Network switch loop

Spanning Tree Protocol (STP) is a Layer 2 network protocol used to prevent looping within a network topology. SW3(config-if)#spanning-tree guard loop. Feb 19, 2023 · Switch A. The root-bridge should be as close to the (logical) centre of the network as possible. The WAN port (port 0) and either of ports 1 TLDR: I've got a possible switch loop in my ER4/Unifi/TP-Link network architecture. The con is potential added latency or downtime as the network recalibrates after changes. Keep the connection of PC1 unchanged, connect PC2 to the F0/3 interface of switch S2026-A, and continue to ping packets between the two PCs. Loops might cause broadcast storms, which degrade network performance. b. A-B-C-A is a loop (ring). Often when you are working with switch configurations and you are plugging/unplugging a device, you should be careful that you don’t create a loop. Dec 25, 2023 · creating a cable connection between two VLANs on a switch can potentially lead to a loop in the network. 2 days ago · First, find out the related conversation using Filter (red arrow) in the MAC Conversation tab. Jul 21, 2014 · SW1. 03-02-2012 01:19 AM. Basically with 2 switches, if you connect 2 cables between those switches (without ling aggregation), then you have a loop. Apr 13, 2023 · Network RJ45 Tester, VXSCAN POE Ethernet Tester for Power Over Ethernet, Network Cable RJ45 Continuity Checking, DC Power, Switch Loop-Back Test 4. 1) Implement Spanning Tree PortFast and BPDUGuard on all edge ports. If you’re lucky you’ll get a MAC address or IP address which you can use in conjunction with Spiceworks inventory to hunt down the Ground Loop in networking is a condition created when two or more parts of a network are grounded at separate points, causing a voltage difference between connected networking components. Segment B. New comments cannot be posted and votes cannot be cast. Rapid Spanning Tree Protocol (RSTP) is an evolution of STP that speeds up responses to topology changes by designating roles to switch ports and proactively establishing alternative paths. Loop Statement to support SONET/SDH products/technologies up to 2040. Buy a managed switch and try it sometime. Are there tools or reporting/logging/alerting features in Unifi (USW-24-POE or Flex Mini) or ER4 to troubleshoot this sort of thing and provide pro-active alerting if I do something stupid to create a loop. If you need to know which circuit it is, turn off the main power supply. The model predicts that this transition exists, one from cell death or the cancerous phenotype directly to cell quiescence, due to the existence of miRNAs. In this scenario the closest deco wirelessy connects to the main deco and since all are on the switch . The value 16 is considered infinity and the A network switch (also called switching hub, bridging hub, Ethernet switch, and, by the IEEE, MAC bridge [1]) is networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device. Mar 11, 2023 · Link aggregation allows you to combine multiple Ethernet links into a single logical link between two networked devices. Scenario 1. In that case you will need Spanning Tree. Those switches are not stackable so I am using a gigabit Sep 10, 2018 · The switch can be a cord type or a standard wall switch. Sep 9, 2019 at 17:02. bedroomA→utility→bedroomB→bedroomA→…) In both situations, you can end up with all packets being sent in a loop forever, jamming the network completely. This works for professional switches, but not for those 5-port consumer switches. To prevent loops, it's essential to implement proper Spanning Tree Protocol (STP) configurations on the switch. 07-06-2008 11:46 AM. This prevents 90% of people from plugging things into them. It's normally impossible to get a bridging loop without another switch at the end of the connection unless you plug a cable from one port directly into another port on the same switch. I've tried to do some research to find out if toggling this on, would benefit our home network or degrade overall performance. On a network with switches connected together to form a packet forwarding loop, packets will circulate endlessly around the loop, building up to very high levels of traffic and causing an overload. Then there is is typically a grounding connection from the metal Mar 29, 2019 · It will detect loops automagically and block ports to break the loop. Now I am expanding the core with two C3560-CX (nwcore3 and nwcore4). Instead, plug one UniFi Network loops happen when you dont config the switches correctly and someone makes a loop. / \. 