- Understanding the Model
- Identifying Key Components
- Applying Architectural Principles
- Applying the Model to FijiNet
Applying the Model to FijiNet
In this section, we apply the architectural model to FijiNet. We combine the requirements, assumptions, and evaluation we formulated in Chapter 2 with the model and principles presented in this chapter.
Identify Key Components for FijiNet
After evaluating the business and functional requirements, we identify key components for FijiNet and find that they are in line with general design for ISP architectures. The core components consist of ISP services, an operating environment, and an operating platform.
ISP Services
FijiNet ISP services are basic, infrastructure, and operation and management services. While value-added services are not offered initially, they may be offered in the future.
Basic Services
FijiNet wants to offer basic services to residential subscribers. These services are email, web hosting, and Internet news. FTP is available for content uploads.
Value-Added Services
FijiNet is not offering value-added services initially; however, they might offer them in the near future.
Infrastructure Services
For FijiNet, all infrastructure services presented in the model apply (DNS, LDAP, RADIUS, DHCP, and NTP). These services represent the workhorse of FijiNet's infrastructure.
Operation and Management Services
Operation and management services for FijiNet are outsourced, including provisioning (billing, registration, and customer care).
NOTE
Operation and management services are beyond the scope of this book. Many resources are available, such as OSS Essential: Support System Solutions for Service Providers.
Operating Environment
The operating environment for FijiNet is a reliable operating system comprised of commercial and open source applications. To minimize cost, open source software is used as much as possible. TABLE 3 lists components for FijiNet's operating environment.
TABLE 3 Operating Environment for FijiNet
Product |
Type |
Description |
Solaris 8 Operating Environment |
Commercial |
Operating system |
Cisco PIX |
Commercial |
Firewall appliance |
Solstice Backup_* |
Commercial |
Backup software (bundled with Solaris 8 OE); free usage for up to 200,000 entries |
Amdocs Horizon (formerly Solect IAF Horizon)* |
Commercial |
Billing system for service providers |
iPlanet_ Directory Server |
Commercial |
Directory software (bundled with Solaris 8 OE); no charge for single server licenses |
Steel-Belted Radius |
Commercial |
RADIUS software for service providers |
DNS |
Open source |
DNS software (free with Solaris 8 OE) |
DHCP |
Open source |
DHCP software (free with Solaris 8 OE) |
NTP |
Open source |
NTP software (free with Solaris 8 OE) |
sendmail |
Open source |
Mail software (free with Solaris 8 OE) |
WUftp |
Open source |
LDAP-compliant FTP software (free/bundled with Solaris 8 OE) |
WUimap |
Open source |
POP/IMAP (post office protocol/Internet mail access protocol) Internet mail software (free/bundled with Solaris 8 OE) |
Apache |
Open source |
Web software (free/bundled with Solaris 8 OE) |
INN* |
Open source |
News software (free/bundled with Solaris 8 OE) |
OpenSSH |
Open source |
Secure SHell software |
Operating Platform
The operating platform for FijiNet is comprised of high-performance enterprise equipment (network, server, storage, etc.). Hardware was chosen based on FijiNet's requirements and cost constraints. The hardware supports an initial 10,000 subscribers and is scalable to 100,000 subscribers. TABLE 4 lists components for FijiNet's operating platform.
TABLE 4 Operating Platform for FijiNet
Product |
Vendor |
Description |
Enterprise server |
Sun Microsystems |
Netra_ t1 |
Enterprise server |
Sun Microsystems |
Ultra_ 280R |
Enterprise storage |
Sun Microsystems |
Sun StorEdge_ D1000 |
Enterprise library |
Sun Microsystems |
Sun StorEdge L280 |
Router |
Cisco Systems |
Cisco 2651 |
Switch |
Cisco Systems |
Cisco 3512XL |
Firewall |
Cisco Systems |
Cisco PIX 525 |
Access server |
Cisco Systems |
AS5400 |
Console server |
Cisco Systems |
AS2511 |
NOTE
The quantity for each component is provided with capacity planning in Chapter 6.
Apply Architectural Principles to FijiNet
We apply each of the principles to FijiNet's requirements, our interpretation and assumptions, and our evaluation. For detailed information supporting each of the principles applied, refer to Chapter 2.
Scalability
Due to cost constraints, we specify the smallest possible hardware that can handle the load. The architecture scales horizontally. Because of the smaller chassis size, the system has limited vertical scalability. For scaling from 10,000 to 100,000 subscribers, horizontal scaling is much more economical and flexible.
Availability
No redundancy is implemented, due to cost constraints. To provide a higher level of data availability at an affordable cost, we implement RAID 0+1. FijiNet's business plan and case do not warrant investment in redundancy for high availability at this time.
Reliability
The hardware we specify, enterprise server and storage, are very reliable. Although the hardware reliability is very high, we acknowledge that a single chassis component could fail, because there is no failover.
Manageability
We settle on a 2-tier architecture for FijiNet, to simplify the design. Due to cost, a single-box solution is the best fit. We acknowledge that if FijiNet wants to implement an N-tier architecture later, they need to implement a new architecture. A 2-tier architecture with a single-box solution cannot be retrofitted or scaled to be an N-tier architecture.
Adaptability
The architecture is based on open standards. We use no proprietary technology; therefore, the architecture should be adaptable and integrate with any open systems, standards-based technology. Also, the design is modular and should be adaptable to changes with no reconfiguration or rearchitecting.
Security
An ACL and packet filters provide a basic front-end filter at the router. We use a premises firewall for access control. At the host level, operating system hardening ensures proper file permission. For the Solaris OE, the Solaris Security Toolkit (JASS) is available from Sun Microsystems for OS hardening.
Performance
Based on benchmark results for various infrastructure services such as DNS and firewall, we are confident that FijiNet's server can be load tested with a simulated load. (Refer to Appendix F for benchmark data.) Note that without real user profile and usage pattern data, it's hard to predict actual load.
Open System
The architecture design for FijiNet uses open systems hardware and software based on recognized industry standards.