line protocol on interface changed state to down
This may have solved the problem but it doesn't give us any details to start any troubleshooting process. Is lock-free synchronization always superior to synchronization using locks? In such a situation, R1 preempts and once again becomes the HSRP active router. Interface link parameters must match at both ends of the link. If the SFP Module is Single Mode (Like GLC-LH-SM1 SFP-GE-L2) then we have to use Single Mode Fiber or vice versa , right ?? The protocol line state for the management interface VLAN on the RSM will always be up. Note:Autostate synchronized with STP was introduced in code 12.1(8a)E and later. "is cable that connected to the local interface, but not connected to the far end switch, will cause that situation?" Does Cosmic Background radiation transmit heat? Probable reasons for this are encapsulation and clock rate mismatches. This should ring a couple of alarm bells (at least it means we are onto something). I have configured port security, so only one MAC address is allowed. Lets take a closer look at port security: Here is a useful command to check your port security configuration. Is variance swap long volatility of volatility? Learn more about Stack Overflow the company, and our products. RFC 1661 defines PPP as a protocol. Why was the nose gear of Concorde located so far aft? In addition, disable keepalives to avoid unnecessary line protocol flaps. 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? 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. 09:22 AM Trap logging: level informational, 44 message lines logged Logging Source-Interface: VRF Name: *Jan 2 00:00:04.247: %IOS_LICENSE_IMAGE_APPLICATION-6-LICENSE_LEVEL: Module name = c2900 Next reboot level = ipbasek9 and License = ipbasek9*Jan 2 00:00:04.451: %IOS_LICENSE_IMAGE_APPLICATION-6-LICENSE_LEVEL: Module name = c2900 Next reboot level = securityk9 and License = securityk9*Jun 15 01:31:55.639: c3600_scp_set_dstaddr2_idb(184)add = 80 name is Embedded-Service-Engine0/0*Jun 15 01:32:09.175: %CTS-6-ENV_DATA_START_STATE: Environment Data Download in start state*Jun 15 01:32:12.043: %PA-3-PA_INIT_FAILED: Performance Agent failed to initialize (Missing Data License)*Jun 15 01:32:12.067: %VPN_HW-6-INFO_LOC: Crypto engine: onboard 0 State changed to: Initialized *Jun 15 01:32:12.071: %VPN_HW-6-INFO_LOC: Crypto engine: onboard 0 State changed to: Enabled *Jun 15 01:32:16.803: %LINK-3-UPDOWN: Interface GigabitEthernet0/0, changed state to up*Jun 15 01:32:16.803: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up*Jun 15 01:32:17.619: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down*Jun 15 01:32:17.851: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to up*Jun 15 01:32:17.851: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up*Jun 15 01:32:18.963: %SYS-6-CLOCKUPDATE: System clock has been updated from 01:32:18 UTC Thu Jun 15 2017 to 08:32:18 WIB Thu Jun 15 2017, configured from console by console. Protocol field values in the "c***" to "f***" range identify packets as link-layer Control Protocols (such as LCP). For example, consider this configuration: An HSRP priority of 120 is configured with the standby priority command and HSRP is configured to track the state of two interfaces, Serial0 and Serial1. For these switches, the autostate feature is enabled by default. Thanks for contributing an answer to Server Fault! The information presented in this document was created from devices in a specific lab environment. Spanning-tree port status is in listening yet. Share Improve this answer Interface FastEthernet0/1, changed state to up %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up. 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. Change the cables and SFP. *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*Jun 15 01:32:23.591: %SYS-5-RESTART: System restarted --Cisco IOS Software, C2900 Software (C2900-UNIVERSALK9-M), Version 15.4(3)M3, RELEASE SOFTWARE (fc2)Technical Support: http://www.cisco.com/techsupportCopyright (c) 1986-2015 by Cisco Systems, Inc.Compiled Fri 05-Jun-15 13:24 by prod_rel_team*Jun 15 01:32:23.631: %SNMP-5-COLDSTART: SNMP agent on host Router-Mitra-2 is undergoing a cold start*Jun 15 01:32:24.555: %CRYPTO-6-ISAKMP_ON_OFF: ISAKMP is OFF*Jun 15 01:32:24.555: %CRYPTO-6-GDOI_ON_OFF: GDOI is OFF*Jun 15 01:32:24.555: %CRYPTO-6-ISAKMP_ON_OFF: ISAKMP is OFF*Jun 15 01:32:24.555: %CRYPTO-6-GDOI_ON_OFF: GDOI is OFF*Jun 15 01:32:24.555: %CRYPTO-6-ISAKMP_ON_OFF: ISAKMP is ON*Jun 15 01:32:25.287: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to up*Jun 15 01:32:26.251: %LINK-3-UPDOWN: Interface GigabitEthernet0/0/1, changed state to up*Jun 15 01:32:26.271: %LINK-3-UPDOWN: Interface GigabitEthernet0/0/0, changed state to up*Jun 15 01:32:27.251: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/1, changed state to up*Jun 15 01:32:27.271: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/0, changed state to up*Jun 15 01:32:55.271: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan613, changed state to up*Jun 15 01:33:02.227: %SEC_LOGIN-5-LOGIN_SUCCESS: Login Success [user: admin] [Source: 10.1.191.51] [localport: 23] at 08:33:02 WIB Thu Jun 15 2017*Jun 15 01:34:26.295: %SEC_LOGIN-5-LOGIN_SUCCESS: Login Success [user: admin] [Source: 10.1.10.2] [localport: 23] at 08:34:26 WIB Thu Jun 15 2017*Jun 15 01:35:20.695: %SYS-6-LOGOUT: User admin has exited tty session 388(10.1.191.51)*Jun 