Bonjour,
Quelqu'un connait-il la description du voyant "Jab" sur un convertisseur
BNC/RJ45 .
Bonjour,
Quelqu'un connait-il la description du voyant "Jab" sur un convertisseur
BNC/RJ45 .
Bonjour,
Quelqu'un connait-il la description du voyant "Jab" sur un convertisseur
BNC/RJ45 .
"Hervé" a écrit dans le message de
news:c7o1hv$98p$Bonjour,
Quelqu'un connait-il la description du voyant "Jab" sur un convertisseur
BNC/RJ45 .
Jabber definition
In networks, a jabber is any device that is handling electrical signals
improperly, usually affecting the rest of the network. In an Ethernet
network, devices compete for use of the line, attempting to send a signal
and then retrying in the event that someone else tried at the same time. A
jabber can look like a device that is always sending, effectively bringing
the network to a halt. A jabber is usually the result of a bad network
interface card (NIC). Occasionally, it can be caused by outside electrical
interference.
Incompatible Ethernet Jabber
Another potential problem in 100Mbps Ethernet is the use of RJ-45 jacks
for
more than one flavor of Ethernet. Since 100BASE-TX and 100BASE-T4 both use
RJ-45 jacks, as do 10Base-T and many other network technologies, the IEEE
802.3 specified an auto-negotiation protocol to allow stations to figure
out
the networking technology to use. Unfortunately, they made its
implementation optional. If you're using equipment that does not implement
IEEE-spec auto-negotiation, the incompatible Ethernet signals could
prevent
one of your stations from connecting to your network, or even simulate
"jabber" by constantly transmitting a TX idle stream and bringing down the
network.
The possibility for this jabber is uncertain, considering that the flavors
of Ethernet use different signal formats in transmission. Even if data is
not exchanged, it is still possible that incompatible Ethernet flavors
could
assume that they have a proper connection. Ethernets using RJ-45
connections
to a hub use a Link Test Pulse to verify link integrity. This pulse is the
same in all flavors of Ethernet if auto-negotiation is not used. The
auto-negotiation protocol itself uses a modified form of these pulses to
negotiate a common Ethernet implementation.
If Ethernet incompatibility jabber were to occur between 100BASE-TX and
another flavor of Ethernet, the results could be catastrophic, as
100BASE-TX
transmits a continuous idle signal between frames. Although transparent to
100BASE-TX, this idle signal would completely busy out a 10Base-T or
100BASE-T4 segment. On the other hand, the 802.3 specifies that a Fast
Ethernet repeater should implement jabber control, automatically
partitioning off any port that is streaming information for more than
40000
to 75000 bits. If the repeater were to partition off the "jabbering" port,
the symptom would be reduced to inability to connect the 100BASE-TX
station
to the network.
Common Ethernet errors
· High rate of collisions : Common with cable faults, misterminations,
hardware failures, and traffic levels in excess of 30%-50%
· CRC (Cyclic Redundancy Check) errors : Indicate receiving station is
detecting a packet received with errors.
· Giants : Frames too long - Indicate that the Ethernet packet received
exceeds the 64-1518 allowed byte range for IEEE 802.3 frames.
· Late collision : Indicates that the network diameter is possibly
exceeding
that permissible in the Ethernet specification (excessive Round Trip
Delay).
· Misaligned packets : Indicate frames contain both alignment and CRC
errors
· Runt packets : Packets with good CRC's that are less than the 64 byte
minimum packet size specified in the Ethernet specification.
· Fragmented packets : Usually the result of collisions
· Backoff failure : A transmitting device fails to back off in a timely
fashion after a collision detection
· Short IPG : Short Interpacket gap
· Duplicate MAC Layer Addresses : Some network interface cards allow
locally
administered Ethernet MAC Layer addresses, which are often used in DECNET
networks. Other manufacturers such as IBM will allow duplicate addresses
on
mainframe front-end interfaces for disaster recovery purposes.
Occasionally,
when a locally administered address plan is implemented, duplicate
addresses
will occur causing problems on the network. This is especially so when
people use a number scheme relating to phone extension, workstation
geographic location, etc., and then users are added and moved throughout
the
building after the network is installed.
· Protocol timeouts : Some LAN protocols require responses within a period
of time, or they will drop or suspend the LAN session. This type of
problem
often occurs in LAN networks connected over WAN circuits that may not have
adequate bandwidth or that take a path where the data is routed through
circuits causing excessive network delay (such as satellite data links).
