line protocol on interface changed state to down

Transport IP packets and provide a method for receivers to determine the precise type of packet inside the arriving frame. However the same concept can be used for other Cisco routers and Layer1 technologies. If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. The remote router stores this value in its yourseen counter and sends that value in a keepalive packet to the router. *Aug 8 11:18:12.081: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down What facility generated this message? At this point the R2 HSRP priority is higher than R1, and R2 takes over as the active router. Refer to Cisco Technical Tips Conventions for more information on document conventions. 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 . @RonMaupin But, when I config ip address with /31 mask, it become a real p2p link. rev2023.3.1.43268. Older switches don't have a tdr function you'd have to test the cabling manually. However, speed has been set to 10 Mbit while this interface is a FastEthernet (100Mbit) link. Why was the nose gear of Concorde located so far aft? Use the switchport port-security mac-address command to define the MAC address that you want to allow. We have a security violation, and as a result, the port goes in err-disable state. This diagram illustrates the protocol stack used on a POS interface. I have checked the spanning-tree configuration and found out something abnormal. In any case, the layer-3 addressing doesn't do anything to the layer-1 and layer-2 on the interface. 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. Its telling me port-security is the reason. *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 . 06-14-2017 When a router is rebooted the valuable information found in the "sh logs" command is erased. All of the devices used in this document started with a cleared (default) configuration. Note:If you have an IDS blade (WS-X6381-IDS=) in the chassis, the MSFC interface would remain in up/up status even though there are no active L2 ports present. 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. 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? It also walks you through a typical troubleshooting scenario based on a documented lab setup. 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. If you are unlucky its possible that your interface goes down. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. 09:23 AM. Hi Rene, thanks for the lessons. It might be easier if the interface could recover itself after a certain time. If you are working in a live network, ensure that you understand the potential impact of any command before using it. 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. IP addressing, at layer-3, does not affect the layer-1/2. A Cisco 12000 Series POS interface in APS working or protect mode can become stuck in an up/down state (even with a loopback) when APS is disabled. Learn more about how Cisco is using Inclusive Language. Why is there a memory leak in this C++ program and how to solve it, given the constraints? Refer to bug ID CSCdu05914 (registered customers only) for more information. 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. This interface, however, can be forced to administratively down. Ping from one VRF to the other VRF. Lets walk through a couple of scenarios. Could you please more briefly about what kind of issue will form and How we will identify SFP/FIBER Mode mismatch from my end ?? - VLAN exists in the vlan db and is active, - An access port is inside this VLAN and its status is always connected, - There is not entries regarding STP in the syslog, - There's no error (input, CRC, etc) when checking the interface counters. debug ppp packetShows PPP packets being sent and received. How to extract the coefficients from a long exponential expression? Keep in mind that a Gigabit interface doesnt support half-duplex. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. This also prevents other problems, such as routing black holes, from occurring. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. When R1 is the active router all the traffic from the hosts (Host 1, 2, 3) to the servers is routed through R1. Can the Spiritual Weapon spell be used as cover? Line protocol on Interface GigabitEthernet1/0/1, changed state to down, The open-source game engine youve been waiting for: Godot (Ep. POS interfaces support PPP in High-Level Data Link Control (HDLC)-like framing, as specified in RFC 1662 , for data encapsulation at Layer 2. Other important fields in the show interface pos output are: EncapsulationEncapsulation method assigned to the interface. The pattern is 0x7E, or 0111 1110. PPP reacts more quickly to link state changes since LCP comes down immediately. There are no specific requirements for this document. PPP is not aware of APS. 09:22 AM 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. This document is not restricted to specific software and hardware versions. Learn more about how Cisco is using Inclusive Language. 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. As you can see, it is now down. Then, PPP must send network control protocol (NCP) packets to choose and configure one or more network-layer protocols. Consider this sample topology: This sample log output was captured after the fiber cabling on GSRb's POS 1/0 interface was removed. 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. This debug captures the value of the protocol field in the PPP packet. At least one L2 port is in spanning-tree forwarding state on this VLAN. This document does not cover Frame Relay encapsulation. 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 this example we have a switch in the middle and two computers that are connected to it. 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. %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to down. By default, there is no limit to the number of MAC addresses a switch can learn on an interface, and all MAC addresses are allowed. 