Questions tagged [switching]
For questions related to traffic switching and troubleshooting the traffic switching process.
481
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In RSTP, where all switches generate their own BPDUs, are they limited to forwarding them only on designated ports? (like in classic STP)
I recently learnt a rule in STP: only Designated ports forward BPDUs.
However, I'm not sure about this in RSTP since ALL switches generate their own BPDUs every few seconds. So, in a certain LAN ...
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2
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Do DSLAM and OLT function like a switch?
Let's say for example we have the following hypothetical topology:
In each network, can each user communicate with each other?
For example, can User 1 ping User 2?
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4
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One VLAN on two switches
I'm trying to understand the specifics of trunking a VLAN on two switches.
Say I have two switches, both hosting half of VLAN 3.
Switch 1: Ports 0-5 on VLAN 3, Port 6 is Trunk
Switch 2: Ports 0-5 ...
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2
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1
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Port only in trunk mode vs encapsulating the frame
A network with 2 switches, each switch has 2 vlan, one called vlan 10 and another vlan 20.
A port-channel with 2 uplinks (trunk). Why in a layer 2 scenario I don't need to configure the trunks with ...
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How to Change the Date on Cisco Catalyst 3750x Switch
We are using cisco catalyst 3750x 24 port switch series
How to Change the Exact Date(Singapore) on a Switch
ASW-G-L09-001#show running-config
Building configuration...
Current configuration : 11883 ...
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2
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Whats the difference between VOICE VLAN and ACCESS VLAN
Can someone please tell me the difference in Layman's termsfor these 2 configurations?
interface FastEthernet0/1
description PHONES
switchport mode access
**switchport voice vlan 51**
spanning-...
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2
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707
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Fiber link loss on Cisco Catalyst 3750x series switch
I have cisco catalyst 3750x 24 port switch series switch, and the switch has C3KX-NM-10G module.
Problem :
I have connected fibre optic in SFP+ transceiver on G2/TE1 (Uplink). After 7 to 8 hours, the ...
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2
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2
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98
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Network ( routing and switching) , security
In my company network i am installing new cisco2811 router but i have problem, my LAN network can not ping and access network. i get point to point internet from ISP.
PTP IP is 192.186.86.200/24 and ...
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1
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527
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Why can't get host's mac address on l2 switch through snmp? But can get it on l3 router
I am trying to get computer's mac address through snmp.
I have an envirmont in GNS3:
l3 R1's image is vios-adventerprisek9-m.SPA.157-3.M3
l2 SW1's image is viosl2-adventerprisek9-m.SSA....
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4
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1
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GNS3 switches vs Real switches performance
I want to emulate the performance of switches in GNS3, and the focus is not the configuration of switches. My questions are:
Do emulated switches perform worst than actual switches?
Are emulated ...
- 99.6k
0
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1
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237
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Is it possible to assign an IP to a tagged dual-mode port (Brocade)
I have a router (ubiquity USG) and a Brocade FCX648 Layer 3 switch. (I have a second one in a stack, but that's unrelated). The end goal is to be able to connect the switch to my router, provide IPs ...
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3
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What are the Major Differences between Juniper EX4200 vs Juniper EX4300?
Can someone please explain that what are the major differences between Juniper EX4200 and Juniper EX4300 switches? Both are standard Juniper Ethernet switches but is there any situation where EX4300 ...
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2
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179
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Need explanation on vlan tag/ip mismatch
What happens if I have a switch configured with an accessport on vlan 20 and someone uses a static ip in a different subnet. vlan 20 has the subnet 192.168.20.0/24 in the router. Suppose the ip used ...
- 32.2k
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Virtual Chassis Setup in Juniper EX4200 Using Mixed Interface Types
We want to setup Virtual Chassis using 2 x Juniper EX4200 switches. In case of Virtual Chassis for EX4200 , we have to use 2 x VC cables (connected back to back) between 2 x Ex4200 switches along with ...
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2
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Endpoint MAC address change detection [closed]
A question regarding a host behavior when gateway mac address has changed (although it deals with Windows, I think it's the best forum).
Assuming a windows host sending trafic to a destination IP, ...
CommunityBot
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3
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What kinds of organizations use routing protocols (aside from ISPs)?
I don't understand why would an organization aside from an ISP even use routing protocols.
Let's say there is a big company with 5000 employees, and they want to have a network throughout their ...
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277
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Fastest way to switch between redundant wireless links
I have a system using 2 redundant point-to-point wireless links to access the internet, and I'm trying to find the fastest way to switch between them if one goes down.
We need to switch within 1 ...
CommunityBot
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1
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96
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Is SONET a physical layer or a data link layer?
According to some sources, SONET is physical layer.
But some sources say that SONET can carry IP directly. Also, SONET defines its own frame -- it has a header and a payload. That must make SONET a ...
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2
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Query regarding LACP System Priority
This is regarding LACP System Priority.
From my research I could find the following info pertaining to system priority.
LACP combines the System Priority value with the MAC address of the switch to ...
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2
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196
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Do X.25/Frame Relay/ATM/MPLS have their own switches?
In the context of networking when we say "switch" we always think of Ethernet switch.
But do we have X.25 switch, Frame Relay switch, ATM switch, and MPLS switch?
If yes, how are they ...
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Query regarding LACP timeout flag
Say we have two swicthes.
Switch A and Switch B.
Switch A sends LACPDU's with timeput flag set to 1 (fast).