· Jabber : Jabber is excessive garbage information being transmitted from
a
station. Generally this results from physical layer problems such as cable
failure or from a malfunctioning network interface. Many high quality
Ethernet LAN hubs feature Jabber Protection on each port which
automatically
partitions the malfunctioning device or segment from the rest of the
network
after receiving a certain number of consecutive erred packets or
collisions.
"Hervé" <IDE@PC.RESEAU> a écrit dans le message de
news:c7o1hv$98p$1@news-reader2.wanadoo.fr...
Bonjour,
Quelqu'un connait-il la description du voyant "Jab" sur un convertisseur
BNC/RJ45 .
Jabber definition
In networks, a jabber is any device that is handling electrical signals
improperly, usually affecting the rest of the network. In an Ethernet
network, devices compete for use of the line, attempting to send a signal
and then retrying in the event that someone else tried at the same time. A
jabber can look like a device that is always sending, effectively bringing
the network to a halt. A jabber is usually the result of a bad network
interface card (NIC). Occasionally, it can be caused by outside electrical
interference.
Incompatible Ethernet Jabber
Another potential problem in 100Mbps Ethernet is the use of RJ-45 jacks
for
more than one flavor of Ethernet. Since 100BASE-TX and 100BASE-T4 both use
RJ-45 jacks, as do 10Base-T and many other network technologies, the IEEE
802.3 specified an auto-negotiation protocol to allow stations to figure
out
the networking technology to use. Unfortunately, they made its
implementation optional. If you're using equipment that does not implement
IEEE-spec auto-negotiation, the incompatible Ethernet signals could
prevent
one of your stations from connecting to your network, or even simulate
"jabber" by constantly transmitting a TX idle stream and bringing down the
network.
The possibility for this jabber is uncertain, considering that the flavors
of Ethernet use different signal formats in transmission. Even if data is
not exchanged, it is still possible that incompatible Ethernet flavors
could
assume that they have a proper connection. Ethernets using RJ-45
connections
to a hub use a Link Test Pulse to verify link integrity. This pulse is the
same in all flavors of Ethernet if auto-negotiation is not used. The
auto-negotiation protocol itself uses a modified form of these pulses to
negotiate a common Ethernet implementation.
If Ethernet incompatibility jabber were to occur between 100BASE-TX and
another flavor of Ethernet, the results could be catastrophic, as
100BASE-TX
transmits a continuous idle signal between frames. Although transparent to
100BASE-TX, this idle signal would completely busy out a 10Base-T or
100BASE-T4 segment. On the other hand, the 802.3 specifies that a Fast
Ethernet repeater should implement jabber control, automatically
partitioning off any port that is streaming information for more than
40000
to 75000 bits. If the repeater were to partition off the "jabbering" port,
the symptom would be reduced to inability to connect the 100BASE-TX
station
to the network.
Common Ethernet errors
· High rate of collisions : Common with cable faults, misterminations,
hardware failures, and traffic levels in excess of 30%-50%
· CRC (Cyclic Redundancy Check) errors : Indicate receiving station is
detecting a packet received with errors.
· Giants : Frames too long - Indicate that the Ethernet packet received
exceeds the 64-1518 allowed byte range for IEEE 802.3 frames.
· Late collision : Indicates that the network diameter is possibly
exceeding
that permissible in the Ethernet specification (excessive Round Trip
Delay).
· Misaligned packets : Indicate frames contain both alignment and CRC
errors
· Runt packets : Packets with good CRC's that are less than the 64 byte
minimum packet size specified in the Ethernet specification.
· Fragmented packets : Usually the result of collisions
· Backoff failure : A transmitting device fails to back off in a timely
fashion after a collision detection
· Short IPG : Short Interpacket gap
· Duplicate MAC Layer Addresses : Some network interface cards allow
locally
administered Ethernet MAC Layer addresses, which are often used in DECNET
networks. Other manufacturers such as IBM will allow duplicate addresses
on
mainframe front-end interfaces for disaster recovery purposes.
Occasionally,
when a locally administered address plan is implemented, duplicate
addresses
will occur causing problems on the network. This is especially so when
people use a number scheme relating to phone extension, workstation
geographic location, etc., and then users are added and moved throughout
the
building after the network is installed.
· Protocol timeouts : Some LAN protocols require responses within a period
of time, or they will drop or suspend the LAN session. This type of
problem
often occurs in LAN networks connected over WAN circuits that may not have
adequate bandwidth or that take a path where the data is routed through
circuits causing excessive network delay (such as satellite data links).
· Jabber : Jabber is excessive garbage information being transmitted from
a
station. Generally this results from physical layer problems such as cable
failure or from a malfunctioning network interface. Many high quality
Ethernet LAN hubs feature Jabber Protection on each port which
automatically
partitions the malfunctioning device or segment from the rest of the
network
after receiving a certain number of consecutive erred packets or
collisions.
