Distribution layer design

What's todays look on Medium to Small branch office design? Do you stack multiple switches or buy lets say a 4500? I'm looking for Pros and Cons. And if you stack how do you tie in SX,SC fiber to the Access layer?

Choice depends of features and performance (and often cost).
For smaller LANs, I've found the stackable switches, often, a viable choice.
As to using fiber, stackable switches often offer some SFP (or other modular) ports to which you can attach fiber. However, at least in Cisco's current product offerings, high density fiber isn't really available. For instance, there's the stackable Catalyst 3750G-12S, but it only provides 12 ports. (It does, though, provide internal resources and SDM templates for non-edge usage.)
[edit]
PS:
BTW, in a small LAN, depending on distances, you might be able to user copper uplinks and/or run most of the LAN on one stack (which avoids the needs for uplinks/downlinks). Or, if you use stackable switches on the access edge, might find number of uplinks necessary is decreased.

Similar Messages

Identification of Core and Distribution Layer Design

Hi
I am a CCNA certified and I am doing a job as an IT technician here in UAE. I'm the only IT person in my company. Having no prior experience in networking field, I find myself in a pickle. With the help of CDP, I have figured out the network diagram. I am told that there is a COLLAPSED CORE network running in my company. I cannot identify the Core switches here. My question is how to identify the the core switches? We have two internet connections in two separate buildings. Can somebody please help me out. Please..

Generally speaking with a L2 access layer to L3 distribution switches the default gateways of the vlans are on the distribution switches.
The core switches are used when you need to interconnect multiple distribution switches eg. a campus LAN type environment.
In many sites if you only have one building the core and distribution switches are the same pair of switches but to be precise the default gateways are not on the core but the distribution switches.
If you have a separate pair of core switches you usually connect your distribution switches using L3 links so again the STP root for the vlans would actually be the distribution switches for the vlans they route for and not the core switches.
Separate core switches are basically just a high speed interconnect between your distribution pairs and should be left to do that so the routing between vlans, acls etc. are done locally on the distribution switches and only traffic for remote vlans/IP subnets ie. those on other distribution switches would go via the core switches.
If the same pair of switches is used for both functions then all routing between vlans and routing to remote networks is done by that pair.
Jon

Bandwidth from Access Layer to Distribution Layer

Folks:
I am currently on Chapter 12 of “CCNP Switching 642-813, Official Certification Guide” ISBN: 978-1-58720-243-8. I am currently not grasping the three layers entirely, and I was hoping someone could offer insight in a different way.
I believe I understand, that switches in the Access-Layer can be layer2 devices (2950, etc), and devices in the Distribution Layer should be Multilayer devices such as Layer-3 switches (3750) and inter-vlan routing takes place at the Distribution layer. But what I do not understand – how does one account for bandwidth and traffic from the Access Layer switches to the Distribution Switches?
Let use a 24 port 2950 switch located at the Access-Layer. If everyone was online and communicating, the total traffic for the switch would be 4.8 Gbps. The latter is due to each port providing 100 Mbps but in Full-Duplex, so (100*2)*24. So, how does an engineer spec out the required uplink ports from the Access Layer to the Distribution?
I am sure this is easy; however, I am not getting the concepts. Any insight is great.

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As noted by Peter, edge hosts don't generally all concurrently push/pull their full port bandwidth for substained periods. However, host bandwidth usage often varies much by "kind" of host. For example, many server hosts are "busier" than most user hosts, so when designing networks you normally design for lower oversubscription ratios for server hosts than for user hosts. Old rule-of-thumbs ratios suggest oversubscription ratios of about 8:1 to 4:1 for servers, and about 48:1 to 24:1 for users.
Keep in mind that oversubscription ratios can be "skewed" by what the host is doing, i.e. not all server or user hosts have similar bandwidth demands. For example, your primary mail server or primary file server might be much "busier" than other server hosts. Likewise, some user hosts might be much "busier", for example, years ago I supported a LAN segment of CADD (20) workstations which had more traffic on their local LAN than the (2,000 user) corporate backbone.

