How is the "active partition" determined when using GPT? Instead R1 would have remained the active router. Is variance swap long volatility of volatility? - Changed cable from straight to cross over and back - Cable has been traced back and is definitely connected to correct port on CN router. - Consolidate network resources down to one or two switches. Use show port-security interface to see the port security details per interface. Now, if the R1 serial 0 interface comes back up, the R1 priority is 105, again. The protocol line state for the VLAN interfaces will come up when the first L2 port (non-router port, that is, not 15/1 or 16/1) belonging to the corresponding VLAN link comes up and is in spanning-treeforwarding state. Hi Rene, thanks for the lessons. Note: Time stamp difference between logs when the line protocol on GigabitEthernet4/10 went up, . 06-14-2017 Cisco Switch Out-Of-Box without console access, How to configure a Cisco Catalyst 2960 to synchronize with an NTP server, Add non-flex switch to existing switch stack, Unplug of Netgear Switch Causes Cisco Link Drop on Remote Switch, Is email scraping still a thing for spammers. After verifying cables and connectors we can check duplex and speed errors. 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. When one side is unplugged, both LEDs go green. Troubleshoot. PPP and HDLC are closely related and share these characteristics: Provide a framing structure with headers and trailers. Lets check it out: We can look at the port security configuration and we see that only 1 MAC address is allowed. Planned Maintenance scheduled March 2nd, 2023 at 01:00 AM UTC (March 1st, admin state Vs link state from a network engineer stand point, Cisco Catalyst cluster heartbeat switch issue - increasing input errors. Lastly, both routers are configured with the standby preempt command. 2. this could me while spanning-tree convergence time. Lets check if all interfaces are up: This is what we are looking for. Learn more about how Cisco is using Inclusive Language. This will prevent routing protocols and other features from using the VLAN interface as if it were fully operational. Why is there a memory leak in this C++ program and how to solve it, given the constraints? If it does, check the equipment on the other end. The autostate feature is not synchronized with the STP state. In the question, the interface is layer-1, and the line protocol is layer-2. For retransmissions, the Identifier can remain unchanged. 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. Move the card to a new slot to restore proper line-protocol status. The last MAC address seen on the interface is 000c.2928.5c6c. As well as helping to identify that the line protocol is down, it explains the show and debug commands to use to troubleshoot the issue for both Point-to-Point Protocol (PPP) and high-level data link control (HDLC) encapsulation. Connect the device to GigabitEthernet4/10 to bring the interface link up. 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. At least one L2 (access port or trunk) port is in spanning-tree forwarding state on the VLAN. Changing it to auto-speed brings back the interface to the land of the living. If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. RFC 1661 defines the Protocol field as one or two octets. The line protocol on an interface configured with PPP comes up only when all LCP and NCP sessions are negotiated successfully. 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. 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. 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. Autostate Configuration on Catalyst Switches, Catalyst 6000 Native IOS / Catalyst 4000 Cisco IOS (Supervisor III and IV) / Catalyst 3550, Catalyst 6000 Hybrid Running CatOS with MSFC card (SUP IA, SUP II, MSFC, MSFC 2), Catalyst 4000 (Supervisor I and II) with Layer 3 Modules, Troubleshooting the Autostate Feature on IOS Based Switches, Troubleshooting the Autostate Feature on CatOS Based Switches, Understanding and Configuring Spanning-Tree Protocol (STP) on Catalyst Switches, Technical Support & Documentation - Cisco Systems. In each case, a higher value is of greater priority. Configure the two ports/interfaces in two different VRFs and in the same subnet. Regarding to the second question: What if the cable is good? So I think it may affect layer 2. Interface FastEthernet0/1, changed state to up %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up. This means that another HSRP router with higher priority can become the active router if that router has the standby preempt enabled. This is the symptom of a VLAN interface on the MSFC being down/down. If the Ping fails, it points to a cable or SFP problem. The router is now looped back to itself. With local loopback the TX is connected to the RX at the port level inside the router. On these switches, the autostate feature is enabled by default, and can be disabled. You can use the show standby command to verify this: When any one of the tracked serial interfaces (either serial 0 or serial 1) go down, the resultant priority is 110. In HDLC and PPP, frame delineation is provided by means of a special interframe fill pattern or idle pattern. On some CatOS platforms, this feature can be disabled in order to allow redundancy in special scenarios. Is lock-free synchronization always superior to synchronization using locks? 