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Table of Contents
Design and implement a network prototype using a network simulator (or lab devices), which
- Introduction..........................................................................................................................................................
- According to Scenario..........................................................................................................................................
- Network design models........................................................................................................................................ - Flat Network Design Models....................................................................................................................... - Ring Network Design Model:...................................................................................................................... - Mesh network design model........................................................................................................................ - Two tier architecture design model..............................................................................................................
- Analysis of the network design and the contribution to the design of a scalable and reliable network.............. - The Access Layer......................................................................................................................................... - Distribution Layer........................................................................................................................................ - The Core layers............................................................................................................................................
- Features of three Tier architecture..................................................................................................................
- and their related issues. The explanations should contain the possible solutions provided at Layer A detailed discussion of LAN redundancy concepts, network features, such as bandwidth and load
- and 3 of the OSI Model......................................................................................................................................
- Possible solution for the above issues referencing layer 2 and layer 3 of the OSI Model.............................
- requirements:.................................................................................................................................................. incorporates redundancy at Layer 2 and 3 and link aggregation features with the following
- Include at least three Layer 2 switches..............................................................................................................
- According to Scenario........................................................................................................................................
- Design with scalable and reliable network.....................................................................................................
- IP configuration and Ip addressing.................................................................................................................
- Using rapid PVST+ as spanning tree protocol with configuration.................................................................
- Use link aggregation in the main active link..................................................................................................
- Provide a redundant gateway using a suitable first-hop redundancy protocol...............................................
- A rationale about the selection of the networking devices for the prototype.................................................
- In the core layer..........................................................................................................................................
- In the Access Layer....................................................................................................................................
- Wireless networking devices......................................................................................................................
- A detailed explanation of how the first-hop redundancy protocols will work for IPv4 and IPv6..................
- Conclusion..........................................................................................................................................................
- organizational requirements. The presentation includes:................................................................................... Part 2: Produce a presentation slides which show an appropriate WAN Solution to a set of
- Introduction........................................................................................................................................................
- About WAN Slides..........................................................................................................................................
- VPN................................................................................................................................................................
- Types of VPN..................................................................................................................................................
- Remote Access VPN..................................................................................................................................
- Site to Site VPNs:.......................................................................................................................................
- Features of VPN..............................................................................................................................................
- Privacy:..................................................................................................................................................
- Software/features:..................................................................................................................................
- Security:.................................................................................................................................................
- Price:......................................................................................................................................................
- Speed:.....................................................................................................................................................
- Cost analysis of VPNS....................................................................................................................................
- NordVPN...............................................................................................................................................
- ZenMate.................................................................................................................................................
- ExpressVPN...........................................................................................................................................
- Issue in VPN...................................................................................................................................................
- Unable to Establish a Tunnel:................................................................................................................
- Rejected VPN connection:.....................................................................................................................
- Acceptance of Unauthorized Connections:............................................................................................
- Conclusion..........................................................................................................................................................
- Hierarchy
- Modularity
- Resiliency Flat Network Design Models The flat network is typically not designed to have more than a couple of hundred stations. Instead, it has one enormous broadcast domain. The flat network model is typically not designed to support the needs of most networks. Its shortcomings are mainly due to its lack of scalability. If a single network interface card failed, the entire network would crash. This effect is caused by the fact that a single broadcast goes through the same NIC. 4
Ring Network Design Model: “In a ring network, every device has exactly two neighbors for communication purposes. All messages travel through a ring in the same direction (either "clockwise" or "counterclockwise"). A failure in any cable or device breaks the loop and can take down the entire network. To implement a ring network, one typically uses FDDI, SONET, or Ring technology. Ring topologies are found in some office buildings or school campuses.” (mitchell, 2019) Mesh network design model 5
