[ Back ] [ Next ]

EXCELLENT

RECOMMENDED

Up to 40% off!

~~~

SIGN | VIEW
GUESTBOOK

CCDA [ Search ]

Small- to Medium-Sized Business Solutions Framework

3. Upon completion of this introduction, you will be able to describe a framework you can use to simplify the complexities associated with analyzing customer network problems and creating Cisco scalable solutions.

Notes

1. Cisco's Small- to Medium-Sized Business Solutions Framework

   • Media
     • Problems
       • Collisions
       • High utilization
     • Solution
       • Switching to divide collision domains.
   • Protocol
     • Problem
       • Broadcasts
     • Solution
       • Routing to divide broadcast domains.
   • Transport
     • Problems
       • Bandwidth
       • Delay
       • Errors
       • Latency
     • Solution
       • Fast Ethernet switching or ATM.

2. Healthy Network

   • Broadcast / multicast below 20%.
   • Cisco CPU utilization below 75%.
   • CRC error not more than 1 of 1,000,000 bytes.
   • Network utilization not exceeds
     • 40% for Ethernet.
     • 70% for Token Ring.
     • 70% for WAN.
   • Peak utilization below 40%.
   • Response time less than 100 milliseconds.
   • Maximum number of workstations in a broadcast domain
     • 500 for IP
     • 300 for NetWare
     • 200 for AppleTalk
     • 200 for NetBIOS
   • Buffer number missed less than 25 / hour.
   • Ignored packets per interface less than 10 / hour.
   • Input queue drops less than 50 / hour.
   • Token Ring soft error less than 0.1% of total packets.
   • Number or ring operations is 1.

Because Class II repeaters have a latency of 0.46 microseconds, you can generally have a maximum of two in a 100Base-T collision domain.  More than two could exceed the round-trip propagation delay of 5.12 microseconds (512 bit times) depending on your cable length.

Bandwidth is calculated by taking a measurement between the highest and lowest frequencies in use. When this difference is calculated during a specific time interval the result is network utilization.

The Chooser is part of the Mac OS that allows a user to locate resources on the network. When a user clicks on a zone and service, multicasts are sent over the network until the Chooser is closed. Version 7.x of the Mac OS reduces the quantity of multicasts by the Chooser when it is left open.

Broadcast traffic should be 20% or less. If this type of traffic becomes a high percentage, it means that a large portion of the traffic is being generated by hosts trying to contact other hosts, rather than traffic which is direct host-to-host. Some methods of reducing the percentage are adding a WINS server to the network, adding entries to the HOSTS and LMHOSTS files, and adding a Helper Address to the router.

When Ethernet segments become saturated a high number of collisions are occurring on the network. As the number of collisions increases, eventually the network becomes unusable as stations spend more and more time producing traffic whose frames are discarded.

The 100 millisecond threshold is where users begin to report delays, such as in the delivery of a web page. Their frustrations increase beyond this threshold, particularly if they are performing a work-related task. Downloading e-mail seems to take forever, and user tolerance declines with each attempt to retrieve data.