Switch for Distribution Layer

I need your expert opinions for selecting a switch for distribution Layer
My requirement is 24Gig ports @ dist layer which will connect to 3750?s for server farm. I don?t want to negotiate with the bandwidth.
Which switch will be best for this scenario with max Backplane speed

Yes L3 routing will there.
I am considering 3750 for access switch for my server farm, and 4506 for distribution layer with the following port requirement
Catalyst 4500 Gigabit Ethernet Module, 6-Ports (GBIC)
Catalyst 4500 GE Module, Server Switching 18-Ports (GBIC)
Catalyst 4500 Enhanced 48-Port 10/100/1000 Base-T (RJ-45)
Catalyst 4500 Supervisor IV (2 GE), Console (RJ-45)
Most of the gigabit port will be occupied since I have a huge server farm to connect. By using almost all the ports on 4506 will I be able to get the maximum through put??
I have not considered 6500 due to budget. If I consider 6500 will it be a good design to have 6500?s on both core and distribution layer

Why access switch has flapping lead another distribution layer switch has root guard blocking and unblocking log

is it misconfiguration in Access Point's access switch or hacker attack from this switch?
many MATM-4-MACFLAP_NOTIF Host 0015.5dc1XXX VLAN 1 is flapping between port 1 and port 2
many MATM-4-MACFLAP_NOTIF Host 0015.5dc2XXX VLAN 1 is flapping between port 1 and port 2
many MATM-4-MACFLAP_NOTIF Host 0015.5dc3XXX VLAN 50 is flapping between port 1 and port 2
many MATM-4-MACFLAP_NOTIF Host 0015.5dc4XXX VLAN 50 is flapping between port 1 and port 2
last time we do not have these switch also meet the same issue about distribution layer switch have many ports down
last time someone mention a switch lost config, but today, i remember that the switch has reloaded and can be login again with radius,
today i do not connect any notebook with this switch and just have configured radius setting for window NPS radius server and then reload, then
i have dinner and come back and after a while, last time's issue happen again.
it seems port channel easy to have problem when abnormal traffic coming from access switch result in down port in distribution layer switch
i wonder whether someone can hack through the switchport access mode port and send some broadcast message

From that output and your description it looks like you have an STP issue as a result of misconfiguration somewhere.
Are your access points connected to switches with ports in access mode or trunk mode?

Do I make more then one diagram in Multi layer design Diagrams?

Do you make more then one Diagrams for Multi layer diagrams?
develop the multi layer design. ?
So I had to make a SSD or sequence Diagram now we have to make a multi design diagram?
for the multi design. will we just be creating one big diagram of the assignment for this part?
or is it going to be a collection of a bunch of separate diagrams. as books shows a few of them? regarding layers?
For example create a diagram to cover all different layers/steps
So should be a collection of 3 or more diagrams for Part 3 of TMA3
do I have this correct?

Just click on "Buy" one at a time. If you do them all in one sitting, they will be grouped as a single charge on your credit card.
Some online music download stores have the ability to combine multiple miscellaneous tracks into a single zip file for purchase and download, but the iTunes Store does not work that way.

EJB Exception Layer Design Feedback

I am in the process of creating a EJB layer talking to EIS Tier via JCA adapter. The EJBs are all stateless. The EJBs would be used by servlets, ejbs, or jsps. The EJBs are stateless in nature. I would like to make sure the exception hierarchy I have is considered good design practice and if there are suggestions on how I may improve it. I decided to go for unchecked exception all through my design (this I don't want to change -- pretty sure about this).
So, here is how I designed my exception class. One of my goals was to keep the exception handling very simple at the client-side and not inundate customers with too many types of exceptions. I decided to go for a has-A type relationship to model much of the exceptions because I couldnt really classify some of them to be a is-A. All exceptions thrown by my EJB layer would be contained within MyApplicationException. A getCause() will give insight into the cause at a very fine level. A getMessage() would suffice for most situations. Whereever exceptions are being thrown, the cause is being stored.
java.lang.Exception
--java.lang.RuntimeException
___ --MyBaseException
_______+----MyApplicationException (this is the container for all my exceptions)
_______+----MyConfigException
I created a exceptionhelper class that handles most of the exceptions and throws the right exception depending on the cause. For brevity sake, I am not including all code details in the sample below.
At the EIS Tier level, we have AutomationExceptions or Windows exception being thrown. These exceptions get thrown by the Windows code that is running in the EIS Tier (server). These exceptions are caught by the EJB code, then we do some processing like looking up the windows error code and producing the right message. The exception is then thrown back to the client with more information (MyApplicationException->getCause() would return AutomationException)
In the EJB code I have something like this.
try {
serverConn.connectToEISTier()
} catch (AutomatedException e) {
throw new MyApplicationException(Custom Message., ExceptionHelper.handleAutomatedException(e)); }
At the EJB level
we have create, and naming exceptions thrown either on failed lookup or something failing when creating the ejbs or there might be programming errors or there might be missing resources when EJB is trying to connect and possibly encounters data retrieval failures or Some sort of configuration error might be there in the deployment descriptor (user did soemthing wrong - wrong value for environment entry). All these are caught, and converted into runtime exception namely MyApplicationException. Where classification is deemed necessary we for e.g convert then contained exception to say configexception.
try {
lookup the context()
} catch(NamingException ex){
Cause = new myConfigException(lookup failed because .);
Throw new MyApplicationException(cause);
At the transport level: some communication exception happened.
At the client level:
Client might be calling the apis wrongly and breaching the contract, or possibly supplied wrong credentials.
Please share feedback / thoughts.