3af/at (Standard/Non-standard) Test Range Power: 0 Troubleshooting Switching Loops. MAC addresses can be obtained easily from the notices given in the Diagnosis tab: Figure 2. i have read about some solutions that may help stopping this happening again. The source interface receives the keepalive packet that it sent out, and the switch disables the interface The port on the Cisco switch is set as a trunk port. 2. I plug two ends of an Ethernet cable into the switch, which creates a broadcast storm and essentially DoSes the whole network. PC-3. Loopback Detection. Connect Multiple Ethernet Switches by Switch Stack Jun 1, 2015 · 0. A network switch is a networking device used to connect two or more devices within a local area network (LAN). Onsite engineers need to check network connections and remove redundant network cables or optical fibers. Through all these mechanisms, Allied Telesis switches keep your network safely loop- and storm-free without compromising service or reliability. Step 1. In the ABCA setup, a link connecting any two switches can fail without partitioning the network. Most Layer 2 issues are related to some kind of loop within the domain and this has multiple problems associated with it, including network downtime. 124) - (I've 4 MS60 ) When connected via CAT6 for ethernet backhaul, this causes severe wifi degradation and network loop/swarm to a point the wifi is inaccessible - this issue that cs4 reported in Jan this year! Aug 10, 2016 · Loop reboots switch. If there’s a loop you’ll see the same traffic being repeated from certain hosts. 100-day hassle-free returns. May 14, 2019 · Music used in Video by NCS Track: TonyZ - Road So Far ( Inspired By Alan Walker) Music provided by NoCopyrightSounds. You can use this feature to detect whether a loop has occurred. show log. I was able to "boot bootflash:ios" and get it to start fine. com/wat This example shows how to detect loops using the MAC move approach. Loop protection increases the efficiency of STP, RSTP, and MSTP by preventing ports from moving into a forwarding state that would result in a loop opening up in the network. If you have a loop, then the switch will see multiple paths to the same MAC address, and possibly multiple MAC addresses on multiple ports, so instead of the traffic being switched efficiently, it will be broadcast to wherever it sees the MACs. BPDUGuard should be enabled on access interfaces. The following figure illustrates a simple network. PC A--SW2-----SW3--PC B. A light switch loop wiring diagram is a visual representation of this wiring configuration, showing the connections and electrical components involved. You can use the following measures to eliminate loops: Physical connection errors may cause loops. Access to Access switch port - UTP Uplink 4. Reply. Jan 7, 2024 · Alternative ways to find network loops. Port 1 on both switches are configured as untagged for VLAN 2. Here's a simple network diagram that I drew up explaining our topology in case it helps: http If a switch receives a packet that it sent, a loop has occurred to the switch. Enjoy complete control over your volume when focusing, socializing and beyond with Loop Switch – 3 levels of manual sound control, 1 convenient earplug. Best Practices. What this indicates that the cable is not really looped, but there is a loopback line configured on the peer. Feb 1, 2021 · The problem is that the switch disables the main deco from connecting as it goes into loop protection mode. At this point the C switch would be isolated, losing the connection to the entire network. We have your standard 2-3 tvs running at any given time, game console at any given time, smart devices and roughly 6-9 cameres monitoring at any Mar 8, 2023 · QNAP unmanaged switch loop detection and blockingQNAP unmanaged switch features network loop detection. The bridge connection between B and C is activated by activating the switch C port. If a network loop is detected, it automatically locks Oct 6, 2017 · Rapid Spanning-Tree is the protocol to use. Slightly better switches has STP (Spanning Tree Protocol), which after configuring will keep this from happening, by cutting the loop at some point and turning it into a tree. Switch C is reconnected and communication is restored. This method involves running a single wire from the power source to the switch and then running another wire from the switch to the light fixture. The entire point of STP is so you can build redundant paths in the network. A "loop" is literally a loop, i. Someone under a desk and you make a mistake = issues. 1 pair, 3 volume settings. But why do they occur? In this What the Pros Know episode, Ronnie uses a simple topology to A very common way to create problems on a network is to build a loop, is to connect two switches to each other and then connect them to each other again, and watch the packets start circling between them as fast as they can go. Loopback Detection (LBD) is a feature on the switch that provides protection against loops by transmitting loop protocol packets out of ports where loop protection has been enabled. Network loops can slow down or stop normal traffic on your network. If the flow of traffic is not carefully monitored and controlled, the data can be caught in a In a simple reachability protocol, such as EGP, the routing loop will persist forever. Sometimes this can happen by accident when connecting cables without knowing the whole network topology. you can enable route guard to minimize the issue : Sep 25, 2012 · Look in several places around the network. 