Jump to content United States-English
HP.com Home Products and Services Support and Drivers Solutions How to Buy
» Contact HP
 
HP ProCurve Networking

» My ProCurve Sign In

HP ProCurve Networking  >  Technical support  >  FAQs

FAQs


  »

HP Networking



The FAQs listed below are for these products:

  • J4093A HP ProCurve Switch 2424m
  • J4110A HP ProCurve Switch 8000m
  • J4111A HP ProCurve Switch 10/100Base-T Module
  • J4112A HP ProCurve Switch 100Base-FX Module
  • J4113A HP ProCurve Switch Gigabit-SX Module
  • J4114A HP ProCurve Gigabit-LX Module
  • J4115A HP ProCurve Switch 100/1000Base-T Module
  • J4115B HP ProCurve Switch 100/1000Base-T Module
  • J4116A HP ProCurve Switch 2424m Gigabit Stacking
  • J4118A HP ProCurve Switch 10Base-FL Module
  • J4119A HP ProCurve Switch 4000m/8000m RPS
  • J4120A HP ProCurve Switch 1600m
  • J4121A HP ProCurve Switch 4000m
  • J4122A HP ProCurve Switch 2400m
  • J4130A HP ProCurve Switch 2424m Gigabit Stacking Module
  • J4131A HP ProCurve Gigabit-SX Transceiver
  • J4132A HP ProCurve Gigabit-LX Transceiver
» View FAQs for a different group of products

Customer Care

»  Overview
»  Services
»  Support
   »  Software
   »  Warranty
   »  FAQs
   »  Knowledge Base
   »  Manuals
   »  Reference library
   »  Configuration examples
   »  Support forms
   »  Security notices

My ProCurve gives you instant access to software update notifications.
» Register or log in now

Commercial help me agent » Contact ProCurve
Auto-negotiation
» Q: Does the factory configure the 10/100 auto-sensing modules with auto-sensing enabled?
» Q: Is 10/100Mbps auto-negotiation the same as Plug-n-Play?
» Q: Is Gigabit Ethernet auto-negotiation the same as Plug-n-Play

Cabling
» Q: Can I use category 3 cables with the HP ProCurve Switch 100/1000Base-T Module?
» Q: What is the maximum length for cables used with the HP ProCurve Switch 100/1000Base-T Module?

Features
» Q: What are the differences between the HP ProCurve Switch 2424m (product number J4093A) and the HP ProCurve Switch 2400m (product number J4122A)?
» Q: What would a topology look like that has a maximum meshed switch hop count of 5?

Gigabit stacking
» Q: Does the HP ProCurve Switch 2424m support stacking?
» Q: Can the HP ProCurve Switch 2424m Gigabit Stacking Module (product number J4130A) be used in the HP ProCurve Switch 8000m, 4000m, 2400m or 1600m?
» Q: Does the HP ProCurve Switch 2424m Gigabit Stacking Module support trunking?

Modules
» Q: Does the 100Base-FX module support 10Base-FL operation?
» Q: What is the supported distance of the Gigabit-SX module?
» Q: Can the HP ProCurve Switch 2424m Gigabit Stacking Module (product number J4130A) be used in the HP ProCurve Switch 8000m, 4000m, 2400m or 1600m?
» Q: What are the features of the HP ProCurve Switch 100/1000Base-T Module?
» Q: Do I need a software update on my switch to use the HP ProCurve Switch 100/1000Base-T Module?
» Q: Is the HP ProCurve Switch 100/1000Base-T Module pre-configured with auto-sensing enabled?
» Q: Can I use category 3 cables with the HP ProCurve Switch 100/1000Base-T Module?
» Q: What is the maximum length for cables used with the HP ProCurve Switch 100/1000Base-T Module?
» Q: What configuration options are available on the HP ProCurve Switch 100/1000Base-T Module?