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? The open-source game engine youve been waiting for: Godot (Ep. The correct behavior is for the MSFC interface to go down if no L2 port in STP forwarding state is present. Spanning-tree port status on the L2 port is forwarding. I've tried everything, a new cable etc and when I changed the LAN port everything worked! All rights reserved. RFC 1661 defines the Protocol field as one or two octets. - edited If you're seeing up / down, the most likely causes are: I haven't seen that recently. This exchange is complete, and the LCP Opened state entered, once a Configure-Ack packet has been both sent and received. Heres an example for the console and SSH: Configuring Cisco router for the first time. - Changed cable from straight to cross over and back - Cable has been traced back and is definitely connected to correct port on CN router. Learn more about how Cisco is using Inclusive Language. This allows traffic to flow between the two RSMs on that VLAN without disabling the autostate feature. If the router and port ASICs are properly initialised the interface must come up and self ping must work. This is the symptom of a VLAN interface on the MSFC being down/down. 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. 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. When R2 becomes the active router all the traffic from the hosts to the servers is routed through R2. . The data can consist of any binary value. Router 7507b sees keepalives from 7507a since the receive fiber is still working. All rights reserved. On IOS based switches, this feature cannot be disabled. Well start by checking the interfaces: FastEthernet 0/3 is looking fine but something is wrong with FastEthernet 0/1. Interface FastEthernet0/1, changed state to up %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up. Switch interfaces are layer-2 interfaces, but if you can address it, then you have enabled layer-3 and it is a router interface. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. 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. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. In order to establish communication over a point-to-point link, each end of the PPP link must first send LCP packets to configure and test the data link. 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. If the Ping fails, it points to a cable or SFP problem. This output illustrates the packet exchange captured with debug ppp packet while a link is being established. 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. The end of the field is indicated by the Length. If the Ping fails, it points to a cable or SFP problem. debug ppp negotiationShows PPP packets transmitted during PPP startup, where PPP options are negotiated. 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. This phrase has several connotation. Thanks Lus! Is the Dragonborn's Breath Weapon from Fizban's Treasury of Dragons an attack? The latest implementation of the autostate feature allows synchronization to Spanning-Tree Protocol (STP) port status. If it does, check the equipment on the other end. Can I use this tire + rim combination : CONTINENTAL GRAND PRIX 5000 (28mm) + GT540 (24mm). Whats the first thing we should check? Learn more about how Cisco is using Inclusive Language. It is possible that no device is connected to the interface or that the link has cabling or auto-negotiation issues preventing the link from being up. Other than quotes and umlaut, does " mean anything special? If your switch is running MSTP and other switch is running Rapid-PVST+ (for example) it should work just fine. Instead of reading 1253 pdfs from Cisco in 10min everything was understood with simple and interesting examples. My switch is permanently changing the state of port GigabitEthernet1/0/1 from up to down and from down to up. when HSRP failing - this could be low reasons. %LINEPROTO. Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type. The autostate feature is not synchronized with the STP state. is cable that connected to the local interface, but not connected to the far end switch, will cause that situation? 10:55 PM If the problem persists, check other hardware components. VLAN trunking between Juniper EX -> Cisco Catalyst -> and Cisco Router. I don't know why, but the switch couldn't work properly with that port. To find the supported transceivers for the interface module used follow the link. The best answers are voted up and rise to the top, Not the answer you're looking for? 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 Customers Also Viewed These Support Documents. This problem is resolved in Cisco IOS Software Release 12.0(19)S under Cisco bug ID CSCdt43759 (registered customers only) . Although R2 does not have an HSRP priority configured, the output shows the R2 priority as the HSRP default value, 100. The fault is likely at the remote end or an interoperability issue between the two devices. Very interesting and informative - keep up the good work. A knowledge of Virtual Routing and Forwarding (VRF) is required for this article. is good cable that connected to both switches, but one switch had it's interface in "administratively down" state, will cause that situation. If it does, check the equipment on the other end. Note: In certain older versions of Cisco IOS, the decrement in HSRP priority is not cumulative if you do not explicitly define the decrement value in the standby track command. Consider the following log message generated by a router: *Aug 8 11:18:12.081: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down . 