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Questions tagged [switch]

For questions about network switches, the term commonly refers to a multi-port network bridge that processes and routes data at the data link layer (layer 2) of the OSI model.

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Multiple DHCP servers detected by access points [on hold]

I’m having an issue with our internal network and voip network. I currently have it setup as a non-converged network separating our two data switches and one voip switch. We preferred not having our ...
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0answers
21 views

Is this setup possible. Multipler user PC's & KVM. 1 Shared PC - Switch [on hold]

I'm not in an IT role or an engineer. In fact i'm usually just on the coding, excel & share point site. However I do have a requirement that i want to check is possible as it seems to have been ...
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1answer
49 views

Do unmanaged switches honour QoS priorities set by managed switches?

Details about the devices We have a 24 port NETGEAR managed POE switch that has QoS capabilities. We also have the following unmanaged switches, 24 port Cisco POE, 48 port Cisco, 48 port NETGEAR, ...
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2answers
41 views

What's the `line protocol` and `Link`?

When I show a switch interface information, there are line protocol and Link: Switch-A(config-if)# show interface gigabitethernet 0/3 Gi0/3 up, line protocol is up (connected) Bridge Port Type: ...
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0answers
13 views

Cisco Packet Tracer - How do I connect these networks through a router? [on hold]

I am trying to connect these two switches through the router as shown and also correctly configure the wireless router on each network so that they connect to their switch. Basically anywhere there's ...
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0answers
19 views

How can I filter the exact interface in huawei switch?

How can I filter the exact interface in huawei switch? you see when I use the include GigabitEthernet0/0/1 to filter, there will get many GigabitEthernet0/0/1* interfaces: <Z178A>dis ...
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2answers
31 views

Firmware Compatibility with 15.x IOS versions

I have a Cisco switch stack with both PoE and non-PoE switches as members. Is there any compatibility issues with the firmware version 15.0.2-SE11 between the following devices? 1x Cisco WS-C3750G-...
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2answers
418 views

OSPF increase bandwidth with load-balancing

This is my current setup where i have 40Gbps links between all 4 switches running OSPF using L3 links between them but now i want to double my bandwidth between switches so i am planning to add (...
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1answer
379 views

Why would a switch ever send an ARP request for a MAC address when it can just wait for the first packet to be received from a device?

I've been reading 'Windows Networking Fundamentals' and in that book it says that a switch can learn what MAC address is associated with a particular port when the connected device makes its first ...
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0answers
33 views

Cisco nexus 9396 rebooted with reason xbar_client

Today my one of cisco nexus 9396PX switch got rebooted and this is what i found, based on following logs what could be wrong? We don't have Cisco support for this switch, trying to see if i can get ...
2
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1answer
16 views

Shoretel ST1D Switch not accepting assigned IP

After configuring a Shortel ST1D switch, I connected the LAN1 Port from Shoretel ST1D to my Cisco 4507R switch. I attempted to ping the IP that I set specifically on the ST1D switch and I wasn't able ...
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0answers
35 views

Cisco nexus spanning-tree logging to syslog

I am trying to send my spanning-tree events to remote syslog but somehow it doesn't work, This is what i have in my config. N3K# sh run | grep logg logging level spanning-tree 7 logging server 172.29....
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1answer
54 views

spanning-tree port type edge trunk on port-channel vs physical interface

If i configure spanning-tree port type edge trunk on physical interface instead of port-channel does that work? Or i have to do spanning-tree port type edge trunk on port-channel ? Example: ...
1
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1answer
155 views

Flooding vs Unknown Unicast Flooding

Can someone clarify what is the difference between Flooding and Unknown Unicast Flooding? Is it the same thing or it contains different meaning? I'm aware that Flooding happens when a switch ...
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1answer
19 views

Cisco swtich stacked NTP configure

I have two cisco switches (WS-C3850-12XS-E) stacked by stack cable. I want to configure ntp on them. How to configure ntp on those about time synchronization?
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1answer
77 views

Does vPC peer-gateway cause unicast flooding

This is my network topology where I have SW-1 is configured for HSRP for multiple VLANs, SW-2 & SW-3 connected to SW-1 using vPC. Last few month I am dealing with this unicast flooding where ...
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3answers
380 views

