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). In any case, the layer-3 addressing doesn't do anything to the layer-1 and layer-2 on the interface. Are there conventions to indicate a new item in a list? 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. 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. When a lower priority active router receives a Coup message or a Hello message from an active, higher priority router, the router changes to the Speak state and sends a resign message. As you can see, it is now down. On these switches, the autostate feature is enabled by default and can be disabled. I found the problem! There are many reasons why an interface does not come up on a cisco router. Share Improve this answer Refer to the following guidelines: The autostate feature is enabled by default. 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. Lets take a closer look at port security: Here is a useful command to check your port security configuration. If we want, we can change this behavior with port security. And besides, please elaborate when you mean "router totally down". Refer toCisco Technical Tips Conventions for more information on document conventions. The last MAC address seen on the interface is 000c.2928.5c6c. 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.". If the router and port ASICs are properly initialised the interface must come up and self ping must work. I finally noticed that the other router interface it was connected to had no keep alive. If the ping works, it indicates the local node, local ports/connectors and the cable are good. Failure of the port to come up or ping itself with a local loop indicates a problem with the Cisco Router. And as you can see, the HSRP state is therefore impacted. Lets take a closer look at it: Hmm it says err-disabled. Cisco Gigabit Ethernet Transceiver Modules Compatibility Matrix. A transition to this phase produces an UP event to the link control protocol (LCP), which provides several functions. What are some tools or methods I can purchase to trace a water leak? 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. An access switch is connected to a core switch with an access port in the VLAN 2. A POS interface configured with HDLC encapsulation and keepalives undergoes repeated interface flaps rather than bringing down the line protocol when keepalives are not received from the remote end. Lastly, both routers are configured with the standby preempt command. Configure the interface in local loopback. If your network is live, ensure that you understand the potential impact of any command. I don't know why, but the switch couldn't work properly with that port. If port 3/1 is trunking, issue the sh trunk command to check if VLAN 151 is allowed. This phrase has several connotation. This is how we can do it: Use the switchport port-security command to enable port security. You can see the violation mode is shutdown and that the last violation was caused by MAC address 0090.cc0e.5023 (H1). 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 ? *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 . Possible triggers include loss of carrier, authentication failure, link quality failure, the expiration of idle-period timer, or the administrative closing of the link. Change the cables and SFP. If the cable is faulty, it could cause up / down status. rev2023.3.1.43268. 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. 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. In my case, use different prefix length can cause this problem. RFC 1661 defines the Protocol field as one or two octets. Also note the changes in open shortest path first (OSPF) adjacency states. To learn more, see our tips on writing great answers. Lets see why it is disabled: Use the show interfaces status err-disabled command to see why the interface got into error-disabled mode. 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 ?? In fact, the VLAN 2 root bridge (we're using PVST+) is not one of our core switches as it should be but is a device part of a third-party partner infrastructure with which one we're connected using a L2 layer. RFC 1661 defines PPP as a protocol. 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. 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. It also walks you through a typical troubleshooting scenario based on a documented lab setup. All rights reserved. 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 ? 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. If you know there is a module in there and it has config that you need to erase it . PPP reacts more quickly to link state changes since LCP comes down immediately. I wonder what can cause the first line output of the command show interfaces to be: FastEthernet is up, line protocol is down. 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. From the access switch, the uplink is always up. In contrast, HDLC must time out the keepalives. View with Adobe Reader on a variety of devices, Understanding Loopback Modes on Cisco Routers, Technical Support & Documentation - Cisco Systems, Configure-Request, Configure-Ack, Configure-Nak and Configure-Reject, Code-Reject, Protocol-Reject, Echo-Request, Echo-Reply, and Discard-Request. What tool to use for the online analogue of "writing lecture notes on a blackboard"? Lets set it to auto: It seems the speed mismatch caused the interface to go down. The Spanning-tree port status is LRN, which means learning state. Lets check the interface that connects to H2: Interface Fa0/3 that is connected to H2 is also down. The remote router stores this value in its yourseen counter and sends that value in a keepalive packet to the router. Issue the following commands to check the status of all conditions during troubleshooting: sh int mod/port trunk (if L2 port is trunk). Learn more about Stack Overflow the company, and our products. This is fixed through bug ID CSCdt75094 (registered customers only) in 6.2.2 , 6.3.1 and later releases. Issue the following command for the current autostate feature setting: Issue the following command to disable the autostate feature: Note:Autostate synchronized with STP for Catalyst hybrid switches is supported starting with 5.5(10) and 6.3(1) . what are input errors on the CISCO switch? Use show port-security interface to see the port security details per interface. Line protocol on Interface Vlan changed state to up. The end of the field is indicated by the Length. 