Analysis of the network design and the contribution to the design of a scalable and reliable network As per the scenario, I have to design a three-architecture of the college network. It helps to create scalable and manageable networks which can adapt to college network growth providing robustness. It is clear design, which makes easy to understand and manage it properly. The Access Layer It is the lowest level of the Cisco three network model. Ensures that packets are delivered to end users devices. It sometimes referred to as the desktop layer, because it focuses on connecting client nodes to the network. This layer device includes hubs, multi-station access units and switch. For the VLANs, implementation access switches propagate 2 broadcast domain t end users. Access switches also run spanning tree protocols for loop-prevention mechanism. At this layer, simple fixed form-factor layer 2 switches are used to support more users without expanding access switches but simply adding more access switches but simply adding more access switch. The access layer provides user access to local segments on the network. The access layer is characterized by switched LAN segments in a campus environment. It is for the end user devices which take the connectivity from the distribution layers. The key attributes of the access layer are defined as follow: - i) High availability vi) Rate Limiting ii) Security vii) STP iii) Authentication viii) PoE iv) Broadcast Control ix) Voice VLAN v) Qos 7
Distribution Layer This layer is responsible for the redundancy connectivity with core and access layer also often consider as the brain of the network reside. Since many decisions such as: - filtering, cloud of service is performed under distribution layer. Distributed layer contains advanced layer 3 switches that can support a wide ray of functionality to support the service required from this layer. Some of the key attributes of this layer are define below: - i) Access control to core devices vi) Route Summarization ii) Redundancy to access devices vii) Policy Routing iii) Routing protocol boundaries viii) Security iv) Redistribution ix) Routing between VLANS v) Filtering x) Separate multicast and broadcast domains. (Using Layer 2 and 3 technologies). xi) Media translation and boundaries (e.g. Fast Ethernet to Gigabit Ethernet) 8
- Reliability and fault tolerance
- Redundancy and load balancing
- Routing services between LANs and VLANs. Features of three Tier architecture Better Performance It is recommended that core layer switches should have very fast switching abilities. The distribution switches should also be very fast and redundant. The result of using very fast core and distribution layer switches would guarantee very fast networks. Better Scalability. When you implement a network a hierarchical network model, expansion is simplified since all the roles are well defined. For example, if you have 5 access layer switches, connected to 2 distribution 10
layer switches, you can add the access layer switches until all the ports on the distribution switches are filled up Better management and troubleshooting It helps to manage and troubleshoot network quickly because of its layered structure. It allows a better filter/policy creation application, such as firewalling and routing. It is the ability to make configuration changes in the network, the use of the hierarchical model eases management of the switches. For example, making changes on one layer would be simplified since we can assume that the role of switches in that layer all perform similar functions, further, the modular design means that management does not mean that the network is down due to maintenance due to redundancy.”(Ikechukwu, 2015) A detailed discussion of LAN redundancy concepts, network features, such as bandwidth and load and their related issues. The explanations should contain the possible solutions provided at Layer 2 and 3 of the OSI Model. Lan Redundancy is the important part of the network design to prevent the disruption of network services. Network redundancy is a key to maintaining network reliability. Multiple physical links between devices provide redundant paths. The network can then continue to operate when a single link or port has failed. Redundant links can also share the traffic load and increase capacity. Multiple paths need to be managed so that Layer 2 loops are not created. The best paths are chosen, and an alternate path is immediately available should a primary path fail. The Spanning Tree Protocols are used to manage Layer 2 redundancy. Redundant devices, such as multilayer switches or routers, provide the capability for a client to use an alternate default gateway should the primary default gateway fail. A client may now have multiple paths to more than one possible default gateway. First Hop Redundancy Protocols are used to manage how a client is assigned a default gateway, and to be able to use an alternate default gateway should the primary default gateway fail. The three-tier hierarchical network design that uses core, distribution, and access layers with redundancy, attempts to eliminate a single point of failure on the network. Multiple cabled paths between switches provide physical redundancy in a switched network. This improves the reliability and availability of the network. Having alternate physical paths for data to traverse the network makes it possible for users to access network resources, despite path disruption. Redundancy in a hierarchical network.Suppose PC1 is communicating with PC4 over a redundant network 11
sending BPDU message. There are different types of spanning tree protocol in which we can select the root bridge of the switches for VLANs also as per requirements. Which helps to use the other redundant link in the network to increase the bandwidth of the network and balance the load evenly among the switches in the network. By selecting a specific root bridge for VLANs in different switches helps to reduce the load on the switches and increase the bandwidth utilizing the unused redundant links in switches. For example, I have used Rapid-PVST spanning tree protocol in switches of NEC LAN network to avoid looping in a network Core switch 1 Core switch 2 13
In the above switches configuration, we can see that in both switches STP protocol is running to prevent looping. In Core switch 1 Rapid per-VLAN spanning tree protocol is running giving VLAN 1-40 as a priority as the root bridge and in Core switch 2 giving VLAN 40- as a priority as the root bridge in that switch. This protocol not only helps to utilize the redundant links of switches but also balance a load of traffic in switches and increases the bandwidth. As the spanning tree protocol blocks the redundant links in switches to prevent routing loop in the network, link aggregation protocol helps to utilize the blocked redundant links by combining the number of physical links between switches into on logical link which also helps to increase the overall speed of the switch to switch communication. For the demo, I have used link aggregation protocol over Ether-Channel interface of core switches to increase the bandwidth and balance the load on switches. 14
Router1 Router 2 In the above configurations, the routers is in HSRP protocol is enabled and the routers are active for some of the sub-interfaces. Router 1 is active for sub-interface fa0/0 and router 2 fa0/0 is also for same interference. Because of this it will not solve only solve layer 3 redundancy issues but it allows to increase the bandwidth of routers by making some of the interference standby. Design and implement a network prototype using a network simulator (or lab devices), which incorporates redundancy at Layer 2 and 3 and link aggregation features with the following requirements: Include at least three Layer 2 switches.
1. Provide redundant link between all the switches. 3. Use Rapid PVST+ as **spanning tree protocol.
- Use link aggregation in the main active link.
- Provide a redundant gateway using a suitable first-hop redundancy protocol.** 16
According to Scenario I am newly appointed network admin of Nepal Education Centre (NEC) which is the leading colleges in Nepal. It has multiple campuses and resources are centralized in head office. It has partnership with different international university and it has agreement to share educational resource including eBooks. There are six branches, which are Kathmandu, Pokhara, Chitwan, Bhaktapur, Lalitpur, and Butwal including one head office in Kathmandu. Currently there is no network between campuses. Now, Management decided to interconnect all the campuses with Private lease line and have public WAN connection with partners. Therefore, to connect all the branch offices and the partners, I have redesigned all the LAN and WAN to fulfill the requirement of the NEC management. I think I have designed suitable structure of network to connect the partners and branches to all over the country. The followings are the detailed explanations and descriptions of proposed network designs and its functionalities. Design with scalable and reliable network According to scenario, I have to follow the Three Tier Network Model. In Modern days, most of the networks are designed with Three Tier Network Design Model. As in the below figure, this network design models have three functional levels of the network as the Core, Distribution, and Access. The highest level is network core which interconnects the distribution layer Resources. Access routers connects to the distribution layer moving up to the model and to workstations and other resources moving down to the model. Fig: Hierarchical Model 17
Using rapid PVST+ as spanning tree protocol with configuration Enabling rapid per VLAN spanning tree in all switches 19
Adding the spanning-tree vlan 2 root primary Spanning-tree vlan 5 root primary Use link aggregation in the main active link. Adding eight-port link between core switch1 and core switch 2 Configuration of ether channel in core switch 1 by writing the command in global configuration mode as int range fa0/8-fa0/11 for configuring ether channel. 20
