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 a Cisco 3560 L2/L3 that will be connecting to an HP 2910al access switch.

On the 3560, I have a few VLans set up. because of the amount of data going across the switches, I want to aggregate the link between the switches.  I have been looking for information on aggregating trunks and have not found much useful information. I find information on aggregating access ports all day  long.

Can someone assist with commands and examples.

Thanks,
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Hi guys

I have an HP network 1820-48G J9981A switch. We have a 192.168.10.0/24 network range on this switch. It has been set with a 192.168.10.10 IP. Prior to this, our network switch was completely vanilla and had no IP configurations.

Now, majority of appliances plugged into this network are on the 192.168.10.0/24 range. However, we have 7-8 devices set to 192.168.9.0/24 range. So now, we are completely unable to get to anything on the 192.168.9.0/24 IP's, as the switch is currently only seeing the 192.168.10.0/24.

My question is, what's the best way now to configure this switch? I don't want to reset it to factory default as we won't have any management. So do I set up VLAN's on all ports? How would you do it?

Or, can I set routing on the switch to say anything on 192.168.9.0/24 network needs to be forwarded on to the 192.168.10.0 gateway?


Thanks for helping
Yash
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Our customer has an HP VC Flex-10 10GB E-net module fail in interconnect bay 2 on his BladeSystem c-Class chassis and was sent a replacement.
The customer's modules have FW 4.45 and he wants the replacement to have the same firm.
We don't handle firmware issues in our small shop and I have no idea what's on the replacement sent to him.
How does he synchronize the FW on both modules if they do not match?
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hosting a Fortnite competition on ipads - what can i do to remove lagging/ latency issues

everyone will be on ipads and my bandwidth is 200 MB dedicated, its a small competition in our company, is there a QOS setting i can apply or any other suggestions

maybe there is a gaming port i need to open on the firewall
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Cisco 2960-x Switch configuration question. I have multiple Vlans setup on my switch. Is it possible to assign a separate IP address to each Vlan in the switch? If so what is the proper syntax?
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Loop Guard and Root Guard on Cisco Switches

I have done some reading about Loop Guard and Root Guard

Loop guard is configured on Non Designated Ports , which means Blocked ports and Root Ports

Root Guard is configured on Designated Ports.

 Well, I believe this is needed just  in a redundant L2 Links Network. in this case , do we have to go to each Non Designated Ports in the Network and configure Loop Guard and to each Designated Port and configure Root Guard ?


I am assuming in the Network that has no Layer 2 redundant links this is not needed at all, except on the Access ports where we need to configure Port Fast and BPDU Guards.

Any Expert to shade some lights on this topic?

Thanks
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First Question.

Ages ago I had two switches given to me: a Cisco 2950 and a 3Com SuperStack 3 3C16592B.  And they've been sitting tossed aside for a long time.  I'm now in the process of decluttering and one has to go.  Which one and why?

Second Question

Now I'm a total noobie when it comes to these switches.  If I remove all passwords and take these machines back to factory or default they can be used as dumb switches, that is, I can plug anything into them and they'll function perfectly normally, getting their IP addresses from my home router?  I've just started playing with the Cisco and examining how it has been configured (shudder VLANs everywhere etc etc etc) so I'd like something simple to start off with before I venture into unknown areas.
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BPDU Guard Role

If I understand BPDU Guard is configured on Edge Ports along with Portfast.
Reading this Cisco artcile:
https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/configuration/guide/cli/CLIConfigurationGuide/SpanningEnhanced.html
It does not say the Portfast has to be configured for BPDU Guard to have effect.

It also states:
you can configure BPDU Guard at the interface level regardless of the typ of the configuration.. what I understand from that, you can even configure it if the interface is a Trunk.

Any Expert to shade some lights on this topic?

Thank you
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Spanning Tree Network Ports vs Normal Ports

In Cisco link :https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/configuration/guide/cli/CLIConfigurationGuide/SpanningEnhanced.html
it talks about Network Ports and Normal Ports.
To me both sounds like Trunk Ports.

Any clarifications on that ?

