Analyzing and Improving

The Dimension Network

An Impact Analysis of Moving To The Cloud

Amir Muhawesh, Denis Bazalirwa, Mohammad Alsahaiti

SEIS 645 Fall 2013

Introduction

In this paper, we will be analyzing the potential impact on the network for Dimension, a large global company, as a result of moving business applications from its data centers internally, to an externally hosted cloud computing setup.Three main application buckets will be examined to potentially be moved into the cloud. The buckets can roughly be categorized into desktop applications (Email, Sharepoint etc), voice and communication, and the DMZ. We will also be analyzing the impact of moving the entire phone system from traditional phone lines to IP telephony. (Adding to the current 3,000 employees already using VOIP)

Proposal and OutcomeUsing our impact analysis and in class learnings throughout the semester, we propose that the three application buckets be moved to the cloud entirely. We are also recommending moving the entire Dimension voice system to IP telephony. In order to ensure enhanced performance, we recommend two instances of the cloud be created to allow globally placed employees equal access to the clouds. We will create one instance of the cloud in North America, and the other will be in Asia. This should evenly distribute employee access to the cloud. The North American instance and Asian instances of the cloud will be connected to the Dimension network via MPLS technology, which will ensure secure connectivity, high performance and QOS between internal servers and the cloud.As a result of moving our three application buckets to the cloud, we will be able to phase out the regional data centers, leaving the primary Dallas Data Center as the only remaining data center. Due to the high performance MPLS provides, internal employees should not be able to notice a discernable difference between using applications as if they were still located on internal servers versus being on the cloud. Because of this, we do not anticipate any level of impact on the network that would be cause for concern. Rather, the real noticeable impact of moving the applications to the cloud will be the major switch to using to Ip telephony as the sole voice communications method within the company, a change that should net a positive for the company in terms of performance. Throughout this analysis, we will provide details regarding the current state of the Dimensions network, assumptions that we have made during our impact analysis, the future state of the Dimension network, and how we propose to reach that future state, walking through the relevant layers of the network.

Considerations What we know about Dimensions current state Dimension is a global manufacturing company (the business type has no impact for our project considerations). Dimension employs 100,000 people in 40 countries. With more 2000 branches, we are given an average of 50 people per branch. Internet DMZs (corporate branches?) in four regions of the world. The primary datacenter is in Dallas, Texas, and the main corporate office is in Minneapolis, Minnesota. Each of the four regions contains a secondary data center. 3000 users at 100 locations are currently using IP telephony, leaving us with 97,000 people and 1,900 locations still using the standard PBX technology. External employees accesses Dimensions network via VPN. Dimension is taking an aggressive approach to adopting the cloud service.(This will influence our assumptions about current and future state)

Some critical business applications will remain on the global datacenter in Dallas

Assumptions about the Current state

Applications will be classified into three general categories:

DMZ and other security Voice and video Desktop applications (includes business applications) All employees will have access to desktop applications and voice, but will not be using it concurrently. Using our assumptions of having an average of 50 employees per branch, we are going to use the following percentages to gauge our network needs.

A maximum of 50,000 employees will ever be concurrently working due to their disbursement around the world. 20 percent of employees may be concurrently using email Only 1 percent will be using video 25 percent of employees may be concurrently using voice

Dimension has made significant network upgrades in past years and has already prepared for future upgrades and upcoming movement into the cloud

Dimension is using a private IP addressing scheme with NAT. This should provide more than enough IP addresses for additional devices that may come onto the network. A SONET network is in place for connections going from company locations into the MPLS WAN. Current LAN and WAN networks are being supported by Standard Ethernet. Each regional data center contains a DMZ.

Desktop and business applications should be able to be moved to the cloud from internal servers with no major impact Remote employees access the company network using a VPN service. When connected, all of their traffic will be routed through the company WAN, whether for personal or business use.

Already using Autonomous system inter-domain path vector routing (BGP) and will further leverage this to provide routing to servers moved from datacenters into cloud. Dimension has implemented BGP path vector routing which should making the move for the servers internally into the cloud easier. Data is saved to the network storage devices that are maintained throughout the four data centers, a majority of the actual applications however, especially business applications, are hosted in the companys primary datacenter in Dallas

Wireless LAN is implemented to a limited degree in most locations TCP and UDP transport protocols are being used

RTP on top of UDP is currently being used for video conferencing, stored video streaming, and other app level communications

Current Data Network

Current Phone System

Assumptions about the Future State

Data centers in South America, Europe, and Asia will be eliminated. The data center in Dallas will remain the primary datacenter.

All three categories of services will be moved into the cloud

Unified communications (IP Telephony, video conferencing, etc.)

