Designing & Implementing an OSPF Network
OSPF Network Design Solutions
Author: Thomas Thomas
Publisher: Cisco Press (53)
“Imagination: A mind once stretched by a
new idea never regains its original dimensions.” Successories
This chapter covers the actual process of sitting down and designing your
OSPF network. The real process of putting the pen to paper and the true
process behind it is covered. It is this chapter's intention to take the
mystery out of designing any type of network. The concepts and steps discussed
have universal application whether your network is BGP or OSPF; of course,
the latter is emphasized. Chapter 6, “Advanced
OSPF Design Concepts,” covered many of the commands necessary
for configuring OSPF. In this chapter, you will become familiar with the
necessary steps to actually begin the OSPF process on a Cisco router. You
already know there are many potential network architectures where you would
have to configure OSPF, and the most common are covered in this chapter.
This chapter has two specific sections as follows:
OSPF Network Design. This section reviews the specific network
design goals that should be the general basis of every network. There
are certain issues that you must be aware of as network designers, and
they are discussed in this section. The six fundamental steps that make
up the Network Design Methodology are covered with special enhancements
given to issues regarding OSPF.
Configuring OSPF on Cisco Routers. At this point in the book,
you have everything you need to know about how OSPF works and how to
go about designing and implementing an OSPF network. But how do you
turn on OSPF? This section addresses basic and advanced configuration
issues as relate to Cisco routers. A bonus area is covered as well that
deals with multi-protocol routers.
This book has discussed the various design techniques for OSPF, from
the various golden rules to the number of routers per area. It is now time
to actually take this information and begin the process of designing an OSPF
network. Let's begin the process by determining what is actually supported
by Cisco Systems.
As discussed in Chapter 4, “Introduction
to OSPF,” there is a variety of RFCs that deal with OSPF. By
now, you should be familiar with the many different features available within
the OSPF protocol. But which RFCs does Cisco support within its products?
RFC 1253: Open Shortest Path First (OSPF) MIB. This RFC contains the information, which provides management information
relating to OSPF.
RFC 1583: OSPF Version 2. Cisco's implementation
conforms to the specifications as detailed in this RFC. They support the following
key features: stub areas, route redistribution, authentication (covered later),
tunable interface parameters, and virtual links.
RFC 1587: Not-So-Stubby-Areas (NSSA). Cisco
equipment supports the use of all types of stub areas.
RFC 1793: OSPF over Demand Circuits. Cisco
supports this RFC as well.
It is not necessary to get into the reasons behind your decision to
build an OSPF network or any of the previously covered definitions of what
a network is. However, the five basic goals that you should keep in mind while
designing your OSPF network (or any network for that matter) should be adhered
“The network must work” is the absolute bottom line. Because
networks are an integral part of enabling individual users to do their jobs,
this is essential. It is here that the use of Service Level Agreements (SLAs)
is essential. You must know what is expected of the network in order to design
As your organization grows, the network must be able to keep pace. Your
network and its initial design must enable it to expand accordingly. A network
that cannot keep pace with the organization's needs is not much use.
Routing summarization is a major factor in the success of designing your
network. If you want to ensure your network can scale properly, the summarization
is the biggest factor on your success. Without summarization, you will
have a flat address design with specific route information for every host
being transmitted across the network, a very bad thing in large networks.
To briefly review summarization, remember that routers summarize at several
levels, as shown in Figure 7-1.
For example, hosts are grouped into subnetworks, subnetworks are then
grouped into major networks, and these are then consolidated in areas.
The network can then be grouped into an autonomous system.
There are many smaller networks that desire to use a “standard”
routing protocol such as OSPF. These networks can, for example, have 100 or
less routers with a relatively small IP space. In these situations, summarization
may not be possible and might not gain much if it were implemented.
Adaptability refers to your network's capability to respond to changes.
In most cases, adaptability refers to your network's capability to embrace
new technologies in a timely and efficient manner. This becomes extremely
important as the network ages because change within networking
is racing forward at breakneck speeds. Though it is not necessary to always
be on the leading or bleeding edgethere is a lot to be said for letting
others find the bugs!
7-1. Route summarization affects network scalability.
To provide “true” proactive network management is the goal
here. The network must have the proper tools and design to ensure you are
always aware of its operation and current status.
In this case, I have saved the true bottom line of network design for
last. The reality of life is that budgets and resources are limited, and building
or expanding the network while staying within the predetermined budget is
always a benefit to your career and proper network design.