2) Verify that currently the proper switch is STP root for all VLANs. Apr 2, 2024 · Loop detection feature will not log ports blocked by STP. The purpose of Spanning Tree is to prevent loops in the LAN and to select the fastest network Jan 31, 2018 · The loop creates broadcast storms as broadcasts and multicasts are forwarded by switches out every port, the switch or switches will repeatedly rebroadcast the broadcast messages flooding the network. Yes, your network will come to a crawl unless spanning tree has been enabled. It was also found that the network involving miR-17-92 exhibits high noise sensitivity due to a positive feedback loop and also maintains resistance to noise from a negative feedback loop. A-B-C isn't a loop. Step 2. Avoid overutilizing the built-in switch ports on your UniFi Gateway. The loop protect feature can be enabled on all APs that have multiple Ethernet ports and it supports tunnel, split-tunnel, and bridge modes. Simply said UDLD is a layer 2 protocol that works like a keepalive mechanism. – grawity_u1686. Network loops can be damaging to network stability and difficult to troubleshoot. 4 out of 5 stars 407 1 offer from $40. Video Link: https://www. How It Works. 99 a. The danger is that, in a sufficiently complex network, switches with multiple inter-switch connections can create loop paths in the network. A typical light switch loop wiring diagram includes a light fixture, a switch, and a power source. The loop protection feature prevents the formation of loops when: An unmanaged switch is connected to one port of an AP and a loop forms in the unmanaged switch. A string (daisy chain) of devices isn't a loop. 5 out of 5 stars 70 1 offer from $39. Take note in the above scenario, Building A. Aug 8, 2016 · CISCO: Switch(config-if)#spanning-tree bpduguard enable JUNIPER: user@switch# set ethernet-switching-options bpdu-block interface ge-0/0/0. Jul 27, 2013 · Hi All, I have little confusion for loop avoidance in network. PC-4. Mar 2, 2012 · Level 7. Mar 4, 2012 · In a non-looped network, one MAC address will only be visible to the switch on a given physical port. Then pigtail all whites together. Jan 1, 2022 · If you have more complicated network needs, we recommend the D-Link DGS-1100-16V2 Easy Smart Managed Gigabit desktop switch, which features an approachable GUI management interface and a well But on many networks, unfortunately, the network administrators, for whatever reason, have decided not to use any type of Spanning Tree Protocol, and they will be susceptible to a switch loop. I have STP enabled, along with loop protect, root protect, TC protect, and others: To answer you question however, most switches will create a loop and bring the whole network down due to a broadcast storm. Apr 12, 2024 · 10 Methods How to Wire Switch Loop. Let's understand this example in detail. CPE Gig 6/0 164 R 7206VXR Gig 6/0. loopback err_disable (the port gets its own keepalive and err_disables the port) Oct 20, 2023 · Additionally, the switch has the Loop prevention feature which will turn off any port where there’s a network loop detected (you will also be alerted by the dedicated LED if there is a network loop detected). A network switch is a tool responsible for the Mar 18, 2014 · It may also depend on whether it is a temporary item (e. Jan 31, 2018 · The loop creates broadcast storms as broadcasts and multicasts are forwarded by switches out every port, the switch or switches will repeatedly rebroadcast the broadcast messages flooding the network. Jun 17, 2020 · 1. Shields grounded in main building (Building A) at a grounded shielded patch panel. 3. If it's a managed switch, you can set ports that aren't connected to other switches as edge ports which prevents delayed startup. One way to wire it is to add a (red) wire from the junction to the switch. Try flipping the switch to see if the light or outlet goes off. a) when you connect a switch to itself, or b) when you connect several switches in a circle/ring (e. Apr 29, 2015 · Here is an example how to see a loop: CPE#show cdp neigh. Oct 1, 2013 · Spanning tree is used to prevent loopbacks. Many people use STP to deal with the rare, accidental loop where Aug 8, 2022 · Step 2: The impact of network loops on cascade switches. So the frame goes to both SW1 and SW3. 