Management and Scalability
Network elements must support, at a minimum, manageability with MIBs and applications. The degree of support acceptable is dependent on the provider. ILECs and PTTs require full SNMP support and full MIB support with counter information on packets, bytes, and LSPs including per VPN and per class of service. However, network elements must scale well when the network management (NM) stations poll these devices for statistics. The ability to process NM requests accurately and the ability to inform NM stations during failure conditions via SNMP notifications are critical to the operation of the network element.
Other scale issues in managing large networks exist when thousands of sites and thousands of VPNs are deployed. These factors are network and operation dependent. Having a provisioning system that can provision thousands of CEs and PEs to connect the VPN sites together is important. Operators cannot rely on the CLI and show commands anymore. Automated management and monitoring tools become necessarynot just necessary, but mandatoryas networks grow larger.
"I think that this (management systems) is actually the biggest issue in provider scalability. Once the hardware architecture is in place, if the network is designed well, network scalability can be achieved by adding more and/or bigger network routers and ancillary devices. However, if the management systems do not scale, the attempt is usually to try and use manpower to overcome the system's limitations. This usually results in high install failure rates. Managing over 10,000 ports with install rates of 500 to 1000 a month means that, without the proper provisioning and management system, installations are slow and problematic. A solid provisioning and automated service activation system is mandatory. The greater the manual intervention at high install rates, the greater the chance of misconstructed VPNs and dissatisfied customers. A look at recent Telemark studies will show that most providers don't fare well in this area as evaluated by customers." Joe Fusco, BT Infonet
When building IP NGN, decision-makers must evaluate which factors are most important to their operational environment and which factors provide the margin to grow their network up to the next upgrade period. As we all know, in reality no network elements can last through network growth forever, and therefore, a determination must be made on how to strike the right balance. A simple rule is to pick the sweet spot based on operational experience and to maximize the return on investment based on that sweet spot. For example, if 10,000 VCs are provisioned in the current Frame Relay edge switch for subscribers, the multi-service device may also support a similar number of VCs (maybe not the same because the multi-service edge [MSE] network element might also support Layer 3 services at the same time).
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