Desktop applications

Internet DMZ

Business applications still be hosted in Dallas We will have two instances of the cloud in order maintain a relatively close proximity to all locations. The cloud(s) are going to host all of systems previously hosted in the regional data centers. Sites continuing to rely on PSTN service will be upgraded to IP telephony. This will allow us to use our MPLS WAN connections between all company sites and employees and reduce our reliance on the PSTN. Our two cloud instances will be connected by MPLS into the Dimension MPLS WAN private network All Dimension phones will be move to IP Telephony and all PBX systems eliminated The current level of voice, video, and desktop usage is not going to change. Likewise, wireless access and VPN demands will not increase or decrease. We are assuming our cloud providers have full control over our environments, and can provide full Iaas and Saas with basically no limitations (for the purpose of this project)

Detailed Network Impact Analysis

Because Dimension has been aggressively preparing for the move to the cloud, the impact of moving desktop applications, communications and DMZs to the cloud should not have a massive impact on its network in terms of how it is laid out. The biggest impact will be moving from PBX to IP Telephony. We will review this impact on each layer.Physical LayerCurrent State User workstations are connected to their local switch using a standard Cat 5 cable. From there, the connection is made to a core switch by fiber optic cable in order to support the bandwidth needs all of the users in the office. We would use a star topology in this case, as a mesh topology would not be needed. From this point a router connects the LAN to the corporate WAN, which is connected through the MPLS WAN via SONET STS-1 fiber optic cables. SONET STS-1 lines provide data rate capacity of 51.84 Mbps, which should support even peak usage.Dimension is currently satisfying its voice needs by mixing PBX and IP telephony. A majority of the phones are connected to PBX to the PSTN using a T-1 line. This provided each office with twenty-four voice channels with a bandwidth of 1.544 Mbps. While this may be adequate for some smaller sites that do not utilize the phone systems to a great degree, larger sites have DS-3 service, providing 44.74 Mbps of bandwidth and more than 600 voice channels. 3000 employees at 100 sites have been upgraded to IP telephony. While the upgrade was being performed, fiber optic lines serving these sites were also upgraded to STS-3, giving us a possible bandwidth of 155.520 Mbps. Each of the four data centers is connected to the WAN via STS-1. The primary data center, (Dallas) acts as the hub, with each regional data center being protected by a firewall DMZ.Future State impactMoving the hosting of desktop applications and getting rid of the some of the datacenters does not raise any potential issues with the physical layer in our perspective, as the amount of usage is not going to change, simply change location. However, WAN traffic will be increased to the cloud instances due to the elimination of the three data centers, the two clouds will be responsible for handling the increased traffic removed data center and creating the need for more bandwidth.The largest impact will be due to the move to IP telephony. Although this conversion will allow us to fully utilize our MPLS WAN, it will require us to take on traffic our network has not previously encountered. Most of our sites have been using STS-1 service until now. Giving us a bandwidth capacity of 51.840 Mbps. Working on the assumption that we will average about 25 percent voice usage and assuming 50 employees at each site, we estimate about the equivalent of DS-1 service, 1.544 Mbps. This should be satisfied by our upgrade of our SONET service from STS-1 to STS-3, which will increase bandwidth from 51.840 Mbps to 155.52 Mbps.The rest of the sites are also using STS-1, including our Dallas data center.Using the same usage assumptions and assuming 200 employees, we calculate roughly 55 employees on average and about 70 at peak usage. This amount of usage can be satisfied using DS-3 at 44.74 Mbps.

Data Link LayerCurrent StateDimension is currently using the standard Ethernet protocol over its STS-1 lines, using 10-base-F implementation. In regards to the wired LAN, there is no need for a collision avoidance or collision detection because we are using a full-duplex switched Ethernet. Our local LANs use a star topology and are connected by backbone networks through both two and three layer switches. The wireless Ethernet utilizes both extended and basic service sets for its architecture, and distributed coordination function MAC protocol for CSMA/CA access.Although virtual LANS are currently being used, none are implemented for voice traffic for the IP telephony users. Dimensions WAN utilized a mesh topology running on SONET over Ethernet. Future State Impact The changes to data link layer will be limited. We will upgrade to the fast Ethernet protocol over STS-3 lines using Non return to zero inverted mapping to give us a maximum of 100 Mbps. The increased available bandwidth will allow us to accommodate increased traffic due to the new IP telephony users.We are planning on creating new VLANs to handle the IP telephony traffic, separating data VLANs and traffic from data traffic. We will be tagging voice frames for quality of service purposes, because separating the voice and data on different VLANs gives us logic, but not physical isolation. On the same note, all remaining layer two switches will be replaced with layer 3 switches to support quality of service prioritization.