1. Check your local codes. Hello, I recently got a switch online and it must have been a clean install or upgrade (not that thats a bad thing). Specifications: Item Name: Network Cable Tester Material: ABS Continuity Function: Cable Type: STP/UTP Maximum Testing Range: 600m Wire Mapping: Emitter + Remote, Emitter + Switch/Routor POE Function: Test Range: DC 5-60V PoE Switch Standard Identify: 802. Traffic flow goes to zero pretty quick. If possible get a 10/100Mbps hub, and put it in-line with the network, and connect the PC with WireShark to the hub (only 3 conections to the hub), which allows you to easily see the traffic, with no config changes to the network. And as they go by, more traffic gets on to the network, and more traffic starts looping. We transport voice to 10 GE: TDM-PDH Multi-services, transport SDH-SONET, PTN MPLS-TP, Carrier Ethernet, Ethernet Switch, Router, PseudoWire, fiber. 09-08-2021 12:49 PM. Spanning-tree protocol loop protection enhances the normal checks that spanning-tree protocols perform Mar 26, 2023 · Yes RING. In this scenario, no loop occurs and all access switches are much closer to the central switch. Click on Within a ring, each switch connects to adjacent switches on either side creating a ring or loop. Network switches operate at the data link layer (Layer 2) of the OSI (Open Systems Interconnection) model and is commonly used to forward data frames between devices in a local network, including computers, servers, printers, and other STP generates a loop-free logical topology by selectively blocking some paths based on factors like link speed and switch priority. When the switch sends out a loop protocol packet and then receives the same packet, it shuts down the port that received the packet. 4 Spice ups. This provides the benefit of adding redundancy as there are two paths to each switch but has the drawback of requiring a protocol such as Spanning Tree Protocol (STP) or Ethernet Protection Switching Rings (EPSR) to prevent broadcast storms from switch# show loop-protect Status and Counters - Loop Protection Information Transmit Interval : 5 (sec) Port Re-enable Timer : Disabled Loop Detected Trap : Disabled Interface 1/5/48 Loop-protect enabled : No Action on loop detection : TX disable Loop detected count : 1 Loop detected : Yes Detected on VLAN : 100 Detected at : 2023-03-20T00:01:17 Interface status : down Tx_port : VTEP_100. Dec 12, 2023 · 10 Easy Steps on How to Wire Switch Loop. Ideally, don't allow non-managed (actually meaning non-STP capable) switches on the premises. Core to distribution switch port - Fibre Uplink 2. Solved (kind of): The switch is going into "loop protection" and shutting down the ports that Google WiFi is connected to. The simplest way is to use “ Task Manager ” in any Windows Operating System. Aug 22, 2005 · Attached is a simple example drawing of scenario 1. jafo. a 5-port switch on someone's desk), or a permanent installation (something bolted to a wall). You could even wire it to a sensor if you wished. The UniFi switch is set to use DHCP to get its address, so the problem isn't with IP conflict. Turn Off the Power: Ensure your safety by turning off the power to the circuit you’ll be working on at the circuit breaker. The single pole switch loop method is one of the most common methods for wiring a light switch. For rackmount devices, they are typically grounded to the metal frame of the rack by being bolted to it. Jan 21, 2022 · Netgear Cable Modem -> MR-60 (v. A loop may occur in a topology with multiple switch. Distribuition to Access switch port- Fibre Uplink 3. This protocol is not part of the spanning tree toolkit, but it does help us to prevent loops. – Turdie. Next, Double-click the conversation to load all related packets and additional information. A device can loop the packets back to the source interface, which usually occurs because there is a logical loop in the network that the spanning tree has not blocked. A9K-BNG Gig 6/0 121 R ASR9K Ser Gig 0/0/0/0. c. Jul 6, 2008 · Level 10. Through the exchange of information, the cut between A and C is detected. PC A wants to communicate with PC B. broadcast storm control. To mitigate Dec 8, 2010 · The switch sends keepalives out all the interfaces by default. Hi. But sometimes sucha topology is actually wanted, once again to ensure high availability if a switch or port of a switch dies. I did a reset from rommon and It rebooted and said it was erasing. For some reason there is a bridging loop, STP is disabled or someone applied a filter in the wrong place or such. Switch#conf t Switch (config)#spanning-tree mode rapid-pvst. These features are only for detection purposes and do not protect the network from the broadcast storms. Switch between Quiet, Engage and Experience modes depending on your environment. The main pro is network stability and prevention of broadcast storms. Open your desktop, right click on the task bar and select “ Task Manager ” from the context menu and navigate to the “ Performance ” tab. In a naive distance-vector protocol, such as the routing information protocol, the loop will persist until the metrics for C reach infinity (the maximum number of routers that a packet can traverse in RIP is 15. Never enable it on trunks. Use a packet sniffer like Wireshark or Microsoft Network Monitor. The fans instantly go to full blast. Single Pole Switch Loop Method. I've been trying to configure 4 new switches to improve the core of the network. 