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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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So, here is my scenario

Currently with network set as VLAN200 on a switch, my router is

Got a cisco 2960 switch as, and set with default GW

However, I need to set a new vlan for a vpn (mikrotik)

Mikrotik ip is

Ive created a VLAN400, as and indicated the ip helper as the mikrotik. After assigning ports to that VLAN, it doesnt acquire IP, neither reach the GW (if I assign static IP to the computer). From the switch, if I try to ping the mikrotik ip, it does not respond (if I connect a computer directly on the mikrotik, I do get an IP, I can access it and even access the VPN services without problems)

Am I missing something?

thank you
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Hi All,

I'd like to change the password on both the Cisco routers/switches please can someone confirm that this is the correct commands to do so???
conf t
line con 0
password xxxxx(orignal password)
line vty 0 4
password xxxxx(new password here)

Many thanks all
Hi all,

I have had a strange problem with the HP 5500 Switches we use in our network infrastructure.

At seemingly random time and locations, some of the HP 5500 switches stop propagating the VLAN 10 across the network. There are other VLANs configured on the switch, but all of them function as intended. The present set-up routes all the VLANs through the router provided by the service provider. The switches are still accessible via VTY, and there seems to be nothing in the logs to indicate why such an incident could occur. And as strange the problem is, a simple reboot of the switch seems to resolve the issue.

Here is how the port is configured:
interface GigabitEthernet1/0/23
 port link-mode bridge
 port link-type trunk
 undo port trunk permit vlan 1
 port trunk permit vlan 2 to 3 10 15 30 67 70 100
 speed 100
 duplex full
 stp edged-port enable

Thanks in advance,
we are using aruba 2530 48-g switch from last 2months but suddenly we are getting Fault led blinking.and network is working properly.
Have an unbalanced power supplies error for 3850 power stack. Cisco tech is recommending the following steps

-Leave power stack and rejoin monitor logs
stack-power switch 4
no standalone

How exactly is this accomplished?
I'm looking to configure my ZL2 and associated HP switches to emulate this article with a vlan I have configured on these switches. I'll warn you that I understand networks but when it comes to config, especially CLI, I am a bit lost.  Some help would be appreciated.
We have a Meraki MX400 firewall, and 11 SG500-52P Switches we are using for Access.  I'd like to get something for Core or Aggregation, what kind of product do you recommend?  Would we benefit from having a 3850 or something along the those lines to serve as the distribution or L3 switch?  Should we create stacks for the 11 SG500-52Ps?

Thank you in advance.

Hi I am not able to connect Nortel switch 5650TD model through putty .
hi folks

i am wondering if anyone ever used Cisco WRVS4400N's port mirroring feature to monitor traffic of a given port?

i have tried any individual port or even all ports together as the source, but i still cannot see any mirrored traffic from listening to the specific port (Port 4), as shown below.

i have no idea why the device doesn't work as expected. do you have any suggestion please?

I am trying to connect two Cisco switches, a 3550 switch to a port on the 4503. I have my 3350 port 0/2 connected to my 4503 on the blade  3/25 port.

I have both ports on both switch configured as follows:

switchport trunk encapsulation dot1q
 switchport mode trunk

both ports are enabled but I am not getting any link lights between the two ports.  I have tried standard and crossover cables.  I am sure I am missing something simple.  We are not running multiple vlans, just default.  Any help would be appreciated.

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Hello everyone!. I was wondering if anyone could help me with this. At the office, it is the second time the whole network stop working because of external causes. The first time somebody connected a patch core from one wall socket to another and everything took me some hours to realized what was happening...The last time, cleaning personal accidentally moved a switch connected to wall socket and because of it almost all packets were lost, again it took me some time to find it out...
Is there any recommendation or advice in order to prevent future problems like this?. I have dlink switches.

