MIS420-Chapter 13 Network Performance

What Exactly Is a Bottleneck?

• A computer system always has a bottleneck
• Avoid waiting for the bottleneck

What Are the Ten Most Common Network Bottlenecks?

1. CPU in the file server
2. amount of memory in the file server

   Conventional Memory (first 640 K)

   Upper Memory (640K - 1 M) used mostly by I/O devices

   Expanded Memory (requires an expansion card)

   Extended Memory (everything beyond first M) used extensively by Windows

3. file server's computer bus

   ISA (Industry Standard Architecture) - 8-16 bit bus introduced with the 286 [8 MHz]

   MCA (MicroChannel Architecture) - 32 bit bus developed for the PS/2 [10 MHz]

   EISA (Extended ISA) - 32 bit bus [8 MHz]

   PCI - 32 bit high-speed bus

4. network card
5. file server's disk drive
6. file server's disk controller card

   ESDI (Enhanced System Device Interface)

   IDE (Integrated Drive Electronics)

   EIDE (Extended IDE) - allows faster and larger drives

   SCSI (Small Computer System Interface) - very high-speed; comes in 32 and 64 bit width

7. configuration options setup for the server
8. DOS!
9. the network cable
10. network devices

The Compulsive Way to Tune Your Network

1. Establish a method for objectively testing ther performance of some aspect of the network (benchmark)
2. Now, change one variable of your network configuration and rerun the test
3. Repeat Step 2 for each variable you want to test

Tuning a Peer-to-Peer Server

• Use Disk Caching - sets aside a portion of RAM to hold disk data
  • DOS SMARTDRV
  • Windows 95
  • Windows NT
  • Netware
  • PC Tools / Norton Utilities
• Enable 32-bit file access for WFWG (VFAT - Virtual File Allocation Table) - remove SMARTDRV & SHARE
• Adjust start-up parameters
• Use a dedicated server

Tuning a Windows 95 Server

Tuning a Netware Server

• use burst mode (requires PBURST.NLM on the server and BNETX.COM on the client)
• SET commands in AUTOEXEC.NCF and STARTUP.NCF
• use RAID (Redundant Array of Inexpensive Disks)
• use superservers (multiprocessors)
• use bridges / routers

Tuning a Client

• turn on disk caching
• store frequently used data on local drives
• use local temporary drives