1. show process cpu <-- flapping interfaces and/or bridging loops will also . We already had two C3650-48TS in stack as network core (nwcore2). Here are two case studies that highlight common network loop situations and the steps taken to resolve them: Scenario 1: Redundant Switch Connections Causing a Loop. Scenario Description: In a medium-sized office network, two access switches were connected to each other using multiple Ethernet cables for redundancy. Loops seriously affect the network performance and even cause service exceptions, so loops need to be eliminated immediately. Dec 3, 2010 · Prior to bringing the redundant link/switch back online, implement Layer 2 safeguards designed to protect against STP loops and mitigate the impact if one does occur. STP helps identify and block redundant paths in the network, preventing loops from forming. 2 HP2524 switches are connected with two cables, from port 1 on switch A to port 1 on switch B, and from port 2 on switch A to port 2 on switch B. In this network, a destination network 1. Fortunately, there are several steps you can take to prevent network loops. A network switch is a multiport network bridge that uses MAC addresses to forward data Jan 9, 2020 · 01-09-2020 03:00 PM. It then started bootlooping and I had to control C to get it to stop it's loop. Yes, if you enable BPDUGuard on all user ports. Now choose which switch will be the root-bridge. Access sw Aug 24, 2023 · A data network switch loop is a situation in which two or more switches are connected in a way that creates a loop in the network, causing broadcast storms and other problems. youtube. Connect black from breaker to black from switch. To add some redundancy, a second switch can be added between the two original network segments, as shown in Figure 5-3. Our protection features help prevent loops from occurring. In most circuits there are three cables, a live, a neutral and an earth. However, due to a RSTP is enabled by default on all switch ports. There is no 'magic bullet' to fix a loop. lendeamer7575 (afeitguy) October 1, 2013, 6:20pm 4. To check for a loop in your network, check the The graphic to the right shows three switches, which are connected in a loop. May 22, 2020 · #Looping #KnowledgeModulationWhile working as a Network Engineer you may face many issues and among one of them is looping between switches, it disconnects y May 17, 2018 · 00:00 Intro01:33 Schematics on how a switch loop works08:24 Layout in detail08:46 OutroFor those of us that are more visual learners, I've made this show one Sep 9, 2019 · 1. send a packet down the link (by fx setting an ip address on the vlan and then try to ping something) Can Unifi protect the network from a loop that is on a non-managed switch that is plugged in a Unifi switch? Archived post. Network administrators can effectively monitor traffic via Port Mirroring, Loop Prevention and Cable Diagnostics features. 1d standard. 0/8 is directly connected to router C on its F0/0 interface. 0 shutdown If there are unmanaged switches on your network that you would like to keep but protect STP and prevent loops you could enable a feature called root guard. The patch panel should be a shielded patch panel if one is used. The port on the UniFi switch is set to allow all VLANs (Assuming that's what they call a trunk port). When your network has a loop, the switch is connected to itself and network traffic is looping and growing continuously instead of reaching its destination and stopping. 6. Obtaining more information on a Routing Loop problem. Depending on whether the receiving interface is the same as the sending interface, loops fall into the following type: The TL SG108E 8 Port Gigabit Easy Smart switch is an ideal upgrade from an unmanaged switch, designed for Small and Medium Business networks that require simple network management. Once the root port and designated ports are selected, the switch blocks all remaining ports to remove any possible loop from the network. 0. Depending on the switch technology, you can look into something like BDPU Guard (Cisco) to help prevent loopbacks. Complete network outages; Device crashes due to traffic overload; These consequences could be network-wide, or concentrated to specific segments of the network. Note: The switch has an internal power supply. Jun 15, 2023 · The Spanning Tree protocol is a networking standard, as defined by the IEEE in the 802. Jul 16, 2022 · Loop detection is an always-on feature of your switch that helps you identify and remove loops on your network. 4. Aug 18, 2013 · last week we had a network outage because someone looped a unmanaged switch port to port. Event log reporting is dependent on the available CPU cycle of the switch. 