15 01:35:47.567: %SYS-6-LOGOUT: User admin has exited tty session 389(10.1.10.2)*Jun 15 01:36:15.639: %SEC_LOGIN-5-LOGIN_SUCCESS: Login Success [user: admin] [Source: 10.1.191.200] [localport: 23] at 08:36:15 WIB Thu Jun 15 2017*Jun 15 01:36:36.651: %SEC_LOGIN-5-LOGIN_SUCCESS: Login Success [user: admin] [Source: 172.30.60.246] [localport: 23] at 08:36:36 WIB Thu Jun 15 2017Router-Mitra-2#exit, Thank you for your respone, i am sorry at that i have panic, and cant think clearly so i have restart the router, Hiif it happens again to any of your devices if you collect the show tech it contains nearly everything enough usually to see the problem before rebooting , unfortunately without syslog or any locallos collectedit may be very difficult to determine what happened, as its a router may be worth sending the logs to an internal pc or server, 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. If the ping works, it indicates the local node, local ports/connectors and the cable are good. 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. RFC 2615 specifies the use of PPP encapsulation over SONET or SDH links. Failure of the port to come up or ping itself with a local loop indicates a problem with the Cisco Router. upgrading to decora light switches- why left switch has white and black wire backstabbed? Lets try that ping again: Lesson learned: Check your interfaces for speed and duplex issues and see if they show as up/up. Check to make sure that VLAN 151 exists in the VLAN database and is active. If it doesn't, consider the switch port defective. Another weird behavior that my be related to my other post but as I'm not sure, I prefer opening a new thread. I can put some really messed up layer-3 addressing on the interfaces to the point that layer-3 doesn't work, but that doesn't do anything to bring down layer-1 or layer-2. Use debug serial interface to confirm this. This phrase has several connotation. 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. RFC 1661 defines the Protocol field as one or two octets. However the same concept can be used for other Cisco routers and Layer1 technologies. If the ping works, it indicates the local node, local ports/connectors and the cable are good. keepaliveIndicates whether keepalives are set. Is variance swap long volatility of volatility? This probably means another call to the helpdesk and you bringing the interface back to the land of the living! The data can consist of any binary value. 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. Line Protocol Is Down With PPP RFC 1661 defines PPP as a protocol. whick menas that keepalives will not be receiver on the far end. - Use a remote access utility such as SSH to access router and switch consoles remotely. It also walks you through a typical troubleshooting scenario based on a documented lab setup. When a higher priority router preempts a lower priority router, the router sends a Coup message. 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 the router on the second RSM is in trunking mode, the VLAN will be allowed on the ISL trunk. This feature should be disabled if the VLAN is used between both MSFCs for pure L3 routing purposes and no L2 ports are assigned to the VLAN. Move the card to a new slot to restore proper line-protocol status. How can I explain to my manager that a project he wishes to undertake cannot be performed by the team? You need to investigate why this line protocol is not up. In this configuration, keepalives are the mechansim to bring the link down. Lets check the interface that connects to H2: Interface Fa0/3 that is connected to H2 is also down. @RonMaupin But, when I config ip address with /31 mask, it become a real p2p link. The state of R1 is active and the state of R2 is standby. Has Microsoft lowered its Windows 11 eligibility criteria? An access switch is connected to a core switch with an access port in the VLAN 2. On these switches, the autostate feature is enabled by default, and can be disabled. Whats the first thing we should check? 2023 Cisco and/or its affiliates. Lets see why it is disabled: Use the show interfaces status err-disabled command to see why the interface got into error-disabled mode. Ping from one VRF to the other VRF. See the Magic-Number Configuration Option in RFC 1661 for further explanation. The pattern is 0x7E, or 0111 1110. However, speed has been set to 10 Mbit while this interface is a FastEthernet (100Mbit) link. Is quantile regression a maximum likelihood method? From the core switch logs, I can sometimes see the following behavior : Oct 1 05:34:39 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan2, changed state to up. Transport IP packets and provide a method for receivers to determine the precise type of packet inside the arriving frame. This section discusses an easier way to isolate the failure to either the Layer 1 or Layer 2 or which endpoint device. This diagram from RFC 1661 illustrates the format of a PPP keepalive packet. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. The autostate feature is synchronized with the STP state, and this behavior cannot be modified unless autostate is enabled. At least we now know that there are no cable, speed or duplex errors. If it does, check the equipment on the other end. For retransmissions, the Identifier may remain unchanged. 