Collision domain question

I'm studying for my CCENT exam, and not quite sure why the book (official Cisco) says that there are 5 collision domains in this example. Isn't it supposed to be 4? The hub on the left, the hub in the ...
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1answer
49 views

No MAC address table shown on Cisco switch

I'm studying CCNA1. following netacad course notes and sending "show mac address-table" to a switch (in packet tracer) I should get a list of the available MAC addresses. I only get the table header ...
2
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1answer
63 views

VTP does not update VLANs in switch

Switch 1 will be server and Switch 4 will be Client! Switch 1 configuration S1#show run Building configuration... Current configuration : 1451 bytes ! version 16.3.2 no service ...
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0answers
10 views

Managed / Unmanaged Switch [duplicate]

This is a basic question, But can someone clearly state what is the difference between managed and unmanaged switch? Also, do managed switches maintain their own routing table?
1
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1answer
50 views

Configure Nexus N9K-C93180YC-EX

I am configuring a switch for the 1st time (Cisco Nexus N9000 Switch) to do some server performance testing in my lab. I have the serial console working and can log into the switch and run commands. ...
1
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1answer
41 views

Connecting networks from different states [closed]

Is it possible to connect 5 networks together using one router as a central component even if the networks aren't close to each other? An example would be 2 networks in Houston and 1 in Dallas Texas, ...
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6answers
1k views

Do I need to protect SFP ports and optics from dust/contaminants? If so, how?

I have a used switch with some SFP ports and some SFP modules installed, which I don't use. All new switches come with little rubbery bungs that block up unused SFP ports, but since this old procurve ...
5
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1answer
44 views

Non-HP transceiver and HP switch

Does a non-HP single-mode transceiver work in a HP switch, and does a non-HP single-mode transceiver communicate with a single-mode HP transceiver?
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2answers
76 views

Obtaining packet switch-port information via a mirrored port?

When sampling a mirrored port of a switch, is there any means of determining the switch-port information of the packet? Since Ethernet packets do not contain this information, I assume the answer is ...
3
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1answer
144 views

Strange flooding during installing new switch in network

This is very strange issue i am noticing. In our datacenter we have every switch in rack has cisco vPC configured in short whole datacenter running vPC so there is no loop for spanning-tree anywhere ...
2
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1answer
57 views

Duplex mismatch between a Fast Ethernet router and Gigabit Ethernet switch with auto negotiation

i am connecting c3745 router on fast ethernet 0/0 interface with a IOSvL2 switch on gigabit ethernet 0/1 on GNS3. i have set the negotiation on the switch to auto for all interfaces on the switch. ...
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1answer
29 views

How does Kismet find WIRED devices when scanning Wi-Fi? [closed]

In an effort to better secure my Wi-Fi network by finding its weaknesses and mitigating them, I have employed the use of Kismet, a well known Wi-Fi security scanning tool. When I use Kismet to scan ...
3
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3answers
75 views

Is it possible that two servers were configured with the same ip under the same switch

I have two physical servers, their configuration as following: ServerI: IPADDR=10.1.1.5 NETMASk=255.255.255.0 ServerII: IPADDR=10.1.1.5 (Same IP) NETMASk=255.255.0.0 (different NETMASK) Because of ...
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2answers
36 views

HP switch “No untagged port”

A network engineer showed me the show vlan output of an HP switch. I know tagged ports are trunk and untagged ports are access in Cisco terms. But can anyone explain the "no untagged port"? How is ...
22
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8answers
4k views

Why can't devices on different VLANs, but on the same subnet, communicate?

I have a question about switching. I have two devices connected to a switch with IP addresses 192.168.5.20 and 192.168.5.10. Both devices have the same prefix, /24. That means they are on the same ...
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1answer
89 views

Cisco 2960L and ISR 4331 throttled WAN speeds

I have tried finding a solution to this issue and the closest I have found thus far can be found here. https://www.reddit.com/r/networking/comments/8f2sn0/throughput_limited_by_cisco_2960_switch/ My ...
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2answers
45 views

How does pfSense control network traffic when plugged into a switch?

