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Switches / Hubs





A switch is a device that filters and forwards packets of data between LAN segments. Switches operate at the data link layer or the network layer of the Open Systems Interconnection (OSI) Reference Model and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs. A hub is a connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports; when a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.

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I have an HP E5406zl switch with several vlans that was set up by a vendor. The switch seamlessly routes traffic for all vlans... meaning there appears to be no security between vlans.
All subnets can reach each other.

Is it possible for the switch to route selectively? Can I create an access list that prohibits certain vlans from communicating? (or is this just wrong?)

I can use a firewall to protect a vlan, but I'd like to do it with the switch itself if that even possible.

Thank you!
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Is Cisco Root Switch the only one that sends Hello Messages

in a network with hierarchical switches , do all switches send Hello messages to their neighbors or  only the Root switch will do that ?

Thank you
I have an older Brocade switch I would like to just use for POE. I have the Brocade FWS648G-POE FastIron 48 Port Ethernet Switch - 7.4.00 L3 image.  

Most of the information on line is for newer switches and my switch doesn't see to follow the same CLI syntax.

I need help and advise with setting this up and configuring this for a very basic setup.
Hey guys,

I’ve two PowerConnect 6224 switches which are linked to a Dell SAN (for redundancy) and one of the switches are then plugged into the local LAN.  I’m changing the local LAN switch but when I connect the Power Connect SAN switch to the new one, it doesn’t work - I can’t access any of the servers on the SAN - it’s a big odd, as there’s no config on the previous LAN Switch- what am I missing?

QNAP LAG info windowWe're trying to configure LAG on a QNAP TVS-EC1680U and a Netgear GS-752TP.

On the QNAP we've linked ports 3 and 4 into 802.3ad on Layers 2 and 3 with a static IP. Strangely, the GUI icon imager shows that ports 2 and 3 are bonded, while the Network Interfaces page shows 3 and 4 per our request -- see attached screen shot.

We've been patching ports 3 and 4 to the switch. Should we be patching ports 2 and 3 instead?

The Netgear manual has no reference to 802.3ad dynamic. Should we not be using this standard?

On the Netgear side, we're using "LAG1" and "ch1."
- Only ports 47 and 48 are members.
- LACP priority is the default, 32768.
- LACP priority is the default 128 for ports 47 and 48 (and all other ports) with timeout set to Short

What are we doing incorrectly?
I have 10 HP/Arruba Procurve 2530 POE+ switches.  We purchased new Ruckus r610 access points that run on 802.3at instead of 802.3af.  They pull about 23 watts at startup, then even out between 5 and 8 watts.  If all ports on the switch are running at 5-8 watts, there is enough power for all of the devices.  But because they do use over 23 watts at startup, the switch won't provide power to all of the ports because it goes over the maximum available power.  They do some calculation of current power and max power and figure out how much they can provide that is more than the running 5-8 watts, but less than the startup 23-25 watts.  Arruba says they can't do anything, as it's POE standard.

I can turn off lldp on the switch, so all ports basically run in 802.3af mode.  The APs all power on and run fine, except they turn off the USB and second ethernet port.  Apparently that is not a setting that I can change on the Ruckus APs.

I really want that second port turned on, but want to avoid purchasing more switches or ac adapters.

Anyone have any ideas on how to do this?

Tried and didn't work:
Manual CLI command for AP to run in 802.3at mode

Turn lldp back on, but limit max power to switch ports to 10W, with and without manual AP command
Please, advice model of switch (from 5 ports) and mirror setup. Switch should work as hub, i.e I need two ports for traffic registration.
I prefer mikrotik, but any other could be used (may be except Cisco).
I have some possible models (Huawei s2700, Huawei s2309, mikrotik as-326-24g, linksys 318, linksys 326, trendnet te-100-f5), but don't have setup for these devices.
Best way to configure spanning tree on HP Procurve switches

What switch should be the root? Best Practice?

