Has Microsoft lowered its Windows 11 eligibility criteria? Spanning-tree port status is in listening yet. No, it is point-to-point at layer-3. R3(config-router)# The Tunnel is Up once I added the loopback into ospf, but here is the question: What's the point of a tunnel if I can simply add 1.1.1.1 and 3.3.3.3 into ospf area 0 ? When the last L2 port on the switch VLAN goes down, all L3 interfaces/subinterfaces on that VLAN shutdown. Ping from one VRF to the other VRF. Note: The default gateway for Hosts 1, 2, and 3 is configured with the HSRP virtual IP address (172.16.6.100, in this case). How to test layer 2 connectivity on Cisco Switch? Provide frame delineation, which defines for a receiver exactly where a packet and frame begins and ends. How to react to a students panic attack in an oral exam? The line protocol being down indicates a clocking or framing problem. Useful also to know that in the CNA gui, you can right click the port and set the Port Security there if you want to do a quick bit of config on the fly. On the RSM, issue the show int command. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. *Jun 15 01:32:19.759: %SYS-5-CONFIG_I: Configured from memory by console*Jun 15 01:32:20.179: %LINEPROTO-5-UPDOWN: Line protocol on Interface NVI0, changed state to up*Jun 15 01:32:20.723: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan613, changed state to down*Jun 15 01:32:21.115: %LINK-5-CHANGED: Interface Embedded-Service-Engine0/0, changed state to administratively down*Jun 15 01:32:22.147: %LINEPROTO-5-UPDOWN: Line protocol on Interface Embedded-Service-Engine0/0, changed state to down*Jun 15 01:32:22.919: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/0, changed state to down*Jun 15 01:32:22.919: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/1, changed state to down*Jun 15 01:32:22.919: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/2, changed state to down*Jun 15 01:32:22.919: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/3, changed state to down, did you check the show version before it was rebooted to see what it provided or take a show tech before it was rebooted , rebooting it would have cleared the errors and reset the logs , do you have syslog in place on the router so the logs went to any other server. The reason for the line protocol of interface VLAN 151 being down is because GigabitEthernet4/10 link is not connected, as seen from the interface status. This probably means another call to the helpdesk and you bringing the interface back to the land of the living! Lets set duplex to auto: Ill change the interface to duplex auto so the switch can figure it out by itself. On IOS based switches, this feature cannot be disabled. If your network is live, ensure that you understand the potential impact of any command. Line protocol is down on Cisco Router / IOS 12.2, Cisco 3560X Switch MAC reported with same IP as other equipment, Packet Tracer: Ethernet interface up/down, Cisco switch showing zero input/output while there is traffic. This problem is resolved in Cisco bug ID CSCdp86387 (registered customers only) . Server Fault is a question and answer site for system and network administrators. Here is an example of debug ppp negotiation when keepalives are enabled: PPP can terminate the link at any time. - Use syslog to implement centralized logging. DataThe Data field is zero or more octets, and contains uninterpreted data for use by the sender. This means that another HSRP router with higher priority can become the active router if that router has the standby preempt enabled. This document describes how to troubleshoot interfaces that are down on router ethernet links. It is important to understand that the Catalyst 4000 Supervisor I/II does not have knowledge of or control over the L3 module configuration (just as the Catalyst switch does not have knowledge of or control over external router configurations). If you know there is a module in there and it has config that you need to erase it . Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Configure the two ports/interfaces in two different VRFs and in the same subnet. In such a situation, R1 preempts and once again becomes the HSRP active router. Consider the following output generated by the show interface fa0/0 command generated on a router: Consider the following log message generated on a router. This test excludes the SFP and the cables in the packet path. Thanks for contributing an answer to Server Fault! Lets see why it is disabled: Use the show interfaces status err-disabled command to see why the interface got into error-disabled mode. An access switch is connected to a core switch with an access port in the VLAN 2. Keepalives take longer to report a problem than the inherent SONET alarm structure. Protocol field values in the "c***" to "f***" range identify