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IP,IPv6 Routing Protocols, Internet protocols version six, IPv6

| 3 responce(s) | Sunday, August 9, 2009
|

Source :
Deploying IPv6 Networks
By Ciprian Popoviciu, Eric Levy-Abegnoli, Patrick Grossetete
...............................................
Publisher: Cisco Press
Pub Date: February 10, 2006
IPv6 Packet Format
IPv6 Routing Protocols

Numerous IPv4 routing protocols (RPs) are available for finding routes between networks, and almost every one of them has an IPv6 correspondent or extension: Routing Information Protocol next-generation (RIPng), Open Shortest Path First version 3 (OSPFv3), Intermediate System-to-Intermediate System (IS-IS), Enhanced Interior Gateway Routing Protocol (EIGRP), and Border Gateway Protocol (BGP). So far, IPv6 has brought few innovations to the IP routing paradigm. There are still interior gateway protocols (IGPs) and exterior gateway protocols (EGPs), distance vectorbased and link-state-based routing protocol algorithms, and so on.

The concept of the autonomous system, defined as a set of networks controlled by a common administrative entity, remains unchanged with the introduction of IPv6 RPs. The same autonomous system (and autonomous system number [ASN]) will route both IPv4 and IPv6. IPv6 IGPs, used to exchange routes within the autonomous system, are namely RIPng, OSPFv3, IS-IS for IPv6, and EIGRP for IPv6. Only BGP4 is available to exchange IPv6 routes between autonomous systems. Multiprotocol extensions provide support in BGP4 for IPv6 routing.

The requirements for IGPs and EGPs are quite different, in terms of routing table size, number of supported routers, convergence time, security, routing policy, and so forth. For that reason, they use different algorithms and mechanisms, which also affect the type of information they exchange and store. IGPs use distance vector and link state, whereas BGP uses the path vector RP algorithm. The following table represents RP taxonomy, and highlights their IPv6 correspondent. For more details on how to choose the RP, refer to Top-Down Network Design, Second Edition, by Priscilla Oppenheimer.

Table 4-1. Taxonomy of Routing Protocols

Deployment Domain

Algorithm

RP

Scalability

Convergence Time

Metric

IPv6 Version

Interior gateway protocol (IGP)

Distance vector

RIP

15 hops

Slow

Hop count

RIPng



EIGRP

1000s routers

Quick (via DUAL algorithm)

Bandwidth, delay, reliability, load

EIGRP for IPv6


Link state

OSPF

1000s routers (100s/area)

Quick (via LSAs and HELLO)

Cost (function of bandwidth on Cisco routers)

OSPFv3



IS-IS

1000s routers (100s/area)

Quick (via LSPs)

Configured host, delay, expense

IS-IS for IPv6

Exterior gateway protocol (EGP)

Distance vector

EGP



Integer <=255



Path vector

BGP AF=IPv4

1000s routers

Slow (via UPDATE)

Function of path attributes and other configurable factors

BGP AF=IPv6


The rest of this section briefly reviews existing unicast RP technologies. The next section reviews each of the available IPv6 RPs and provides configuration examples. Then the last two sections cover the topic of multihoming and deployment aspects, respectively.



IP Mobility, IP, IPv6, IP version 6, Internet protocol

| 1 responce(s) |
|

Source :
Deploying IPv6 Networks
By Ciprian Popoviciu, Eric Levy-Abegnoli, Patrick Grossetete
...............................................
Publisher: Cisco Press
Pub Date: February 10, 2006

IP Mobility


The Internet has become so pervasive that no matter where you are, you can plug your computer into a wall, or attach to a wireless LAN, and, after a while, you will be able to communicate. Is not this mobility? Well, not quite.

That type of "mobility" is achieved by getting a new IP address within the network of attachment and losing all sessions bound to the previous IP address. This might be acceptable for corporate users moving from work to home, but can be much more cumbersome for road warriors, and it can be a showstopper for IP telephony.