Although there are five basic goals of network design that can be followed
in any situation, I think there also should be a certain mindset during the
process. This mindset is regarding the
actual technology you will be using. It is very important to use state-of-the-art
technologies whenever possible, though this does not mean to use unproven
or inadequately tested technology. The reasoning behind this is that by spending
a little extra money up front, you are investing with an eye to the future
knowing that the network you are building will be able to grow, from a technological
standpoint, longer than otherwise possible.
Up until this point, the various network design goals and the methodology
needed to make the goals become a reality have been discussed. There are also
certain design issues that you must consider when working through the network
Reliability. When designing networks, reliability is usually the most important
goal, as the WAN is often the backbone of any network.
Latency. Another big concern with users occurs
when network access requests take a long time to be granted. Users should
be notified about a latency problem in the network.
Cost of WAN resources. WAN resources are expensive,
and as such, frequently involve a tradeoff between cost efficiency and full
network redundancy. Usually cost efficiency wins.
Amount of traffic. This is a very straightforward
consideration. You must be able to accurately determine the amount of traffic
that will be on the network in order to properly size the various components
that will make it up. As you implement the network, you should also develop
a baseline that can be used to project future growth.
Allowing multiple protocols on the WAN. The
simplicity of IP is of great benefit to any network. For example, by only
allowing IP-based protocols on the network you will avoid the unique addressing
and configuration issues relating to other protocols.
Compatibility with standards or legacy systems. Compatibility is always going to be an issue within your network throughout
its life. As a network designer, you need to always keep this in mind as you
Simplicity and easy configuration. Having
been a network engineer for many years and involved in network management,
this feature is doubly important to me. You might only be involved in the
design and implementation of the network and not the management. In that case,
the knowledge you will develop will need to be passed on to those who will
manage the network. Ensure that you keep the ideas of simplicity and ease
of configuration in mind while you develop your design documents for the network.
Support for remote offices and telecommuters. In today's telecommunications environment, remote satellite offices
are becoming commonplace and require network connectivity, so you must plan
accordingly. The estimates say that every day you will see companies increase
the number of telecommuters. You must keep this in mind as you determine the
placement of network components to ensure that they can handle this requirement
when it becomes a priority for your organization.
six common steps that can be used to design your OSPF network, or any network
for that matter. This are not set in stone and will not guarantee the “perfect”
network, but they will provide you with realistic steps and considerations
that if taken into account will make for well designed network. These steps
will also help you avoid getting caught up in all the “bells and whistles”
available in the new-enhanced-ultra-secret-turbo-series-network-equipment
which is the answer to all your networking needs.
These steps to designing a network have been proven not only over time,
but also through countless networks that have been designed and implemented
based upon this standard.
Analyze the requirements.
Develop the network topology.
Determine addressing and naming conventions.
Provision the hardware.
Deploy protocol and IOS features.
Implement, monitor, and maintain the network.
Although your network might not have the technology du jour, it might not
really need it if you objectively determine the needs of a network by following
this design methodology (as shown in Figure
This step will detail the process of determining expectations and then converting
those into a real network or explaining why everyone can't have video conferencing
on the desktop.
What do you know? Going into
Step 1, you know that an OSPF network is required but not what it will need
to accomplish for your users or how you will need to physically design the
Granted, the needs of users are always changing, and sometimes they do not even know
what they need. There I said it! However, it is true; they know what they
want and when they want it, which is always now or yesterday. Nevertheless,
from a network design prospective, they do not always know what they need
or why they need it.
Nevertheless, you, as the network engineer involved in the design of
the network, must still objectively listen and determine user needs. In the
end, they are going to be the customers of network, and the customer is always
right. You must also take into consideration what the future might hold for
them. Therefore, you should ask the users what needs they see themselves having
in the future. This question should be directed toward their jobs because
it is your responsibility to take their response and turn that into the requirements
of the network.
A corporate vision is always important. For example, do the long-range
corporate plans include having a Web site? If so, what will it be doing? How
about running voice over the network? What about video conferencing; is that
going to be a corporate need?
Additional data you might want to consider gathering is the current
organization structure, locations, and flow of information within the organization
and any internal or external resources available to you. Armed with this information,
your networks need analysis, you should then begin determining the cost and
benefit analysis. Of course in many cases you will not be able to get all
the equipment or bandwidth you think is necessary. Therefore, it is also advisable
to create a risk assessment detailing the potential problems or areas of concern
regarding the network design.
As you go through the process of determining the network
requirements, keep in mind some important questions regarding the requirements
of OSPF. The answers to these questions will help you further define the requirements
of your OSPF network.