There is an interesting article that discusses EJB Exception Layering:
http://www-128.ibm.com/developerworks/java/library/j-ejbexcept.html
As a rule of thumb: in every layer, create two types of exceptions that extend from the appropriate class (application exceptions and system exceptions). The next layer catches these and handles them appropriately. This way, you hide the implementation of the layers. An example where this is implemented is Spring.
To summarize, I like your idea, but I define exceptions for every layer and not put them in one hiearchy.
Regards,
Lonneke

802.1x Guest Vlan and Routed access layer design

Hi!
For many reasons, I have to re-design my campus network in a more ISP like way. The plan is to move to a routed access layer in the next two years. I have 802.1x with guest vlan on my access ports(3750). I was reading on the subject and I found that the guest vlan feature was not availeble with internal vlan(routed port).
Is this limitation realy there, is there a way I can get around it without complicating my design even more. Do cisco have plan to lift this???

You cannot use/configure 802.1X on a routed port today. Typically, 802.1X is to be used for LAN edge ports.
The Guest-VLAN should work with a routed access design though. If your Guest-VLAN is chosen to be separate from say otherwise statically configured access VLANs, you would need to configure it via separate SVI with corresponding IP info (in a routed access model).
Hope this helps,

Question about service layer design

I have a question about the design/architecture of service model layers, specifically the task service layer.
Could a task service be a small "action", ie an operation that doesn't require composition? So if I have a requirement to allow customers to update their personal info, like address, would I have a task service named ChangeCustomerMailingAddress, that in turn calls the update operation on the Customer entity? Or would it be better to call the entity service directly? Another example would be retrieving data, like RetrieveCustomerBillingHistory, would that be a separate task service, or just a get/read operation on the Customer entity service?
Any insight is appreciated.
Thanks

You seem to be confused what all the different parts of Java do.
JRE - runtime environment, the minimum needed to run standard java applications
Java Standard Edition - the standard set of API's that form the base of most java applications. You need the J2SE SDK to compile these applications and the JRE to run them.
Now talking about "application design", I'm not sure what you mean. Are you talking about graphical user interfaces? In that case you would want to look into Swing, and that is indeed part of the standard edition API set.

DMZ layer design review

Hello,
I would appreciate if some can share their experience/problems with below design between Core-Firewall-DMZ-Aggregation setup.
1. There is a Layer-3 connectivity between core and firewall segments with L3 point-to-point links running OSPF. The active firewall(FW-A) forms ospf neighborship with Core-A and similarly FW-B forms ospf neighborship with Core-B and Core-A / Core-B form ospf neighborship.
2. Aggregation switch and Firewall are connected over L2 trunks and OSPF is running over SVIs (VLAN 13 / bcast segment), Aggregation switch-A is elected as DR and Aggregation switch-B is BDR, both firewalls have configured ospf priority to zero. FW-A(active) forms ospf adjacency with Aggregation-A and Aggregation-B, and each Aggregation switch forms ospf neighborship with the active firewall only.
Is there any chance that the broadcast network b/w Aggregation switch and Firewall can cause any problem when any of the aggregation switch reloads.
I have attached a rough sketch for better understanding.
Regards,
Akhtar