I am designing a network for a new building. There will be a main server room and 5 IDFs. In each IDF I want to have as much redundancy as possible, so in each IDF there will be 2 XG/aggregate switches. The idea is that no matter how many 48-port switches are in a cabinet, EACH one will connect to 2 XG switches (one fiber cable to each). Then, to get from one IDF to the next, each XG switch in turn will have a dedicated fiber connection to the other XG switch in the next cabinet. The IDFs are connected in a star topology, meaning one "central" IDF has 2 fiber connections to each of the other 4 IDFs - one in each corner of the building. So the redundancy here is that every 48 port switch itself is connected to 2 XG switches, and in turn every IDF has 2 paths to the central IDF.

Here is a partial diagram to illustrate what I mean:

Partial Network Diagram


The red lines indicate fiber connections.
The blue lines also indicate fiber connections but may be overkill (Within each IDF, a single fiber cable connects the 2 XG switches to each other)

I am using RSTP on all switches, with the default settings except I made the following change:  I gave each of the 48-port switches a priority of "32,768" while all of the 16-port switches have a priority of "16,384". My assumption is that STP will choose each XG switch over a 48 port switch when building out its path (but I suspect there is more to it than that)

A few questions:

1. Is "Priority" the same as …
Configuring VLAN
Newbie to VLANS so haven't a clue of this stuff folks.

What is the differences with hybrid, trunk and Access vlans. Also I thought a trunk port was auto tagged, why would I get asked do I want it tagged or untagged.

Using a d link dgs-1510-28p that im trying to get me head around Ta
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This is 100k sqaure feet, two storey, new manufacturing facility, on its stage of network/architect design.
We estimate that there will be 200 spots that need network access, for computers, VoIP phones, WiFi APs, smart TVs and security cameras.
In about 80 spots of the above, a VoIP phone and a PC will coexist.  These spots are the sitting spots or cubicles for engineers, managers and office staff.

The main question - should we run two network drops or one network drop in each of above 80 spots?
Option1: Two drops - One for VoIP phone, the other one for the computer.
Option2: One drop - VoIP phone and the computer will be daisy chained.

Not trying to over complicate the above main topic, we do have a few other questions as below in case you'd like to share some insights as well
1. Should we separate VoIP phones and computers into different VLANs? Why?
2. If we put VoIP phones on a separate VLAN, will the above Option2 still be doable?
3. Should we deploy CAT6A or CAT6 cables? 10G network is getting popular.
4. Should we run all cables directly from the end spots to the server room? Or, install some switches in the middle?
5. Any other thoughts? Or anything we should be aware of?

Thanks in advance!
I have 3 switches. I have 1 vtp mode server (A) and 2 transparent (B & C). I changed the B & C from transparent to client. I added another vlan on A. But only B updated its vlan database. I am not sure why C did not. A is directly connected to B via copper. B is connected to  C via fiber.
Aruba (procurve) 2920 is showing only ports 1-24 on the console.  Is this correct?
I have cisco slm224g switch
I have a windows server 2016 with Hyper-V rule
I have three vlans 2, 3
Hyper-V on port 1
adsl router on port 2
client work station on port 3
on Hyper-V I have a pfsense as vm with two network interface the first one with vlan id =2 and the second one vlan id=3 on the same interface.
I want to assign client ,Hyper-V to vlan 2 and should connect over port 1 to first interface on Hyper-V
I want to assign adsl router to vlan3 and should connect  over port 1 to second interface on Hyper-V
regarding above:
port 1 should be trunk  for vlan id 2,3
port 2 should be access to vlan 3
and port 3 should be access as vlan 2
I tried that but it's not working so what the basic configuration for that ?
I have a Ubiquiti USG device here.

Its a quite simple setup.

-  Its WAN1 port is connected to my modem-router.
-  its LAN 1 port is connected to an Ubquiti Edge Switch

I can get internet perfectly if i plug cable from modem into switch. However, when internet goes thru the USG device to Switch - I get no internet.

It is as if the USG is blocking internet to the switch.

The USG is acting as DHCP server. What could be blocking the internet in the USG? Any suggestions would be much appreciated.

