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Q: What are the differences between the A and B versions of the HP ProCurve Switch 408?
The A version of the HP ProCurve Switch 408 (J4097A) supports MDI-X/MDI on one port, selected by a button. The B version (J4097B) support HP Auto-MDIX on every port, and automatically detects and corrects reverse polarity between the transmit and receive twisted pair, adapting for either straight-through or crossover cables.
The power adapter for the A version produces 19 volts DC with a maximum current of 0.55 amps. The B version produces 13 volts DC with a maximum current of 0.8 amps.
Both the A and B versions of the HP ProCurve Switch 408 support automatic learning of hardware addresses. The A version has an 8,000 entry address-forwarding table, and the B version has a 1,000 entry address-forwarding table
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Q: What are the features of the HP ProCurve Switch 408?
The HP ProCurve Switch 408 is a multiport switch that can be used to build high-performance switched workgroup networks. This switch is a store-and-forward device that offers low latency for high-speed networking. With this switch you can build a switched network infrastructure by connecting it to hubs, other switches, or routers; or you can connect directly to computers, printers and servers to provide dedicated bandwidth to those devices. The features of the Switch 408 include:
- 8 autosensing 10/100Base-TX RJ-45 ports -- all ports can sense the connection speed, 10 Mbps or 100 Mbps, and automatically operate at that speed
- HP Auto-MDIX on all ports (on J4097B) or MDI-X/MDI selection button for one port (on J4097A)
- Plug and play networking -- all ports are enabled -- just connect the network cables to active network devices and your switched network is operational
- Automatic learning of the hardware addresses in the switch's address forwarding table, with up to 1,000 entries on the J4097B or up to 8,000 entries on the J4097A
- Auto-negotiation of half-/full-duplex on all ports (IEEE 802.3u)
- Auto-negotiation of flow control for ports operating at full-duplex (IEEE 802.3u)
- Back pressure flow control for ports operating at half-duplex
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Q: What cables are used with the HP ProCurve Switch 408?
For the J4097B, because HP Auto-MDIX is supported on all ports, you can use either "straight-through" or "crossover" twisted-pair cables.
For the J4097A, all of the twisted-pair ports are wired as MDI-X. Therefore, to connect end nodes, servers, or other MDI-type devices to these ports, use "straight-through" twisted-pair cables. To connect to hubs, switches, or other MDI-X type devices, use "crossover" twisted-pair cables. Port 8 on the J4097A can be set to be either an MDI-X or MDI port, so a "straight-through" cable can be used with that port regardless of what kind of device is connected.
For connections to the switch ports, when they are operating at 10 Mbps, you can use Category 3, 4 or 5 unshielded twisted-pair cable, as supported by the IEEE 802.3 Type 10Base-T standard.
For connections to the switch ports, when they are operating at 100 Mbps, use Category 5 or better, as defined by the IEEE 802.3u Type 100Base-TX standard. Only twisted-pair cables with solid conductors are supported to the full 100 meters; do not use braided or drop cables.
Twisted-Pair Cable for Switch (MDI-X) to Computer (MDI) Network Connection
All twisted-pair wires must be twisted through the entire length of the cable. The wiring sequence must conform to AT&T 258A (not USOC). To connect PCs or other MDI network devices to these ports, use a "straight-through" cable as shown here:
Twisted-Pair "Crossover" Cable for Switch-to-Switch (or Switch-to-Hub) Network Connection
To connect hubs or switches or other MDI-X network devices to these ports, use a "crossover" cable.
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Q: Does the HP ProCurve Switch 408 support full duplex?
The HP ProCurve Switch 408 will auto-negotiate half- or full-duplex. When
connected to a full-duplex auto-negotiating device, the
HP ProCurve Switch 408 will choose full-duplex. If auto-negotiation
fails, or does not exist, then the switch defaults to
half-duplex. Note that the device connected to the HP
ProCurve Switch 408 must be compliant with the IEEE 802.3u
standard. A non-standard device may experience some problems.