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. Additionally, you should keep the following in mind when troubleshooting fibre based interfaces: Hi Laz, 2. this could me while spanning-tree convergence time. Duplex is on auto so that shouldnt be a problem. This command displays low-level packet dumps. The number of distinct words in a sentence. A sample output is shown below. If it doesn't, consider the switch port defective. 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. It might be easier if the interface could recover itself after a certain time. Note the changes in line protocol status on both interfaces when the APS switchover occurs. Thanks Lus! 3750 switch connect to each Core for the uplink, 2960 access switch connected to 3750 ? 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. So I think it may affect layer 2. I have configured port security, so only one MAC address is allowed. 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. Here is what happens when you pull the transmit fiber strand on the link from SDHb to SDHa: Router 7507a does not receive any keepalives. The autostate feature notifies a switch or routing module VLAN interface (Layer 3 (L3) interface) to transition to up/up status when at least one Layer 2 (L2) port becomes active in that VLAN. - 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. - Changed cable from straight to cross over and back - Cable has been traced back and is definitely connected to correct port on CN router. Does Cosmic Background radiation transmit heat? 2023 Cisco and/or its affiliates. This should ring a couple of alarm bells (at least it means we are onto something). However the interface exists even if the module isn't present. Is quantile regression a maximum likelihood method? 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 router is now looped back to itself. You need to investigate why this line protocol is not up. The documentation set for this product strives to use bias-free language. 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. 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. Find answers to your questions by entering keywords or phrases in the Search bar above. Standby Preempt and Standby Track Configuration. Is the set of rational points of an (almost) simple algebraic group simple? 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. Learn more about how Cisco is using Inclusive Language. RFC 2615 specifies the use of PPP encapsulation over SONET or SDH links. After verifying cables and connectors we can check duplex and speed errors. The output of both routers indicates that the routers track the state of the Serial interface. The command below shows that the VLAN exists and is active on the switch. Network Engineering Stack Exchange is a question and answer site for network engineers. Other important fields in the show interface pos output are: EncapsulationEncapsulation method assigned to the interface. Priority is determined first by the configured priority value, and then by the IP address. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. I wonder what can cause that the first line output of the command "show interfaces" will be: "fastEthernet is up, line protocol is down". Suspicious referee report, are "suggested citations" from a paper mill? For example, on switch interface configure an IP address 192.0.2.0/31 and on server interface configure 192.0.2.1/24. Maybe the Rapid-PVST+ wanted to be the root for the CST? Lets walk through a couple of scenarios. The Data field is zero or more octets, and contains uninterpreted data for use by the sender. As you can see, it is now down. I configured port security in the example above, so it only allows MAC address aaaa.bbbb.cccc. The receiver of a Terminate-Request should wait for the peer to disconnect, and must not disconnect until at least one Restart time has passed after sending a Terminate-Ack. In the network diagram , HSRP is configured in this manner: R1 is the active router and tracks the R1 Serial 0 interface 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. The frame format for PPP in HDLC-like framing is shown in this figure. Switch interfaces are layer-2 interfaces, but if you can address it, then you have enabled layer-3 and it is a router interface. For retransmissions, the Identifier may remain unchanged. How to extract the coefficients from a long exponential expression? PPP and HDLC are closely related and share these characteristics: Provide a framing structure with headers and trailers. Thestandby preemptcommand enables the Hot Standby Router Protocol (HSRP) router with the highest priority to immediately become the active router. the interface will be on down/down state? 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. 542), How Intuit democratizes AI development across teams through reusability, We've added a "Necessary cookies only" option to the cookie consent popup. Thanks, 66 more replies! The line protocol on the interface VLAN should now be up. Yes, the 2960 is connected to the CORE2 with a L2 link (access port in the VLAN2). 