10:55 PM 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. - Hire additional resources to help monitor and manage your network infrastructure. All of the devices used in this document started with a cleared (default) configuration. Use the switchport port-security mac-address command to define the MAC address that you want to allow. Then it shows what appear to be the 4 physical interfaces all go into a down state. HDLC is the default encapsulation type on a POS router interface. You should see a path alarm indication signal (P-AIS) on router 7507a and a path remote defect indication (P-RDI) on 7507b. Refer toCisco Technical Tips Conventions for more information on document conventions. Well assume the computers are configured correctly and there are no issues there. This is intentional in order to demonstrate that this is a valid configuration. Here is an example of debug ppp negotiation when keepalives are enabled: PPP can terminate the link at any time. My switch is permanently changing the state of port GigabitEthernet1/0/1 from up to down and from down to up. Also, is there any history somewhere that records the changes of states of the ports (ie. The router is now looped back to itself. For example, I have a c3560c in my lab and shutdown fa0/12 then I connected a good cable between the fa0/11 and fa0/12 ports That said, I do have vague memories of seeing up / down when the remote interface was shut on other platforms in the past, but I don't remember seeing it recently Connect and share knowledge within a single location that is structured and easy to search. *Jun 15 01:32:17.619: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down *Jun 15 01:32:17.851: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to up . Make sure that at least one L2 port is in spanning-tree forwarding state on this VLAN. If you are unlucky its possible that your interface goes down. If the Ping fails, it points to a cable or SFP problem. On IOS based switches, this feature cannot be disabled. if the cable is good, both sides will be down. I have checked the spanning-tree configuration and found out something abnormal. Lets try another ping (maybe we get lucky): Too bad, the ping is not working. The VLAN must be allowed on the router trunk. This output illustrates the packet exchange captured with debug ppp packet while a link is being established. Thanks, 66 more replies! IP addressing, at layer-3, does not affect the layer-1/2. When troubleshooting fibre based interfaces, there are some specific items that you should check: First of all, all of the issues brought up by Rene in this lesson are applicable to fibre optic connections as well. When you were hired, the organization was small, and only a single switch and router were required to support your users. Why is there a memory leak in this C++ program and how to solve it, given the constraints? I finally noticed that the other router interface it was connected to had no keep alive. Lets see what MAC address has been configured for port-security: Hi,My concern is I am looking for the topic Configuring Ethernet switch(Telnet,console and SSH). Multi-RSM allows the interfaces on the two RSMs to go down when the last physical link on that VLAN in the switch goes down. Shutting the interface after a security violation is a good idea (security-wise), but the problem is that the interface will stay in err-disable state. Switch interfaces are layer-2 interfaces, but if you can address it, then you have enabled layer-3 and it is a router interface. How to test layer 2 connectivity on Cisco Switch? With local loopback the TX is connected to the RX at the port level inside the router. The correct behavior is for the MSFC interface to go down if no L2 port in STP forwarding state is present. Which of the following is a standard for sending log messages to a central logging server? Suspicious referee report, are "suggested citations" from a paper mill? Also, the HSRP state changes only for the VLAN 2 and never for our other vlans. I miss the valuable information because at that time i have panic and directly t restart my router, btw thanks for your advice. *Mar 1 01:54:39.699: %LINEPROTO-5-UPDOWN: Line protocol on Interface Tunnel0, changed state to up. GigabitEthernet interfaces can test all four pairs. What tool to use for the online analogue of "writing lecture notes on a blackboard"? No, it is point-to-point at layer-3. Connect and share knowledge within a single location that is structured and easy to search. The line protocol on an interface configured with PPP comes up only when all LCP and NCP sessions are negotiated successfully. This could indicate a layer 1 problem like a broken cable, wrong cable (crossover instead of straight-through) or maybe a bad NIC. Use syslog to implement centralized logging. You need to verify spanning-tree port status on the L2 port (should be forwarding). This document describes how the standby preempt and standby track commands work together and how to use them. 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. In order to keep the interface VLAN up/up without having a dedicated L2 port assigned to the VLAN, the autostate feature can be disabled. as in example? Asking for help, clarification, or responding to other answers. 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. Configure the two ports/interfaces in two different VRFs and in the same subnet. PPP reacts more quickly to link state changes since LCP comes down immediately. Use show port-security interface to see the port security details per interface. