Perfigo Design Comparison Overview

Transcription

1 Perfigo Design Comparison Overview The University of Utah has chosen the Cisco Perfigo product to provide a replacement for the University WANA product. The Perfigo initial implementation will replace only the existing WANA functionality. The University will not deploy any additional feature sets. The Perfigo installation will cover the entire University/University Hospital campus network system. Due to the nature of the Perfigo product and the current implementation layout of the campus network system, the University has different design choices available to it. The optimum choice will combine ease of maintenance, distribution of load and the minimizing of costs. The basic design of the Perfigo product is a Smart Manager that controls 1 or more of the Smart Servers. The Smart Manager communicates to the Smart Servers via secure routed connections. The individual Smart Servers communicate directly to the wireless Access Points via a Layer 2 connection. The Smart Servers have two main functions in the initial deployment of the U. They act as authentication devices for clients attempting to connect to the wireless network and they act as routers that take the layer 2 traffic and route it appropriately. Figure 1 shows the basic Perfigo conceptual drawing. Figure 1 Perfigo Basic Conceptual Diagram Page 1 of 6

2 Detail The Perfigo design options break into two discrete options with a third option that is simply a variation of one of the former two. In all design options, the University of Utah would maintain two Smart Manager units. One Smart Manager would reside in the Komas Datacenter or EBC Datacenter. The other unit would reside in either the Hospital datacenter or the EBC Datacenter. Perfigo Design 1 Distributed Smart Servers The first design option for the Perfigo deployment is a simple replacement of the existing WANA boxes with Perfigo Smart Servers. The individual Smart Servers would reside in the location of each of the campus distribution nodes (note: campus distribution node refers to either the hospital or lower campus distribution node) exactly like the current WANA boxes do today. Virtual Local Area Networks (VLANs) span from the campus distribution nodes onto the individual departmental switches and terminate at the Access Points. Table 1 shows some of the pros and cons of this design option. Figure 2 shows a rough diagram of the design. Table 1 List of Pros and Cons for Perfigo Design Option One Pros Cons Design already proven, no real change Highest server count (hardware and software license) Simple replacement of existing WANA boxes No redundancy for servers or networks (can add redundant servers at a cost No spanned vlans across the campus backbone, Distributed power/cooling requirements in multiple limits any spanning tree issues locations (increase of costs) No requirement for additional physical resources, i.e. fiber and fiber installation Page 2 of 6

3 Figure 2 Diagram of Perfigo Design option 1 Perfigo Design 2 Aggregated Smart Servers with spanned vlans The second design option for the Perfigo deployment aggregates the Smart Servers in the datacenter. The Smart Servers would reside completely in a datacenter and not distribute across the node locations. VLANs from the aggregated Smart Servers would span across the campus backbone into a department s network equipment and terminate at the Access Points. Table 2 shows some of the pros and cons of the Perfigo Design Option Two. Figure 3 shows a rough diagram of the design. Table 2 List of Pros and Cons of Perfigo Design Option Two Pros Cons Stability of servers in a very hardened datacenter Spanned vlans offer a possible impact on the whole campus infrastructure Potentially fewer servers for a campus-wide Introduction of additional latency by traversing deployment campus (on order of milliseconds) No requirement for additional physical resources, No redundancy for servers or networks (can add i.e. fiber and fiber installation redundant servers at a cost) Page 3 of 6

4 Figure 3 Diagram of Perfigo Design option 2 Perfigo Design 3 Aggregated Smart Servers with fiber The third design option for the Perfigo deployment replicates the design of option two with the exception of how it delivers layer 2 functionality to the Access Points. The third design brings layer 2 functionality from the datacenter to the distribution node via private fiber instead of a spanned VLAN. From the distribution node switch to the Access Point, the design would use a spanned VLAN over departmental switches and terminate at the Access Point. Table 3 Lists of Pros and Cons of Design Option Three Pros Cons Stability of servers in a very hardened datacenter Use of fiber and fiber installation resources (raises costs) Provides physical isolation of a portion of the Bypasses use of existing backbone resources (raises wireless network from the campus network costs) No spanned VLANs from distribution point to the Introduction of additional latency by traversing datacenter campus (on order of milliseconds) Potentially fewer servers for a campus-wide No redundancy for servers or networks (can add deployment redundant servers at a cost) Page 4 of 6