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. These debug commands are useful for when you troubleshoot POS interface problems. 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. 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. Make sure by checking the switch, as shown below. Sometimes people like to bring an extra switch from home to the office. Router 7507b sees keepalives from 7507a since the receive fiber is still working. Are these the complete logs from the router. Try moving the connection to a different switch port to see whether the problem follows the move. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. debug ppp packetShows PPP packets being sent and received. 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. More information about the function and output of each of these commands is provided in the Cisco Debug Command Reference publications: debug serial interfaceVerifies whether HDLC keepalive packets are incrementing. 2023 Cisco and/or its affiliates. In contrast, HDLC must time out the keepalives. IP addressing, at layer-3, does not affect the layer-1/2. Asking for help, clarification, or responding to other answers. Priority is determined first by the configured priority value, and then by the IP address. Thats looking better! Why does the line protocol for this specific VLAN sometimes go up/down ? Line protocol on Interface GigabitEthernet1/0/1, changed state to down, The open-source game engine youve been waiting for: Godot (Ep. - edited 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. What can I do? Switch interfaces are layer-2 interfaces, but if you can address it, then you have enabled layer-3 and it is a router interface. If you are unlucky its possible that your interface goes down. The trailer provides error checking. Magic-NumberThe Magic-Number field is four octets, and aids in the detection of links which are in the looped-back condition. Autostate is implemented on CatOS and IOS Cisco based switches by default. Once each of the chosen network-layer protocols has been configured, datagrams from each network-layer protocol can be sent over the link. When you finish using a debug command, remember to disable it with its specific no debug command or with the no debug all command. Heres an example for the console and SSH: Configuring Cisco router for the first time. 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. Sorry, I have only these pictures. I wonder what can cause the first line output of the command show interfaces to be: FastEthernet is up, line protocol is down. 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. LCP Echo-Request and Echo-Reply packets provide a Layer 2 loopback mechanism for both directions of the link. Until the Magic-Number Configuration Option is successfully negotiated, the Magic-Number must be transmitted as zero. 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. On reception of an Echo-Request in the LCP Opened state, an Echo-Reply must be transmitted. Server Fault is a question and answer site for system and network administrators. For example, on switch interface configure an IP address 192.0.2.0/31 and on server interface configure 192.0.2.1/24. As a result, our Cisco switch will learn the MAC address of H1 and H2 on its FastEthernet 0/1 interface. On MSFC, issue the show int vlan command. Perform a local loop test first, and then a remote test. Making statements based on opinion; back them up with references or personal experience. For this reason, use debug commands only to troubleshoot specific problems or during troubleshooting sessions with Cisco technical support staff. Line protocol on Interface Vlan changed state to up. Also note the changes in open shortest path first (OSPF) adjacency states. This could indicate a layer 1 problem like a broken cable, wrong cable (crossover instead of straight-through) or maybe a bad NIC. One of these is for a 2.5Gbps link that the switch was plugged into. In such a situation, R1 preempts and once again becomes the HSRP active router. To sugget better, we would like to see your configuraiton and topology ? Thanks. Since the only port (3/1) is diabled, !--- the line protocol for interface VLAN 151 is down. 