"Hervé" a écrit dans le message de
news:c7o1hv$98p$Bonjour,
Quelqu'un connait-il la description du voyant "Jab" sur un convertisseur
BNC/RJ45 .
Jabber definition
In networks, a jabber is any device that is handling electrical signals
improperly, usually affecting the rest of the network. In an Ethernet
network, devices compete for use of the line, attempting to send a signal
and then retrying in the event that someone else tried at the same time. A
jabber can look like a device that is always sending, effectively bringing
the network to a halt. A jabber is usually the result of a bad network
interface card (NIC). Occasionally, it can be caused by outside electrical
interference.
Incompatible Ethernet Jabber
Another potential problem in 100Mbps Ethernet is the use of RJ-45 jacks
for
more than one flavor of Ethernet. Since 100BASE-TX and 100BASE-T4 both use
RJ-45 jacks, as do 10Base-T and many other network technologies, the IEEE
802.3 specified an auto-negotiation protocol to allow stations to figure
out
the networking technology to use. Unfortunately, they made its
implementation optional. If you're using equipment that does not implement
IEEE-spec auto-negotiation, the incompatible Ethernet signals could
prevent
one of your stations from connecting to your network, or even simulate
"jabber" by constantly transmitting a TX idle stream and bringing down the
network.
The possibility for this jabber is uncertain, considering that the flavors
of Ethernet use different signal formats in transmission. Even if data is
not exchanged, it is still possible that incompatible Ethernet flavors
could
assume that they have a proper connection. Ethernets using RJ-45
connections
to a hub use a Link Test Pulse to verify link integrity. This pulse is the
same in all flavors of Ethernet if auto-negotiation is not used. The
auto-negotiation protocol itself uses a modified form of these pulses to
negotiate a common Ethernet implementation.
If Ethernet incompatibility jabber were to occur between 100BASE-TX and
another flavor of Ethernet, the results could be catastrophic, as
100BASE-TX
transmits a continuous idle signal between frames. Although transparent to
100BASE-TX, this idle signal would completely busy out a 10Base-T or
100BASE-T4 segment. On the other hand, the 802.3 specifies that a Fast
Ethernet repeater should implement jabber control, automatically
partitioning off any port that is streaming information for more than
40000
to 75000 bits. If the repeater were to partition off the "jabbering" port,
the symptom would be reduced to inability to connect the 100BASE-TX
station
to the network.
Common Ethernet errors
· High rate of collisions : Common with cable faults, misterminations,
hardware failures, and traffic levels in excess of 30%-50%
· CRC (Cyclic Redundancy Check) errors : Indicate receiving station is
detecting a packet received with errors.
· Giants : Frames too long - Indicate that the Ethernet packet received
exceeds the 64-1518 allowed byte range for IEEE 802.3 frames.
· Late collision : Indicates that the network diameter is possibly
exceeding
that permissible in the Ethernet specification (excessive Round Trip
Delay).
· Misaligned packets : Indicate frames contain both alignment and CRC
errors
· Runt packets : Packets with good CRC's that are less than the 64 byte
minimum packet size specified in the Ethernet specification.
· Fragmented packets : Usually the result of collisions
· Backoff failure : A transmitting device fails to back off in a timely
fashion after a collision detection
· Short IPG : Short Interpacket gap
· Duplicate MAC Layer Addresses : Some network interface cards allow
locally
administered Ethernet MAC Layer addresses, which are often used in DECNET
networks. Other manufacturers such as IBM will allow duplicate addresses
on
mainframe front-end interfaces for disaster recovery purposes.
Occasionally,
when a locally administered address plan is implemented, duplicate
addresses
will occur causing problems on the network. This is especially so when
people use a number scheme relating to phone extension, workstation
geographic location, etc., and then users are added and moved throughout
the
building after the network is installed.
· Protocol timeouts : Some LAN protocols require responses within a period
of time, or they will drop or suspend the LAN session. This type of
problem
often occurs in LAN networks connected over WAN circuits that may not have
adequate bandwidth or that take a path where the data is routed through
circuits causing excessive network delay (such as satellite data links).
· Jabber : Jabber is excessive garbage information being transmitted from
a
station. Generally this results from physical layer problems such as cable
failure or from a malfunctioning network interface. Many high quality
Ethernet LAN hubs feature Jabber Protection on each port which
automatically
partitions the malfunctioning device or segment from the rest of the
network
after receiving a certain number of consecutive erred packets or
collisions.