Mobile IP provides a network layer for hosts that enables them to maintain the same IP address no matter where they are in the Internet, and keep receiving traffic as they move.

"Advanced ServicesIPv6 Mobility," MIPv6 is compared to MIPv4. Even though MIPv4 is a mature and deployable technology, it faces limitations because of the nature of IPv4. At the same time, IPv6 mobility is considered as one potential enabler for IPv6. The number of IP-enabled devices and the need for any-to-any communications among them is driving requirements that IPv4 cannot easily satisfy, and it is opening opportunities for IPv6. By integrating functionalities designed for Mobile IPv4 into standard IPv6 protocols, and by leveraging existing IPv6 capabilities, MIPv6 has built up a MIP model that is much more compelling than its IPv4 counterpart.

It must be noted that enhancements to mobility are largely taking place in IPv6 related working groups, even though a fraction gets retrofitted into the IPv4 standards. Although MIPv6 has benefited greatly from its MIPv4 parent, it is now the driver of the evolution of IP mobility, and it is widely expected to be a foremost steering force for IPv6 deployments.

In terms of deployment, it must be considered that IP mobility enables new flows, which impact the wireless infrastructure: Telephony over IP demands a higher level of coverage, latency, and QoS enforcement, whereas peer to peer imposes always-on reachability and multimedia capabilities.

The application of the MIP and NEtwork MObility (NEMO) standards is not limited to hosts and routers that actually roam around the Internet as a usual behavior. Sales of consumer routers are plummeting. At the moment, they are related to IPv4 NAT operations. With IPv6, it can be expected that people will deploy unmanaged yet globally addressable networks at home. NEMO support by the home gateways would enable a service provider to deploy preprovisioned devices, and could save hundreds of thousands of network-renumbering operations per year as customers move from one home to the next.

At the core, MIP builds dynamic tunnels, and NEMO exchanges routes over those tunnels. In a way, this is a revamping of the traditional model of the core where BGP routers exchange the bulk of the Internet routes over peering tunnels. But whereas the model of the Internet is designed for fixed, aggregated routes that are locally injected and slowly distributed throughout its fabric, MIP and NEMO techniques enable a new model where routes are projected where and when they are needed, on-demand; this opens to a new level of hierarchy for the fine-grained mobile routes, and a new order of scalability for the Internet.

But the Internet of today is not fully ready for IP mobility. Even if IPv6 can exist over an IPv4 fabric as a transitional method, a significant number of improvements must be made to cope with the latency of the protocol and enable multimedia interactive applications such as voice calls and video.



Data Cabling Rules,Reliable Cabling, Poor Cabling Cost

| 6 responce(s) | Sunday, August 2, 2009
|

The Golden Rules of Data Cabling,The Importance of Reliable Cabling,The Legacy of Proprietary Cabling Systems, Cabling and the Need for Speed, Cable Design , Data Communications 101, Speed Bumps: What Slows Down Your Data, The Future of Cabling Performance. Learn how to Cabling, Know that better than the best.


Source: Cabling:The Complete Guide to Network Wiring (Third Edition)
Author : David Barnett, David Groth, Jim McBee.

“Data cabling! It’s just wire. What is there to plan?” the newly promoted programmer turned MIS-director commented to Jim. The MIS director had been contracted to help the company move its 750-node network to a new location. During the initial conversation, the director had a couple of other “insights”:
He said that the walls were not even up in the new location, so it was too early to be talking about data cabling.
To save money, he wanted to pull the old Category 3 cabling and move it to the new location. (“We can run 100Base-TX on the old cable.”)
He said not to worry about the voice cabling and the cabling for the photocopier tracking system; someone else would coordinate that. Jim shouldn’t have been too surprised by the ridiculous nature of these comments. Too few people understand the importance of a reliable, standards-based, flexible cabling system. Fewer still understand the challenges of building a high-speed network. Some of the technical problems associated with building a cabling system to support a high-speed network are comprehended only by electrical engineers. And many believe that a separate type of cable should be in the wall for each application (PCs, printers, terminals, copiers, etc.). Data cabling has come a long way in the past 20 years. This chapter discusses some of the basics of data cabling, including topics such as:

