Performance Considerations for a Network Configuration
Go Up to Database and Server Performance
This section describes performance considerations you should know when configuring a network configuration.
Contents
Choosing a Network Protocol
InterBase supports two protocols: TCP/IP when connecting to any server, and NetBEUI when connecting to a Windows server. See Network Protocols for more details.
NetBEUI
You can use NetBEUI on a network with fewer than 20 users without significant performance costs. Use TCP/IP if you have more active users on your network simultaneously.
NetBEUI is a network protocol designed for use on small local area networks. It is commonly used for filesharing services. It is a connectionless protocol, which means that it broadcasts packets to the entire network. This causes a growing amount of “noise” on a LAN. Noise, from the point of view of any given host, can be defined as network traffic that is not intended for that host. On a LAN with many hosts, enabling NetBEUI can overwhelm the network and reduce the available bandwidth for everyone to use. On most enterprise networks, IT experts discourage the use of NetBEUI.
TCP/IP
TCP/IP is a connection-based protocol, which means packets are routed to the intended recipient. This reduces the saturation of the network and the load on individual hosts. There is effectively more bandwidth available to all hosts, and a large number of hosts can share the same network with less performance penalty.
Configuring Hostname Lookups
Each host on a TCP/IP network has a designated IP address, and TCP/IP traffic is routed to hosts by address. TCP/IP requires a mechanism for clients to translate hostnames to their numeric addresses. Each client host can store the hostname/address associations in a file called hosts. You can alternately store this information on a central server, and the clients then retrieve the information on demand using a protocol called DNS. The client requests that the DNS server resolve a hostname, and the server returns the IP address. Then the client can use the IP address to communicate directly with the intended destination. In this configuration, the client must keep only one IP address locally: that of the DNS server host.
Depending on the load on the network and the DNS server itself, hostname resolution can take several seconds. This translates directly into delays when making a network connection. This is related to the message you might see in a web browser, “Looking up host name…” followed by, “Connecting to host name…”. This indicates the delay while querying a DNS server to resolve a hostname.
You can speed up hostname resolution by adding the hostname/address mapping of the database server to the hosts file on the client computer. The client can resolve the hostname to its address much faster and more reliably by looking it up in a local file than by querying a service running on another host over the network. This reduces the hostname resolution delay when initiating connections to hosts listed in the local hosts file.
If you use this technique and later change the address of your database server, you must manually update the hosts files on each client workstation. Depending on the number of workstations in your enterprise, this can be tedious and time consuming. That is why DNS was invented, to centralize TCP/IP address administration. The suggestion to keep the database server address in a local file is intended to provide improved connection performance, but you should be aware of the administrative workload that it requires.
If you object to the general IP address administration tasks required by using TCP/IP (independently from the DNS issue), consider using DHCP to simplify the task of assigning and tracking IP addresses of each host on the network. InterBase works in a DHCP environment as long as the client host has some means to resolve the IP address of the server correctly at the time a client application requests an InterBase connection.