Networks Horizon

Enterprise Network Needs and AVVID Model

Networking Challenges: Performance, Scalability and Availability

Performance
Network performance decides how well network is going to perform. It is decided with the combination of a few facts called metrics:

1. Responsiveness: How the user perceive the performance of the application in his view. Therefore, It is based on perception, doesn't matter how well your network graphs sees the network. So it has importance to users. If customer is not happy Responsiveness Metric is treated as BAD.
2. Throughput: How many packets are going through per second. It is related to utilization. When throughput increases, utilization increases but after maximum limit throughput drops/ collapse. This is called congestive collapse for throughput. Therefore, throughput information is critical to Operational management.
3. Utilization: Maximum utilization will eventually produce congestive collapse for throughput. So this needs to be checked that how much utilization we can have without having congestive collapse. It is important for Executive management.

Scalability
It is another area of concern for a Network designer. When designing a network following basic principals involves to imporve scalability of network:

Topology: Ensuring that changing the cabling, adding or removing network devices will not affect the existing network. So, we should have a plan in advance.
Addressing: Applicability of summarization and hirarical addressing wherever required and adaptability with new addressing schemes without affecting existing network
Routing Protocol:  An administrator has to decide and agree on a protocol which is suitable for the network. He must have concern on how scalable and suitable a routing protocol is for the network

Availability
A. Fault tolerance and redundancy

•     Hardware redundancy ( Primary/Backup device)
•     Link redundancy (Primary/Backup links)

B. Protocol resiliency (Routing protocol is able to handle the situation when routes are flapping or down)
C. Network Capacity Design: If we plan for the worse and never get there we can be successful as network a designers.

Two Models have been used to fulfil Enterprise Network Needs.

1. Cisco's AVVID framework ( Architecture for Voice, Video and Integrated Data)
2. Enterprise Composite Network Model-Cisco's Brand New design Model

Cisco AVVID framework
Today's networks transport an increasingly wide array of services such as voice and video, and application traffic including critical e-business and communication services. To assist network architects in the proper design of capable networks, Cisco created the Architecture for Voice, Video, and Integrated Data (AVVID).

• It is not restricted to LAN/WAN and deals things enterprise-wise
• It works as a standard and can be used with variety of product or various environment like Health care, Retail, Finance sector, Govt sector, Manufacturing or Education.

The AVVID architecture is based on an open, multiservice model and is composed of four interrelated, yet distinct layers as follows:

1. Network Infrastructure Layer
2. Services Control Layer
3. Application Intelligence Layer
4. Client Layer

Key components for AVVID framework

• Common network infrastructure (routers, switches, voice GWs or whatever that makes a network.
• Intelligent Network Services (Securing and controlling the environment like QoS, IPSEC, authentication, Network Management
• Network Solution: Applications or final services like IP telephone, content Networking, Storage Networking

Building blocks of AVVID:

• Network Clients and application servers (IP phones, PCs, wireless units, servers in Data Centre)
• Network Platforms(routing/switching routers,switches,hubs, firewalls)
• Intelligent Network services: like QoS(jitter,bandwidth, packet-loss), IPSEC,Autentication,Access list,Network Management (management tools), IP multi-casting (PIM,

Benefits of AVVID model:

Integration:

By using the Cisco AVVID architecture and applying the network intelligence imbedded within IP, companies can develop comprehensive tools to improve productivity.

Intelligence:

AVVID promotes the prioritization of traffic and delivers intelligent network services to maximize network efficiency and performance.

Innovation:

Cisco customers can adapt quickly to a changing business environment.

Inter-portability: Standards-based APIs enable integration with third-party developers.

In next chapter we will discuss Cisco's Enterprise Composite Network Model