How should the OSPF Autonomous System be delineated? How many
areas should it have and what should the boundaries be?
Does your network and its data need to have built-in security?
What information from other Autonomous Systems should be imported
into your network?
Which sites will have links that should be preferred (lower
Which sites will have links that should be avoided (higher
As you go through the process of determining the network requirements, keep in mind the load
balancing feature of OSPF. In the Cisco implementation of OSPF, any router
can support up to four equal-cost routes to a destination. When a failure
to the destination is recognized, OSPF immediately switches to the remaining
OSPF will automatically perform load balancing allow equal-cost paths.
The cost associated is determined (default) by the interface bandwidth statement
unless otherwise configured to maximize multiple path routing.
Before Cisco's IOS release 10.3, the default cost was calculated by
dividing 1,000,000,000 by the default bandwidth of the interface. However,
with IOS releases after 10.3, the cost is calculated by dividing 1,000,000,000
by the configured bandwidth of the interface as illustrated in Figure
In IOS 11.3, this issue has been addressed with the command ospf
auto-cost reference bandwidth.
OSPF convergence is extremely fast when compared to other protocols; this was one
of the main features included within its initial design. To keep this desirable
feature fully functional in your network, you need to consider the three components that determine how
long it takes for OSPF to converge:
The length of time it takes OSPF to detect a link or interface
The length of time it takes the routers to exchange routing
information via LSAs, rerun the Shortest Path First algorithm, and build a
new routing table
A built-in SPF delay time of five seconds (default value)
Thus, the average time for OSPF to propagate LSAs and rerun the SPF
algorithm is approximately 1 second. Then the SPF delay timer of five seconds
must elapse. Therefor OSPF convergence can be a anything from 6 to 46 seconds,
depending upon the type of failure, SPF timer settings, size of the network,
and size of the LSA database. The worst case scenario is when a link fails
but the destination is still reachable via an alternate route, because the
40 second default dead timer will need to expire before the SPF is rerun.
This step will cover the process of determining the
networks physical layout. There are generally only two common design topologies:
meshed or hierarchical. The following sections take a look at each to see
which is the most efficient design for today's networks.
What do you know? Going into Step 2, you've
developed a list of the requirements associated with this OSPF network. You
have also begun to lay out the financial costs associated with the network
based upon this information. These costs could include equipment, memory,
and associated media.
In a meshed
structure, the topology is flat and all
routers perform essentially the same function, so there is no clear definition
of where specific functions are performed. Network expansion tends to proceed
in a haphazard, arbitrary manner. This type of topology is not acceptable
to the operation of OSPF. It will not correctly support the use of areas or
In a hierarchical
topology, the network is organized in layers that will have clearly defined
functions. In this type of network there are three layers:
Core Layer. This would make an excellent place for
OSPF Backbone Routers that are all connected through area 0. All of these
routers would be interconnected, and there should not be any host connections.
This is because its primary purpose is to provide connectivity between other
It is here that you would locate other OSPF areas all connected
through Area Border Routers (ABRs) back to the Core Layer (area
0). This is also a good location to begin implementing various network
policies such as security, DNS, etc.…
Access Layer. This is where the inter-area routers
that provide connections to the users would be located. This layer ID is where
the majority of the hosts and servers should be connecting to the network.
By using this type of logical layered network design, you will gain
some benefits that will help you design the network as shown in Figure
The benefits of the OSPF hierarchical topology as implemented in Figure
7-4 are as follows:
Scalable. Networks can grow easily because
functionality is localized so additional sites can be added easily and quickly.
Ease of Implementation. This physical topology
fits easily into OSPF's logical hierarchy, making network implementation easier.
Ease of Troubleshooting. Because functionality
is localized, it is easier to recognize problem locations and isolate them.
layered approach, the functionality of each layer is much more predictable.
This makes capacity planning and modeling that much easier.
Protocol Support. Because an underlying physical
architecture is already in place if you want to incorporate additional protocols,
such as BGP, or if your organization acquires a network running a different
protocol, you will be able to easily add it.
Manageability. The physical layout of the
network lends itself towards logical areas that make network management much
There are other variations of the three-layered hierarchical design
that are available are one layerdistributed, hub and spokeand
two layers, but they are beyond the scope of this book. At this point, though,
you can see that the three layered hierarchical model fits perfectly into
OSPF's logical design, and it is this model on which you will be basing your
network design. Before discussing how to implement and design this type of
model, you need some basic OSPF backbone design suggestions.