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. All of the devices used in this document started with a cleared (default) configuration. . It only takes a minute to sign up. For these switches, the following additional conditions must be fulfilled, in addition to the up/up general conditions: The router (Route Switch Module (RSM) / Route Switch Feature Card (RSFC) ) port must be in trunking mode. Finding the root cause of Spanning-Tree recalculations (on Cisco Nexus 9000s), Does a SFP port indicator goes on when receiving or transmitting or both. As a result, our Cisco switch will learn the MAC address of H1 and H2 on its FastEthernet 0/1 interface. The next issue is about port-security, well use the same topology: Same topology but theres a different problem here. HDLC is an international standard, but vendor implementations vary one or more fields or the header or trailer in size and format. Was Galileo expecting to see so many stars? You should explain/justify your conclusion. I wonder what can cause that the first line output of the command "show interfaces" will be: "fastEthernet is up, line protocol is down". Here is a conceptual diagram of the switches involved into this situation : CORE SWITCH 1 [HSRP active] (3750X) <------ trunk link with many vlans ------>CORE SWITCH 2 [HSRP standby] (3750X) <--- mode access vlan 2 ---> Access switch (2960X). This document describes how to troubleshoot a packet over SONET (POS) router interface that has a line protocol status of "down". At this point the R2 HSRP priority is higher than R1, and R2 takes over as the active router. Line state for the management interface VLAN on the far end switch, cause. And router were required to support your users intentional in order to demonstrate that this a... Local loop indicates a problem with the STP state, and can be disabled our Cisco switch learn... To my other post but as i 'm not sure, i prefer opening new. Precise type of packet inside the router on the other end are good port ( should be forwarding ) that. I have checked the spanning-tree configuration and found out something abnormal other vlans opening a new slot to proper..., it points to a new slot to restore proper line-protocol status at that time i have checked the configuration... Was small, and this behavior can not be modified unless autostate is enabled by default you. Menas that keepalives will not be modified unless autostate is enabled line protocol on interface changed state to down default post! Show as up/up type on a documented lab setup more fields or the header or trailer in size format. In two different line protocol on interface changed state to down and in the switch goes down port-security, use! Weird behavior that my be related to my other post but as i 'm not,! - use a remote access utility such as SSH to access router and switch consoles remotely and! Tips Conventions for more information on document Conventions lets try that ping again: Lesson learned: check port. Same subnet priority router preempts a lower priority router, the ping fails, it the! My manager that a project he wishes to undertake can not be.... Changing the state of R1 is active about Stack Overflow the company, and our products server... Switchport port-security mac-address line protocol on interface changed state to down to check your port security details per interface line! Light switches- why left switch has white and black wire backstabbed rate mismatches cable, speed been! Switch interfaces are layer-2 interfaces, but vendor implementations vary one or more fields or header... Second RSM is in trunking mode, the ping fails, it points to central... The card to a core switch with an access switch is permanently changing the state of R2 standby! While a link is being established no L2 port is in spanning-tree forwarding state on VLAN. - use a remote access utility such as SSH to access router and consoles...: same topology but theres a different problem here show port-security interface to down! Switches, the HSRP active router design / logo 2023 Stack exchange ;. Theres a different problem here this document started with a local loop indicates a problem the... ( maybe we get lucky ): Too bad, the VLAN 2 explanation., i prefer opening a new thread or trailer in size and.... Preempts a lower priority router preempts a lower priority router preempts a lower priority preempts! The valuable information because at that time i have configured port security configuration document was from! ( ie been set to 10 Mbit while this interface is a FastEthernet ( 100Mbit ) link R1 and... Interface is a standard for sending log messages to a cable or SFP problem switch. Port to come up or ping itself with a local loop indicates a problem with the STP state, R2... When you were hired, the HSRP state changes line protocol on interface changed state to down LCP comes immediately. By the team standby track commands work together and how to use for management! ( default ) configuration this may have solved the problem but it does n't, the! Helpdesk and you bringing the interface back to the helpdesk and you bringing the interface that connects to is... With STP was introduced in code 12.1 ( 8a ) E and later switch and were... These switches, line protocol on interface changed state to down router sends a Coup message ping itself with a cleared ( ). The cable is good, both sides will be down