Avaya P580 - Manual (Page 182)

5-2 Avaya P550R, P580, P880, and P882 Multiservice Switch User Guide, v5.3.1
Chapter 5
Physical Port Features
This section describes the following features that are available when
configuring the physical parameters on the ports:
■
Autonegotiation
■
Flow Control
Auto-
negotiation
Autonegotiation is an extension of the link test methods used by
10Base-T and 10Base-FL to verify the integrity of the link between
devices. Autonegotiation advertises a device's abilities by encoding a
16-bit data packet, called a link code word (LCW), within a burst of
17 to 33 link pulses, called a fast link pulse (FLP) burst. FLP bursts
have an approximate duration of 2 µs and are transmitted in 16.8 µs
intervals (the same interval as for the normal link pulses used by
10Base-T and 10Base-FL).
However, this does not hold true for the Half Duplex/Full Duplex
(HD/FD) selection. If a non-autonegotiating device running FD is
connected to a negotiating device, the negotiating device runs at
HD, and the link does not operate properly.
* Note: A Gigabit Ethernet device negotiates at HD or FD, speed
is always one Gigabit.
M5520-TX (P/N M5520-100TX) boards manufactured
with a Quality Phy do not auto-negotiate with Xircom
brand adapter cards. If you have this problem, disable
auto-negotiation on the affected ports, and set the port
speed and duplex state manually.
You may experience difficulties with auto-negotiation
between some releases of the 10/100Base-TX Module
(M5510-100TX, M5520-100TX, M5510R-100TX,
M5512R-100TX) and adapter cards using physical
interfaces manufactured by National Semiconductor.
The symptom is loss of connectivity. If you do. do one of
the following:
• Disable auto-negotiation
• Use a patch cable that is longer that 5 meters
* Note: The factory default for the National Phy Mode is
Enable.