●The golden rules of data cabling
●The importance of reliable cabling
●The legacy of proprietary cabling systems
●The increasing demands on data cabling to support higher speeds
●Cable design and materials used to make cables
●Types of communications media
●Limitations that cabling imposes on higher-speed communications
●The future of cabling performance

You are probably thinking right now that all you really want to know is how to install cable to support a few 10Base-T workstations. Words and phrases such as attenuation,crosstalk,twisted pair,modular connectors, and multi-mode optical-fiber cable may be completely foreign to you. Just as the world of PC LAN's and WANs has its own industry buzzwords, so does the cabling business. In fact, you may hear such an endless stream of buzzwords and foreign terminology that you’ll wish you had majored in electrical engineering in college. But it’s not really that mysterious and, armed with the background and information we’ll provide, you’ll soon be using cable speak like a cabling professional.

The Golden Rules of Data Cabling

Listing our own golden rules of data cabling is a great way to start this chapter and the book. If your cabling is not designed and installed properly, you will have problems that you can’t even imagine. From our experience, we’ve become cabling evangelists, spreading the good news of proper cabling. What follows is our list of rules to consider when planning structuredcabling systems:

●Networks never get smaller or less complicated.
●Build one cabling system that will accommodate voice and data.
●Always install more cabling than you currently require. Those extra outlets will come in
handy someday.
●Use structured-cabling standards when building a new cabling system. Avoid anything
proprietary!
●Quality counts! Use high-quality cabling and cabling components. Cabling is the foundation of your network; if the cabling fails, nothing else will matter. For a given grade or category of cabling, you’ll see a range of pricing, but the highest prices don’t necessarily mean the highest quality. Buy based on the manufacturer’s reputation and proven performance, not the price.
●Don’t scrimp on installation costs. Even quality components and cable must be installed correctly; poor workmanship has trashed more than one cabling installation.
●Plan for higher speed technologies than are commonly available today. Just because 1000Base-T Ethernet seems unnecessary today does not mean it won’t be a requirement in five years.
●Documentation, although dull, is a necessary evil that should be taken care of while you’re setting up the cabling system. If you wait, more pressing concerns may cause you to ignore it.

The Importance of Reliable Cabling

We cannot stress enough the importance of reliable cabling. Two recent studies vindicated our evangelical approach to data cabling. The studies showed:

●Data cabling typically accounts for less than 10 percent of the total cost of the network infrastructure.
●The life span of the typical cabling system is upwards of 16 years. Cabling is likely the second most long-lived asset you have (the first being the shell of the building).
●Nearly 70 percent of all network-related problems are due to poor cabling techniques and cable-component problems.

Of course, these were facts that we already knew from our own experiences. We have spent countless hours troubleshooting cabling systems that were nonstandard, badly designed, poorly documented, and shoddily installed. We have seen many dollars wasted on the installation of additional cabling and cabling infrastructure support that should have been part of the original installation. Regardless of how you look at it, cabling is the foundation of your network. It must be reliable!

The Cost of Poor Cabling

The costs that result from poorly planned and poorly implemented cabling systems can be staggering. One company that had recently moved into a new office space used the existing cabling, which was supposed to be Category 5 cable. Almost immediately, 100Mbps Ethernet network users reported intermittent problems.

These problems included exceptionally slow access times when reading e–mail, saving documents, and using the sales database. Other users reported that applications running under Windows 98 and Windows NT were locking up, which often caused them to have to reboot their PC. After many months of network annoyances, the company finally had the cable runs tested. Many cables did not even meet the minimum requirements of a Category 5 installation, and other cabling runs were installed and terminated poorly.


 

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