Switches / Hubs

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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 multiple Cisco switches, from 2960's to 3750's.  I have them all configured via SSH, and randomly, after a few weeks, I can't connect via SSH anymore into them.  I use PRTG to monitor them, and I noticed that when something happens to the certificate, that's when I can't log in anymore, so my monitoring system displays an error for the cert.  When configuring SSH, does the default cert expire after a certain amount of time or something?

Any ideas how to fix this?
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Optimum High-Definition Video Viewing and Control
Optimum High-Definition Video Viewing and Control

The ATEN VM0404HA 4x4 4K HDMI Matrix Switch supports 4K resolutions of UHD (3840 x 2160) and DCI (4096 x 2160) with refresh rates of 30 Hz (4:4:4) and 60 Hz (4:2:0). It is ideal for applications where the routing of 4K digital signals is required.

We are provisioned Two 2960x Cisco Switches and linked up with a FlexStack Plus cables/modules. All connected devices (e.g. Windows Servers) has two UTPs connecting to the switches, one to switch A and another one to switch B. The switches are implementing Channel Group using LACP where port from Switch A and Port from Switch B are belongs to the same Channel Group for network resilience purpose. Also, we have created TWO VLAN on the switches where each VLAN span across the two switches some network device are belong to VLAN 1 and some are VLAN 2. This is a floor level implementation and we have an uplink router (Core Switch) to route packet between VLANs.

We are planning to add more devices and we are running out of switch ports. Our expansion planning are as follows:

Option 1) Add another two network switches (i.e. 2960x) to the FlexStack cluster and create additional channel groups with switch port from Switch C and Switch D. So that the new devices can connecting to the new Switch C & D while still maintaining the resilience requirement as well as able to communication with the original devices connecting to switch A & B.

Option 2) Option 1 is only feasible if we have enough room to accommodate another two switches on the same rack. If however, we need to put the new two switches on another rack with is around 10-20 meters away still connecting themselves with FlexStack Plus, we are planning to purchase a 10G SFP+ module on the switches and link up Switches A/B …
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bgp
I have the topology shown above. I have configured BGP on R1 which is in AS1 and on R2 which is in AS2
now when I run Show Ip BGP command on each router I get the output shown below. I need an Expert to explain the meaning of the Output  below. especially the lines :
r> 2.2.2.2/32       192.168.12.2             0             0 2 i
*  192.168.12.0     192.168.12.2             0             0 2 i
*>                  0.0.0.0                  0         32768 i




R1#sh ip bgp              
BGP table version is 5, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 1.1.1.1/32       0.0.0.0                  0         32768 i
r> 2.2.2.2/32       192.168.12.2             0             0 2 i
*  192.168.12.0     192.168.12.2             0             0 2 i
*>                  0.0.0.0                  0         32768 i
R1#

Open in new window


R2#sh ip bgp         
BGP table version is 5, local router ID is 2.2.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
r> 1.1.1.1/32       192.168.12.1             0             0 1 i
*> 2.2.2.2/32       0.0.0.0                  0         32768 i
*  192.168.12.0     192.168.12.1             0             0 1 i
*>                  0.0.0.0                  0         32768 i
R2#

Open in new window

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Good afternoon Experts,

Our Security Manager asked me to upgrade his existing IP camera network from 10/100 to Gigabit from our Control Room to our guard stations, roughly 150 meters away. The existing network we have been using is 2 Comnet devices, model CNFE6+2USPOE. More details on this device here:

http://www.comnet.net/comnet-products/ethernet/self-managed-switches/cnfe62uspoe.html

I decided to purchase 2 Netgear, model ProSafe-GS110TP:

https://www.netgear.com/support/product/GS510TPP.aspx

Connected with TrendNET TEG-MGBSX SFP Modules

https://www.trendnet.com/products/proddetail?prod=200_TEG-MGBSX


My issue is that I get no link light when I set up a switches in both locations. I have tested the units side by side and it all works, but for some reason when I get them set up in their specific location I no longer get link lights. I'm using the existing fiber run that the Comnet devices are on, and have confirmed it's 50/125 fiber, and I've tested the new short fiber cables we bought and they work as well. The TrendNET SFP modules should be rated at 550 meters.

In my other experience things like this just fire up, then you make sure the VLAN's are correct, but in this case I get link down in the Netgear GUI and obviously no sweet flashing green light.

Am I missing the forest through the trees here?

Thank you for any guidance.
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Hi guys,

We currently have a 6 switch stack (SG500's) and we are moving to another building that will require us to increase our switch size to 9.  We are aware that only 8 SG500's are available per stack so I was wondering what the optimal switch setup should be.  Do we need to buy a core switch to maintain performance?

Thanks in advance.
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Hi

With this config from POE switch s5500 connected to core S5120 i got the phone working but i could connect or ping the S5500 ip address switch ... What's wrong !!

Is it the write config for a voice vlan setup like this (Core switch + poe) phone-pc connection !!