I apologize for this n00b question, but I'm trying to learn networking to help at a non-profit where the old IT guy is no longer there. They have several Cisco switches and one pfSense instance that ...
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1answer
38 views

Can't install OS on S6000-ON

I have a Dell Networking S6000-ON. I'm trying to install an OS with ONIE but am running into an issue with the EEROM TLV info. Using some of the onie-syseeprom commands came back with this: ONIE-...
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0answers
32 views

sflow configuration Cisco Nexus 9396PQ

We have Cisco a Nexus switch with M12PQ 12x40G GEM expansion card. Today when i enabled sflow on one of 40G interface i got following error: # sflow data-source interface e2/12 In order to enable ...
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1answer
70 views

Is there a MTBF related to port linking?

During a firmware upgrade, I've noticed one problem: An equipment keeps linking/unlinking on a specific port of a PowerConnect 3548(stp portfast, switchport access mode). I've contacted the local ...
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0answers
29 views

Why does my 1921 Router not bring up its interfaces?

I have the 'no shut' command entered on both interfaces. They work when I enter the command. I copy run start 'wr' Power was cycled for the Router, Switch (3560x-24), Cable modem and AP. They were ...
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1answer
55 views

cisco switch iOS running into problem

I updated Cisco 2960x iOS, but when it started to operate I encountered this error. "Mar 25 12:02:19.878: %ILET-1-AUTHENTICATION_FAIL: This Switch may not have been manufactured by Cisco or with ...
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1answer
45 views

Arp Cache Timeout [closed]

I'm trying to poll the arp table from a backbone switch but i want to understand which records are up. I just want to know if there is a specific time for the switch to keep a record on the arp table ...
1
vote
1answer
21 views

Can a hub be used for sniffing traffic from a device?

My intention is to analyze all network traffic which is coming to and originating from a network connected device I have. From the configurations of the device I am able to proxy all the HTTP traffic ...
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0answers
38 views

Colocation network setup - 2 switches with each 1 uplink - redundant configuration question

I have a question about the network configuration when connecting 2 switches in a colocation rack via 2 uplinks (1 uplink to each switch) to 2 other switches of the datacenter itself. My topology ...
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0answers
31 views

DHCP over Frame Relay [closed]

I have two co-operate buildings. Building A is connected to building B via frame relay. Building A has the main switch server (with VLAN info) and a DHCP server. I need Building B devices to receive ...
3
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1answer
27 views

Access and uplinks ports QoS Queuing model

On an access switch, does the uplinks egress QoS Queuing model (multiple traffic classes and bandwidth reservation), should be different than the access ports egress Queuing model ? Is there a sense ...
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2answers
61 views

Is it correct to assume that ordering of frames at switch level is not important?

My understanding is that if the payload of the frame contains any data that needs to be reassembled, at least for TCP payload, it can be done at the OS level, once all the packets are received and ...
1
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1answer
70 views

Switch Configuration for Connecting LAN and WAN

Totally new on networking and on switches, so excuse me if I use some wrong terminology. Problem I have 1 computer and 7 instruments. I would like to form a network setup fulfilling the following ...
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1answer
372 views

Assigning a single switchport to different VLANs

I've been trying to figure out how to achieve the outcome below. VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- ...
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2answers
66 views

How to: Setting up SNMP on various Cisco platforms & Can you recover or configure a switch using SNMP?

How do you setup SNMP on different Cisco switches or routers? Is it possible to limit the IP addresses/subnets, that can access the SNMP communities via access lists? How do you recover or configure ...
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2answers
53 views

How is Ethernet traffic sent between computers with multiple switches in-between? [duplicate]

I've wondered how Ethernet packets sent from Laptop-A to Laptop-B on the local network segment are delivered, when multiple switches are in-between. For hubs, that just replicates the packet on all ...
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0answers
41 views

Wireshark switch ping

I understand that a switch will broadcast to all ports if it doesn't have the destined destination in its mac address table but when I analysed a scenario in wireshark I got confused at what happened. ...
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0answers
9 views

What happens within a switch when a frame is moved from Device A on Switch 1 to Device B on Switch 2? [duplicate]

This might be a noob question but what happens within a switch (regarding mac tables) when a frame is moved from Device A on Switch 1 to Device B on Switch 2? I'm assuming the 2 switches are connected ...