Switch B sends LACPDU's with timeout flag set to 0 (slow).
By researching came to know that ...
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2
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Criteria to match for lacp status to come up
I did research and found that below are the minimum requirements for LACP to be Up.
One of the side should be active.
All the port speed should be same.
Duplex settings need to be same.
Also I have ...
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1
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804
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Sending a gratuitous ARP on an interval - Cisco
In response to my question Propagating Static MAC Addresses , I realize I can not avoid the unknown unicast problem. Essentially I have hosts that forward their traffic via an L2 frame to a ...
CommunityBot
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1
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Wants to understand traffic flow of Catalyst layer3 Switch 3850 . what are sequence this switch will check to delivery packet to destination
i wants to know clear understanding about how Cisco layer3 switch checks in sequence order when traffic arrive to its L3 Interface . i want to know traffic flow in Cisco layer 3 switch ,because switch ...
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2
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735
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Connecting switches together
I have L2 switches which will be daisy chained together (yes I know, daisy chaining isn't great, but anyway..) The L2 switches will then link to a L3 switch.
Both the L2 and L3 switches have x4 10GbE ...
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0
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Issue with PIM-SSM Multicast Configuration ISR4431s
I have an issue with my PIM-SSM multicast configuration using ISR4431s.
I am wanting to forward broadcast data from an application from one VLAN in on the multicast source to another VLAN on a ...
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0
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3
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320
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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 ...
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Do switches allow parallel connections?
I am new to networking and not from Engineering domain. Sorry If I sound silly.
I came across an article on Network Switches and How they work. Diving deep into it, I found some interesting topics ...
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2
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Same MAC address on different VLANs
I am facing a situation where on the core network I have around 15k MAC addresses, and on the edge switches (Access Layer), I am finding switches with 27k MAC addresses. Access switches are configured ...
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4
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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 ...
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Frame relay, PVC and DLCI
Regarding the frame relay technology, could you confirm to me that traffic using permanent virtual circuit use the same ISP routers in the path for all packets sent ?
I'm a little bit confused.
Frame ...
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3
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3
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Native VLAN on a router subinterface (RoAS)
I am aware of all the background information to native VLANs, just to repeat here that they are used for 'control traffic', that is CDP / VTP / PAgP / DTP.
On a router, sub-interfaces can be defined ...
- 99.6k
4
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2
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How does the switch analyse the EtherType field in Ethernet frame?
What exactly happens when switch receives the frame with given EtherType? Does it analyze it at all or only looks if the TPID is present?
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Sending Broadcasting Frames after sending Unicast Frames
Absolute newbie here guys,
I was reading the compTIA Network+ guide by Mike Meyers, and a section reads: "The frame propagates down the wire into the central box. The switch sends
unicast frames to ...
- 99.6k
4
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2
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Is there a way to detect how many switches are between a host and the router?
As switches don't decrease the IP TTL header field, I can't detect how many steps are between a host and the router by using tracert. Are there any ways to detect the number of switches between a host ...
- 99.6k
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3
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180
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Switching and MAC Address representation?
Since the destination and source MAC addresses in a frame in a LAN change, how does it know where to finish, as the destination is only the next hop?
And if there is a switch, which connects to hosts ...
- 99.6k
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1
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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?...
- 99.6k
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3
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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 ...
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631
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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 ...
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ping in the same VLAN with multiple switches in between
Refreshing VLAN knowledge with PT7.3, I came across some unexpected behavior.
Why does a chain of switches having proper trunk configuration between them DROP packets? Trying to ping hosts from the ...
- 99.6k
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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? ...
- 99.6k
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2
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Vlan vs. Subnet Broadcast Domain
It is my understanding that Vlans separate broadcast domains, but I often see people say, "subnets define a broadcast domain" as well.
Is it correct to say, "Vlans define a L2 broadcast domain, and ...
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2
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Difference between Giant Frame and Jumbo Frame
Can someone enlighten me the difference between Giant Frame and Jumbo Frame?
From what I hear, Giant frame is a frame with the size greater than 1518 Bytes excluding Preamble, Frame Delimiter and ...
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1
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99
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Unknown device mac address listed in switch table on start out
After playing a little bit with a topology randomly created in packet tracer, I figured out that the switch (Switch0) stores a unknown device mac address on start out, wich I think that it belongs to ...
CommunityBot
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What is the effect of having too many bridges / routers between 2 devices?
I am building a network, with each node connected to each other using fiber media converters. They are actually a bridge with 2 ports: one Ethernet and one optical (or one single-mode and one multi-...
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How would a bridge loop occur?
As I understand it, STP is used to prevent bridge (/switch) loops, which will typically occur in the case of redundant links on a switch.
But how can a loop occur and cause a broadcast storm?
If a ...
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4
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Accessing devices on different subnets using a switch
I have two devices which come up with default IP addresses:
Device 1 - 192.168.168.168 mask 255.255.255.0
Device 2 - 192.168.1.254 mask 255.255.255.0
I can commonly deduce that both the devices ...
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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 ...
- 99.6k
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Switch doesn't learn MAC of a connected device
I am new to networks. What does it mean when a switch doesn't learn the MAC address of the connected device? And how can VLANs can impact that?
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VLAN based subnets, where should I untag a VLAN?
I have attempted to search this problem but I don't really know how to explain it properly (possibly a sign I've taken on more project than I can handle).
Anyway I am currently working on chopping ...
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