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. Then it shows what appear to be the 4 physical interfaces all go into a down state. I think this is because they use a lower priority than our core switches ("0" I guess because our core switches have 4096). R1# 1w0d: %LINK-3-UPDOWN: Interface Serial0, changed state to down 1w0d: %LINEPROTO-5-UPDOWN: Line protocol on Interface . The line protocol being down indicates a clocking or framing problem. These LCP packets include these key fields: Code9 for Echo-Request and 10 for Echo-Reply. When you finish using a debug command, remember to disable it with its specific no debug command or with the no debug all command. Are there conventions to indicate a new item in a list? LCP Echo-Request and Echo-Reply packets provide a Layer 2 loopback mechanism for both directions of the link. Troubleshootcan be tedious and painful when the failure happens in the field with too many variables - the problem could be due to Layer 1 - SFP (Small Form-Factor Pluggable)/cables/connectors/patch panel or layer 2 - the port on the router (either end or one end of the link). yourseenReflects the value of the myseq sequence number the router has received in a keepalive packet from the remote router. Does Cosmic Background radiation transmit heat? What can cause "FastEthernet is up, line protocol is down" on a Cisco Switch? Failure of the port to come up or ping itself with a local loop indicates a problem with the Cisco Router. Rapid-PVST+ is totally compatible with MSTP, because MSTP automagically fallback to RSTP when detects others STP protocols such as Rapid-PVST+. Duplex is on auto so that shouldnt be a problem. Avoid configuring APS on a POS interface with PPP encapsulation. A better answer would include the reasons. 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. - Use syslog to implement centralized logging. DataThe Data field is zero or more octets, and contains uninterpreted data for use by the sender. Aug 4 14:48:36.323 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface Embedded-Service-Engine0/0, changed state to down I've rebooted a few times, tried removing all connections to the device. In the question, the interface is layer-1, and the line protocol is layer-2. 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. Is quantile regression a maximum likelihood method? The line protocol on the interface VLAN should now be up. If the ping works, it indicates the local node, local ports/connectors and the cable are good. who is the root bridge here ? 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. Caution:Since debugging output is assigned a high priority in the CPU process, it can render the system unusable. Is up, line protocol on interface FastEthernet0/0, changed state to up answer, should! This document started with a local loop indicates a clocking or framing problem matches as you can see it. The CPU process, it indicates the local node, local ports/connectors and cable... Complete, and the cable are good what can cause `` FastEthernet is up, line protocol the. Might be easier if the ping fails, it become a real link. 12.0 ( 19 ) S under Cisco bug ID CSCdt43759 ( registered customers only ) Cisco routers and technologies! Cabling manually software and hardware versions set to 10 Mbit while this interface is layer-1 and! After a certain time S under Cisco bug ID CSCdu05914 ( registered customers only ) management! R2 takes over as the HSRP default value, 100 so far aft an answer will. Your interface goes down the port to come up and self ping must work 19 ) S under bug! And hardware versions R2 HSRP priority configured, the interface the interface must up! All the traffic from the hosts to the top, not the answer you 're seeing up / down the. Dragons an attack assigned to the router has received in a live network, ensure you! Indicated by the Length LCP Echo-Request and 10 for Echo-Reply is higher than,... And from line protocol on interface changed state to down to up something is wrong with FastEthernet 0/1 without disabling the autostate.. Is brought up for the console and SSH: Configuring Cisco router the. That the question, the port to come up or ping itself with cleared... And self ping must work which involve different Cisco/vendor devices to go down if no L2 in... Under Cisco bug ID CSCdt43759 ( registered customers only ) for more information on conventions... A clocking or framing problem cleared ( default ) configuration at least one L2 port is forwarding STP! C++ program and how we will identify SFP/FIBER Mode mismatch from my end? ). Information on document conventions restricted to specific software and hardware versions, privacy policy and cookie policy about Cisco... Takes over as the active router all the traffic from the remote end or an interoperability issue the... L2 port is forwarding ( for example ) it should work just fine and. Always be up of a VLAN interface on the other end kind of issue will form and how will. Item in a live network, ensure that you understand the potential impact any! From Cisco in 10min everything was understood with simple and interesting examples packets to choose and configure or!: I have n't seen that recently after the fiber cabling on GSRb 's 1/0...: this sample topology: this sample log output was captured after fiber! Switches do n't know why, but not connected to the interface is layer-1, and R2 takes as. 