All Questions
86
questions
0
votes
1
answer
213
views
How do layer 2 switches route based on MAC when daisy-chained?
Trying to think about this from a hardware design perspective, if I had to design an FPGA or a uC or something to manage a single port being the gateway port and one or more switched ports for routing,...
0
votes
0
answers
31
views
Why are connected switches not a good substitute for the network layer? [duplicate]
Unless I am missing something, because switches can be chained together, I am not sure why the network layer is needed. Theoretically, one can dedicate a frame to any MAC address, and assuming there ...
- 109
0
votes
3
answers
176
views
One layer 2 switch in the middle of router network
In general,
The connection should be like
PC---SW---ROUTER---Many ISP router---Router---SW---PC
so the packet will be from
layer 2 ---layer 3---layer 2
What if I put one layer 2 switch in the network
...
- 45
1
vote
4
answers
3k
views
Communication between different VLANs
In my previous understanding, there is no way to communicate between two VLANs using only layer 2.
After all, this is the purpose of having VLAN.
I found a forum that claims the following.
1.VLANs can ...
- 45
1
vote
1
answer
836
views
Can a switch fragment a jumbo frame?
In all resources seen that tackle the term of "jumbo frame", I understand that it is applied in a LAN, because:
It's a Jumbo frame, and a frame is for Layer 2
These resources talk a lot ...
- 63
8
votes
6
answers
5k
views
How Does A Layer 2 Switch Differentiate Between Different Networks?
I know that different IP-based networks can be connected to the same layer-2 switch. and I know each network's nodes can communicate just fine, however, no normal traffic can occur between two nodes ...
- 285
1
vote
1
answer
451
views
How FDB (Filtering Database) is filled out
I would like to understand what is used as a VLAN column in the FDB. For ACCESS port it is PVID if frame untagged or frame VID if frame is tagged, for TRUNK it is allowed VLANs?
We can represent the ...
- 141
0
votes
0
answers
29
views
Why collision domain occurs in hubs but not switches [duplicate]
if anyone knows the actual point and in depth answer to my question please help. the links in the comments didn't helped at all
Most of the websites which i saw are just vaguely saying that collision ...
- 101
0
votes
3
answers
2k
views
No internet access on VLAN
I'm trying to setup VLAN on my TL-SG3210 (3.0).
I created simple VLAN:
vlan 10
name "vlan10"
Then, I assigned port 2 & 3 to VLAN.
I also created interface:
interface vlan 10
ip ...
1
vote
0
answers
78
views
What are non-learning and learning VLANs?
I was going through some IEEE standards for switches (IEEE 802.1aq and IEEE 802.1Qca), and came upon a terminology of learning and non-learning VLANs.
I read that learning VLANs are used in Shortest ...
- 63
0
votes
2
answers
455
views
How do layer-2 devices (bridges/switches) join a multicast MAC address?
I was going through the IEEE 802.1Q (2018) standard on my own. The standard speaks about group addresses, and how these group addresses are learned by transit bridges, which is all fine.
But how do ...
- 63
1
vote
2
answers
291
views
Proxy-ARP when the destination device is connected to the same layer-2 switch, but belongs to a different subnet
I have recently learned about Proxy-ARP and am slightly confused about what would happen in the following scenario. Let's say I have two host devices A (IP: 10.0.0.10/24) and B (IP: 10.0.1.10/24) that ...
- 13
6
votes
2
answers
4k
views
How do I know the switch is layer 2 or layer 3?
Is it possible to find the switch is Layer3 or Layer2 in (Switch)CLI? Is there any command to check whether the switch Layer(Layer 3 or 2) in CLI?
- 125
0
votes
1
answer
35
views
Where can I find virtual switches to learn about layer 2 [closed]
I am learning about layer 2 networking, arp, cam tables, mac addresses etc. I will like to see some of these things in action but I do not have access to physical hardware now, does anyone know of a ...
- 137
1
vote
2
answers
306
views
How does an L3 Supported Switch differentiate L2/L3 Packets?
I had a managed or layer 3 supported switch (it can process both layer 2 and layer 3 packets). Now a packet from a connected host comes to it, sending traffic. How does the switch decide to process it ...
- 11
0
votes
0
answers
28
views
Switch vs. Router and sequence of OSI Model [duplicate]
As I understand it:
A switch (layer 2) seems to define a LAN and a router (layer 3) enables communication between distant LANs.
