3Com CoreBuilder 3500, Руководство по внедрению, Страница: 84 / 592

84 C
HAPTER
5: E
THERNET
PACE Interactive
Access
PACE Interactive Access prevents excessive network jitter (variation in the
timing of packet delivery that can cause garbled sound, jerky images, and
delays). PACE technology also improves timing and optimizes LAN
bandwidth utilization.
Important
Considerations
■
You can use this command to configure the same setting on multiple
ports simultaneously. When you specify multiple port numbers, the
system prompts you to choose the setting and then applies it to all of
the ports.
■
Use PACE Interactive Access only on half-duplex Ethernet links
between a switch and a single end station. (This setting has no effect
on full-duplex links.)
■
Do not use PACE Interactive Access when a repeater is connected to a
switch port.
Standards,
Protocols, and
Related Reading
The system supports these Ethernet standards:
■
IEEE 802.3 — 10BASE-T Ethernet over unshielded twisted pair (UTP)
wiring
■
IEEE 802.3u — 100BASE-T Fast Ethernet over UTP or fiber-optic cable
■
IEEE 802.3z — 1000BASE-SX Gigabit Ethernet over multimode
fiber-optic cable and 1000BASE-LX Gigabit Ethernet over multimode
or single-mode fiber-optic cable
Ethernet Protocols
■
IEEE 802.3 — Carrier Sense Multiple Access with Collision Detection,
which controls Ethernet access. A station that intends to transmit
listens for network traffic. If it detects none, it transmits.
If two or more stations transmit at about the same time, their packets
experience a
collision and the colliding data streams do not reach their
destinations. The sending stations stop transmitting, send a collision
alert to other stations, and wait a random amount of time before
trying again.