Spanning tree protocol
» Q: What should I do if my switch (which has switched ports to the desktop) reports many Spanning Tree Protocol (STP) topology changes, even if I am not having connectivity problems?
» Q: When I power on my PC, I get the message "a file server could not be found." How do I fix that?
» Q: Why is my Macintosh system unable to use AppleTalk services?

Troubleshooting
» Q: How can I troubleshoot problems when my Apple devices (iMac, PowerMac, Mac II, etc.) cannot access the network through my HP ProCurve switch?
» Q: Why won't my Xircom Realport-REM56G-100BTX Notebook NIC operate properly with my HP ProCurve switch in full duplex mode at 100Mbps?
» Q: When I power on my PC, I get the message "a file server could not be found." How do I fix that?
» Q: Why won't my iMac, which is directly attached to an HP ProCurve switch, NetBoot from an OS X Server, even though it worked correctly when my iMac was plugged directly into a hub?
» Q: Why is my Macintosh system unable to use AppleTalk services?

Trunking (HP & Fast EtherChannel (FEC)
» Q: Can the HP ProCurve Switch 8000m, 4000m, 2424m, 2400m, or 1600m connect to the HP AdvanceStack Switch 2000 or 800t with HP Port Trunking?
» Q: Is the Fast EtherChannel feature compatible with Cisco internetworking equipment?
» Q: How many links can I connect to my Unix server?
» Q: Does the HP ProCurve Switch 2424m Gigabit Stacking Module support trunking?

VLANs
» Q: How many VLANs can be configured on the HP ProCurve Switch 8000m, 4000m, 2424m, 2400m, and 1600m?
» Q: What is the recommended way to connect multiple VLANs between a routing switch and a layer 2 switch?

Answers

Q: What should I do if my switch (which has switched ports to the desktop) reports many Spanning Tree Protocol (STP) topology changes, even if I am not having connectivity problems?
You can view how many topology changes are occurring by looking at the Topology Change Count in the Status and Counters—SpanningTree Information screen on your HP ProCurve Switch 8000m, 4000m, 2424m, 2400m, or 1600m.

STP was developed to manage switch-to-switch links, or bridge-to-bridge links as they were initially called. For most of STP's lifetime, a topology change was a serious event as it indicated a change in the LAN topology. It also indicated a likelihood that STP had to bring (at least) a portion of the LAN down for awhile in order to rebuild a new working topology. Of course, in a LAN we expect the topology to change only rarely.

Over the past few years, the cost of switch ports has dropped dramatically. Users can now afford to dedicate switch ports to end nodes.

Once an STP topology is stable, establishing an Ethernet link on a switch port results in a topology change. This happens every time a user powers up their PC (assuming that the PC is directly connected to a switch port), resets the PC, or brings up the PC's network stack. The establishment of this link causes the topology change count to increment in:
  1. the switch to which the end node is directly attached; and
  2. "upstream" switches. That is, the root switch and the switches between the root switch and the switch to which the end node is directly connected.

This scenario does not result in any topology issues or changes. It does not result in any loss of connectivity in the LAN. If the incrementing of your topology change count is due to this type of scenario, you do not need to take any action.

The above discussion applies to Hewlett-Packard switches in general and HP ProCurve switches in particular when configured in STP Normal mode. When an HP ProCurve switch's port is configured in STP Fast mode, the switch will not increment the topology change count as a result of link changes on that port. Please see the switch's Management and Configuration Guide for details on normal and fast modes.

» Return to top

Q: When I power on my PC, I get the message "a file server could not be found." How do I fix that?
This is a well-known issue given the following situation:
  1. The PC is directly-connected to a switch
  2. The PC is running Novell's VLMs or Client32
  3. The switch has Spanning Tree Protocol (STP) enabled
In this situation, when the directly-connected PC is powered on, the switch senses linkbeat on that port. This causes the switch to go through the four Spanning Tree states: blocking, listening, learning, and forwarding. It takes 30 seconds for the switch to complete that sequence and begin forwarding packets to and from that port. During those 30 seconds, Novell sends 3 requests for a server, then stops looking. By the time Spanning Tree completes its job, Novell reports that "a file server could not be found."