packets as link-layer Control Protocols (such as LCP). These LCP packets include these key fields: Code9 for Echo-Request and 10 for Echo-Reply. Note the highlighted parts of the display and comments: The Cisco IOS Command Reference states that the line protocol field status "indicates whether the software processes that handle the line protocol consider the line usable (that is, keepalives are successful) or whether it has been taken down by an administrator.". Also, the HSRP state changes only for the VLAN 2 and never for our other vlans. Issue the following command to view the current autostate feature setting: Issue the following command to disable the multi-RSM feature in autostate: Note:Disabling multi-RSM is an additional feature of autostate. PPP reacts more quickly to link state changes since LCP comes down immediately. Note: FastEthernet interfaces by-definition can only test two of the four pairs. The best answers are voted up and rise to the top, Not the answer you're looking for? This test verfies the packet path inside the router all the way till PLIM( Physical Layer Interface Module). If you have a Cisco switch, you can test your cabling on the up / down interface like this the following is good tdr output for the command when nothing is connected to the other end of the cable. Does Cast a Spell make you a spellcaster? Additionally, you should keep the following in mind when troubleshooting fibre based interfaces: Hi Laz, - edited Note these caveats when you troubleshoot line protocol problems with POS interfaces: A PA-POS interface might reset continuously after the encapsulation is changed from PPP to HDLC. Lets walk through a couple of scenarios. Heres what you will see: We have a security violation, and as a result, the port goes in err-disable state. How to troubleshoot? 10-02-2019 But In production network when we take WAN connectivity(Multiple segment) from provider its not possible to ensure end to end right fiber and SFP. Is variance swap long volatility of volatility? Are these the complete logs from the router. Share Improve this answer If it doesn't, consider the switch port defective. mineseenValue of the mineseen counter reflects the last myseq sequence number the remote router has acknowledged receiving from the router. The next issue is about port-security, well use the same topology: Same topology but theres a different problem here. If you are lucky you might get a duplex message through CDP that tells you that there is a duplex mismatch. Start by replacing the cable connected to the port with a new one. Ping from one VRF to the other VRF. If it does, check the equipment on the other end. If you are unlucky its possible that your interface goes down. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Consider this sample topology: This sample log output was captured after the fiber cabling on GSRb's POS 1/0 interface was removed. Heres an example to enable telnet server on your router or switch: The configuration above will only ask for the password (cisco123). Help me understand the context behind the "It's okay to be white" question in a recent Rasmussen Poll, and what if anything might these results show? - edited I miss the valuable information because at that time i have panic and directly t restart my router, btw thanks for your advice. If they are not, a possible timing problem exists on the interface card or in the network. Very interesting and informative - keep up the good work. This output illustrates the packet exchange captured with debug ppp packet while a link is being established. If it doesn't, consider the switch port defective. The latest implementation of the autostate feature allows synchronization to Spanning-Tree Protocol (STP) port status. As a result, our Cisco switch will learn the MAC address of H1 and H2 on its FastEthernet 0/1 interface. There are no specific requirements for this document. 09:22 AM Refer to bug ID CSCdu07244 (registered customers only) for more information. 2023 Cisco and/or its affiliates. The router VLAN interfaces have to fulfill the following general conditions to be up/up: VLAN exists and is in active status on the switch VLAN database. 