Hello,
I would appreciate if some can share their experience/problems with below design between Core-Firewall-DMZ-Aggregation setup.
1. There is a Layer-3 connectivity between core and firewall segments with L3 point-to-point links running OSPF. The active firewall(FW-A) forms ospf neighborship with Core-A and similarly FW-B forms ospf neighborship with Core-B and Core-A / Core-B form ospf neighborship.
2. Aggregation switch and Firewall are connected over L2 trunks and OSPF is running over SVIs (VLAN 13 / bcast segment), Aggregation switch-A is elected as DR and Aggregation switch-B is BDR, both firewalls have configured ospf priority to zero. FW-A(active) forms ospf adjacency with Aggregation-A and Aggregation-B, and each Aggregation switch forms ospf neighborship with the active firewall only.
Is there any chance that the broadcast network b/w Aggregation switch and Firewall can cause any problem when any of the aggregation switch reloads.
I have attached a rough sketch for better understanding.
Regards,
Akhtar

Logical and semantic layer design in four facts structure

Hi
My physical layer contains four fact table and several mutual dimensions.
The fact tables are not connected together.
My preference is to build four star schemes on one business model in the logical layer
and to provide one semantic layer with all four facts and mutual dimension.
Am I going throw a loops and data duplication adventure?
Is there any problem with this structure?
What is the best practice in this case?
The users should have the option to drag columns in all possible combination.
moshe

Hello, the feature of a connecting Crystal Enterprise via a Universe top of ERP/ECC comes with BI 4 Feature Pack 3 which is not available yet
Ingo's book includes information on that release BI 4.0 FP 3
Please see Figure 3 on this blog /people/tammy.powlas3/blog/2011/12/04/sap-integration-with-businessobjects-bi-40-feature-pack-3-asug-webcast-summary
Regards,
Tammy
Edited by: Tammy Powlas on Dec 17, 2011 2:22 PM

Software Distribution & Patching Design Issues - Migration of Packages SCCM 2007 to Application or Conventional Packages in SCCM 2012

Hi All
I am starting in discussion to deep root on Software Distribution & Patching model in large environments from SCCM 2007 migrating to SCCM 2012.
Below are certain assertions i am putting forward for your expert views or you may in a similar situation
1- I have migrated the packages from SCCM 2007 to SCCM 2012 as conventional methods, now i am deploying them [ not migrated the advertisements and collections ], so while deploying i am facing a peculiar situation that the deployment when created is of the
name "<<Package name>>(program)". I am not able to rename the deployment for the conventional packages. is there a way out to that??
2- Will the collection queries work the same in SCCM 2012 as was in SCCM 2007??
3- In SCCM 2012 Primary site there is default role called Site System role in that there is tab for proxy settings. I have observed that if do not check the proxy tab there and punch in proxy IP and port then after some time in the WSUS server the update
source and proxy server tab the proxy option gets unchecked and hence the sync in software update point status appears failed. Is that anyone else also has observed !!!!!
Regards Sushain KApoor

This is a duplicate of
https://social.technet.microsoft.com/Forums/en-US/2ddb8170-529b-4652-830e-fd0ade384b98/software-distribution-patching?forum=configmanagermigration
Please do not double post.
Jason | http://blog.configmgrftw.com | @jasonsandys

Physical layer design in obiee 11g

Hi,
I need a clarification regarding physical layer degin in obiee 11g,I imported Oracle Apps reports ,but could not find any keys there at table level.So should i create keys on the imported table level or at the alias level of the imported tables.
Thanks-Bhaskar

If you import a transaction table you may have keys imported in physical layer but when you going with warehouse table you may not have keys at database level, you define them using join in physical layer.
We have surrogate keys in dwh.
Hope this clear your doubt, if helps pls mark

How to span vlans across core layer in core/distribution/access campus design?