If you experience problems you should check with the manufacturer
of the device and if necessary update the drivers for
that device. You may also experience problems if the device
connected to the HP ProCurve Switch 408 has a fixed configuration
of full-duplex. See the FAQ entitled "Is
10/100 Mbps auto-negotiation the same as plug-and-play?"
for more information.
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Q: Does the HP ProCurve Switch 408 support IEEE 802.3u auto-negotiation?
The HP ProCurve Switch 408 supports full IEEE 802.3u auto-negotiation, including the latest revision that includes flow-control auto-negotiation. Note that the device connected to the HP ProCurve Switch 408 must be compliant with the IEEE 802.3u standard. A non-standard device may experience some problems. If the device is older, or is using pre-standard drivers, the device may have difficulty auto-negotiating with the HP ProCurve Switch 408. If you experience problems you should check with the manufacturer of the device and if necessary update the drivers for that device.
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Q: Can the HP ProCurve Switch 408 be used as a desktop switch?
Yes, the HP ProCurve Switch 408 is designed to be used primarily as a desktop switch to which end nodes, printers and other peripherals, and servers are directly connected, as shown in the illustration below. Notice that the end node devices are connected to the switch by "straight-through" twisted pair cables.
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Q: Can the HP ProCurve Switch 408 be used as a segment switch?
Yes, the
HP ProCurve Switch 408 can be used as a segment switch.
Although it was designed as a desktop switch, with its
high performance and large address table, it can be used
for interconnecting network segments by simply connecting
the network hubs that form those segments to the switch.
In the illustration below, two Ethernet hubs with PCs, printers, and local servers attached, are both connected to an HP ProCurve Switch 408. The devices attached to the two hubs can now communicate with each other through the switch. They can also all communicate with the server that is connected to the switch. Connecting the server through a 100 Mbps connection allows a large number of users to access the server without causing network congestion.
The connections between the switch and the MDI-X ports on the hubs are with "crossover" twisted pair cables. If the hubs have MDI ports or MDI/MDI-X selectable ports, you can connect them with "straight-through" cables. The 100 Mbps connection to the server is with a Category 5 "straight-through" twisted-pair cable.
The switch, in turn, is connected to a backbone switch using "straight-through" twisted pair cable connected to port 8 with the MDI-X/MDI Select button set to MDI. Now, all the devices on these network segments can access other network resources that are connected elsewhere on the network backbone.
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Q: How can the LEDs on the front of the HP ProCurve Switch 408 be used to troubleshoot networking problems?
The following is a chart with an explanation of the LED behavior.
| Indication: |
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The power cord is plugged in and the Power LED
is not lit. |
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| Problem: |
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The switch is not plugged into an active AC power
source, or the switch's power supply may have failed. |
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| Solution: |
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- Verify that the power cord is plugged into
an active power source and to the switch. Make
sure these connections are snug.
- Try power cycling the switch by unplugging
and plugging in the power.
- If the Power LED is still not on, verify that
the AC power source works by plugging another
device into the outlet. Or try plugging the
switch into a different outlet.
If the power source is OK and this condition persists,
the switch may have failed. Call your HP Authorized
Reseller, or use the electronic support services
from HP to get assistance. Refer to your Customer
Support/Warranty booklet for more information. |
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| Indication: |
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The Power LED is ON and the Fault LED is on for
a prolonged period of time. |
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| Problem: |
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A switch hardware failure has occurred during
self-test. |
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| Solution: |
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Try power cycling the switch. If the fault indication
reoccurs, the switch may have failed. Call your
HP Authorized Reseller, or use the electronic support
services from HP to get assistance. Refer to your
Customer Support/Warranty booklet for more information. |
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| Indication: |
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The Power LED is ON, the Fault LED is OFF, and
the Port Link LED is OFF with a cable connected. |
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| Problem: |
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The network connection is not working properly. |
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| Solution: |
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Try the following procedures: |
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- For the indicated port, verify that both ends
of the cabling, at the switch and the connected
device, are secure.