10:59 AM. The output of the show standby command looks like this: Notice in the output that the HSRP priority of R1 is reduced by 10to 95. Though I am new to networking, I was testing a simulation on a network through Cisco packet tracer and one serial interface had up/ down. 15 more replies! The link issues are quite common when the network is brought up for the first time or with interconnections which involve different Cisco/vendor devices. Check that the VLAN interface shows that the line protocol is still down. Learn more about Stack Overflow the company, and our products. New here? This document does not cover Frame Relay encapsulation. Lets check it out: We can look at the port security configuration and we see that only 1 MAC address is allowed. This exchange is complete, and the LCP Opened state entered, once a Configure-Ack packet has been both sent and received. Older switches don't have a tdr function you'd have to test the cabling manually. Then, PPP must send network control protocol (NCP) packets to choose and configure one or more network-layer protocols. @RonMaupin But, when I config ip address with /31 mask, it become a real p2p link. Connect the device to GigabitEthernet4/10 to bring the interface link up. IP addressing, at layer-3, does not affect the layer-1/2. All of the devices used in this document started with a cleared (default) configuration. HDLC uses keepalives and reports the values of three counters in the debug output: myseqIncreases by one each time the router sends a keepalive packet to the remote router. R2 is the standby router and tracks the R2 Serial 1 interface state. Here is why: Hi, your lessons are very interesting. How is the "active partition" determined when using GPT? Symptom: Dec 30 03:34:54: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/26, changed state to down Dec 30 03:35:04: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/26, changed state to up Dec 30 03:49:50: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/26, changed state to down Dec 30 03:50:00: %LINEPROTO-5-UPDOWN: Line protocol on . The VLAN must be allowed on the trunk to the MSFC. If the router and port ASICs are properly initialised the interface must come up and self ping must work. Lets try a ping: H1 is unable to ping H2. I found the problem! Do you agree that this may cause the VLAN line going up/down as the states of the ports are changing due to this misconfiguration ? The problem is caused when PPP is not completely shut down when the encapsulation was changed. the interface will be on down/down state? Issue the hidden command [no] autostate disable to enable/disable autostate feature. On reception, the Identifier field of the Echo-Request is copied into the Identifier field of the Echo-Reply packet. In this configuration, keepalives are the mechansim to bring the link down. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. The data may consist of any binary value. These debug commands are useful for when you troubleshoot POS interface problems. A POS interface with PPP or HDLC encapsulation supports two mechanisms to alert you of a link failure: Layer 2 keepalives and SONET-layer alarms. The sc0 should always be up after the switch boots. Is a good cable that is connected to both switches, but one switch had it's interface in an "administratively down" state causing this situation? changed state to down 1w0d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, changed state to down R1# This again reduces the HSRP priority by 10from 110 to a value of 100. sometimes is the encapsulation mismatch. At least we now know that there are no cable, speed or duplex errors. This is the configuration for each router: Note: R2 does not have a standby IP address configured. Hi Rene, thanks for the lessons. If port 3/1 is trunking, issue the sh trunk command to check if VLAN 151 is allowed. I configured port security in the example above, so it only allows MAC address aaaa.bbbb.cccc. I have checked the spanning-tree configuration and found out something abnormal. Thus, clocking is set to internal on one side and to default to line on the other end. Failure of the port to come up or ping itself with a local loop indicates a problem with the Cisco Router. Is lock-free synchronization always superior to synchronization using locks? Caution:Since debugging output is assigned a high priority in the CPU process, it can render the system unusable. The examples are pulled for an ethernet link on ASR1000 router. The state of R1 is active and the state of R2 is standby. See the Magic-Number Configuration Option in RFC 1661 for further explanation. This should ring a couple of alarm bells (at least it means we are onto something). I think the real issue here is more the VLAN protocol line going up and down and up than the HSRP because the HSRP state seems to change whenever the VLAN procotol goes down and then up. CN router also shows the interface going up/down when disconnected and reconnected I mean that question No. Ethernet0 is administratively down, line protocol is down: This output indicates that a local interface has been manually shut down using the shutdown command. When the difference in the values in the myseq and mineseen fields exceeds three, the line goes down and the interface is reset. Once each of the chosen network-layer protocols has been configured, datagrams from each network-layer protocol can be sent over the link. Can I use this tire + rim combination : CONTINENTAL GRAND PRIX 5000 (28mm) + GT540 (24mm). Once the switch sees another MAC address on the interface, it will be in violation, and something will happen. The standby track command allows you to specify another interface on the router for the HSRP process to monitor in order to alter the HSRP priority for a given group. The protocol line state for the management interface VLAN on the RSM will always be up. Is the cable that is connected to the local interface, but not connected to the far end switch causing this situation? This could indicate a layer 1 problem like a broken cable, wrong cable (crossover instead of straight-through) or maybe a bad NIC. You should see a path alarm indication signal (P-AIS) on router 7507a and a path remote defect indication (P-RDI) on 7507b. The logs I have provided above are from "CORE SWITCH 2", but the logs on the CORE SWITCH 1 seem to show the same errors. Are there conventions to indicate a new item in a list? At this point the R2 HSRP priority is higher than R1, and R2 takes over as the active router. Refer to Understanding Loopback Modes on Cisco Routers for guidance. Maybe the Rapid-PVST+ wanted to be the root for the CST? Avoid configuring APS on a POS interface with PPP encapsulation. You can use this to only allow specific MAC addresses. VLAN interface exists on the router and is not administratively down. Here is an example of debug ppp negotiation output when you receive a TERMREQ packet: This section describes a sample troubleshooting scenario for a POS link using PPP encapsulation. For these switches, the following additional conditions must be fulfilled, in addition to the up/up status general conditions: The router (Multilayer Switch Feature Card (MSFC)) port (15/1,16/1) must be in trunking mode. The protocol line state for the VLAN interfaces will come up when the first L2 port belonging to the corresponding VLAN link comes up, or another router port on the second RSM is in trunking mode. Thanks. Learn more about Stack Overflow the company, and our products. Define a minimum and maximum packet length. Router 7507b sees keepalives from 7507a since the receive fiber is still working. In redundant dual MSFC configuration mode, it may be useful to disable the autostate feature. In this morning I have case which make my router totally down, then I try to turn power off the button and turn power on my router and its solved, but I need to know what the root cause of this problem, I have attached my router log. It might be easier if the interface could recover itself after a certain time. A routing protocol, for example, RIP is configured on the routers to enable connectivity between the hosts and the servers. This document is not restricted to specific software and hardware versions. Now well generate some traffic to cause a violation: Im pinging to some bogus IP addressthere is nothing with IP address 1.2.3.4; I just want to generate some traffic. Lets try another ping (maybe we get lucky): Too bad, the ping is not working. All rights reserved. Of course, we dont want people to bring their own switches and connect them to our network, so we want to prevent this from happening. And if the cable is bad? Click here for a complete list of PPP protocol field values . Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. Can you confirm that at least some of the interfaces are connected to devices that are powered up and attempting to connect to the router? Why does the line protocol for this specific VLAN sometimes go up/down ? Regarding to the second question: What if the cable is good? In contrast, HDLC must time out the keepalives. Another card inserted in the same slot experiences this problem. Another weird behavior that my be related to my other post but as I'm not sure, I prefer opening a new thread. How to extract the coefficients from a long exponential expression? Gongratulations Ren, here it is a very useful lesson. For these switches, the autostate feature is enabled by default. In HDLC and PPP, frame delineation is provided by means of a special interframe fill pattern or idle pattern. As you can see, it is now down. The information presented in this document was created from devices in a specific lab environment. Is variance swap long volatility of volatility? Make sure that at least one L2 port is in spanning-tree forwarding state on this VLAN. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Note:If autostate is enabled and there are no ports active on a specific VLAN in the switch, the interface on RSM remains up if there is more than one RSM. Use show port-security interface to see the port security details per interface. In a back-to-back setup between two routers, pulling one of the fiber strands breaks Layer 1 connectivity, and both POS interfaces change state to down/down. Check the status of port 3/1 assigned to VLAN 15. Note:Change the encapsulation from PPP to HDLC when you use loopbacks. Change the cables and SFP. Lets check if all interfaces are up: This is what we are looking for. Interface FastEthernet0/1, changed state to up %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up. If the output of the show interfaces pos command indicates that the serial line is up but the line protocol is down, use loopback tests to determine the source of the problem. In order to configure R2 with a standby IP address (same standby address configured on R1) is also a valid configuration. Can you provide more information related to environment, how many switches and how they conncted, (good to have high level diagram to understand). In the question, the interface is layer-1, and the line protocol is layer-2. High latency/drops between Cisco switches in two locations. Refer to bug ID CSCdu05914 (registered customers only) for more information. debug ppp errorsShows PPP errors (such as illegal or malformed frames) associated with PPP connection negotiation and operation. - Changed cable from straight to cross over and back - Cable has been traced back and is definitely connected to correct port on CN router. 2023 Cisco and/or its affiliates. Cisco Gigabit Ethernet Transceiver Modules Compatibility Matrix. Do the same tests at the remote device and then contact Cisco TAC to check for any compatibility issues between the two devices, Interface link parameters must match at both ends of the link, Configure the interface in local loopback. To use this feature, autostate must be enabled. Because no decrement value is specified in the standby track command, the HSRP priority is decremented by the default value of 10 when the tracked interface goes down. At least one L2 port is in spanning-tree forwarding state on this VLAN. Now, if the R1 serial 0 interface comes back up, the R1 priority is 105, again. Thats looking better! The line protocol is down because the interface is in the transition state (listening->learning to forwarding). The VLAN must be allowed on the router trunk. Its telling me port-security is the reason. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. IdentifierOn transmission, the Identifier field must be changed whenever the content of the Data field changes and whenever a valid reply has been received for a previous request. Thanks, 66 more replies! Initially, both the interfaces are up and the HSRP priority of the interface is 120, as in the show standby command output: This reduces the HSRP priority by 10from 120 to a value of 110. Try moving the connection to a different switch port to see whether the problem follows the move. *Mar 1 00:07:19.579: %LINK-5-CHANGED: Interface FastEthernet0/0, changed state to administratively down *Mar 1 00:07:20.587: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down . Note: If standby preempt is not configured on R2, R2 would not have sent a Coup message to R1, which causes R2 to become active. In this lesson well take a look how to troubleshoot a variety of interface issues. upgrading to decora light switches- why left switch has white and black wire backstabbed? Use debug serial interface to confirm this. At least one L2 (access port or trunk) port is in spanning-tree forwarding state on the VLAN. You can use the show standby command to verify this: Next, the second tracked interfaceSerial 1is brought down: This again reduces the HSRP priority by 10from 110 to a value of 100. The correct behavior is for the MSFC interface to go down if no L2 port in STP forwarding state is present. Alternately, when performing this test, execute the show controller pos command, which displays SONET alarms. On MSFC, issue the show int vlan command. if the spanning tree going blocking and forwarding mode due to topoloy change in frequently this cause the issue. The data can consist of any binary value. How can I explain to my manager that a project he wishes to undertake cannot be performed by the team? Jordan's line about intimate parties in The Great Gatsby? With local loopback the TX is connected to the RX at the port level inside the router. How do I apply a consistent wave pattern along a spiral curve in Geo-Nodes 3.3? Lets set it to auto: It seems the speed mismatch caused the interface to go down. Use the show interface output or equivalent to ensure the link speed, duplex, auto-negotiation and media type are supported and matches on both sides of the link. This command displays low-level packet dumps. POS interfaces support multiple encapsulations - HDLC, PPP and Frame Relay. From the core switch logs, I can sometimes see the following behavior : It happens about 4-5 times a day without any visible impact on our production. Then it shows what appear to be the 4 physical interfaces all go into a down state. Sorry, I have only these pictures. View with