Thanks in advance

I try to configure mutiple vlans on my switch HP 2620, with windows 2008 r2

Windows Server - IP (AD, DHCP, DNS, is the secondary domain, sync over VPN)
Router Draytek - IP  (with vpn lan to lan, to another office)

VLAN98 USERS     -  -
VLAN 99 CCTV      -  -
VLAN GUEST        - - (Only internet acess)

Subnet in Router: next-hop next-hop next-hop


hostname "SW-2620"
console idle-timeout 300
console idle-timeout serial-usb 300
max-vlans 30
timesync sntp
sntp unicast
sntp server priority 1
time timezone 60
ip route
ip routing
snmp-server contact "Dep. IT" location "office2"
vlan 1
      name "VLAN1 - DEFAULT_VLAN"
      no untagged 1-24
      tagged 25-28
      no ip address
vlan 97
      name "SERVERS"
      untagged 1-24
      tagged 25-28
      ip address
      ip igmp
vlan 98
      name "Users"
      tagged 25-28
      ip address
      ip helper-address
      ip igmp
vlan 99
      name "CCTV"
      tagged 25-28
      ip address
      ip helper-address
      ip igmp
vlan 100
      name "Guests"
      tagged 25-28
      ip address
      ip helper-address
      ip igmp
We currently have a Palo Alto firewall with 3 ports configured. One for LAN, one for WAN, and one for the DMZ. I have a standalone netgear switch connected to the DMZ port with the relevant servers connected to that. On the LAN port I have a mix of 5 switches - 2 older HP devices, 2 3 Coms, and a Netgear.

I have 5 new Aruba 2920 switches that I am replacing the older equipment with. I thought I could also eliminate the netgear switch on the DMZ by running VLANS on the new Aruba stack.

Our current setup (with different IP's): - Local LAN - Local LAN #2 (through MPLS) - Local LAN #3 (through MPLS) - DMZ

Firewalls/Switches: - Palo Alto LAN port - Aruba Switch - Palo Alto DMZ port

On the first switch I set  VLAN 2 to the 10.100.2.x subnet, and VLAN 50 for the 10.100.50.x subnet. I set ports 3-30 untagged on VLAN 2 and ports 31-44 untagged on VLAN 50. I tagged port 1 for VLAN 2 and have that port currently connected to the older switches (I am not stacking the other 4 switches and replacing the older equipment until I have this working correctly) and that is connected and working as far as I can tell. I set port 2 tagged to VLAN 50 and connected it to the DMZ netgear router. I did enable routing as it seemed I needed it.

vlan 2
   name "VLAN 2"
   no untagged 1/31-1/44
   untagged 1/1,1/3-1/30,1/45-1/48
   tagged 1/2
   ip address
I am trying to add a non cisco SFP between two catalysts, and am getting the error %PHY-4-SFP_NOT_SUPPORTED: The SFP in (PortNo#) is not Supported.

I have tried running the commands:

Switch(config)#service internal
Switch(config)#no errdisable detect cause gbic-invalid
Switch(config)#service unsupported-transceiver
Switch(config)#int gi0/49
Switch(config-if)#no shutdown
Switch(config-if)#do copy run start

However, the issue is still occurring. I have rebooted the switch after the above with no joy. Cable being used is a StarTech 3m SFP+ 10-Gigabit Ethernet (10Gbe) Twinax Cable. I will be upgrading the firmware to 15.2.6 while waiting for a reply.

Any help will be appreciated.

Switch Ports Model                     SW Version            SW Image            
------ ----- -----                     ----------            ----------          
*    1 50    WS-C2960X-48TS-LL         15.2(2)E6             C2960X-UNIVERSALK9-M
I am trying to see what the best way to assign vlans to my subnets. The below is what I was planning for with the 3rd octet as the vlan#:
- vlan 8 - ( -
- vlan 18 - ( -

But now we are breaking to the below. Any tips on assigning the vlan #?
vlan8 -
vlan? -
vlan? -
vlan? -
Hi guys,

i am new to networking, we have a requirement where we need to design a network for a small office,
there are 15 users with ip(cisco)  telephony  headsets.