Network LayerCurrent StateWe have three thousand users currently on IP telephony. The private addressing scheme being used (10.0.0.0) will cover Dimensions move to purely IP telephony, and we have enough public IP addresses to allay any concerns. Packets leaving the network LAN will pass through an NAT router which will translate the private IP address with the source address, as well as translate incoming packets from their public to private IP address. Layer two and three switches, with traditional routers are currently being used to handle traffic in the LAN. Media access control is being used by the layer 2 switches from the hosts network card to determine where each frame should be forwarded to. These are used because of their efficiency in forwarding, as no modification is done to the data packets.Future state Because we are transferring to an all IP telephony model, new IP addresses will be needed. Because all of these IP addresses will be private, our existing IP addresses will not need to be renumbered. As mentioned earlier, Dimensions currently owns a sufficient number of public IP addresses to handle the switch without issue. Due to the fact that our internet service provider is not being changed, the NAT global address currently being used for external communications does not need to be changed. Circuit switched communication is inherently more reliable than IP telephony, IP alone doesnt give an assurance that data packets are going to be delivered in the correct sequence or that packets will not be dropped during congestion. This means we will need to rely on the transport and application layers to reach the QoS needed for IP telephony, as well increasing the available bandwidth as mentioned in the physical layer. By transferring some DMZs, our desktop applications, and communications to the cloud, we find ourselves in need of a switch smart enough to handle QoS and forward necessary packets throughout the network. For this, we will use a layer 3 switch. This will allow us to place the switches throughout the network, while lowering latency, utilizing high performance packet switching, increasing security and the ability to implement QoS.

Transport LayerBecause we are moving our desktop applications, unified communications, and DMZs to the cloud, the majority of our transport layer should be unaffected, which hold the responsibility of connecting processes through process to process delivery. Since these processes and applications are moving to the cloud, they take a large part of the consideration of the transport layer with them.Current StateWindow sizes for TCP have already been maxed out with 65,000 byte receiver window size and assumption that all operating systems being used support window scaling. Port numbers being used currently to classify processes sending and receiving traffic will remain unchanged, as well as the current UDP and TCP protocols which will shouldnt have an impact on applications moving into the cloud.Future State ImpactAs mentioned, our main concern on the transport layer will simply be the increased traffic on the network. There are a few things we can do in this layer to potentially alleviate some of this impact. Our use of the real time transport protocol on top of UDP could be expanded to handle the increased IP telephony load on the network. It is necessary to start controlling congestion by increasing available bandwidth as the physical layer to address the increase in network traffic, however voice traffic is fairly predictable for an individual connections, so the main consideration is the number of simultaneous connections occurring.Our main weapon on the transport layer will be end to end quality of service to ensure IP telephony is given main priority. In order to do this, VOIP traffic both locally and over the wide area network must be given high priority, which means, again, that layer three hardware must be used. Additionally, we will use the weighted fair queuing scheme to prioritize traffic. IP telephony would be given highest priority, using the H.323 protocol (over UDP). This would be followed in priority by streaming live broadcasts, and streaming stored video.

IP TelephonyFor all call within Dimensions, no PSTN connection will be made. This has the potential for large saving in terms of long distance charges. This will require an initial connection via the MPLS WAN into the IP telephony server which lies in the cloud. Once this connection is established, the two devices will be able to communicate directly through the MPLS WAN without the need for the IP telephony server in the cloud. A call going from an internal phone to an external number will be started on the MPLS WAN through an IP telephony server, again on the cloud. A voice gateway will the call through the PSTN. Data will then flow through the MPLS WAN, IP telephony server, through the gateway to connect the devices. An incoming call will be handled in the same manner, but in the opposite order of events.

Summary & Conclusion

Due to Dimensions approach of aggressive adaptation to the cloud, its network infrastructure was already in a decent state to move to the cloud. Because of this we found the impacts on the network to be minimal. As mentioned, the main impact will be moving from traditional phone systems to IP telephony. The following summarizes the impacts discussed in this paper. Physical Layer New IP Telephones No need for new Ethernet jacks or cables We can plug phones into existing jacks, and plug PCs into phones STS-3 optical cables to carry increased traffic Data Link Layer Upgrade to Fast Ethernet network protocol New VLANs will be configured to provide a separation of voice and data Eliminate layer 2 switches implement layer 3Network Layer Impacts of IP Telephony in the Cloud Configure QoS to provide proper priority for voice traffic Require additional IP addresses allocated from our private network address scheme for up to 100,000 new IP phones Transport Layer Impacts of IP Telephony in the Cloud Transport protocols RTP on top of UDP Quality of Service Need end-to-end QoS across both LAN and WAN with level 3 awareness Begin using the Weighted Fair Queuing scheme

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