------------------------------------------------------------

Port connected from S5500  to core  S5120 port 10

interface GigabitEthernet1/0/48
 port link-mode bridge
 port link-type hybrid
 port hybrid vlan 210 tagged
 port hybrid vlan 1 untagged

--------------------------------------------------------------------

Phone port on S5500

interface GigabitEthernet1/0/19
 port link-mode bridge
 port link-type hybrid
 undo port hybrid vlan 1
 port hybrid vlan 210 tagged
 poe enable

---------------------------------------------------

Port on core switch S5120 connected to S5500 on  port 48

#                              
interface GigabitEthernet1/0/10
 port link-type hybrid          
 port hybrid vlan 210 tagged    
 port hybrid vlan 1 untagged    
 undo voice vlan mode auto      
 qos priority 6
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Hi All

Can I have you're help with the all commands needed for a single switch port to assign this up address.

172.16.0.10/30 255.255.255.252

Appreciate you all your help thank you
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Hello experts. I am trying to setup a VLAN in a test environment and I am not able to get it to work so far. I have searched this board and researched online but just can't seem to get it to work.

Right now I have two Comcast internet circuits coming into a peplink balance 20 (will be upgraded to the balance 305) I have one cat 6 patch cable going from the router lan port 1 to Switch 1, port 1. I have a total of 5 sg200 switches, all connected by 4 port LAGS and fiber.

I want to have 3 VLANS. On the peplink under LAN--->network settings I created the VLANS as 10 with an IP of 192.168.10.1 with DHCP enabled for 192.168.10.2 - 192.168.10.250, VLAN 20 as 192.168.20.1, VLAN 30 as 192.168.30.1 all with DHCP enabled. Under LAN--> port settings I have port 1 set to trunk and tagged the 3 VLANS.

I have the VLANS setup on all of the switches. On Switch 1, port 1 where the router is connected I have it set to tag the 3 VLANS I created.

On Switch 1, port 5 I have a laptop connected to test. I have that port set to access and VLAN1 to exclude, VLAN10 as untagged. From this point I am unable to get a dhcp address and if I enter a static ip I am unable to get internet access.

Is everything correctly configured so far? Right now everything is operating from the one switch. I haven't tried other ports on other switches.

What do I configure the LAGs as?

Any help will be VERY much appreciated!

Thanks in advanced,
CJ
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Can you configure a routed interface to use both the global and VRF routing table?
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Dear, we found an old switch Cisco 2960 in warehouse, it still works when we plug in the power but we 'd like to make sure it will not suddenly die. So how can I check the health of that switch? Can anyone please suggest some commands to check:
- When was it used for the first time?
- How long can it be used?

We want to utilize it for a new project so please help! Many thanks!
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Hello all,

I wanted to see if I could get some advice and/or recommendations for a project that I am working on.

Our internet: 2x Comcast cable 250/25 package
Switches: 2x Cisco SG200-50

Router: Peplink balance series (not bought yet)

Situation: This is for an events center. Every now and then I will need to make changes to meet the clients needs. I want to have both Comcast circuits load balance the traffic in the building. When we have events in the building that stream I want to have that traffic go through one of the Comcast circuits and nothing else. The rest of the traffic can use the other circuit. I know with the peplink router I can set it to have certain IP addresses travel out of whatever circuit I want. I think the peplink and managed switches would do what we need.
Are there better ways to go about this without going too crazy with cost. I would like everything to be able to be controlled remotely as much as possible.

 I also need a few VLANs that I can't see to get to work. I want to separate our office and servers from the rest of the building. How can I setup a VLAN so that they can all access the internet but can't pass traffic between the VLANs. On the peplink I created a new LAN with different IP addresses and it is VLAN 2. In order to get it to the switches do I set port 4 for example as trunk and tag it to VLAN 2? If I connect peplink port 4 to switch #2 port 8 - what do I do with that port? Do I also set it to trunk?  If our office ports…
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Hello Experts,

I want to segment my wireless network traffic into Guest, student and teacher.We have sonicwall, multiple switches and Access point.

I dont want filtering on computers those are connected through ethernet. i just want to segment my wireless network and assign them to Iboss security device for content filtering .

Any suggestions???

Thanks
Nakul
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I have 2 Mikrotik switches that connected via 2 port to router.
2 uplink port is bridge,because they are using 1 subnets.
 i found that Mikrotik switches works:
1-all interface use 1 master port
or
2-all interface in 1bridge.