There are several workarounds available:
  1. Disable Spanning Tree on the switch (if Spanning Tree is not needed, i.e. no loops in the network topology).
  2. For VLMs, add a "pause" just after calling VLM.EXE in STARTNET.BAT. When the user reboots a PC, have them wait at least 30 seconds before continuing the sequence. This workaround is documented on Novell's Knowledgebase (www.support.novell.com, search for document 2920460).
  3. For Client32, add a registry entry in the PC, as documented on Novell's Knowledgebase (search for document 2925582).

In the Fall of 1998, HP released switch firmware (version C.05.07 or greater) with an enhancement to resolve this timing problem between Novell and STP. The enhancement allows users to configure Spanning Tree so that it does not go through the 4 states, on a port-by-port basis. Instead, for those configured ports, Spanning Tree will immediately begin forwarding packets to and from the port. This allows Novell clients to communicate with the server as soon as the network card (NIC) is enabled. After that, the switch continues to listen for and send Spanning Tree packets on those configured ports. This protects the user who might inadvertently connect a hub or switch to that port and create a network loop—Spanning Tree will detect the loop after a short time, since the port listens for and sends STP packets on that port.

» Return to top

Q: Can the HP ProCurve Switch 8000m, 4000m, 2424m, 2400m, or 1600m connect to the HP AdvanceStack Switch 2000 or 800t with HP Port Trunking?
Yes. The HP Port Trunking implemented in the HP ProCurve Switch 8000m, 4000m, 2424m, 2400m, and 1600m has been enhanced from the version implemented in the HP AdvanceStack Switch 2000 and 800t. But you can still connect any of these switches together using HP Port Trunking.

» Return to top

Q: Is the Fast EtherChannel feature compatible with Cisco internetworking equipment?
Yes.

» Return to top

Q: Does the factory configure the 10/100 auto-sensing modules with auto-sensing enabled?
Yes.

» Return to top

Q: Does the 100Base-FX module support 10Base-FL operation?
No, there is a separate card to support 10Base-FL fiber optic Ethernet connectivity.

» Return to top

Q: What is the supported distance of the Gigabit-SX module?
Model Bandwidth Distance Covered if 62.5 Core Diameter

Distance Covered if 50 Core Diameter
160 MHz.km   220 meters

  N/A
200 MHz.km   275 meters

  N/A
400 MHz.km   N/A

  500 meters
500 MHz.km   N/A   550 meters
The distances noted above are correct for the IEEE Draft P802.3z/D4.2 (Gigabit Draft 4.2) specification.

The better the quality of the cable, the greater the modal bandwidth and the greater the distance supported.

» Return to top

Q: How many links can I connect to my Unix server?
You can configure anywhere from 1-4 100Base-T links using the Fast EtherChannel feature.

» Return to top

Q: Is 10/100Mbps auto-negotiation the same as Plug-n-Play?
No. The following configuration will cause severe network problems:

Node configuration diagram

The hub, switch, or router will correctly sense (not auto-negotiate) the 10Mbps or 100Mbps speed. Since the end node was configured for a specific speed and duplex state, and therefore does not negotiate, the hub, switch, or router 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 1Mbps!." 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 of each network device. That is, check both how you configured it and also that it comes up as you expect, for example, at 10Mbps/half-duplex.

» Return to top

Q: Is Gigabit Ethernet auto-negotiation the same as Plug-n-Play?
No. By the time the IEEE issued the 802.3z specification, they knew about the 10/100Mbps auto-negotiation problem (see the FAQ "Is 10/100Mbps auto-negotiation the same as Plug-n-Play?"). To prevent it, 802.3z auto-negotiation requires that, if one side of a connection is configured to auto-negotiate, the other side must also auto-negotiate if the connection is to come up. In other words, if a switch is configured to auto-negotiate and its attached end node is configured to, say, 1000Mbps/full-duplex, the 803.2z spec requires that the switch NOT allow the link to come up.

