SNMP

In order to provide Network Management to the Washington District WAN, we will be using the Simple Network Management Protocol (SNMP) across out WAN. SNMP requires an SNMP Management console on one router, and an SNMP agent on all other routers, hubs and switches. In order to maintain stability, the Management console will be attached to the router at the data center, but not on the public backbone (for privacy reasons). SNMP agents will be installed on all routers within the WAN, and on each switch and hub at each school. The central Management Information Base (MIB) will be on the Data Center router, with local MIB's at all router/switches/hubs. The hierarchical structure of the WAN lends itself to the use of SNMP and allows us to have a central information center.

Traffic Flow Estimate

Each school can realistically expect to receive a maximum bandwidth of 1.544 Mbps for internet connectivity. If we assume an average of 10% of computers are connected at any one time, with a theoretical maximum of 40% then we can prepare some estimated scenarios.

• Worst Case Scenario:
• Acacia has 250 student and 75 admin computers
• 40% of students (100 computers) and 60% of admin (45 computers) are connected to the internet
• 1.544Mbps / 145 machines = 10.6 Kbps per computer (average dialup rate is approx. 46Kbps)
  • This is disappointing

• If all eleven schools on a router are maxed out then

  • Max bandwidth = 4(T1 Lines)*1.544(T1 Rate) = 6.176
  • Users = 11(Schools) * 145(Users) = 1595
  • Rate per User = 3.87Kbps (about 10% of dial-up rate)

If internet connectivity is critical then upgraded lines (maybe T3) or more T1 lines will be required, however it is unlikely that all schools will 'max-out' at the same time.

Time to Convergence

The Washington district is made up of three central routers, each of those being connected to 11 schools via another router. Before routing updates have taken place, each router in the WAN core knows about the other two, and each school's router knows about all the networks at each school. After the first routing update each router in the core will know about the other two's primary school connection, and each one will have the full routing table for their own school. Following the second update this information will be shared with the other two routers, so time to convergence is two routing updates, or approximately one minute.