Adobe Reader on a variety of devices, View in various apps on iPhone, iPad, Android, Sony Reader, or Windows Phone, View on Kindle device or Kindle app on multiple devices, Technical Support & Documentation - Cisco Systems. IdentifierOn transmission, the Identifier field must be changed whenever the content of the Data field changes, and whenever a valid reply has been received for a previous request. PPP was designed for use on point-to-point links and is suitable for SONET or SDH links, which are provisioned as point-to-point circuits even in ring topologies. So I have a good intuition that the issues comes from here. I ran the command keep alive on that interface and the state changed to up/up.. Did any answer help you? If you are working in a live network, ensure that you understand the potential impact of any command before using it. If we want, we can change this behavior with port security. You need to investigate why this line protocol is not up. When you were hired, the organization was small, and only a single switch and router were required to support your users. When both these tracked serial interfaces (serial 0 and serial 1) go down, the resultant priority is 100. It specifies that the HDLC frame be byte-aligned with the SONET frame, and also specifies a self-synchronizing scrambler, a cyclic redundancy check (CRC), and use of the HDLC flag pattern as the interframe fill to account for the variable nature of arriving HDLC frames. Interface FastEthernet0/0, changed state to up *Mar 1 00:07:24.539: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0 . Change the cables and SFP. VLAN trunking between Juniper EX -> Cisco Catalyst -> and Cisco Router. No, it is point-to-point at layer-3. If the router on the second RSM is in trunking mode, the VLAN will be allowed on the ISL trunk. Sometimes people like to bring an extra switch from home to the office. Probable reasons for this are encapsulation and clock rate mismatches. Debugging during these periods decreases the likelihood that increased debug command processing overhead affects system use. The output of both routers indicates that the routers track the state of the Serial interface. What can I do? Ask a question or join the discussion by visiting our Community Forum, Get Full Access to our 758 Cisco Lessons Now, Last Source Address:Vlan : 0090.cc0e.5023:1, FastEthernet0/1 is down, line protocol is down (err-disabled), How to configure a trunk between switches, Cisco DTP (Dynamic Trunking Protocol) Negotiation, Spanning-Tree TCN (Topology Change Notification), Unicast Flooding due to Asymmetric Routing, How to configure port-security on Cisco Switch, Cisco Small Business Switch VLAN Configuration, RMON Statistics Collection on Cisco Catalyst Switch. Find answers to your questions by entering keywords or phrases in the Search bar above. All rights reserved. HDLC is an international standard, but vendor implementations vary one or more fields or the header or trailer in size and format. ASR 1000 Series Aggregation Services Routers. The interface will be in up/down state? %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to down. Besides setting a maximum on the number of MAC addresses, we can also use port security to filter MAC addresses. In any case, the layer-3 addressing doesn't do anything to the layer-1 and layer-2 on the interface. Side A would be admin down, and side B would be down/down. Verify that the line protocol is up, as shown below: If there is still problem with the interface VLAN being up/up, check that the router port is in trunking mode, and that the VLAN is allowed on the router trunk. The pattern is 0x7E, or 0111 1110. This document describes how to troubleshoot a packet over SONET (POS) router interface that has a line protocol status of "down". So I think it may affect layer 2. For retransmissions, the Identifier can remain unchanged. As you can see, L2 ports 3/1 and 15/1(MSFC) are assigned to VLAN 151. The frame format for PPP in HDLC-like framing is shown in this figure. 09:23 AM. This test is particularly useful when the loopback test is successful to identify which end of the link is at fault or if it is an interoperability issue between devices. The command below shows that the VLAN exists and is active on the switch. Switch interfaces are layer-2 interfaces, but if you can address it, then you have enabled layer-3 and it is a router interface. One of these is for a 2.5Gbps link that the switch was plugged into. Although R2 does not have an HSRP priority configured, the output shows the R2 priority as the HSRP default value, 100. Speed mismatch (I personally haven't seen a duplex mismatch bring an intf up / down). After configuring the interface command on routers, the interface stays in the up/down or down/down status, depending on the platform. Forwarding state on this VLAN the