A device on a LAN will give it's MAC address to the switch upon ...
0
votes
2
answers
413
views
Some extra clarification regarding VLANs and SVI
Good afternoon guys,
I've got a question regarding VLANs and SVIs.
First of all, I know some concepts about VLANs, and I've been in the IT field for a while.
But this one is a bit confusing for me.
...
- 3
0
votes
3
answers
346
views
Propagating Static MAC Addresses
I have a situation where I need to place a static MAC on a switch as the server in question does not generate any outbound traffic. This static MAC seems as if it will work for hosts on the same ...
0
votes
1
answer
80
views
How loops appeared when skipped listening and learning state?
In STP convergence process, I just know that after a link failed a blocking port become listening state for 15 seconds then learning state for 15 seconds. I've read a CCNA 200-301 Guide explained me ...
1
vote
1
answer
150
views
How a wifi AP handle packets
Computers are connected to a wifi AP. The wifi AP is connected to a L2 switch. A server is also conected to this switch.
When computers sends packets to the server, how the wifi AP manages the paquets?...
- 13
0
votes
1
answer
671
views
Why does the Layer 3 switch drop the ping packet?
I am trying to ping from PC2 (not PC1, there's typo in the picture) to the router's int g0/0, but the packet is dropped at the L3 switch which is along the path. I have tried setting a default static ...
- 1
1
vote
1
answer
58
views
Can use virtual port as the port mirroring's destination port?
Port mirroring can mirror several source port to a destination port(mirroring port).
I have several questions about port mirroring.
in the dest port, how to differentiate the different source port? ...
- 1,777
0
votes
3
answers
606
views
Using MSTP with RSTP
I have two layer-3 switches connected with two redundant links that I'm trying to run PTP OSPF sessions across, a la:
(OSPF)
VLAN 1002
- - - - - - - - - - - -
/ ...
- 43
1
vote
3
answers
230
views
How are packets ( received from the server ) sent to the host from the gateway ( which is present in the host network )?
If the host is receiving packets from a server, these packets have a destination IP address of the host and it is first received by the gateway present in the host network. Now the gateway checks the ...
- 15
1
vote
1
answer
311
views
How do (LANCOM) Tag-Based vlan groups work and on which vlan does the device respond?
I just started a new job and part of it is to manage and maintain the ICT. As the previous network/system engineer left the company i'm on my own to figure out how everything works.
I have ...
- 219
0
votes
2
answers
1k
views
EXOS layer2 Configure on a Summit x440-G2-24p
I search since Days for a working configuration for a layer2 connection from another extreme switch to this switch. What I connected Physically on my Summit x440-G2-24p:
the ethernet(lan) cable from ...
- 11
2
votes
2
answers
1k
views
How do computers send switches packets, if switches don't have IP or MAC addresses?
I am new to networking, so please excuse me if I am saying stupid stuff.
From my understanding, PCs are sending packets to switches, which then decide which physical port to forward that packet to. ...
- 135
4
votes
1
answer
8k
views
What is the purpose of native VLAN on a trunk link?
Most VLAN articles I've read recommend avoid using VLAN1 for ports with untagged traffic (aka access ports). I've heard enough of this nonsense. Except for the reserved values of 0x000 and 0xFFF, a ...
- 433
3
votes
4
answers
2k
views
LACPDU packets to pass through unmanaged switch
I have two buildings connected through the CAT6 cable and both ends have cisco-sg350 (capable of etherchannel). Due to the limitations of the cable both the switches are connected through a unmanaged ...
0
votes
1
answer
42
views
Broadcast Timer [duplicate]
This question is regarding in the process of L2 MAC Address learning.
As we know, if a sender sends a packet to some receiver host which switch doesn't know, it will broadcast for learning.
Assume an ...
user60007
2
votes
1
answer
3k
views
Ping across VLANs using layer 2 switch
I'm trying to ping one PC on one particular VLAN (VLAN 80) from another PC on a different VLAN (VLAN 50). I have a layer 2 switch (Cisco 2950T), so I can't do it from within itself.
How would I be ...
- 63
2
votes
6
answers
3k
views
Is a "LAN" a layer 2 or a layer 3 concept, in TCP/IP?
I think my question is purely theoretical and a matter of definitions; it derives from the fact that a L2-switch with VLAN capabilities is able to "create" different virtual LANs, and thus I am led to ...