Thank you
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eth

How L2/L3 Etherchannel does Load-Balancing

Considering the diagram above ,  assuming that there are many PCs in 192.168.1.0/24 network and many PCs in 192.168.2.0/24 network
What is the best method to choose for load-balancing in this case (Source-Destination IP, Source Destination Mac,etc....) ?

another case is , Let's say in network 192.168.2.0/24 there are separate servers  that procide services to  PCs in the network 192.168.1.0/24
in this case what would be the best Load-Balancing Method ?

Thank you
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Recently we bought a new firewall fortinet 100D to secure our company network.Our network is 192.168.101.0/24

now our network is flat network and we would like to implement VLAN also.

we have one unit Cisco 3750 switch ,now we already configure. firewall LAN port using 192.168.101.1/24 and connected to switch port directly and working without any issue.

question:
1.If we configure create the subinterface 10(Management),20(Server),30(Users),40(Wifi) and 200(Voice)what should i need to configure for the switch port connected to firewall ?
*All the traffic must visible in our firewall.

2.Our DHCP server is running inside the hyper-v and now the switch port i configure LACP with switch port mode access to allow VLAN 1 only.Do i need to configure to trunk and native VLANs ?if native VLANs is require which VLANs should i configure ?

3.How to migrate all my server to VLANs 10 without downtime ?

4.What is the purpose of management VLANs  i put it there just research online many people are design in this way.

5.How to configure the switch port which is user connected ?now all the user arw connect thier PCs via Cisco IP Phone ?
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I have a unifi us-48 port switch
I have removed all connections to the switches and connected a pc and two servers to the switch.

Each server into the SFP+ ports
They can both ping the switch IP, the PC but not each other.

I have opened two command prompts on the PC and tried to ping each server in a different window.
If you get a reply from one server the other drops.
It looks like only one SFP+ port can be active at a time.

I need them both to be fully available on the network all the time.
Any ideas ?
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Hello, I got Cisco SF-220 48ports = 2 in the same rack, the first SF-220 48 ports connect to the second 48 ports via GE1 port.
the second 48 ports connect to another remote location via SFP MGBSX1 for both 2 ports.

my question is can the SF-220 48 ports GE1 and GE2 can use at the same time with both SFP MGBSX1?
since my current situation the SFP won't work if the GE1 or GE2 are in used.

thanks
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Native Vlan function

I would like to know how  the untagged traffic  that arrives to Cisco switch  is handled by the switch that has a native vlan in addition to customized vlans.
For instance in Vmware you can create VM port Groups and do not assign them to any Vlan, so the traffic that stem from those VMs and reach the physical switch , how is it  forwarded to its destination ?

Example:
VM with IP :10.10.10.12 /24 trying to reach another VM with IP : 192.168.20.20
Both VMs are in different ESX hosts and in port groups that are not assigned to any VLAN.


Thanks
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Using two microphones with Audacity (Mac High Sierra)

I have two microphones working as inputs with Audacity, via this box:

https://www.google.com/search?source=hp&ei=nt4TXNHgDMOw5wKClbP4Cw&q=UMC202HD&btnK=Google+Search&oq=UMC202HD&gs_l=psy-ab.3..0l10.1107.3443..3840...0.0..0.316.1964.0j4j4j1......0....1..gws-wiz.....0..35i39j0i131.Xobu0FE3zh0

But, Audacity creates a single track with Left and Right sub-channels for a single channel, while I need each to have each microphone in its own channel.

Or, is there a way to convert a track with Left and Right to two distinct channels?

Thanks
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hi guys

I was looking into cloud switching, such as the tools being offered by Cisco Meraki. They keep saying that you can have your switches in the cloud. But I'm trying to understand how that would work.

Would that mean that in my organisation which consists of two stacks of x 7 switches, totalling 14 switches, that I would suddenly no longer need that anymore if I implemented Meraki's?

We have around 300 people in our office. All of those people have to be connected/patched to a port on the wall and those need to be patched into a switch.  I can't exactly get rid of those physical switches can I? So I'm not really understanding the whole cloud switching situation with Meraki's?

Or have I totally misunderstood the cloud switching scenario?

thanks for helping
Yash
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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
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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.
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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 …
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Host Mac address in multiple switches CAM table

I would like to know if a MAC address of a computer or Router that is connected to Switch1 will be also found in CAM table of Switch2 , Switch3 ,etc... assuming all switches are connected to each other.