The process of designing
backbone area has been previously discussed, so it will be only briefly
reviewed here. Always keep the backbone area as simple as possible by
avoiding a complex mesh. Consider using a LAN solution for the backbone.
The transit across the backbone is always one hop, latency is minimized,
and it is a simple design that converges very quickly. Figure
7-5 illustrates a simple OSPF backbone design.
You know that you should keep users off the backbone because it is
only a transit area, but that is not enough. You also need to consider
securing your backbone physically. As a network critical shared resource,
the routers need to be physically secure. If you use the previously
mentioned LAN backbone solution, then securing your network can be relatively
easy; just put it in a secure closet or rack as shown in Figure
7-6. Isolate the backbone and secure it both physically and logically.
You will have to design
your OSPF network with areas to make the network scalable and efficient.
have been discussed in previous chapters, but let's briefly review them
at this point. Areas should be kept simple, stubby, with less than 100
(optimally 40-50) routers, and have maximum summarization for ease of
routing. The network illustrated in Figure
7-7 demonstrates these suggestions.
Even though these design suggestions are helpful, what are you really
going to gain in your network by adding stub areas? Simply put, they
will summarize all external LSAs as one single default LSA that applies
only to the external links from outside the autonomous system. The stub
area border router sees all the LSAs for the entire network and floods
them to other stub area routers. They keep the LSA database for the
stub area with this additional information and the default external
route. Figure 7-8 illustrates
the operations in a stub area.
There are also totally stubby areas that you could design within your
network. Totally stubby areas are a Cisco-specific feature available within
their implementation of the OSPF standard. You can use totally stubby areas
in Cisco IOS Release 9.1 and later.
If an area is configured as totally stubby, only the default summary
link is propagated into the area by the ABR. It is important to note
that an ASBR cannot be part of a totally stubby area, nor can redistribution
of routes from other protocols take place in this area. Figure
7-9 shows the operations in an example totally stubby area.
The main difference between a stub area and a not-so-stubby area (NSSA)
is that the NSSA imports a limited
number of external routes. The number of routes is limited to only those required
to provide connectivity between backbone areas. You may configure areas that
redistribute routing information from another protocol to the OSPF Backbone
as a NSSA.
NSSAs are discussed later in this chapter.
To design this type of model network, you should gather a list of
the different locations requiring network connectivity within your organization.
For purposes of this example and ease of understanding, let's consider your
organization, as an international corporation, and you have been tasked with
building its OSPF network within the United States. You have determined that
you have the following divisions (each with various business units within
it), as shown in the following hierarchy, which groups the units by location
and then by function.
The listed units will become the basis of OSPF areas. Contained within
the areas will be OSPF inter-area routers that connect to the various hosts.
Of these groupings, you should select essential locations at which to
locate the backbone routers. For our example, you know that Headquarters will
have a backbone router that will be connected to area 0. You have been given
several requirements based upon traffic flow and corporate requirements:
All divisions must be within the same area, regardless of
All divisions must be able to connect to headquarters
In our company, area 0 links all major continental locations
throughout the globe
All region clusters must have alternate routes
Internet connectivity for entire company
If backbone router fails, network operation within U.S. division
Engineering and Manufacturing must communicate quickly and
Begin separating the sites into areas and picking
one location within each area at which will reside the area border router
(ABR). This will result in a proposed set of OSPF routers deployed as follows:
Backbone router (area 0): Connects to global area 0
ABR (area 1): Executives and legal department
ABR (area 2): Human resources
ABR (area 3): Sales
ABR (area 4): Manufacturing and Engineering
ASBR: Internet connectivity
The remaining sites will each be assigned an inter-area router to connect
them to the network. One main site within each geographical area will be the
hub site for that geographic area, thereby reducing bandwidth costs.
At this point, you should have your organization separated into areas
or layers and an overall topology map laid out. Figure
7-10 illustrates the example network described up to this point.
I want to throw out a couple of disclaimers here before people start
tearing up my example. First, remember requirement number 1 (All divisions
must be within the same area, regardless of geographic location). Second,
there are many ways of designing a network and this is just one way and one
person's opinion. Third, there is no substitute for actual network design
experience, because everyone makes mistakes. Fourth, now that you think you
have a solid network design, have someone else look at it and consider modeling
it in a software package such as NetSys from Cisco.
Step 3 covers the actual process of assigning
the overall network-addressing scheme. By assigning blocks of addresses to
portions of the network, you are able to simplify addressing, administration,
routing and increase scalability.