» Return to top

Q: What are the differences between the HP ProCurve Switch 2424m (product number J4093A) and the HP ProCurve Switch 2400m (product number J4122A)?
The HP ProCurve Switch 2424m has 24 10/100Base-TX autosensing ports like the HP ProCurve Switch 2400m, but the HP ProCurve Switch 2424m also has a module slot that can be used for stacking, gigabit connectivity or port expansion.

» Return to top

Q: Does the HP ProCurve Switch 2424m support stacking?
The HP ProCurve Switch 2424m has a slot for the two port HP ProCurve Switch 2424m Gigabit Stacking Module (product number J4130A). This module stacks up to 7 switches with the HP ProCurve Switch 2424m Gigabit Stacking Kit (product number J4116A). One stacking module must be purchased for each switch and one stacking kit must be purchased for every stack of two switches. The stacking module can also be used as a dual gigabit uplink module with the HP ProCurve Gigabit-SX Transceiver (product number J4131A) and/or the HP ProCurve Gigabit-LX Transceiver (product number J4132A). In addition, the following modules, which are supported in the HP ProCurve Switch 8000m, 4000m, 2400m, and 1600m, are also supported in the HP ProCurve Switch 2424m for uplink connectivity or for additional desktop ports:
  • HP ProCurve Switch 100/1000Base-T Module (product number J4115A and J4115B)
  • HP ProCurve Switch 10/100Base-T Module (product number J4111A)
  • HP ProCurve Switch 100Base-FX Module (product number J4112A)
  • HP ProCurve Switch Gigabit-SX Module (product number J4113A)
  • HP ProCurve Switch Gigabit-LX Module (product number J4114A)
  • HP ProCurve Switch 10Base-FL Module (product number J4118A)

» Return to top

Q: Can the HP ProCurve Switch 2424m Gigabit Stacking Module (product number J4130A) be used in the HP ProCurve Switch 8000m, 4000m, 2400m or 1600m?
No, this stacking module was designed specifically for the HP ProCurve Switch 2424m. It will not slide into a slot on any other switch. But the optional modules supported on the HP ProCurve Switch 8000m, 4000m, 2400m, and 1600m are supported on the HP ProCurve Switch 2424m.

» Return to top

Q: Does the HP ProCurve Switch 2424m Gigabit Stacking Module support trunking?
Yes, the HP ProCurve Switch 2424m Gigabit Stacking Module supports trunking. Port trunk links can be configured only between like media types:

  • Gigabit-SX with Gigabit-SX
  • Gigabit-LX with Gigabit-LX
  • HP ProCurve Switch 2424m Gigabit Stacking Kit transceiver with HP ProCurve Switch 2424m Gigabit Stacking Kit transceiver

» Return to top

Q: What are the features of the HP ProCurve Switch 100/1000Base-T Module?
The HP ProCurve Switch 100/1000Base-T Module (J4115A and J4115B) is an accessory that can be added to the HP ProCurve Switch 1600m, 2424m, 4000m, and 8000m. The HP ProCurve Switch 100/1000Base-T Module provides one twisted-pair port with an RJ-45 connector for 100Mbps or 1000Mbps (Gigabit) operation over category 5 cable. Like all of the switch modules available for this line of products, the HP ProCurve Switch 100/1000Base-T Module is shipped ready for network operation as soon as a viable network cable is connected. The LEDs on this module provide information on the link status, network activity, connection bandwidth, and communication mode (half or full duplex). And, as with all other HP ProCurve modules, it features "hot-swap" operation, meaning addition or replacement of a module can be achieved without having to shut down the switch (changing the module type in a given slot does require a switch reset).