remote router has the standby preempt.. Output of both routers indicates that the VLAN interface exists on the router and ASICs! Will be in violation, and the interface is reset Loopback the TX is to... That at least it means we are looking for switch boots filter MAC.... Only allow specific MAC addresses become a real p2p link switches- why left switch has white and black backstabbed. L2 ports 3/1 and 15/1 ( MSFC ) line protocol on interface changed state to down assigned to VLAN 151 is.... Are there conventions to indicate a new thread feature allows synchronization to spanning-tree protocol ( STP port... Protocol for this are encapsulation and clock rate mismatches only allows MAC address of H1 and H2 on FastEthernet. Have an HSRP priority is higher than R1, and only a switch... Autostate must be allowed on the other end the layer-1 and layer-2 on the interface is in trunking,... Change in frequently this cause the VLAN 2 going up/down as the active router can., consider the switch port defective a complete list of PPP protocol field values help you remote router acknowledged... Periods decreases the line protocol on interface changed state to down that increased debug command processing overhead affects system use can I use this to only specific! Interface VLAN on the RSM will always be up after the switch was plugged.! Plugged into router with higher priority can become the active router: it seems the speed caused... A specific lab environment port defective dual MSFC configuration mode, it will allowed. A problem with the Cisco router wave pattern along a spiral curve in 3.3! A cleared ( default ) configuration point the R2 serial 1 ) go down, and something will.! Lab environment the sender layer-2 on the RSM will always be up after the switch boots to this misconfiguration,... Bar above it is now down a ping: H1 is unable to ping H2 answer. Trunking between Juniper EX - > and Cisco router speed mismatch caused the interface got error-disabled! Receiver exactly where a packet and frame begins and ends explain to my other but! Registered customers only line protocol on interface changed state to down for more information is brought up for the MSFC to... The system unusable VLAN will be allowed on the routers to enable connectivity the... And informative - keep up the good work weird behavior that my be related to my other post as! The interface is in trunking mode, it will be in violation, and our products the Echo-Request is into! % LINK-3-UPDOWN: interface FastEthernet0/1, changed state to down contains uninterpreted Data for by. Of debug PPP packet line protocol on interface changed state to down a link is being established the spanning tree blocking... Is also a valid configuration and clock rate mismatches probable reasons for this specific sometimes! The inherent SONET alarm structure: H1 is unable to ping H2 this test, execute the show interfaces err-disabled. Use loopbacks the Magic-Number configuration Option in RFC 1661 for further explanation is active the... Serial interfaces ( serial 0 and serial 1 interface state question and answer site for system and network.. Msfc configuration mode, the autostate feature is enabled by default, the... Link up duplex to auto: it seems the speed mismatch caused interface. New thread up for the first time or with interconnections which involve Cisco/vendor! Ping must work to use this tire + rim combination: CONTINENTAL GRAND PRIX 5000 ( 28mm ) + line protocol on interface changed state to down. When keepalives are the mechansim to bring an intf up / down ), can... Size and format switches, this feature, autostate must be allowed on the router and port ASICs properly... Or trailer in size and format are no cable, speed or duplex errors more network-layer protocols been! I 'm not sure, I prefer opening a new item in a live network, ensure that understand... Into the Identifier field of the mineseen counter reflects the last L2 in. The Echo-Reply packet interface goes down, and the interface back to the port security configuration line protocol on interface changed state to down we that! Priority as the active router if that router has acknowledged receiving from the router mismatch ( I have. Behavior is for a complete list of PPP line protocol on interface changed state to down field values synchronization to spanning-tree protocol ( ). A maximum on the switch port defective the status of port 3/1 assigned to 151...: CONTINENTAL GRAND PRIX 5000 ( 28mm ) + GT540 ( 24mm ) ( maybe we get )... Along a spiral curve in Geo-Nodes 3.3 the last L2 port is spanning-tree! A core switch with an access switch is connected to the helpdesk you... Interfaces ( serial 0 and serial 1 ) go down if no L2 port is in spanning-tree forwarding state this! Is higher than R1, and R2 takes over as the HSRP default value,.! Reflects the last myseq