Because OSPF supports variable-length subnet masking (VLSM), you can
really develop a true hierarchical addressing scheme. This hierarchical addressing
results in very efficient summarization of routes throughout the network.
VLSM and CIDR were discussed at great length earlier in the book, and it is
in this step of designing your OSPF network that you should begin applying
these two techniques.
Proposed network design: topology map.
What do you know? Coming into Step 3, you have determined your
network's requirements and developed a physical network topology. You
have continued to keep track of the costs
both one time and recurring while planning. In this step, you will determine
the addressing and naming conventions that you plan on using.
A good rule of thumb to remember when determining whether to use public or private
address space is that your address scheme must be able to scale enough to
support a larger network because your network will most likely continue to
Now you must determine what range of IP addresses you are going to deploy
within your network. The first question you need to answer is: “Do I
have public address space assigned to me by the InterNIC or am I going to
be using private address space as specified in RFC 1918 and 1597?”
Either choice will have its implications on the design of your network.
By choosing to use private address space and with having to connect to the
Internet, you will be faced with having to include the capability to do address
translation as part of your network design.
To further complicate the issue, you might also have to deal with a
preexisting addressing scheme and/or the need to support automatic address
assignment through the use of Dynamic Host Configuration Protocol (DHCP) or
Domain Naming System (DNS). That type of technology is beyond the scope of
this book and will not be covered.
DHCP is a broadcast technique
used to obtain an IP address for an end station.
DNS is used for translating the names of network nodes into IP addresses.
Figure 7-11 shows a good example
of how to lay out the IP addresses and network names for the example
The operation and benefits of
have been discussed in previous chapters. At this point though, you
should realize the importance of proper summarization on your network.
The OSPF network in Figure 7-12
does not have summarization turned on. Notice that by not using summarization,
every specific-link LSA will be propagated into the OSPF backbone and
beyond, causing unnecessary network traffic and router overhead. Whenever
an LSA is sent, all affected OSPF routers will have to recompute their
LSA database and routes using the SPF algorithm.
OSPF will provide some added benefits if you design the network with
summarization. For example, only summary-link LSAs will propagate into
the backbone (area 0). This is very important because it prevents every
router from having to rerun the SPF algorithm, increases the network's
stability, and reduces unnecessary traffic. Figure
7-13 demonstrates this principle.
No route summarization will cause network problems.
Proper route summarization
improves OSPF network stability.
IP addresses in an OSPF network should be grouped by area, and you can
expect to see areas with some or all of the following characteristics:
It is important that hosts, subnets, and networks be allocated in a
controlled manner during the design and implementation of your OSPF
network. The allocation should be in the form of contiguous blocks that
are adjacent so OSPF LSAs can easily represent the address space. Figure
7-14 shows an example of this.
Allocation of IP addresses should be done in powers of two so that these “blocks”
can be represented by a single summary link advertisement. Through the use
of the area range command you will be able to summarize
large contiguous blocks of addresses. In order to minimize the number of blocks
you should make them as large as possible.
Bit splitting is also a very useful technique discussed in previous
chapters, and you might now want to consider using it if you have to split
a large network number across more than one OSPF area. Simply
put, bit splitting borrows some subnet bits for designated areas, as discussed
in Chapter 5, “The Fundamentals of OSPF Routing
To differentiate two areas, split one bit.
To differentiate 16 areas, split four bits.
Figure 7-15 demonstrates this
bit splitting technique.
The example uses four bits for the area and uses 32-bit numbers to represent
four of the 16 possible areas. The area numbers appear in dotted decimal notation
and look like subnet numbers. In fact, the 32-bit area numbers correspond
to the summary advertisement that represents the area.
Variable-length subnet masking (VLSM) has been discussed previously,
so this section will not dwell on it too
deeply. But suffice it to say that the reasons behind it are similar
to bit splitting. Remember to keep small subnets in a contiguous block
and increase the number of subnets for a serial meshed network. Figure
7-16 provides a good example of VLSM OSPF mappings.
Subnets become discontiguous when
they are separated by one or more segments represented by a different major
network number. Discontiguous subnets are supported by OSPF because subnets
masks are part of the link-state database.
Consider the following example: The OSPF backbone area 0 could be a
class C address, while all the other areas could consist of address
ranges from a class B major network as illustrated in Figure
OSPF supports discontiguous subnets regardless of whether summarization
is configured within the network. Although, everything within your network
will route better and have a more stable design if summarization is configured.
