for the "Aironet Extensions" for both the 802.11a and the 802.11g radios. Click "Apply." At that point, the 1242 will provide a wireless network ready for client computers to join.



More Related: Password Recovery on Cisco 1242 Access Point

 



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CCNA Certification: IPv6 Features

January 16 2012 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Routers

Main Feature of IPv6 

IPv6 address a lot concerns and issues that are faced today in using IPv4. Cisco CCNA Certification requires that a candidate must have a general overview of IPv6 and what new features it brings into the world of networking. Here we will go through some of the features of Internet Protocol Version 6 (IPv6).

 

The main feature of IPv6 are described in the sections below

Larger Address Space 

IPv6 addresses are 128-bits long which gives us a theoretical address space of 3.4 x 1038 addresses, like IPv4 some address space is reserved for special purpose but still there is a huge number of public routable addresses.

 

Aggregation 

A larger address space allows for large address allocations to ISPs and Organization. This allows them to use a single prefix for the entire network making summarization easy and flexible which turn promotes efficient and scalable routing.

 

New Improved Header Format

Optional and non-essential fields are removed from the IPv6 Header and are moved the Extension Header that is placed after the IPv6 Header. Fewer fields of fixed lengths mean Header overhead is minimized and processing performance is improved.  Another significant enhancement is that all routers in a path do need to do checksum recalculation for an IPv6 Packet instead error detection is handled by data-link layer technologies checksums of the end-to-end connection at transport layer. 

Allocation

IPv6 addresses are composed of two parts, 64-bit Network Prefix and 64-bit host part. The IPv6 address allocation follows a generally acceptable assignment policy as shown in figure 1. This allows for an efficient, hierarchical, and summarizable routing infrastructure.

 

Easy Address Assignment Methods

IPv6 has three assignment methods

  • Static
  • DHCPv6 (Stateful)
  • Autoconfiguration (Stateless)

An IPv6 host can configure a link-local address for each interface automatically. By using ICMPv6 router discovery messages, a host can also determine the addresses of routers, additional addresses, and other configuration parameters.

 

Built-in Security

IPSec is built into IPv6 unlike IPv4 in which it is optional. IPSec requirement is mandatory in IPv6 Protocol Suite Implementation. IPv6 networks have potentially more end-to-end security because of IPSec availability on all nodes.

 

Extensibility

New futures for IPv6 can be added through the use of Extension Headers. At present there are various Extension Headers specified for QoS, Security, Mobility and Routing purposes.

 

Mobility

Mobility is built in to IPv6 which allows any node to use Mobile IP. Mobility is achieved using Mobility Extension Headers.

 

Better Quality of Service Support

IPv6 Header includes a new field called Flow Label that allows routers to identify and provide special handling for packets that belong to a particular flow. This field allows for easier identification of traffic without doing any tricks even when the packet payload is encrypted with IPSec.

 

Neighbor Discovery Protocol

Neighbor Discovery Protocol uses ICMPv6 messages to perform various functions such as

  • Stateless Auto-configuration
  • Router Discovery
  • Prefix Discovery
  • Address Resolution
  • Neighbor Unreachability Detection
  • Link MTU Discovery
  • Duplicate Address Detection
  • Next Hop Determination

 

Transition

The transition options supported by IPv6 to transition from IPv4 are another key feature of the protocol. Many Transitions mechanism are available for different scenarios. They are mentioned below

  • Dual-Stack
  • Tunneling IPv6 over IPv4 networks
  • Protocol Translation

 

Within each option are various different techniques to support transition. A few tunneling mechanism are mentioned below

  • Static GRE Tunnels
  • 6to4 Tunnels
  • ISATAP
  • Automatic IPv4-Compatible IPv6 Tunnels

 

These rich features of IPv6 enable easy deployment, migration and operation of IPv6 networks.

 

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How to Make Your Web Site Popular?

January 13 2012 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Routers

Anyone can put up a web site. The hard part is helping people discover it, and then stay with it. Your first priority: Make your site people friendly. Your second: Make it search-engine friendly.

Make-Your-Web-Site-Popular.jpg

Here are a few more specific suggestions:

Design it well. Make it pleasing to the eye, and easy to navigate. If the site has a lot of pages, develop a structure that people can easily navigate, rather than throwing too many links up at once.

 

Write well. Re-read your text before posting it. Correct spelling and grammar errors. Use clear and concise language.

 

Stick to your subject(s). Don't be all over the map with content. Keep the site focused, at most, on a handful of topics that you're passionate about.