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. The data can consist of any binary value. Well assume the computers are configured correctly and there are no issues there. Learn more about Stack Overflow the company, and our products. The correct behavior is for the MSFC interface to go down if no L2 port in STP forwarding state is present. However, when two router POS interfaces connect across a Telco cloud with SONET/SDH equipment, Layer 1 loss information is not propagated to the remote end. Is the set of rational points of an (almost) simple algebraic group simple? A POS interface configured for automatic protection switching (APS) brings down the line protocol if the interface is the protect channel and not the working channel. Note the changes in line protocol status on both interfaces when the APS switchover occurs. There are no specific requirements for this document. 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.". This may have solved the problem but it doesn't give us any details to start any troubleshooting process. 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. Very interesting and informative - keep up the good work. Connect and share knowledge within a single location that is structured and easy to search. The autostate feature is synchronized with the STP state. FWD to BLK) ? However the same concept can be used for other Cisco routers and Layer1 technologies. PPP reacts more quickly to link state changes since LCP comes down immediately. 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. How to react to a students panic attack in an oral exam? The value in this field identifies the datagram encapsulated in the Information field of the packet. For these switches, the autostate feature is enabled by default. @RonMaupin But, when I config ip address with /31 mask, it become a real p2p link. Note:Time stamp difference between logs when the line protocol on GigabitEthernet4/10 went up, and Interface Vlan151 is around 30 seconds, which represents 2xforwarding delay in STP (listening->learning->forwarding). In this example we have a switch in the middle and two computers that are connected to it. This is intentional in order to demonstrate that this is a valid configuration. *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. VLAN interface exists on the router and is not administratively down. mineseenValue of the mineseen counter reflects the last myseq sequence number the remote router has acknowledged receiving from the 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. So I have a good intuition that the issues comes from here. All rights reserved. This phrase has several connotation. If the Ping fails, it points to a cable or SFP problem. The correct behavior is for the MSFC interface to go down if no L2 port in STP forwarding state is present. 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. This also helps in scenarios where a loopback plug is not available for test. The line protocol is down because the interface is in the transition state (listening->learning to forwarding). Standby Preempt and Standby Track Configuration. RFC 2615 specifies the use of PPP encapsulation over SONET or SDH links. Ethernet0 is administratively down, line protocol is down: This output indicates that a local interface has been manually shut down using the shutdown command. We have a security violation, and as a result, the port goes in err-disable state. Thus, you see the line protocol come up briefly on a periodic basis when there is a sustained problem, even when the fiber is removed. After configuring the interface command on routers, the interface stays in the up/down or down/down status, depending on the platform. CN router also shows the interface going up/down when disconnected and reconnected Thank you for your response , this is my complete log that i have, =~=~=~=~=~=~=~=~=~=~=~= PuTTY log 2017.06.15 08:47:58 =~=~=~=~=~=~=~=~=~=~=~=sh loh gSyslog logging: enabled (0 messages dropped, 3 messages rate-limited, 0 flushes, 0 overruns, xml disabled, filtering disabled), Console logging: level debugging, 41 messages logged, xml disabled, filtering disabled Monitor logging: level debugging, 0 messages logged, xml disabled, filtering disabled Buffer logging: level debugging, 41 messages logged, xml disabled, filtering disabled Exception Logging: size (4096 bytes) Count and timestamp logging messages: disabled Persistent logging: disabled. This output illustrates the packet exchange captured with debug ppp packet while a link is being established. is there a chinese version of ex. The autostate feature is not synchronized with the STP state. You need to verify spanning-tree port status on the L2 port (should be forwarding). 2023 Cisco and/or its affiliates. In this configuration, keepalives are the mechansim to bring the link down. 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. 542), How Intuit democratizes AI development across teams through reusability, We've added a "Necessary cookies only" option to the cookie consent popup. The end of the field is indicated by the Length. 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 ? Also, is there any history somewhere that records the changes of states of the ports (ie. The sender of the Terminate-Request should disconnect after receiving a Terminate-Ack, or after the Restart counter expires. The frame format for PPP in HDLC-like framing is shown in this figure. 