Thank you
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Recenly we received call from our client said that network down and we visit onsite found that is looping .

She buy two unmanage switch try to connect by her self ,we found out she connect one of the cable back to the switch .

Actually they have are using HP 5130 as the core switch and all the access switch is HP/Aruba 2530.

I would like seek for expert advice ,what we can help them to avoid this problem occur again.
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We have a device that we cannot connect to our network.  

This device was connected to a Linksys hub through a patch panel to Device#1.  It has a 192.168.3.0/24 assignment on this specific device#1.  


For testing purposes we tried using an ethernet switch to connect Device #1 to the network and we discovered that when we connect Device#1 to a switch ethernet port and amber light comes up for that switch port connection.  If we connect a different device (Device#2) to that same switch port we have a green light and communication works.  Hence, the connection from the switch port to the patch panel and then to the end device is a good connection.

It was suggested that either:

- Duplex-mismatch (perhaps Device#1 is forced to full duplex) since it was originally setup to connect through a hub and that did not work.
- Something else is wrong with Device#1

Since we do not have administrative access to this specific switch or to Device#1, it was suggested that we use a crossover cable to connect the devices from the switch or the Hub to Device#1 to see if that will all network communication.

Can someone explain to me how a cross-over cable may fix a duplex mismatch problem?  I have only used a cross-over cable to connect 2 PC's together; but, I have limited experience with crossover cables.
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I am setting up a switch. Completed all the configs, and can ping all the switches in the rack to and from the new switch.

Can also ping the TACACS+ server from all the other switches.

But when I add the AAA configs below, I cannot ping the TACACS+ server from the new switch.

AAA Setup Steps

!!! Create Local User !!!
!!! Insert Commands Below !!!
aaa new-model
!
tacacs server PRI-ACS
address ipv4 xxx.xxx.xxx.xxx
key 7 1449248SCK50382F
!
tacacs server SEC-ACS
address ipv4 xxx.xxx.xxx.xxx
key 7 1449248SCK50382F
!
radius server PRI-ACS
address ipv4 xxx.xxx.xxx.xxx auth-port 12345acct-port 12345
key 7 1449248SCK50382F
!
radius server SEC-ACS
address ipv4 xxx.xxx.xxx.xxx auth-port 12345 acct-port 12345
key 7 1449248SCK50382F
!
aaa group server tacacs+ ACSTACACS
server name PRI-ACS
server name SEC-ACS
!
aaa group server radius ACSRADIUS
server name PRI-ACS
server name SEC-ACS
!
aaa authentication login default group ACSTACACS local
aaa authentication enable default group ACSTACACS enable
aaa authorization exec default group ACSTACACS if-authenticated
aaa authorization network default group ACSRADIUS
aaa authorization auth-proxy default group ACSRADIUS
aaa accounting update newinfo periodic 1440
aaa accounting dot1x default start-stop group ACSRADIUS
!
!!! LOG OUT !!!
!!! LOGIN WITH LOCAL !!!
!!! INSERT COMMANDS BELOW !!!
!
aaa authorization commands 1 default group ACSTACACS if-authenticated
aaa authorization commands 15 …
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Parsing every line of a Cisco 3850 switch.

When I was in Seminary, we had to parse Greek verbs.

For example, luei – present active indicative.

By way of analogy, in order to better understand the 3850 switch, I want to be able to parse every line of the running config.

Honestly do not understand most of config.

For example,

class-map match-any CM-BRDCST-VIDEO

I understand the words, but the meaning alludes me as well as which command placed this line in the config.
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Hi All,

I’ve got a situation where our network which is a flat one vlan network with 2 Cisco switches (one PoE dedicates to phones, other dedicated to data) and we’ve found after looking over the data switch logs that we’re getting MAC flaps.

After more in depth digging it seems it’s the Unify / Ubiquity access points that are causing the flapping. (Probably when a MAC roams between AP’s)

However, we’re experiencing network problems probably when this happens it causes a “freeze” on the whole vlan, not enough for the PC’s to notice but the phone calls drop.

My question is, would the above be feasible ? And would a quick fix be to turn off spanning tree on the AP ports?

My long term fix would be to put the AP’s in its own VLAN which would stop things like this effecting the native vlan.

Cheers
Shaun
0

Switches / Hubs

21K

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.