» Return to top

Q: Do I need a software update on my switch to use the HP ProCurve Switch 100/1000Base-T Module?
Yes. Your HP ProCurve Switch requires software version C.07.20 or later to support the J4115A HP ProCurve Switch 100/1000Base-T Module, and software version C.07.27 or later to support the J4115B HP ProCurve Switch 100/1000Base-T Module. The new software is found on the floppy disk included with the module. You can also download the software from this web site (select "software" in the right navigation box on this page). After installation of the software you can install the module into a slot on the switch.

» Return to top

Q: Is the HP ProCurve Switch 100/1000Base-T Module pre-configured with auto-sensing enabled?
Yes. In the default state, 100/1000Mbps connections can auto-negotiate for MDI/MDI-X, Full/Half Duplex, 100/1000Mbps, Flow control on/off, and, in 1000Mbps only, for master/slave.

» Return to top

Q: Can I use category 3 cables with the HP ProCurve Switch 100/1000Base-T Module?
No, only category 5 100-ohm UTP or STP cables are supported. In fact, for the most robust connections you should use cabling that complies with the Category 5E specifications, as described in Addendum 5 to the TIA-568-A standard (ANSI/TIA/EIA-568-A-5).

» Return to top

Q: What is the maximum length for cables used with the HP ProCurve Switch 100/1000Base-T Module?
The maximum length is 100 meters using category 5, 100-ohm UTP or STP cable. This distance is correct for the IEEE 802.3ab specification.

» Return to top

Q: What configuration options are available on the HP ProCurve Switch 100/1000Base-T Module?
Three options are available:
  • Auto - The module auto negotiates connection speed (100 or 1000Mbps), communication mode (full or half duplex), and MDI or MDI-X port operation.
  • 100 Full - The module is forced to 100Mbps speed and the communication mode is set to full duplex.
  • 100 Half - The module is forced to 100Mbps speed and the communication mode is set to half duplex.

Note: If you configure the port to one of the fixed 100Mbps modes, the port will then operate only as an MDI-X port.

» Return to top

Q: How many VLANs can be configured on the HP ProCurve Switch 8000m, 4000m, 2424m, 2400m, and 1600m?
These switches support up to 30 VLANs when using software version C.06.06 or later.

» Return to top

Q: What is the recommended way to connect multiple VLANs between a routing switch and a layer 2 switch?
The diagram below illustrates the question.
 
VLAN Diagram A

The following HP switches provide VLANs and have a single MAC/Ethernet address (filtering) table: Switch 800t, 2000, 1600m, 2400m, 2424m, 4000m, 8000m. In the diagram above we show a Switch 8000m, but the following discussion applies to all of the switches listed in the previous sentence. The HP ProCurve Routing Switch 9304m, 9308m, or 6308m-SX, as a default gateway, has a single MAC address (for all of its VLANs) if using virtual Ethernet interfaces. In the diagram above we show a 9304m, but this could be a 9308m or 6308m-SX as well.

Let's consider PC "A" attempting to send an IP packet to PC "B". PC "A" will send the 8000m a packet with the 9304m's MAC address in the destination field. If the 8000m has not yet learned this MAC address, the 8000m will flood the packet out all of its VLAN1 ports, including the VLAN1 link to the 9304m. The 9304m will then route the packet toward PC "B" via its link with the 8000m's VLAN2 connection. The 8000m will enter the 9304m's MAC address into its MAC address table as located in VLAN2. The 8000m will also forward the packet to PC "B".

Let's consider a second packet that PC "A" sends to PC "B". PC "A" sends the packet, again addressed to the 9304m's MAC address, to the 8000m. The 8000m will check its address table and find that the 9304m appears to be located on VLAN2. Since the 8000m believes that this MAC address is not located on VLAN1, the switch will discard the packet.

