Proxim Wireless Corporation U58-100 Manual Do Utilizador
INSTALLATION AND MAINTENANCE MANUAL
Tsunami FAMILY
FAST ETHERNET WIRELESS BRIDGES
December 2001
Tsunami FAMILY
FAST ETHERNET WIRELESS BRIDGES
December 2001
SECTION 4: TROUBLESHOOTING
PAGE 4-1
4. Troubleshooting
Also refer to Appendix E fold-out as an additional guide
Requirements for Full Duplex
For a network to support Full Duplex, both devices must support and be configured for Full Duplex. Full
Duplex is intended to increase the speed of a direct link between two devices. i.e., between switches, or
between an end-station and a switch. Switches support Full Duplex, hubs do not. Configuring an
adapter for Full Duplex operation while connected to a hub or other half duplex device (NIC, etc.), can
cause many network issues such as slowness, packet loss or station drop-offs.
What is Auto-Negotiation?
Auto-Negotiation is a protocol between devices where they negotiate highest common speed. Also
known in the industry as NWAY. Since every frame is tested for speed and configuration, auto-
negotiation takes away from the maximum bandwidth possible through a network. When possible, do
not use auto-negotiation especially when the port configuration is known (e.g. 10 or 100Base, half or full
duplex, etc.). Tsunami radios are especially sensitive and work best only with devices hard set to the
radio’s configuration (e.g. full duplex, 10BaseT) and NOT in auto-negotiation nor auto-sense.
Requirements for Full Duplex
For a network to support Full Duplex, both devices must support and be configured for Full Duplex. Full
Duplex is intended to increase the speed of a direct link between two devices. i.e., between switches, or
between an end-station and a switch. Switches support Full Duplex, hubs do not. Configuring an
adapter for Full Duplex operation while connected to a hub or other half duplex device (NIC, etc.), can
cause many network issues such as slowness, packet loss or station drop-offs.
What is Auto-Negotiation?
Auto-Negotiation is a protocol between devices where they negotiate highest common speed. Also
known in the industry as NWAY. Since every frame is tested for speed and configuration, auto-
negotiation takes away from the maximum bandwidth possible through a network. When possible, do
not use auto-negotiation especially when the port configuration is known (e.g. 10 or 100Base, half or full
duplex, etc.). Tsunami radios are especially sensitive and work best only with devices hard set to the
radio’s configuration (e.g. full duplex, 10BaseT) and NOT in auto-negotiation nor auto-sense.
What is the difference between 10 and 100BaseT (or F)?
These are fully different and mostly incompatible Ethernet communication. Ten (10)Base is any
throughput speed from 1bps to 10Mbps, 100Base (also known as Fast Ethernet) is any throughput from
1bps to 100Mbps with the 10BaseT standard NOT capable of transmitting the full throughput of a
100Base device. Each has its own set of communication rules and need to be considered separately
when communicating with either standard. Many hubs, switches and routers will auto-negotiate between
these two speeds, but Tsunami radios (in order to maximize their throughput) do NOT auto-negotiate.
Many throughput problems have been found when the computer’s Ethernet NIC card is set to auto-
negotiate when it should be set (through Network Properties) to NOT auto-negotiate. Although if the
switch, router or NIC is set for auto-negotiation, the interface will function but the throughput speed can
suffer considerably and high latency can result. All NICs & routers and most “managed” switches can
be hard set or programmed to not auto-negotiate (both 10/100Base and full/half duplex) and is the
desired set-up for maximum Ethernet throughput with any network especially those with wireless
components.
These are fully different and mostly incompatible Ethernet communication. Ten (10)Base is any
throughput speed from 1bps to 10Mbps, 100Base (also known as Fast Ethernet) is any throughput from
1bps to 100Mbps with the 10BaseT standard NOT capable of transmitting the full throughput of a
100Base device. Each has its own set of communication rules and need to be considered separately
when communicating with either standard. Many hubs, switches and routers will auto-negotiate between
these two speeds, but Tsunami radios (in order to maximize their throughput) do NOT auto-negotiate.
Many throughput problems have been found when the computer’s Ethernet NIC card is set to auto-
negotiate when it should be set (through Network Properties) to NOT auto-negotiate. Although if the
switch, router or NIC is set for auto-negotiation, the interface will function but the throughput speed can
suffer considerably and high latency can result. All NICs & routers and most “managed” switches can
be hard set or programmed to not auto-negotiate (both 10/100Base and full/half duplex) and is the
desired set-up for maximum Ethernet throughput with any network especially those with wireless
components.
Hub Vs Switch
All the devices connected to a hub are in the same collision domain. These devices share the bandwidth
of the hub (10 Mbps for Ethernet or 100 Mbps for Fast Ethernet). By contrast, each port of a switch is
actually the entrance to a separate collision domain with its own dedicated bandwidth. Each domain is
either shared by other devices or dedicated to a single device. If many devices and the network is
utilized over 25%, a switch is necessary to optimize Ethernet traffic. If economics allow, a
programmable or managed switch is desirable for many reasons such as for the reasons above and that
spanning tree can be easily accomplished if needed in a network.
All the devices connected to a hub are in the same collision domain. These devices share the bandwidth
of the hub (10 Mbps for Ethernet or 100 Mbps for Fast Ethernet). By contrast, each port of a switch is
actually the entrance to a separate collision domain with its own dedicated bandwidth. Each domain is
either shared by other devices or dedicated to a single device. If many devices and the network is
utilized over 25%, a switch is necessary to optimize Ethernet traffic. If economics allow, a
programmable or managed switch is desirable for many reasons such as for the reasons above and that
spanning tree can be easily accomplished if needed in a network.
Response time slower with switch than it was with a hub
Low volume on the network could cause a slowness in performance when a switch is introduced into an
environment where a hub was used previously. There may not be enough traffic on the network to
warrant a switch. When network utilization starts to reach 25 - 30%, the conditions are good for a
switching product.
Low volume on the network could cause a slowness in performance when a switch is introduced into an
environment where a hub was used previously. There may not be enough traffic on the network to
warrant a switch. When network utilization starts to reach 25 - 30%, the conditions are good for a
switching product.