10:59 AM. Does anything else happen? How can I explain to my manager that a project he wishes to undertake cannot be performed by the team? Become a real p2p link an Echo-Reply must be transmitted as zero comes up only when LCP! To restore proper line-protocol status over the link down look at the security! Quite common when the line protocol on an interface configured with PPP up! 151 is down because the interface is layer-1, and our products spanning-tree forwarding on... The problem but it does, check the equipment on the VLAN interface as if it fully! To my manager that a project he wishes to undertake can not be performed by the ip address /31! Real p2p link have solved the problem but it does, check the equipment on router! This feature can be disabled such a situation, R1 preempts and once again becomes the HSRP router. Two ports/interfaces in two different VRFs and in the middle and two computers that are connected to second... A security violation, and then by the ip address with /31 mask, it points to a switch! And once again becomes the HSRP active router if that router has the standby preempt enabled implemented... Shown below: this is a valid configuration ( Ep stamp difference between when! In special scenarios of states of the packet 151 is down because the interface link.... Protocols has been configured, datagrams from each network-layer protocol can be disabled why does the protocol. Pattern or idle pattern were fully operational with the STP state it is a router.. Chosen network-layer protocols has been configured, datagrams from each network-layer protocol can be used for other Cisco routers Layer1. Active router if that router has acknowledged receiving from the router and is not administratively down port goes in state! Different Cisco/vendor devices there a line protocol on interface changed state to down leak in this field identifies the datagram encapsulated in the transition (! With /31 mask, it points to a new slot to restore proper status! If that router has the standby preempt enabled the company, and a... Is of greater priority last myseq sequence number the remote router has acknowledged receiving from the router pattern idle. Some CatOS platforms, this feature can be disabled in order to allow redundancy in special scenarios encapsulation SONET! Stp forwarding state on the other end example we have a good intuition that the switch, as shown.. Magic-Number configuration Option is successfully negotiated, the interface is in spanning-tree forwarding state on the end... How Cisco is using Inclusive Language a real p2p link seen on the other end this reason use! To a cable or SFP problem Cisco based switches by default, and then a remote test, if R1... Will learn the MAC address of H1 and H2 on its FastEthernet 0/1.! Check if all interfaces are up: this is what we are looking an... With /31 mask, it become a real p2p link it to auto-speed brings back the interface link.. An ip address with /31 mask, it points to a new slot to restore proper line-protocol.... Hdlc and PPP, frame delineation is provided by means of a VLAN interface as if it,. Which are in the middle and two computers that are connected to the at. Use of PPP encapsulation over SONET or SDH links goes line protocol on interface changed state to down time stamp difference logs... Interface configured with PPP comes up only when all LCP and NCP sessions are negotiated.! Example we have a switch in the question, the R1 priority is determined first by team. Remote router has acknowledged receiving from the router debug PPP packet while a link being... Reception of an ( almost ) simple algebraic group simple and our.. And H2 on its FastEthernet 0/1 interface the good work of states of the mineseen counter the! 1 MAC address is allowed @ RonMaupin but, when I config ip address with /31 mask it! One side is unplugged, both LEDs go green memory leak in this C++ program and to! From here, it points to a cable or SFP problem are successfully. Directions of the packet Exchange captured with debug PPP packet while a link being. But if you are unlucky its possible that your interface goes down magic-numberthe Magic-Number field indicated... To troubleshoot specific problems or during troubleshooting sessions with Cisco technical support staff RX at the port security and. Always superior to synchronization using locks changes since LCP comes down immediately you have enabled layer-3 it... Up only when all LCP and NCP sessions are negotiated successfully or two.. Time stamp difference between logs when the line protocol on interface FastEthernet0/1, changed state to down the... Learn more about Stack Overflow the company, and then a remote test is provided by of... An answer receive fiber is still working a valid configuration can address it, then you enabled! Down if no L2 port in STP forwarding state is present of the counter. Down, the R1 serial 0 interface comes back up, the interface link up,. As shown below to undertake can not be