10
votes
Accepted
MAC Address learning process
It depends on the manufacturer. For Cisco switches:
Switch port configured as access and frames received tagged on
different VLAN
Frame is dropped
Switch port configured as trunk and frames ...
- 62.5k
8
votes
Accepted
What is the springing mechanism for on the top of this transceiver module?
Some Ethernet SFP modules have them, some do not. What is the yellow springing mechanism and the attached metal wire meant for?
Every SFP I have ever seen or used has some sort of mechanism for ...
- 26.7k
7
votes
Accepted
How does a Layer 2 Switch know which port is a neighboring switch port and which port is connected to a host?
A switch simply record the source MAC addresses of frames ingressing on a given port. It doesn't care if there's a single host, or another switch connected on a port (for that purpose).
If a single ...
- 18.4k
6
votes
Accepted
Can VLANs with same no but on different switches communicate with each other?
Yes, assuming the switches are connected together and VLAN 10 is forwarding on the connected ports. Both ports have to be configured the same, so that VLAN 10 is either tagged on both or untagged (...
- 62.5k
6
votes
What is the springing mechanism for on the top of this transceiver module?
It releases the retaining clip. (the tiny black bit) The wire is the pull bar.
- 29.6k
6
votes
Accepted
How does a switchport learn a MAC address
A switch will learn a MAC address as soon as a frame enters the switch. It looks at the source address on the frame and adds to, or updates, its MAC address table with the interface where the frame ...
- 93.6k
6
votes
Accepted
cisco switchport trunk native vlan
The problem is not the traffic from the server to the switch, but the return traffic, from the switch to the server.
Since the VLAN is native, the switch will sent the traffic for this VLAN untagged, ...
- 18.4k
5
votes
Accepted
How can I config multi switch port efficiently?
You can use interface range to select multi continuous ports.
sw1(config)#interface range fastEthernet 0/2 -24
sw1(config-if-range)#shutdown
- 1,128
5
votes
Accepted
What's the `line protocol` and `Link`?
For this particular interface, the line protocol is ethernet.
The Link Up/Down Trap is enabled message is telling you that the SNMP trap for when the link goes up or down, for whatever reason (admin ...
- 93.6k
5
votes
Why STP has to be disable on Trunk Ports?
You should not disable spanning tree on trunk interfaces. In fact, STP needs to be on links between the switches, which should be the trunk interfaces.
You can also leave STP enabled on the access ...
- 93.6k
4
votes
Forwarding to multiple output ports using SDN
Yes, the openflow protocol supports the creation of flows with multiple actions, and each action can be to send a frame/packet out a certain port.
However, whether or not your openflow switch ...
- 2,628
4
votes
can i check the ip of the machine attached with the network switch port from the switch console
This would entirely depend on the capabilities of the device and how it is configured.
The simplest way would be is if the device in question was configured for DHCP snooping/IP source guard. This ...
- 26.7k
4
votes
can i check the ip of the machine attached with the network switch port from the switch console
In the general case, you can't find directly the IP address of the attached device.
What you can find is the MAC address of the device, by looking at the switch mac address table.
This table list the ...
- 18.4k
4
votes
Switch syntax, vlanXX and vlan [space] XX
vlan 35 is used to refer to the (tagged or native) VLAN with VID 35.
vlan35 is a named interface (or anything else you can name), usually a switch virtual interface (SVI) - the name may default to ...
- 70.5k
4
votes
Accepted
Best Practice for Voice and Data VLAN on single port
802.1Q tagging allows you to run multiple VLANs over a single, physical link. With phones, often the normal PC client VLAN remains untagged (access VLAN) while the VoIP VLAN is tagged.
Using a DHCP ...
- 70.5k
4
votes
System default switchport shutdown on Arista EOS
Even though this is a bit late, but since this result popped up in my Google search, the way to do this is in Arista EOS is using (this also works for setting default MTU):
interface defaults
...
- 41
4
votes
Accepted
How Can a VPC ping the Router through an Etherswitch that behaves in one port as router and in the other as switch
You did not include the full configurations as asked, but there seem to be a few problems:
I do not see that you have enable routing on EWS10 with the ip routing command.
I do not see that you have ...
- 93.6k
4
votes
Accepted
Why switch uses Mac address during implementation of spanning tree protocol (STP)?
Switches that run STP do have MAC addresses because they generate BPDUs. Those frames require a source address.
It may be helpful to understand the difference between control plane and data plane. ...
- 62.5k
3
votes
HP ProCurve 2524 - CLI Command to find Fiber Transceiver's Serial Number
Try display transceiver interface <interface-id>.
- 107
3
votes
HP ProCurve 2524 - CLI Command to find Fiber Transceiver's Serial Number
show tech transceiver should work on the old Procurves, at least it does on the 2510 and 2600 series.
Somewhat newer Provision switches (2910, 2530, ...) support show interfaces transceiver [n] ...
- 70.5k
3
votes
Accepted
Save switch config in USB
According to the Installation Manual, only USB 1.1 and USB 2.0 are supported, along with FAT and FAT32 file systems. If I were you, I'd try to find a USB 2.0 2-4 GB stick and format it with FAT32.
...
- 2,229
3
votes
Accepted
L3 routing between switches with some VLAN's trunked
The difference is, in the first example, your VLANS can span several switches. In the second example, the VLANs terminate on the router interface.
As an example, with the first configuration, you ...
- 62.5k
3
votes
Accepted
Cisco, No dot1q tunnel mode on switchport
As QinQ is ISP feature the key was in Not in Use entservice license state:
show license all
...
StoreIndex: 1 Feature: entservices Version: 1.0
License Type: PermanentRightToUse
License ...
- 41
3
votes
Accepted
How do I enable port security on Cisco switch?
Enabling port security is extremely easy at its core. It gets more complicated with the options.
Enabling port security on a switch port is done with a simple command: switchport port-security
Cisco ...
- 93.6k
3
votes
Accepted
Switch Port Configuration
The Cisco interface range command is really a macro that allows you to configure the same commands on a range of interfaces, and they don't necessarily need to be contiguous.
Example:
spanning-tree ...
- 93.6k
3
votes
Accepted
When are Native VLANs used? Are there times when a Native VLAN will never be used?
If you have an 8-port switch with ports 1-4 on VLAN 10, and 5-7 on VLAN 20, port 8 as trunk and default VLAN 1 ...
It's correct, VLAN 1 shouldn't be used
Watch for
Untagged frames arriving on the ...
- 15.9k
3
votes
Accepted
HP switch "No untagged port"
It means the "tagged" port does not also allow untagged frames. In the Cisco world, this is equivalent to having no native VLAN.
- 62.5k
3
votes
HP switch "No untagged port"
As a configuration command, no vlan xy untagged n (or just no untagged n when you're in the vlan xy context) removes the VLAN xy as untagged from port n - so there's no untagged/native VLAN.
In Cisco ...
- 70.5k
3
votes
Accepted
Obtaining packet switch-port information via a mirrored port?
No.
Ethernet switches are transparent devices, so they do not alter the ethernet frames (except to add and remove 802.1Q tags for trunks). There is nothing in the ethernet frame header that supports ...
- 93.6k
3
votes
What's the `line protocol` and `Link`?
On Cisco equipment, the physical interface can have the following states:
- 1,700
Only top scored, non community-wiki answers of a minimum length are eligible