 

Link with words, not pictures. For web navigation, a word is worth a million pictures. A link that reads "The eternal allure of the Three Stooges" says more about the page it leads to than a photo of Larry, Moe, and Curly. That holds true for search engines as well as for people.

 

Use title and description tags. Search engines give priority to the text in these tags, and usually display their contents in result pages. So think carefully about what you want to put here.

 

Try to read your title through the eyes of a stranger. It should clearly describe the page. See the comments on this post to see how I messed up in this area.

 

And where do you put this text? In your page's HTML code, the title text goes between the <title>and </title> tags. The description goes inside a meta tag that looks something like this:

·         <meta name="description" content="This is where you put the content of your description. It can be longer and thus more descriptive than a title." />.

 

Describe your images. When you do use pictures, give them descriptive file names. Also, describe the picture in the image tag's alt attribute. The Alt text is there for people who can't see the images, but it also helps search engines. In the HTML code, that tag looks something like this:

 

·         <img src="http://urltopicture/filename.jpg" alt="Put your alt text here" />.

 

Finally, links can be extremely helpful in drawing people to your site. That's one of several reasons why I always suggest that people read the original forum discussion. And then I include additional links in the italicized "bio" paragraph below.

 

More news and info about  networking you can visit: http://blog.router-switch.com/

 

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Overview on CISCO 7200VXR Series Routers

January 12 2012 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Routers

With processing speeds up to 2 million packets per second, port- and service adapters ranging from NxDS0 to Gigabit Ethernet, and OC-3 as well as an unparalleled number of high-touch IP services, the Cisco 7200 VXR series is the ideal Services Aggregation WAN/MAN edge device for enterprises and service providers deploying any of the following solutions:

WAN edge-Award-winning quality-of-service (QoS) feature performance

Broadband aggregation-Up to 16,000 Point-to-Point Protocol (PPP) sessions per chassis

Multiprotocol Label Switching provider edge (MPLS PE)-Number one choice for provider edge deployment today

Voice/video/data integration-Time-division multiplexer (TDM)-enabled VXR chassis and voice port adapters

IP-to-IP Gateway Support-Direct IP-interconnections

IP Security virtual private networking (IPSec VPN)-Scalable to 5,000 tunnels per chassis

High-End Customer Premises Equipment (CPE)-For managed WAN services saving equipment, transport and administrative cost

 

The Cisco 7200 VXR addresses these solution requirements by integrating functions previously performed by separate devices into a single platform. Through this integration, the Cisco 7200 VXR provides a single, cost-effective platform that supports:

• High-density LAN and WAN interfaces

• Broadband subscriber services aggregation, including PPP, RFC 1483 termination, and Layer 2 Tunneling Protocol (L2TP) tunneling

• Digital T1/E1 TDM trunk termination for voice, video, and data

• High-density multichannel T3/E3 and T1/E1 with integrated channel service unit/data service unit (CSU/DSU)

• ATM and Packet over SONET (POS) connectivity

• ATM IMA (Inverse Multiplexing over ATM) for voice, video, and data

• Light-density Layer 2 Ethernet switching

 

 The Cisco 7200 VXR Router Series with Network Processing En

The Cisco 7200 VXR Router Series with Network Processing Engine NPE-G2

 

The Cisco 7200 VXR Series offers a rich set of capabilities that address requirements for performance, density, high reliability, availability, serviceability, and manageability.

 

Cisco 7200 VXR Features and Benefit

Features

Benefits

Up to 2 Mpps Processing Capability

Provides high-performance routing and processing performance

Maximum Connectivity Options

Meets a variety of topology requirements with the widest range of port densities and interface options

Breadth of Services

Supports QoS, security, MPLS, broadband, multiservice, voice, IP-to-IP Gateway and management features for next-generation networks

Investment Protection

Low initial investment with upgrade and redeployment capability

 

Hardware for Cisco 7200 VXR Series Router includes:

7204 VXR or Cisco 7206 VXR chassis

• Network Processing Engine

• Input/Output controller

• Processor memory

• Input/Output controller memory

• Power supply

• Console and auxiliary cables

• Second power supply, accessories

• Port adapters

• Service adapters

 

More Notes: If you need to know more about Cisco 7200VXR series (for enterprise head offices and service provider edge), such as its applications, Specifications--- Cards, Ports, Slots; Components--- Chassis, Environmental Conditions; Processors, Input/Output Controllers, Port Adapter Jacket Card, Interfaces, Performance---Memory; Network Management, Power; Protocols; Product Regulatory Approvals and Compliance; Software Requirements, you can visit Cisco's official website...

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