- Verify that the connected device and switch
are both powered on and operating correctly.
- Verify that you have used the correct cable
type for the connection.
- For twisted-pair connections, in general,
for connection to an end node, use a "straight-through"
cable; for connecting to MDI-X ports on
hubs or other switches, use a "crossover"
cable.
- Verify that the connected devices comply with
the IEEE 802.3 standard, including transmission
of the Link signal.
- If the cable still isn't working, it may not
be compatible with the IEEE 802.3 Type 10Base-T
or 100Base-TX standards. The twisted-pair cables
attached to the HP ProCurve Switch 408 must
be compatible with these standards. To verify
that your cable is compatible with these standards,
use a qualified cable test device. HP also offers
a wire testing service. Contact your HP Authorized
Reseller or your local HP sales office for more
information.
- If you have two PCs on the network, both connected
to the switch, you can use a link-level packet
test (link-test) or Ping test to verify that
the entire communication path between the two
PCs is functioning correctly. Refer to your
LAN adapter documentation for more information
on running a link test or Ping test.
- Try using a different port or a different
cable.
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Q: Does the HP ProCurve Switch 408 support 802.1Q/802.1p?
The HP ProCurve Switch 408 allows 1522 byte size packets tagged with an 802.1Q tag but does not decode the VLAN ID. The switch does not participate in VLAN tagging or VLAN priorities. The packets will be forwarded without any problems.
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Q: Is 10/100Mbps auto-negotiation the same as Plug-n-Play?
No. The following configuration will cause severe network problems:
The HP ProCurve Switch 408 will correctly sense (not auto-negotiate) the 10 Mbps or 100 Mbps speed. Since the end node was configured for a specific speed and duplex state, and therefore does not negotiate, the HP ProCurve Switch 408 will choose the communication mode specified by the 802.3u standard, namely half-duplex.
With one device running at half-duplex and the device on the other end of the connection at full-duplex, the connection will work reasonably well at low levels of traffic. At high levels of traffic the full-duplex device (end node, in this case) will experience an abnormally high level of CRC or alignment errors. The end users usually describe this situation as, "Performance seems to be approximately 1 Mbps!". Often, end nodes will drop connections to their servers.
In this same situation, the half-duplex device will experience an abnormally high level of late collisions. The network administrator must take care to verify the configuration of each network device during installation. Also, check the operational mode ("100" and "Fdx" LEDs on the HP ProCurve Switch 408) of each network device.
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Q: Why won't my iMac, which is directly attached to an HP ProCurve Switch switch, NetBoot from an OS X Server, even though it worked correctly when my iMac was plugged directly into a hub?
This issue is not specific to HP switches. Rather, it is a timing problem in early versions of the iMac Boot ROM. Apple Computer, Inc has fixed this NetBoot issue by releasing both an updated Boot ROM image and Mac OS X Server version 1.2. Please advise customers with iMac NetBoot issues to contact Apple Computer, Inc Technical Support.
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Q: Why won't my Xircom Realport-REM56G-100BTX Notebook NIC operate properly with my HP ProCurve switch in full duplex mode at 100Mbps?
HP knows that this Xircom NIC, at full duplex over 100Mbps, does not operate with our HP ProCurve Switch switches. HP has no reports of any other vendors' NIC having a similar issue with our ProCurve switches. While this NIC's data sheet states support of full duplex, HP has not been able to get this NIC to operate at full duplex over a 100Mbps connection, regardless whether it is configured to Auto-negotiate or full duplex, fixed configuration.
We are not aware of any fixes for this issue.
Failure symptoms include poor performance and lost connections. See the discussion of "Q: Is 10/100Mbps auto-negotiation the same as Plug-n-Play?" on this same page for more details on the problem symptoms.
The workaround is to operate the NIC in half-duplex mode or to use a different NIC.
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