Please suggest me which Cisco router(small bussiness) with part number is suitable for the requirement.
So I have always used Cisco with 10GbE stack cable's where you stack each switch to the one below and the last to the first so if an individual switch goes down the rest of the stack stays up.

I am now looking at a Meraki setup where we have a small stack on several floors going back to two switches that have the external connections. 1Gb is fine here, I don't need the 10Gb as this is just for desktops not servers.

The two switches have SFP to the first in each switch stack, the first switch then has a copper uplink to the other switches. This seems odd to me.

I would have thought that I should copper all the switch stacks from first to last and then the last in the stack copper to the next switch stack. That way all stacks have the SFP for normal operation but can fail to copper to the next switch I the stack up or down and the stack can fail across to the next stack if the SFP switch goes down.

I'm setting up a Huawei layer 2 switch Monday morning. Haven't done one of these before. I'm familiar with HP and Cisco. Could some one assist with some cli commands.

I need a few vlans configured and a trunk port from the firewall.

i had a question , can a port in the switch be a part of both access and trunk ?  

what is native v-lan can any one explain ?
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Need some advice.  Upgrading my 10/100 network with about 50 device connections, to Gigabit and running new Cat6 Cabling.  It is a 2 story building, with all the connected devices on the 1st floor and the server room in the basement.  I was thinking of installing a switch and patch panel, centrally on the first floor and running a fiber trunk to the basement switch.  Does this sound reasonable?  Suggestions on switches and design?
I want to secure my network down by splitting up devices into seperate vlans so that they are inaccessible to each other but they can all access the internet on one port situated on the default vlan.

My setup is as follows

HP 2524 switch connected to a virgin router via CAT 5 on port 13 to the internet. The virgin router has an IP of


(Vlan 1 Default) Port 13 = Connection to router

(Vlan 5) Port 4 = Connection to Device 1, no ip on vlan, static ip on device connected is

How do I get the device on vlan 5 to get out to the internet on vlan 1 ? I want my device to be on a seperate subnet and to be invisible to other devices.
Good Evening All,

I ideally would like some ideas based on a potential request that might be coming down the pipeline.

My primary internet comes over a P2P link from another location, that terminates into a fiber patch panel then splits into two separate internet connections.

Connection 2 terminates into a 12p fiber switch then uplinks to our core router. This is where the bulk of our traffic comes through. Connection 2 also provides telephone access to main office and out to the outside world.

Connection 1 terminates into a FW, uplinks to a couple switches then another router. This is our second provider out to the real world.

(traffic is routed via gateway addresses, to determine what ISP to use)

There is also a satellite link, which is connected to the same router as connection 1 , and this provides long distance calling only.

Based on the fact we have three connections out, if we want to  shutdown all comms, including the P2P link (WHICH WE DO NOT MANAGE, ISP DOES) and we ONLY have access to CON1 & CON2 routers/switches is there a way to completely sever the link?

Has anyone installed anything or written a script that can run putty commands to shut down switch interfaces?

Here is a diagram to refer to

I am looking for some good quality unmanaged network switch for my small business.

They will be running everything from Pcs to cameras.

I would like something of very good quality and reliability/

Best POE Silent 10/100 and Gigabit UnManaged Network Switch

Thank you.
I've been asked to setup QoS on HPE 5130 to prioritise VOIP traffic sent on port TCP/UDP 5060.

I can't VLAN the devices as these are normal office PCs running softphones and so need to differentiate by the protocol.

I'm sure I'm missing something obvious but doesn't appear to be achievable from the GUI

Can anyone give me a brief nudge in the right direction regarding CLI commands?
I've examples for other switches but for some reason are struggling with these.

Many thanks,

I am not sure how to prevent this and hoping you can help. In the image, when vlan 1 goes down, I'm unable to ping the router inside interface at all. How can I make sure that I am still able to reach it. It shows UP and UP either way. This is becoming an issue when it comes to to my TACACS server since the TACACS cannot reach the inside IP.

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.