The naming scheme used in your network should also be designed in a
systematic way. By using common
prefixes for names within an organization, you will make the network
much easier to manage and more scalable. All of this is shown in Figure
It is also important to carry a naming convention into your routers
as well. This will assist everyone dealing with your network because the router
names actually hold some meaning, instead of an abstract like an order number.
In Step 4, you must use vendor documentation,
salesmen, and system engineers to determine the hardware necessary for your
network. This is for both LAN and WAN components.
For LANs, you must select and provision router models, switch models,
cabling systems, and backbone connections.
For WANs, you must select and provision router models, modems, CSUs/DSUs,
and remote access servers.
What do you know? Coming into Step 4 you have
determined your network requirements, developed a physical network topology,
and laid out your addressing and naming scheme for the network. In this step,
you will begin selecting and provisioning the necessary network equipment
to implement the design.
When selecting and provisioning routing or switching hardware, consider
the following areas:
In Step 5, you will need to deploy the more specific features possible
by the OSPF protocol and the routers IOS. It is not necessary to have a network
with every single option turned, nor is it something you are likely to see.
Some of the features you should consider implementing are covered in the two
sections that follow.
What do you know? Coming into Step 5 you have
determined your network requirements, developed a physical network topology,
laid out your addressing and naming scheme, and begun the provisioning of
the network equipment. In this step, you will begin deploying the OSPF and
IOS features that you will be using within the network.
This area covers some of the features of OSPF (authentication
and route redistribution between protocols) that you should consider deploying
within your network. There can be only one choice concerning which feature
should be first for you to consider.
Protecting corporate resources, security, policing the network, ensuring
correct usage of the network, authenticationthey are all different
labels for a similar need within every network: network security. Network security
should be built into the network from day one, not added as an afterthought.
Mistakes have already happened in the networking environment you know today. Nevertheless, how could they not with
the almost required Internet presence and “www” logo seen on
almost every business card? The open unsecure protocols such as Simple Mail Transfer Protocol (SMTP)
or Simple Network Management Protocol (SNMP) are essential for business and
network management, though they are also vulnerable for exploitation. Hopefully,
the respective working groups will get moving towards solving
this problem. All is not doom and gloom though, as OSPF comes with built-in
authenticationthe way it should be!
OSPF's built-in authentication set is extremely useful and flexible.
In the OSPF specification, MD5
is the only cryptographic algorithm that has been completely specified. The
overall implementation of security within OSPF is rather straightforward.
For example, you assign a key to OSPF. This key can either
be the same throughout your network or different on each router's interface
or a combination of the two. The bottom line is that each router directly
connected to each other must have the same key for communication to take place. Further detailed discussion of this OSPF feature will
take place in later chapters.
Route redistribution is another very useful Cisco IOS software feature.
To review redistribution
is the exchange of routing information between two different routing processes
(protocols). This feature should be turned on in your routers if you have
separate routing domains within your Autonomous System and you
need to exchange routes between them.
For example, the engineering department might be running OSPF and the
accounting department might be running IGRP as shown in Figure
7-18. Redistributing routing information between protocols.
Figure 7-18 depicts
one router connecting the two separate touring processes (protocols),
which need to share routing information. This sharing process is called
redistribution. The router shown in Figure
7-18 is configured to run both IGRP and OSPF routing.
When routes are redistributed between major networks, no subnet information
Some of the features of the IOS that you should consider deploying
within your network are as follows:
The last step is also the first step to continually managing the growth
of your network. Some time is spent on this subject later in the chapter,
but Chapter 9, “Managing Your OSPF Network,”
will delve more deeply into the network management arena. In the context of
this step you should consider the following actions:
Using network management tools for monitoring
Performing proactive data gathering
Knowing when to scale the network to meet new demands (new
hardware, upgrade circuit speeds, support new applications)
What do you know? Coming into Step 6 you have
determined your network requirements, developed a physical network topology,
laid out your addressing and naming scheme, provisioned your network equipment,
and deployed the necessary OSPF and IOS features. In this step, you will begin
to implement the network, institute monitoring, and engage in proactive network management.
Network management applications that use Simple
Network Management Protocol (SNMP) provide a useful array of tools
to control internetwork support costs:
One of the primary architects of OpenCable, Michael
Adams, explains the key concepts of this initiative in his book
Broadband, Second Edition
by George Abe
Introduces the topics surrounding high-speed networks
to the home. It is written for anyone seeking a broad-based familiarity
with the issues of residential broadband (RBB) including product
developers, engineers, network designers, business people, professionals
in legal and regulatory positions, and industry analysts.