0
votes
1
answer
359
views
Layer 2 and Layer 3 traffic with one cable
Hers the topology.
L2 switch
L3 switch
Router
There are 2 VLANs. One VLAN ends on the L3 switch 1 VLAN on the router.
Here is the question. Can i connect the L3 switch and the router with just 1 ...
- 313
3
votes
2
answers
692
views
What are neighboring ports?
I know this is as basic as it gets but I can't find a direct answer to this question.
Are they ports on two different switches (or routers) that are connected by a cable?
Are they the ports ...
- 33
1
vote
1
answer
521
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 ...
- 163
4
votes
3
answers
1k
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 ...
4
votes
2
answers
3k
views
Nexus 3172T MTU
I am attempting to set the L3 mtu on a Nexus port.
The mtu option is only available if I set "no switchport" which then prevents me configuring VLAN related settings.
Am I missing something obvious? ...
- 127
6
votes
2
answers
495
views
How to connect a special device in a network
I have a question which is puzzling me.
I have a couple of custom electronic devices (are identical, one is a master and the other is a slave) which implement only up to level 2 of the ISO/OSI layer, ...
- 61
1
vote
1
answer
342
views
Help with small office setup - Cisco SG350 28 port switch
I have very limited knowledge in Cisco IOS but in a crucial state to setup up a small office network. I have bought 2 Cisco SG350 28 port Layer 3 switch,
Switches should be enabled with VLAN and VTP.
...
- 11
7
votes
3
answers
10k
views
Posible to connect VLAN switch through dumb switch?
Is it possible to connect a VLAN switch into a dumb switch ?
The router will know how to reach network connected by a VLAN through the dumb switch please ?
No edge effect ?
By example, a schema of ...
- 71
2
votes
2
answers
90
views
Can Multicasting be duplicated by broadcasting on a subnet?
Is there any functional difference between:
A) Broadcasting to a range of addresses
B) Putting the range of addresses into a subnet and broadcasting to that subnet
Would it matter if there was a ...
- 23
1
vote
1
answer
2k
views
Layer 3 switch model 3950 encapsulation
How to ensure trunk link in the switch are using dot1q encapsulation, when dtp (dynamic trunking protocol) is enable along with vtp.
I know when manually setting trunk links, you can force the trunk ...
1
vote
1
answer
525
views
Frame transfer from one switch to another configured with VLANS
Hi,
My question is related to the Vlan. And this question would consist of 2 parts.
1)Would Switch 1 know all the devices present in Vlan 2 or Vlan 3, including the ones present in the Switch 2.
...
- 405
3
votes
2
answers
1k
views
Does it make sense to map a VLAN to each LAN?
I saw a picture of a network-structure with VLANs in it:
Why would somebody structure their network like this? Does this even make sense? I mean, they are in a different LAN, why then mapping a VLAN ...
- 782
1
vote
1
answer
76
views
Advertise routes in simple switched network
I'm trying to build a fairly simple network.
I've got a few devices acting as the network core, which are basically all connected to each other by a simple Ethernet switch.
Each of these devices (I ...
- 113
1
vote
2
answers
320
views
CSMA/CD - CSMA/CA switch mix
Suppose I have 2 switches; one CSMA/CA (gigabit) and the other CSMA/CD (gigabit), would they work together when connected and if so would there be any dip in network performance?
Thanks in advance!
- 13
3
votes
2
answers
4k
views
What is the difference between CAM and FIB table?
As far I know,
CAM table is Content Addressable Memory table where MAC address is stored
FIB table is Forward Information Base table which is a dynamic table that maps MAC addresses to ports.
Both ...
- 613
0
votes
3
answers
2k
views
Cannot Ping Linux PC through L2 Switch
I’m a little embarrassed to be asking this but here goes.
In a training video for CCENT, I see a switch connected to 2 PCs that are pinging each other on the same subnet. I try to replicate the ...
- 3
3
votes
1
answer
247
views
VLAN Isolate Setup
How can I set up a switch so that devices on one switch port are isolated from devices on other switch ports? I'm guessing this should be done with VLANs, but I'm open to other options as well.
...
- 165
3
votes
2
answers
6k
views
Router vs VLAN in networking?
Why do we need Routers at all when we have VLAN ?
Vlan breaks the broadcast domain.
Vlan along with the use of SVI can be used for routing.
So why do we need routers for in networking ?
- 149