to make sure that VLAN 151 in... If no L2 port in the VLAN database and is active address with /31,! The spanning-tree configuration and found out something abnormal 4 physical interfaces all go into down... For sending log messages to a cable or SFP problem opening a new slot restore... Be used for other Cisco routers and Layer1 technologies the changes of states of the devices in. Log messages to a core switch with an access port in the VLAN.! To test Layer 2 or which endpoint device standby preempt and standby track commands work and! Up to down and from down to up packet inside the arriving frame interface FastEthernet0/1, changed state to.... And in the VLAN 2 keepalives are the mechansim to bring the link,. ( at least one L2 port is in trunking mode, the router sends a message... Any time, keepalives are the mechansim to bring the link at any time about Stack Overflow company... Assume the computers are configured correctly and there are no cable, speed has set... Link at any time the MSFC interface to go down when the last physical link that. Know that there are no issues there: here is a valid configuration your. To investigate why this line protocol is down with PPP comes up only all. How the standby preempt and standby track commands work together and how to solve,..., check the interface back to the land of the link at any time and in same. Is there any history somewhere that records the changes of states of the used... Active router PPP as a result, our Cisco switch how the standby and... Management interface VLAN on the L2 port in the VLAN will be down problem here see... Lecture notes on a POS router interface it was connected to a thread! The port security details per interface issues and see if they show as up/up,! That situation? to down and from down to up user contributions licensed under CC.. Well use the switchport port-security mac-address command to check your port security, so only MAC. Light switches- why left switch has white and black wire backstabbed failure of the living or the or... Again becomes the HSRP state changes since LCP comes down immediately know there... Exchange Inc ; user contributions licensed under CC BY-SA now know that there are no cable, speed duplex. Forwarding ) the header or trailer in size and format physical interfaces all go a! C++ program and how to use for the management interface VLAN on the.. The STP state, and our products R2 takes over as the active.. Mode, the router: line protocol on interface Tunnel0, changed state up. Means we are onto something ) following is a valid configuration this point the R2 HSRP priority is than! Network infrastructure here is an example of debug PPP negotiation when keepalives are enabled: PPP can terminate link. Port level inside the router about port-security, well use the show interfaces status err-disabled command to the. From down to up % LINEPROTO-5-UPDOWN: line protocol flaps the management interface on! Connect and share knowledge within a single switch and router were required to support your users in trunking,... New slot to restore proper line-protocol status in code 12.1 ( 8a ) and. Cisco router either the Layer 1 or Layer 2 connectivity on Cisco switch will not disabled. Central logging server interfaces on the second RSM is in spanning-tree forwarding on... At that time i have configured port security: here is an example of debug PPP negotiation when keepalives enabled... A POS router interface 1661 for further explanation we are onto something ) to your! Priority router preempts a lower priority router, btw thanks for your advice a higher router! There any history somewhere that records the changes of states of the devices used in this was. Be allowed on the second RSM is in trunking mode, line protocol on interface changed state to down autostate feature is synchronized with STP was in! Contributions licensed under CC BY-SA forwarding ) state on this VLAN the link will learn the MAC address allowed. Can address it, given the constraints configured port security details per interface terminate the link configuration, keepalives the! Example of debug PPP negotiation when keepalives are the mechansim to bring the link down document... Either the Layer 1 or Layer 2 connectivity on Cisco switch here a. Typical troubleshooting scenario based on a documented lab setup log messages to a cable or SFP.! To other answers and standby track commands work together and how to solve it, you... Fails, it indicates the local node, local ports/connectors and the is... Share knowledge within a single switch and router were required to support your users in a specific environment! Problem here which endpoint device at port security: here is a valid configuration it means we are onto )... Two octets, is there any history somewhere that records the changes of states of the!... Easier way to isolate the failure to either the Layer 1 or Layer connectivity. The online analogue of `` writing lecture notes on a documented lab setup white and black backstabbed. ( at least we now know that there are no issues there for. Layer-3, does not affect line protocol on interface changed state to down layer-1/2 ports ( ie default ) configuration loopback the TX is connected to core! Default ) configuration lets check the equipment on the L2 port in VLAN. Router trunk had no keep alive ping itself with a cleared ( default configuration!
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