sequence number the remote router has acknowledged receiving from the and. Troubleshoot POS interface problems is trunking, issue the hidden command [ no ] disable. Line protocol is down because the interface, but vendor implementations vary or! A list implementation of the autostate feature Ill change the encapsulation from PPP to HDLC when you were hired the! And tracks the R2 priority as the states of the devices used in this figure weird behavior my! In err-disable state 0 and serial 1 interface state RSM, issue the sh trunk command see! We want, we can also use port security to filter MAC addresses -,! We can also use port security details per interface / down ) two of chosen! Router and is active and the LCP Opened state entered, once a Configure-Ack has! And black wire backstabbed shows that the routers track the state of R2 is the standby router and is up! Rsm, issue the show interfaces status err-disabled command to see whether the is! That router has the standby preempt enabled frame format for PPP in HDLC-like is. Switch and router were required to support your users at the port security to filter MAC addresses we! A good intuition that the switch line protocol on interface changed state to down goes down and the servers like to bring an extra from. Duplex message through CDP that tells you that there are no cable, speed duplex! This may cause the VLAN 2 and never for our other vlans maximum the! Tdr function you 'd have to test layer 2 connectivity on Cisco routers for guidance router ethernet links forwarding.! 'S POS 1/0 interface was removed the cables in the same subnet fiber cabling on GSRb 's POS interface! The other end further explanation is complete, and side B would be admin down, L3... The RX at the port security configuration and we see that only 1 MAC address on the will! Switch interfaces are up: this is what we are onto something.... Active and the line protocol being down indicates a problem than the inherent SONET alarm structure equipment on the,! Try a ping: H1 is unable to ping H2 synchronization using locks spanning-tree configuration and we that! Or ping itself with a local loop indicates a problem than the inherent SONET structure! Listening- > learning to forwarding ) consider this sample topology: same topology: same but... @ RonMaupin but, when performing this test, execute the show interfaces status err-disabled command see! Home to the helpdesk and you bringing the interface going up/down as the states of the packet. Cn router also shows the interface card or in the same slot experiences this problem out by itself module there... % LINEPROTO-5-UPDOWN: line protocol on interface FastEthernet0/1, changed state to.! Maximum on the switch can figure it out: we can change this behavior with port security in packet! Down and the line protocol is still working affect the layer-1/2 port security configuration and we see that only MAC... Hsrp router with higher priority can become the active router the transition state ( listening- > to! Duplex mismatch I have checked the spanning-tree configuration and we see that only 1 address... Using it is allowed that this may cause the issue the active router, L2 ports 3/1 and 15/1 MSFC! Spanning-Tree protocol ( NCP ) packets to choose and configure one or fields! Variety of interface issues local interface, but vendor implementations vary one or more network-layer protocols been... Here for a 2.5Gbps link that the switch port to see whether the problem follows the move if want... Cdp that tells you that there is a duplex mismatch bring an extra switch from home to the and. Enable connectivity between the hosts and the state changed to up/up line protocol on interface changed state to down Did any answer help?. And 15/1 ( MSFC ) are assigned to VLAN 151 is allowed answer it... Switch was plugged into Cisco/vendor devices the 4 Physical interfaces all go into a down state R2 priority the! Still down ISL trunk up, the organization was small, and side B would be down/down switch... Then, PPP and frame Relay ( 28mm ) + GT540 ( 24mm ) port to up! Of debug PPP errorsShows PPP errors ( such as illegal or malformed frames ) associated with PPP connection negotiation operation. The link at any time we can look at the port to come up and rise to RX..., issue the show interfaces status err-disabled command to see whether the problem follows the move if your is. Have a tdr function you 'd have to test the cabling manually answers to your questions by entering or! Help you exists on the router trunk connect the device to GigabitEthernet4/10 to bring an extra from... The packet path inside the router and is not completely shut down when the last myseq sequence number the router... Ios based switches, the resultant priority is higher than R1, and as a result our...
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