Later, when the 9304m transmits a packet to the 8000m via the VLAN1 link, the 8000m will update its address table to indicate that the 9304m's MAC address is located in VLAN1 instead of VLAN2. As you can see, the 8000m's location information for the 9304m's MAC address will vary over time between VLAN1 and VLAN2. For this reason, some packets directed through the 8000m for the 9304m's MAC address will be discarded. Performance may appear to be poor or connectivity may appear to be broken.

To avoid this issue, simply use one cable between the 8000m and the 9304m instead of two, making sure that the two VLANs use tags on that link, as shown below.

VLAN Diagram B

» Return to top

Q: What would a topology look like that has a maximum meshed switch hop count of 5?
Up to 12 switches are supported in a switch mesh domain (See the Management and Configuration Guide), and a maximum meshed switch hop count of five is allowed in the path connecting two nodes via a switch mesh domain topology.

"Hops" refers to inter-switch links, not the number of switches crossed. The limit is 5 meshed links. The rest of this discussion will use the word links instead of hops. In the diagram below, the numbers and arrows above the switches show the link count value in the mesh protocol packets. There are six switches between End Node A and End Node B, but only five links:

Topology Diagram 1

The switches learn the mesh topology by sending mesh protocol packets to each other. Each switch initiates this learning process by sending a mesh protocol packet with a link count of zero. When its neighbor switch receives this packet, the neighbor increments the link count (for example, from zero to one), then propagates the packet to the next switch. Switches do not send mesh protocol packets with a link count of 5 or larger.

In the diagram above, you can see that Switch 1 sends a mesh protocol packet containing a link count of zero. Switch 2 receives it and sends a mesh protocol packet with a link count of one. Switch 3 receives it and sends a mesh protocol packet with a link count of two. And so on.

Note that if we were to violate the mesh link count limit by adding a 7th switch between Switch 6 and End Node B, then Switch 7 would not receive any mesh protocol packets from Switch 1. Since Switch 7 would be unaware of the Switch 1, end nodes on Switch 1 would not be able to communicate with end nodes on Switch 7.

Consider now an illegal topology:

Topology Diagram 2

If we add an apparently redundant link:

Topology Diagram 3

In this topology, we appear to have redundant connections. Switch 1 is connected to Switch 7 through the upper link, and again through the "lower" link. You can see that Switch 7 learns that it is directly connected to Switch 1 through the "lower" link.

Switch 1 and Switch 7 do not know that they have a connection through the upper link, since mesh protocol packets will not travel across that many links. All traffic between End Node A and End Node B will travel along the lower link. In other words, we do not have a usable redundant link, since the topology is illegal.

In the diagram above, if the lower link becomes broken, we get the situation shown below:

If we add an apparently redundant link:

Topology Diagram 4

In the above topology, Switch 7 knows that it no longer receives mesh protocol packets from Switch 1 (through the lower link), but it does not know that it has an alternate path through the upper link. Connectivity between End Node A and End Node B is lost, and the mesh protocol cannot recover it.

Conclusion: For the switch mesh to work properly you must satisfy both limits:
  • a maximum of 5 meshed switch links between nodes; and
  • a maximum of 12 switches per mesh.

» Return to top

Q: Why won't my iMac, which is directly attached to an HP ProCurve 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.

» Return to top

Q: Why is my Macintosh system unable to use AppleTalk services?
Possible symptoms include: no AppleTalk services, only local network AppleTalk services, performance problems, and intermittent network services. If you remove the Macintosh from its dedicated switch (or routing switch or router) port and connect it to a hub, the problem goes away.

If the switch (or routing switch or router) has Spanning Tree Protocol enabled, see Apple Computer, Inc's Tech Info Library entry "Spanning Tree Protocol: AppleTalk and NetInfo Issues".

» Return to top

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 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.

» Return to top

Printable version
Privacy statement Using this site means you accept its terms
© 2010 Hewlett-Packard Development Company, L.P.