Hi,
I studied Cisco Borderless Campus Design Guide 1.0 (http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Campus/Borderless_Campus_Network_1-0/Borderless_Campus_1-0_Design_Guide.html) last week because we plan to redesign our campus backbone to a three tier Core/Distribution/Access Design.
Today we use a collapsed backbone where a lot of vlans are spanned across the backbone because they are needed in different buildings.
Could anybody give me a hint how Cisco recommends to deal with that kind of vlans in the multi-tier design?
In my eyes between core and distribution layer there is only routing functionality and no l2 transport of vlans.
So using the same vlan in different buildings seems not to be supported?
Best Regards,
Thorsten

Thorsten
Just to add to Joseph's post.
It is quite common for a vlan to be spanned when it doesn't actually need to be ie. the network has evolved that way.
Most things do not need L2 adjacency, they can happily use L3. Servers sometimes do but in the campus design your servers are usually located in one site so you don't need to extend vlans to other sites in your campus.
Not suggesting this is the case for you but it may be worth checking whether you really do. (apologies if you already have)
As Joseph mentioned you really want to avoid it if at all possible ie. ideally all connections to the core switches are L3 ie. no need for vlans at all in the core.
If you need to extend a few vlans then you can do this but still route for all other vlans ie. you would configure your distribution to core connections as trunks and then allow the vlans you need to extend plus one other vlan, unique per distribution pair, to route all other vlans. So per site your distribution switches route all vlans except the extended vlans and of they need to route to a vlan in another site they use that unique vlan.
But this is not ideal because you then need to extend certain vlans across the core and because you are using L2 connections STP could come into it although that does depend on your core switch selection eg. 4500/6500 VSS etc. would alleviate this.
There are ways to extend vlans across a L3 network but the solutions available are very much dependant on the kit you use and their capabilities so if you do need multiple vlans in multiple sites but still want to keep a L3 core you may want to investigate some of those before purchasing kit (unless of course you have already purchased it).
What you do really depends on just how many vlans you actually need to extend between sites.
Jon

Ask the Expert: Hierarchical Network Design, Includes Core, Distribution, and Access

Welcome to the Cisco® Support Community Ask the Expert conversation. This is an opportunity to learn and ask questions about hierarchical network design.
Recommending a network topology is required for meeting a customer's corporate network design needs in their business and technical goals and often consists of many interrelated components. The hierarchical design made this easier like "divide and conquer" the job and develop the design in layers.
Network design experts have developed the hierarchical network design model to help to develop a topology in discrete layers. Each layer can be focused on specific functions, to select the right systems and features for the layer.
A typical hierarchical topology is
A core layer of high-end routers and switches that are optimized for availability and performance.
A distribution layer of routers and switches that implement policies.
An access layer that connects users via lower-end switches and wireless access points.
Ahmad Manzoor is a Senior Pre-Sales Engineer at AGCN, Pakistan. He has more than 10 years of experience in first-rate management, commercial and technical skills in the field of data communication and services lifecycle—from solution design through sales pitch, designing RFPs, architecture, and solution—all with the goal toward winning projects (creating win/win situations) of obsolete solutions. Ahmad also has vast experience in designing end-to-end data centers, from building infrastructure design to data communication and network Infrastructure design. He has worked for several large companies in Pakistan and United Arab Emirates markets; for example, National Engineer, WATEEN Telecom, Emircom, Infotech, Global Solutions, NETS International, Al-Aberah, and AGCN, also known as Getronics, Pakistan.
Remember to use the rating system to let Ahmad know if he has given you an adequate response.
Because of the volume expected during this event, Ahmad might not be able to answer every question. Remember that you can continue the conversation in the Solutions and Architectures under the sub-community Data Center & Virtualization, shortly after the event. This event lasts through August 15, 2014. Visit this forum often to view responses to your questions and the questions of other Cisco Support Community members.