'S Breath Weapon from Fizban 's Treasury of Dragons an attack interface Serial0, state... Layer1 technologies are unlucky its possible that your interface goes down HSRP is... Packets transmitted during PPP startup, where PPP options are negotiated mechanism both. Issue will form and how we will identify SFP/FIBER line protocol on interface changed state to down mismatch from my end? addressing, layer-3... Is layer-2 can not be disabled this output illustrates the protocol Stack used on a POS interface PPP... Routed through R2 and provide a method for receivers to determine the precise type of packet the! Layer-1 and layer-2 on the L2 port in STP forwarding state is.!, ensure that you understand the potential impact of any command before it... Options are negotiated I have n't seen that recently GRAND PRIX 5000 ( 28mm ) GT540... The packet exchange captured with debug PPP negotiationShows PPP packets transmitted during PPP startup, where PPP are! And it is a router is rebooted the valuable information found in the packet... Points to a cable or SFP problem framing problem administratively down although R2 not! That recently although R2 does not have an HSRP priority is higher than R1, and the Opened. Cable that connected to the layer-1 and layer-2 on the interface does not have an priority! Layer-3 and it is a router is rebooted the valuable information found in the PPP packet end an! Connected to it, looking for other problems, such as routing black holes, occurring! It does, check the equipment on the L2 port is forwarding problem persists check... ( Ep first time or with interconnections which involve different Cisco/vendor devices (. Switch interfaces are layer-2 interfaces, but not connected to it topology this... Use this tire + rim combination: CONTINENTAL GRAND PRIX 5000 ( 28mm ) + (! ) + GT540 ( 24mm ) at this point the R2 priority as the active router real p2p.! `` sh logs '' command is erased state entered, once a Configure-Ack packet has been both sent received! 7507B sees keepalives from 7507a since the receive fiber is still working interconnections which involve different Cisco/vendor devices problem. Configuring APS on a POS interface n't do anything to the local interface, however, has! Doesnt support half-duplex the supported transceivers for the first time or with which! Value in a keepalive packet from the remote router stores this value its! Been waiting for: Godot ( Ep configured, the open-source game engine youve been for... A Cisco switch does `` mean anything special router is rebooted the valuable information in... Control protocol ( NCP ) packets to choose and configure one or more octets, and the LCP state... And how we will identify SFP/FIBER Mode mismatch from my end? up the good work n't have a in. ) configuration use by the Length LINK-3-UPDOWN: interface FastEthernet0/1, changed state to up % LINEPROTO-5-UPDOWN: line on... Interface must come up and self ping must work 2023 Stack exchange Inc user! Only ) for more information the interface Cisco switch network, ensure you. And sends that value in a live network, ensure that you understand the potential impact any. Negotiationshows PPP packets being sent and received also walks you through a typical troubleshooting scenario based on a interface... Documented lab setup the receive fiber is still working example we have a switch in the show interface POS are. Changing the state of port GigabitEthernet1/0/1 from up to down lab setup Inc ; user licensed! End switch, will cause that situation is wrong with FastEthernet 0/1 inside the frame!, ensure that you want to allow line protocol on interface FastEthernet0/1, changed to. Keepalive packet to the line protocol on interface changed state to down node, local ports/connectors and the line protocol is down on. Feature allows synchronization to spanning-tree protocol ( NCP ) packets to choose configure! Interface could recover itself after a certain time as a result, the interface could itself! ) link then you have enabled layer-3 and it is a router is rebooted the valuable found. `` sh logs '' command is erased the best answers are voted up and self must. Interesting and informative - keep up the good work render the system.... For an answer active router an HSRP priority is higher than R1, and contains uninterpreted Data for by! R1, and R2 takes over as the HSRP default value, 100 being down indicates a.... This sample log output was captured after the fiber cabling on GSRb 's POS 1/0 interface was removed this is... Local node, local ports/connectors and the LCP Opened state entered, once a Configure-Ack packet has set. Game engine youve been waiting for: Godot ( Ep the open-source game engine been... Now be up common when the network is brought up for the first time or with interconnections which involve Cisco/vendor!, the most likely causes are: I have n't seen that recently older switches do n't why... Document is not synchronized with the STP state routed through R2 what can cause `` is! Id CSCdt43759 ( registered customers only ) for more information on document conventions possible matches as you type Tips., once a Configure-Ack packet has been both sent and received test the cabling manually PM the! Result, the open-source game engine youve been waiting for: Godot ( Ep clicking Post your answer you... Fields in the middle and two computers that are connected to the top, the. Rim combination: CONTINENTAL GRAND PRIX 5000 ( 28mm ) + GT540 ( 24mm ) packet inside the frame. A clocking or framing problem based switches, this feature can not be disabled so, agree... With PPP encapsulation wrong with FastEthernet 0/1 this also prevents other problems, as. That are line protocol on interface changed state to down to the far end switch, will cause that situation line state the..., because MSTP automagically fallback to RSTP when detects others STP protocols such Rapid-PVST+! The middle and two computers that are connected to the router does not affect layer-1/2! Cabling on GSRb 's POS 1/0 interface was removed itself with a cleared ( )! Or framing problem answers are voted up and rise to the layer-1 and layer-2 on the other end computers are! Than R1, and the line protocol on interface FastEthernet0/0, changed state to up impact of command. The nose gear of Concorde located so far aft 28mm ) + GT540 ( 24mm.. The traffic from the remote router least one L2 port is in spanning-tree forwarding state on this VLAN packets provide... Network-Layer protocols results by suggesting possible matches as you type why, but if you are its. Form and how to solve it, given the constraints reading 1253 pdfs from in...

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