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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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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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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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 am attempting to connect a Dell PowerConnect 2724 on port 24 to Cisco 3560G on port Gi0/3. I want to be able to pass through traffic from VLANs 30 and 34 which already exist on the Cisco switch. How do I need to configure the ports I mentioned above? Basically we are using this switch in our location to connect laptops to do imaging and other work. Thank you for any help you can provide!
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Hello Experts

We are in discussion with our ISP to connect the remote branch office with the HQ. We have decided to go with MPLS IP VPN.
Hence, I need know what configuration I need to on the Customer Edge ( HQ and Branch). ISP will provide there router equipment on the branch side.
What information should be provided to ISP ? What IP Subnets and VLANs I need to setup on our layer 3 switches


Please advise me because this is the first time to take this service
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Hi Experts,

we are going to use new ARISTA switches for our datacenter.
Do you have any recommended tips how to setup the switches ?
Maybe you also have a basic config ?
Thanks in advance.
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Hi Experts

We had one of our 3750's hardware fail, will not power on. Were currently purchased a new 3750 to replace. Would like some general guidelines on the steps to do so. the most important we want the vlan information to come across.
Do we backup the config on an existing switch and apply it on the new one? - We tried and received a lot of errors
Do we apply the vlan and other port information (below is our existing) to match what we already have.
How do we place the switch back in the stack, unpowered and connect all the stacking cables and then power it on?
What Impact will that have on the stack, will it power down?
What will and will not come across after we add the switch to the stack, do we need to set a password on the new switch, I know after you add the switch the master takes over and it applies some information - firmware.

The switches in the stack has a lower SW Version than the new switch being added will it be downgraded automatically or something we have to do manually.  (sw version of the switches in stack 12.2(25) SEB4 \ New Switch 12.2(55)SB


interface FastEthernet1/0/12
 switchport access vlan 10
 switchport voice vlan 20
 srr-queue bandwidth share 10 10 60 20
 srr-queue bandwidth shape  10  0  0  0
 mls qos trust device cisco-phone
 mls qos trust cos
 auto qos voip cisco-phone
 spanning-tree portfast



Thanks Much
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I have a cisco 2960G 24 port switch that for some reason, once in a while, drops or cuts network access.
I lose all communications to the switch, and since it's my main switch for my ISP, SIP trunks, LAN, WAN, etc... my entire network is crippled.
Besides show log, are there any other commands that will allow me to see the log for the entire day or past few days, so I can see what's going on?
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Quick question.

I'm setting up 4 switches with end users connected. Between my core switch and router, I'm planning on putting in a hardware firewall.

Should the default gateway for the switches and PCs be the internal interface of the firewall (Cisco ASA) or the router?

All hardware is Cisco kit.

Thanks
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I am looking to add config files for my HP Procurve 2920 switches configs. I need to know what files I need to backup in the event any of my switches should fail and need to replace. Looking to reduce my downtime.
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Hi.
I want to know that Catalyst 3550 switch's tftp service configure default value.

So I wanna disable tftp service.

If it is able to use tftp service for default , let me know how to disable this service like that configure.
I am looking forward to hearing from you.

Thanks & Regards
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Dear all, is there any mechanism to set a timer on Cisco Router and Switch?

For example: shutdown/restart an interfaces on pre-defined schedule, change the default route on schedule,...

Many thanks in advance.
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Dear guys, I have this scenario:
- The original IP network which ISP provide: 13.14.24.160/28 (no worry, it's fake)
- I don't know why the IT guy who worked here before request ISP to split that network to 2 subnets: 13.14.24.160/29 and 13.14.24.168/29
- However, I was handover the instructions to get Internet for LAN network as the attached picture without any other explanation

Can anyone help me to answer these?
- Please explain the way end-users in LAN network to go the Internet. Which IP network should we configure in users' PCs?
- Please give me some ideas that clarify the purpose of the splitting?
- Can I place the pfSense firewall in the Router position? If so, is there any device/configuration we need to focus?

Many thanks as always!
Diagram.png
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Dear zealots, I am configuring Routers and Switch to mitigate DDoS attacks, following this article: http://www.infosecwriters.com/Papers/HChau_Cisco-DoS-DDoS.pdf

However, when I enter "no ip directed-broadcast" into Router and Switch's interface mode, then it cannot be displayed when I hit "show run". Do you know why? My devices' version is 12.2 (Switch 3750/3560) and 15.1 (Router 3925)

And should I apply this command on VLAN interfaces in Switches?
1
Dear Experts,

My colleague somehow remove / deleted the HP switch files.

When I turn it on, it displays this?

System is starting...
Press Ctrl+D to access BASIC-BOOTWARE MENU
Booting Normal Extend BootWare
The Extend BootWare is self-decompressing......................Done!