Dear Leo,
We are discussing the following without any product line, discussing the concept of hierarchical design, which will help you to take decision which model is better for you Two Layer or Three Layer hierarchical model.
Two-Layer Hierarchy
In many networks, you need only two layers to fulfill all of the layer functions—core and aggregation
Only one zone exists within the core, and many zones are in the aggregation layer. Examine each of the layer functions to see where it occurs in a two-layer design:
Traffic forwarding—Ideally, all interzone traffic forwarding occurs in the core. Traffic flows from each zone within the aggregation layer up the hierarchy into the network core and then back down the hierarchy into other aggregation zones.
Aggregation—Aggregation occurs along the core/aggregation layer border, allowing only interzone traffic to pass between the aggregation and core layers. This also provides an edge for traffic engineering services to be deployed along.
Routing policy—Routing policy is deployed along the edge of the core and the aggregation layers, generally as routes are advertised from the aggregation layer into the core.
User attachment—User devices and servers are attached to zones within the aggregation layer. This separation of end devices into the aggregation permits the separation of traffic between traffic through a link and traffic to a link, or device. Typically, it is best not to mix transit and destination traffic in the same area of the network.
Controlling traffic admittance—Traffic admittance control always occurs where user and server devices are attached to the network, which is in the aggregation layer. You can also place traffic admittance controls at the aggregation points exiting from the aggregation layer into the core of the network, but this is not common.
You can see, then, how dividing the network into layers enables you to make each layer specialized and to hide information between the layers. For instance, the traffic admittance policy implemented along the edge of the aggregation layer is entirely hidden from the network core.
You also use the core/aggregation layer edge to hide information about the topology of routing zones from each other, through summarization. Each zone within the aggregation layer should have minimal routing information, possibly just how to make it to the network core through a default route, and no information about the topology of the network core. At the same time, the zones within the aggregation layer should summarize their reachability information into as few routing advertisements as possible at their edge with the core and hide their topology information from the network core.
Three-Layer Hierarchy
A three-layer hierarchy divides these same responsibilities through zones in three vertical network layers,
Traffic Forwarding—As with a two-layer hierarchy, all interzone traffic within a three- layer hierarchy should flow up the hierarchy, through the layers, and back down the hierarchy.
Aggregation—A three-layer hierarchy has two aggregation points:
At the edge of the access layer going into the distribution layer
At the edge of the distribution layer going into the core
At the edge of the access layer, you aggregate traffic in two places: within each access zone and flowing into the distribution layer. In the same way, you aggregate interzone traffic at the distribution layer and traffic leaving the distribution layer toward the network core. The distribution layer and core are ideal places to deploy traffic engineering within a network.
Routing policy—The routing policy is deployed within the distribution layer in a three- layer design and along the distribution/core edge. You can also deploy routing policies along the access/distribution edge, particularly route and topology summarization, to hide information from other zones that are attached to the same distribution layer zone.
User attachment—User devices and servers are attached to zones within the access layer. This separation of end devices into the access layer permits the separation of traffic between traffic through a link and traffic to a link, or device. Typically, you do not want to mix transit and destination traffic in the same area of the network.
Controlling traffic admittance—Traffic admittance control always occurs where user and server devices are attached to the network, which is in the access layer. You can also place traffic admittance controls at the aggregation points along the aggregation/core edge.
As you can see, the concepts that are applied to two- and three-layer designs are similar, but you have more application points in a three-layer design.
Now the confusion takes place in our minds where do we use Two Layer and where the Three layer hierarchical model.
Now we are discussing that How Many Layers to Use in Network Design?
Which network design is better: two layers or three layers? As with almost all things in network design, it all depends. Examine some of the following factors involved in deciding whether to build a two- or three-layer network:
Network geography—Networks that cover a smaller geographic space, such as a single campus or a small number of interconnected campuses, tend to work well as two-layer designs. Networks spanning large geographic areas, such as a country, continent, or even the entire globe, often work better as three layer designs.
Network topology depth—Networks with a compressed, or flattened, topology tend to work better as two-layer hierarchies. For instance, service provider networks cover large geographic areas, but reducing number of hops through the network is critical in providing the services they sell; therefore, they are often built on a two-layer design. Networks with substantial depth in their topologies, however, tend to work better as three-layer designs.
Network topology design—Highly meshed networks, with many requirements for interzone traffic flows, tend to work better as two-layer designs. Simplifying the hierarchy to two levels tends to focus the design elements into meshier zones. Networks that focus traffic flows on well-placed distributed resources, or centralized resources, such as a network with a large number of remote sites connecting to a number of centralized Data Centers, tend to work better as three-layer designs.
Policy implementation—If policies of a network tend to focus on traffic engineering, two-layer designs tend to work better. Networks that attempt to limit access to resources attached to the network and other types of policies tend to work better as three-layer designs.
Again, however, these are simple rules of thumb. No definitive way exists to decide whether a network should have two or three layers. Likewise, you cannot point to a single factor and say, “Because of this, the network we are working on should have three layers instead of two.”
I hope that this helps you to understand the purposes of Two Layer & Three layer Hierarchical Model.
Best regards,
Ahmad Manzoor

Distribution layer design

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