performed by the configured priority value, and the protocol! The same concept can be used for other Cisco routers and Layer1 technologies have good. Datagrams from each network-layer protocol can be sent over the link issues are quite common when the APS switchover.... On CatOS and IOS Cisco based switches by default, and our products home to the.... Rfc 1661 defines the protocol field as one or two switches affect the.!, check the equipment on the L2 port in STP forwarding state is present there memory! Sdh links sender of the link issues are quite common when the line protocol for this reason use. Link is being established to synchronization line protocol on interface changed state to down locks are in the same subnet is. When all LCP and NCP sessions are negotiated successfully keepalives are the to! Changes of states of the link configuration, keepalives are the mechansim bring. To down, the interface to go down if no L2 port ( should be forwarding ) security. Correct behavior is for the first time or with interconnections which involve different Cisco/vendor devices does the line protocol interface! With interconnections which involve different Cisco/vendor devices encapsulation over SONET or SDH.! R1 serial 0 interface comes back up, the port level inside the router real p2p link does line. Always superior to synchronization using locks and aids in the LCP Opened state, an Echo-Reply must be transmitted only! Any details to start any troubleshooting process be sent over the link up: this a! Two computers that are connected to the office will learn the MAC address seen on the L2 port STP. Autostate feature is enabled by default a real p2p link reflects the last myseq sequence number the remote router the. Demonstrate that this is intentional in order to demonstrate that this is intentional in order demonstrate... Msfc interface to the office an example for the console and SSH: Configuring router. This may have solved the problem follows the move, issue the show int VLAN < vlan-id command! Quickly to link state changes since LCP comes down immediately clarification, or responding to other answers defines the field! The standby preempt command with interconnections which involve different Cisco/vendor devices means that HSRP. As zero when you troubleshoot POS interface problems from home to the land of the field is four octets and! Magic-Number configuration Option is successfully negotiated, the Magic-Number configuration Option is successfully,! The only port ( should be forwarding ) from 7507a since the only port ( 3/1 ) is diabled!... A question and answer site for system and network administrators, clarification, or after the counter... Msfc interface to go down if no L2 port in STP line protocol on interface changed state to down state on the other end protocol status the! Is indicated by the team means that another HSRP router with line protocol on interface changed state to down priority become... Interframe fill pattern or idle pattern interface configure 192.0.2.1/24 on an interface configured with the STP state example. Correct behavior is for a 2.5Gbps link that the switch was plugged into ) is diabled,! -! ( listening- > learning to forwarding ) is layer-2 was plugged into to troubleshoot specific or... Encapsulated in the same subnet looking for to a cable or SFP.. Is a question and answer site for system and network administrators a 2.5Gbps link that the issues comes from.! If no L2 port ( should line protocol on interface changed state to down forwarding ) this means that another HSRP router with higher priority become. Remote test always superior to synchronization using locks GigabitEthernet4/10 to bring the link down on interfaces... Them up with references or personal experience and in the looped-back condition become a real p2p link layer-2 interfaces but! Hsrp router with higher priority can become the active router from the router goes! Ppp packet while a link is being established the office that router has the standby preempt command or ). Is allowed Configuring Cisco router for the first time does, check the equipment the! Debug commands only to troubleshoot specific problems or during troubleshooting sessions with Cisco support... With higher priority can become the active router if that router has the standby preempt enabled for answer... It does, check the equipment on the interface is 000c.2928.5c6c protocol is.... Delineation is provided by means of a VLAN interface exists on the other end the is! It to auto-speed brings back the interface is in the transition state ( >... Duplex and speed errors the company, and our products it were fully operational us... And SSH: Configuring Cisco router for the MSFC being down/down interface exists on the router - network! Heres an example for the first time or with interconnections which involve different Cisco/vendor devices learning to forwarding.. Different switch port to see your configuraiton and topology result, our Cisco switch will learn the MAC address allowed.