****************************************************************************
*                                                                          *
*            HPE 1920-8G Switch JG920A BootWare, Version 1.17              *
*                                                                          *
****************************************************************************
Copyright (c) 2010-2016 Hewlett Packard Enterprise Development LP

Compiled Date       : Jan 18 2016 09:58:32
CPU Type            : MIPS4kec
CPU L1 Cache        : 16KB
CPU Clock Speed     : 500MHz
Memory Type         : DDR3 SDRAM
Memory Size         : 128MB
Memory Speed        : 300MHz
BootWare Size       : 3MB
Flash Size          : 32MB


BootWare Validating...
Application program does not exist.
BootWare password: Not required. Please press Enter to continue.


How can I resolve this?
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First, If I am correct:
Standard Access-list  can match traffic based on Source IP address only
Extended Access-list can match traffic based on Source/Destination IP address , port number, protocol, etc...

well, there is also  Named Access-list. We can have Standard Named Access-list and Extended Named Access-list
  Is Standard Named Access-list similar to Standard Access-list, it can match traffic based on Source IP address only ?
Is Extended Named Access-list  similar to Extended  Access-list ,it can match traffic based on Source/Destination IP address , port number, protocol, etc. ?

Thank you
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We have been asked to connect a 200Mbps fibre connection (expandable to 1Gb) to 10 independent business units in a small business park. The fibre provider will put a Cisco 1921 router on the end. They have no interest in managing the ongoing connections to the individual business units. That's down to us. Someone recommended a Cisco SG500 switch to add to this to satisfy the requirements:

1. control of bandwidth to each unit so they each get what they have asked for (and paid for) and no more
2. separate public IP assigned to each business unit (one each)
3. each unit can only access internet and not each other's networks

This is a little outside my day-to-day networking experience so rather than fumble my way forward, any pointers, issues to watch out for would be much appreciated.

Thanks,  Andy.
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Which VLAN   to enable ARP inspection

I would like to know which VLAN to enable ARP Inspection. Is it going to be on the same VLAN where the Trusted DHCP server resides on ?
Or on every VLAN in the network ?

Switch(config)#ip arp inspection vlan <VLAN Name>



I also wants to know about the DHCP Option 82 configuration.
Using IP helper-address <IP address> is enough or  we need to add:
ip dhcp relay information option

Thank you
0
Hi, does anyone know any weakness of Cisco devices (router, switch, Firewall)? Is there any way/tool to assess their vulnerabilities?
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Hi All,

I'd like to get the config file off both these makes of cisco equipment does anyone know the proper command config to do so/

thank you for your help
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If I am correct, BPDU Guard on all switch ports , protects the switch from a loop. If a user plugs in another switch to a port, it will go into err-disable state.


Switch-port port-security violation , will achieve the same purpose in that regard.

the only difference I see is  Switch-port port-security violation has other option such as, Protect, Restrict, Shutdown.

I would like to know form Network Experts, which command is mostly used in switches access ports to prevent rogue switch from being introduced to the network ?

Thank you
0
I am planning to upgrade the firmware of catalyst 2960
I checked the version I saw below

Switch#sho ver
Cisco IOS Software, C2960X Software (C2960X-UNIVERSALK9-M), Version 15.0(2a)EX5, RELEASE SOFTWARE (fc3)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2015 by Cisco Systems, Inc.
Compiled Mon 16-Feb-15 08:16 by prod_rel_team
ROM: Bootstrap program is C2960X boot loader
BOOTLDR: C2960X Boot Loader (C2960X-HBOOT-M) Version 15.2(3r)E1, RELEASE SOFTWARE (fc1)
Switch uptime is 46 weeks, 2 days, 1 hour, 0 minutes
System returned to ROM by power-on
System restarted at 07:50:33 UTC Fri Jul 22 2016
System image file is "flash:/c2960x-universalk9-mz.150-2a.EX5/c2960x-universalk9-mz.150-2a.EX5.bin"

I downloaded below files and I have TFTP server ready to upload the files.
c2960x-universalk9-mz.152-5b.E.bin
c2960x-universalk9-tar.152-5b.E.tar

How to upgrade to 152.5?
Your help is appreciated
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Hi, the title said it all. Can anyone draft me some pros and cons of stacking switches?

And is it possible to simulate this techniques in GNS3, Packet Tracer or something else?
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Assuming I have 2 switches connecting to each other.
on one switch I configure  Port-channel Load-balance src-mac
and on the other switch I configure Port-channel Load-balance dst-mac

I have not tried yet it, but wonder if it will work

Thank you
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I have a security camera project that requires a run of about 1000FT for a few cameras.

I know Cat5/6 are not options due to the 300ft limitation.  I guess I could use POE switches at 300/600/900 ft as repeaters but that doesn't sound like a viable solution.

any ideas?
0

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.