Please help me to change the time on my OXE WBM switchboard
Cannot ping or access via ip new cisco switch

show running-config
v2.4.0.94 / RTESLA2.4_930_181_045
CLI v1.0
file SSD indicator encrypted
ssd config
ssd file passphrase control unrestricted
no ssd file integrity control
ssd-control-end cb0a31af4e4430033719968c0
unit-type unit 1 network gi uplink te
unit-type unit 2 network gi uplink te
unit-type unit 3 network gi uplink te
unit-type unit 4 network gi uplink te
spanning-tree mode mst
vlan database
vlan 3,5
voice vlan oui-table add 0001e3 Siemens_AG_phone________
voice vlan oui-table add 00036b Cisco_phone_____________
voice vlan oui-table add 00096e Avaya___________________
voice vlan oui-table add 000fe2 H3C_Aolynk______________
voice vlan oui-table add 0060b9 Philips_and_NEC_AG_phone
voice vlan oui-table add 00d01e Pingtel_phone___________
voice vlan oui-table add 00e075 Polycom/Veritel_phone___
voice vlan oui-table add 00e0bb 3Com_phone______________
bonjour interface range vlan 1
hostname SG350x
management access-list admin
ip http authentication aaa login-authentication https local radius
snmp-server server
snmp-server location "Server Room"
no ip domain lookup
ip name-server
ip telnet server
interface vlan 1
 no ip address dhcp
interface vlan 3
 name "Corpyy"
interface vlan 5
 name "Guest"
interface GigabitEthernet1/0/1

We are using HP Pro curve POE switches.

Some of its access ports are not getting power and they are in searching mode and because of that when I try to connect any end device, it does not work.

Please assist me in this matter



Any idea how to improve the network design to ensure the network performance , link redundancy (RSTP) and compatibility on layer 2 to layer 3 are working fine on  video management system?


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When dealing with MTU in a networking environment, how do you verify what MTU size is being used/generated from within two systems?  Also, can you explain or share the size of MTU of the default or best practice MTU size for communication on different networks and or devices?
Hello there,

Can someone help me locate management packs for HPE Aruba Switches? Alternatively, easy to use documentation on how to incorporate its SNMP into SCOM (System Center Operations Manager) would be helpful too.
Hi -

I have two 1920 HP switches and I would like to share VLANs between the two. Coming from a Cisco background, I thought setting up a trunk would take care of it but no luck.

Basically what I did was to create a trunk port on each of the switches and directly connect them with a network cord. That did not work, the VLANs did not propagate.

What am I missing here?

Thank you for your help!
We have 3 Zyxel XGS2210-52HP switches uplinked from fiber SPF ports. VLAN's have been configured on all switches. From VLAN Port Setup, I select VLAN Trunking for PVID created, (40), and SFP port, (52). When I Apply, the switch looses connectivity with network. Only option is to power cycle switch to reconnect. Please educate me on what I'm doing wrong and proper way to trunk the 3 switches.  Current Zyxel XG2210 firmware is running, (4.50)
Thank you!

VLAN Port Image
I had issues routing voice traffic across two same make/model switches, one as a core and the other as edge.   Managed to resolve this by tagging ports in the respective vlans on the switches, simple fix but not something im used to.  
However we are now trying to get two older HP/3com switches to do the same.

Switch Config overview:

HP1910 switch using default vlan1 across all ports.  Connected to:
HP2910 switch vlan1 interface (acts as core and routes to firewall).  Connects to:
HP/3com2952 switch vlan1 interface.  This will connect to:
A new HP2910 switch.  This will in turn re-route back to the HP1910 above to form chain topology rather than current loop.  I'm assuming this is good?

I am not using any trunks or LACP.

Part one will be to route the new HP switch back to the 2952, once working ill then connect this back to the 1910.

So far i have created a new vlan20 on the old 2952 and tagged the port thats connected to the new 2910.   Here is the config:

[3Com Baseline Switch]display current-configuration
 version 5.20 Release 1101P10
 sysname 3Com Baseline Switch
 super password level 3 simple
 domain default enable system
 telnet server enable
 ip ttl-expires enable
vlan 1
vlan 20
 description Voice
radius scheme system
domain system
 access-limit disable
 state active
 idle-cut disable
 self-service-url disable
user-group system
local-user admin
 password simple

need to make my fortiWifi-80CM to be wireless client to connect to my ipad personal Hotspot so that my internal network able to connect to internet.

can't settle wireless client screenshot



Switches / Hubs





A switch is a device that filters and forwards packets of data between LAN segments. Switches operate at the data link layer or the network layer of the Open Systems Interconnection (OSI) Reference Model and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs. A hub is a connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports; when a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.