5 Other Considerations Campus to Departmental VLAN implications Each of the three design options poses the problem of the spanned VLAN from the distribution node into the end department. This problem has multiple facets. The spanned VLAN requires cooperation between the end department and the central campus. The central campus must either administer the VLAN span or trust the local network administrator to correctly deploy the spanned VLAN across the departmental network. The department and central campus must also agree whether the IP space on VLAN is from the central campus pool or from the department s allocation of IP space. Generally, the allocation of campus IP space will probably make more sense but individual entities might have requirements due to firewall or other restrictions that will require use of their IP allocation. The hospital is potentially a case in point. For those entities that can use the campus allocation within their network borders, those entities will benefit by being able to treat the wireless users as completely foreign users. Power treatment All of the options have specific power requirements and, therefore, treatment of the power grid is necessary to understand the full implications. For example, if the Perfigo deployment uses option 2 or 3, all the servers could potentially be in the same datacenter. If a disaster happens to that datacenter, all web authenticated wireless access will fail. However, if the deployment follows option 1, then personnel will have to ensure that each distribution node has adequate power/cooling hardening, thereby, increasing the total cost. Implications of changes in campus physical topology The lower campus is slowly changing the physical topology of its distribution nodes. Over time, the lower campus portion of the network is collapsing the distribution nodes into two physical hardened datacenter areas. This collapse directly affects the Perfigo designs. For the first design, less Perfigo servers will be necessary to provide equivalent services. For the third design, the effect is to less the amount of fiber and fiber installation necessary to cross-connect the servers in the datacenter with the actual distribution node. The collapse does not necessarily affect the second design unless the campus also chooses to also collapse the number of distribution nodes. Spanned VLAN discrepancies The University of Utah Hospital and the lower campus view spanned VLANs across a campus backbone in distinctly different ways. The hospital spans numerous VLANs across its core to accommodate various applications. The lower campus has maintained a strictly routed backbone. The hospital manages networks to the desktop or at least to the switch port. The lower campus manages some networks to the desktop and some networks to a departmental router. At the departmental router, the lower campus network group must either trust the competency and judgment of the end network administrator or take steps to protect the core from mishaps. This discrepancy has implications regards the design option two. Remote clinics/campus treatment None of the three options gives adequate treatment to remote clinics/campuses. Due to the nature of the Perfigo product, one must deliver layer 2 services from the main campus to the remote clinic/campus. Delivery of the layer 2 services lies outside the scope of the Perfigo deployment. Options that exist: a) arrange for connectivity to remote clinics/campuses that allow layer 2 service deployments b) deploy a wireless vendor that supports proprietary layer 2 services to the Access Point c) deploy layer 2 services over some sort of tunneling mechanism to the remote sites. Page 5 of 6

6 Hardware Treatment The hardware necessary for the CleanAccess Manager and CleanAccess Servers can vary widely, depending on the expected load and features required for a particular implementation. The University can approach the problem of hardware purchases by one of two options: a) buying the best servers today and amortize them over the next 3 years b) using existing hardware and upgrade the hardware as usage requires. The top of the line option would comprise: Cisco Clean Access Server machines o Lower campus - (4 x) HP DL380G4 w/2 gig of memory $5103 o Upper campus (2x) HP DL380G4 w/2 gig of memory $5103 Cisco Clean Access Manager machines o Lower campus (1x) HP DL380G4 w/2 gig of memory $5103 o Upper campus (1x) HP DL380G4 w/2 gig of memory $5103 The second option uses existing hardware. The campus currently owns the following hardware: (6x) Pentium 4 2.6GHz 512MB RAM dual 80GB hard-drive dual Gig interface Of these 6 boxes, 4 would be available for use for rolling out the Cisco CleanAccess boxes. The campus would have to purchase 4 more boxes for the complete project. The campus would also have to roll out the project in a manner which retained current images of the existing hard drives in case of problems. The existing boxes currently run the WANA system today. These boxes are around 6 months old. Recommendation For the design recommendation with accompanying budget requirements, please see the document: Cisco CleanAccess (a.k.a. Perfigo) Design Recommendation. The title reflects the re-branding of the Perfigo product acquisition by the Cisco marketing team. Summary The initial University of Utah Perfigo deployment will completely replace the WANA deployment that provides web authentication for much of the wireless infrastructure. This deployment has two distinct options and a variation of one of the options. The University must decide on an appropriate option and deploy. Other considerations exist outside the deployment itself that directly impact the deployment. Page 6 of 6