08-10-2016 03:51 AM - edited ‎03-08-2019 06:56 AM. in this case you see 2 neighbors, myself and the remote device. Found this by logging into switch and doing: "telnet localhost" (yes, on the switch), "enable", then "show tech-support". Jul 31, 2015 · One of the solutions to create a stable network, instead of using wireless, is through the use of structured cabling and network Ethernet switches. There is a Loop Prevention switch on the back that I can toggle on or off. 124) -> Netgear Switch GS108 -> MS60 (v. The other protocol we can use to deal with unidirectional link failures is called UDLD (UniDirectional Link Detection). Log in to the two switches to check the CPU utilization. Port 2 on both switches are configured as untagged for VLAN 3. 2 A prevention loop on an Ethernet switch, often called Spanning Tree Protocol (STP), stops network loops which can cause broadcasts to endlessly circulate, clogging the network. I have a TP Link managed switch that I have enabled STP in, but it's not detecting a loop in the network, and brings the entire lan down. Switch loops due to different ports connected to each other in access level - which causes loops and traffic interruption. STP operations Thanks to STP's automated configuration mentioned above, network communication can occur without worrying about any loops causing disruptions. 2 ports on my phone - plug both in = issues. If there is a loop it is expected to see both loop detection and MAC flap detection logs. I want to know that which commands I should configure on switch ports for 1. (at this stage we cannot remove the unmanaged switches) 1. You will see CPU, Memory and Network utilizations. The easiest way to form a L2 loop is to turn off spanning-tree and then connect a cable into two ports in the same switch. The connect red from switch to black to light. e. The power source, usually a circuit breaker panel, provides the electrical current to the circuit. •. STP was created to avoid the problems that arise when computers exchange data on a local area network ( LAN) that contains redundant paths. Next, we make sure switches are behind locked doors. Loop Telecom designs, develops, and manufactures hardware and software for the telecommunications industry. Aug 22, 2013 · steveirvine7443 (stephenjirvine) August 22, 2013, 6:47am 4. These voltage differences typically occur because of nonuniformities in the electrical characteristics of the grounding at different locations. Vinoth, Things you may want to first look into is access switch logs and core switches logs if any, look for flapping interfaces specially if you have dual uplink connections to a dual core switches, go over these links bellow. Nov 24, 2020 · When connecting Gigabit switches through star topology, a powerful switch (such as 40G switch) often acts as the core, which then connects to the access switches (such as 10G switches). Oct 19, 2020 · Switching loops often occur when working with multiple switches. Switches, of course, determine where traffic goes based on the destination MAC address that’s within a frame. With 3 switches A,B and C, and a single cable between A-B, one between A-C and one between B-C you also have a loop. In the case of the switch loop these cables arrive at the light fitting. Sep 8, 2021 · what are the causes of switch loops & how to troubleshoot it. d. It first ARPs for the MAC of PC B, the destination is a broadcast with MAC ffff. ffff. Routing loops example. In the switch you cap off the white and connect black an red to be switched. Jun 23, 2017 · เมื่อในระบบ #network มีการต่อ switch/hub หลายๆตัว ต้องระมัดระวังเรื่อง #loop ด้วยนะ Understanding Loop Protection for Spanning-Tree Instance Interfaces. Did this at the direction of tech support. Sep 3, 2020 · The loop test function of the switch. Network Apr 29, 2020 · 2 Answers. Now two switches offer the transparent bridging function in parallel. g. Link aggregation is sometimes called by other names: The most common device combinations involve connecting a switch to another switch, a server, a network attached storage (NAS) device, or a multi-port access point. A bridging loop or spanning-tree loop caused a network outage. The main factor in a switch loop is that two cables will become live. Convenient and comfortable. 47 Eliminating Loops. 5 Spice ups. Consider what will happen when PC-1 sends a frame to PC-4. Linksys LGS116P 16-Port Ethernet Switch Aug 24, 2020 · NOYAFA NF-488 POE Tester for Power Over Ethernet, Network Cable Continuity Checking, Switch Loop-Back POE Detector 4. As soon as I disable loop protection on the switch they all work normally and report they are all connected by enternet. On a physical level, we put tape over unused ports. Again, please note the strategic use of shielded or unshielded patch cords to avoid a ground loop. Jan 11, 2024 · When a packet for the destination C arrives, it will loop endlessly between routers: A and B. xz yg qb sr qf sp pb wd nk vo