switches clients did not ping other often.always restart the switch solution of problem and i guess because of switching mechanism in Mikrotik.
Can i help me find problem correctly?
Mikrotik.PNG
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I have an unmanaged Cisco/Linksys SG 100-24 switch. It has gigabit capibility.  My servers are connected to this switch at 1 GB and it's on auto detect however my PC's which are capible of gigabit are only connected a 100 mbs.  I've tried to make them 1000 full duplix but I'm only seeing 100.
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Hello - we have a Windows Server 2012 that has 2 NICs that are bonded into a Team Nic connection.  It was working for a short time, where it was successfully able to access the Internet and network resources, but then a yellow exclamation mark appeared on the NIC icon in the service tray and it stopped getting out to the Internet.   I was also not able to RDP to it (strangely however, my cohort was able to remote to it).  so I went on to the machine's console and "Diagnosed" it.  it wanted to remove the NIC teaming and when both adapters are separated, it works - meaning I am able to assign static addresses to the adapters and it connects fine.  I forgot to mention that at first, when I diagnosed the Team connection, it wanted to switch it to DHCP and then the yellow mark went away.  I was not able to make it a STATIC IP assigned - it only takes DHCP.  But now that the NICs are separated again, I can assign static IPs. Looking for some insight.
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Dear Zealots, is there any method to observe, monitor the traffic from one (or multiple) IP address (es) to a IP address?
We are using Cisco Router 3925, Switch 3560, 3750, 2960
Many thanks in advance,
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Dear Team, we have several Catalyst 500 acting as Access switches for users, printers, Finger prints (FP) and Access points.

Here is a problem: 2 FingerPrints -----------------------90 m---------------------------- A small switch (LinkSys)  ----------20 m----------- Catalyst 500

In Catalyst 500, there are few modes for port operations; such as Switch, Router, Access Point, PC, Printer,... When I configure a port (which connected to a small switch) in Switch mode, I cannot ping those 2 FPs, but when I set that port to Access Point or Router mode, I can ping them.

Besides, it only works for few hours before disconnected (request time out). I have to reboot FPs to ping them again.

Can you please explain?
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Hello,

All the trunk port needs  be connected using cross over cable or depends on the switch? IF MDI is enabled then don't need it ?
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How to block unmanaged switches from network. I have already apply BBDU Guard on interface but where unmanaged switches attached port will not block. and in show spanning-tree interface detail command no BpDU received. So please help is required for block unmaanged switches fron network. Other than port security please
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Hello
I have 2 switch that connect each other with 4 layer 2 etherchannel links(4*1G)
my load balance method is src-dst port.
Zabbix show me that traffic goes among beetwen link Approximately equal.
Can i say we have maximum 4G bandwidth in my network?
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Hey Guys,

I have ESXi 5.5 and the server has 2 nics. The 1st nic is going to a switch, and that switch lately seems to be having issues with dropping packets, i have a lot of leg work to do to completely remove (Which is the plan soon), now i have a second switch on the same vlan and i can run a cable to that switch for us to work off of. Should i set this is up as NIC teaming or can i actually use this new NIC as part of the same network without any downtime - essentially move everything to this nic without making network changes ?
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This question is in relation to a previously posted question I posted a few months back regarding cross-stack EtherChannel between Cisco 3850-12s & Cisco 2960x switch stacks. The original question related to the theory that I was trying to achieve, whereas this relates to a few configuration issues I'm having. I thought it would be more relevant to post a new question.

Setup is a follows:-

- 5 x Cisco 2960x stacks (lowest stack count = 2 switches and highest stack count = 4 switches)
- 1 x Cisco 3850-12s stack consisting of 2 switches

Each 2960 stack has at least 1 x fibre link to each 3850 in the stack (4 x links per 2960 stack), my questions are as follows:-

- I have conflicting information as to whether or not PAgP is supported in a cross-stack EtherChannel model, can anybody confirm for 100% what the stance is on this? I have read conflicting Cisco documentation, one article has categorically confirmed that PAgP ISN'T supported whereas I have also read cisco config guides with the examples given using PAgP? What gives? I have no problem in using LACP, it's just that my environment is 100% Cisco, so I thought PAgP would be nice.

- What are the best practices for spanning-tree configuration when it comes to EtherChannel? I see each EtherChannel as 1 x logical link, therefore is spanning-tree actually required? If so, does anybody have any experience with this kind of configuration?

Any help and advice would be greatly appreciated.

Cheers,
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I have cisco 3650-48fq-s with 4 TenGigabitEthernet sfp ports trying to connect to at&t 1gig ase circuit but link not coming up.

Here is the config on the port:
Interface TenGigabitEthernet 1/1/4
Switchport trunk allowed vlan 110
Switchport mode trunk
Speed nonegotiate


Then I tried on cisco 2960-XR with 1gig sfp port on it and it worked.

I have 4500 series cisco L3 switch at another location with TenGig sfp port on it with same above config and works there.
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hey ,

the port that has the sfp SR does not come up , i have tried to do a shutdown no shodwon and still does not come , when i do shutdown command the port does not go for orange color .


i am confused !

BR
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I just got a general question :
 
If there is a company with 2 Managed switches(Dlink) and all computers and servers are connected to the switches. And has a dlink router.
If a user complains, accessing files to the server is slow from my computer .
How do i troubleshoot? from where do i start? is there any specific tools/softwares to troubleshoot.
I AM just new in networking career. so sorry guys if its a simple question.
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Switches / Hubs

20K

Solutions

17K

Contributors

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.