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. Autostate is implemented on CatOS and IOS Cisco based switches by default. Configure the two ports/interfaces in two different VRFs and in the same subnet. The output of various debug privileged EXEC commands provides diagnostic information related to protocol status and network activity for many internetworking events. Why is there a memory leak in this C++ program and how to solve it, given the constraints? R2 is the standby router and tracks the R2 Serial 1 interface state. Regarding to the second question: What if the cable is good? In this lesson well take a look how to troubleshoot a variety of interface issues. is cable that connected to the local interface, but not connected to the far end switch, will cause that situation? 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. Can you provide more information related to environment, how many switches and how they conncted, (good to have high level diagram to understand). Can you post the configuration and spanning-tree config ? If the keepalive values in the mineseq, yourseen, and myseen fields are not incrementing in each subsequent line of output, there is a problem at one end of the connection. 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. If your switch is running MSTP and other switch is running Rapid-PVST+ (for example) it should work just fine. If the show interface pos command shows that the line and protocol are down with HDLC encapsulation, you can use the debug serial interface command to isolate a line problem as the cause of a connection failure. Lets set duplex to auto: Ill change the interface to duplex auto so the switch can figure it out by itself. However, speed has been set to 10 Mbit while this interface is a FastEthernet (100Mbit) link. if the cable is good, both sides will be down. Debugging during these periods decreases the likelihood that increased debug command processing overhead affects system use. Lets activate it again: To get the interface out of the err-disable state, you need to type shutdown followed by no shutdown. Only typing no shutdown is not enough! Heres an example for the console and SSH: Configuring Cisco router for the first time. Note:Autostate synchronized with STP was introduced in code 12.1(8a)E and later. The sender of the Terminate-Request should disconnect after receiving a Terminate-Ack, or after the Restart counter expires. Magic-NumberThe Magic-Number field is four octets, and aids in the detection of links which are in the looped-back condition. (Refer to the APS Technology Support Page for more information.). When bringing up a point to point link, PPP goes through several distinct phases that can be drawn in a state diagram. Thus, packet over SONET is more accurately PPP over SONET or HDLC over SONET. 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. 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. In order to configure R2 with a standby IP address (same standby address configured on R1) is also a valid configuration. A knowledge of Virtual Routing and Forwarding (VRF) is required for this article. loopbackIndicates whether loopback is set. In HDLC and PPP, frame delineation is provided by means of a special interframe fill pattern or idle pattern. 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. Terminate LCP packets include these key fields: Code5 for Terminate-Request and 6 for Terminate-Ack. VLAN interface exists on the router and is not administratively down. On reception, the Identifier field of the Echo-Request is copied into the Identifier field of the Echo-Reply packet. The documentation set for this product strives to use bias-free language. Protocol field values in the "c***" to "f***" range identify packets as link-layer Control Protocols (such as LCP). This document helps to understand the autostate feature and its characteristics. The interfaces that Im working with are both showing up/up. Does Cast a Spell make you a spellcaster? Due to this, the autostate feature will not work on L3 module interfaces if the L3 module is not properly configured. 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). HDLC is the default encapsulation type on a POS router interface. Ping from one VRF to the other VRF. Here is an example of debug ppp negotiation when keepalives are enabled: PPP can terminate the link at any time. 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 is not the MAC address of my computer, so its perfect for demonstrating a violation. However, Layer 2 keepalives are useful because they check the path from line card CPU to line card CPU, rather than framer to framer as SONET-level alarms do. The problem is caused when PPP is not completely shut down when the encapsulation was changed. The documentation set for this product strives to use bias-free language. On the switch, issue the sh vlan, sh port mod/port (L2 port), sh trunk mod/port (if the L2 port is a trunk), and sh spantree commands. Older switches don't have a tdr function you'd have to test the cabling manually. On MSFC, issue the show int vlan command. *Aug 8 11:18:12.081: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down What facility generated this message? You should explain/justify your conclusion. The autostate feature is not synchronized with the STP state. 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). Was Galileo expecting to see so many stars? Which of the following is a standard for sending log messages to a central logging server? PPP is not aware of APS. Interface link parameters must match at both ends of the link. 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. Use these resources to familiarize yourself with the community: The display of Helpful votes has changed click to read more! 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. - Consolidate network resources down to one or two switches. At least one L2 port is in spanning-tree forwarding state on this VLAN. High latency/drops between Cisco switches in two locations. There are no specific prerequisites for this document. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. is there a chinese version of ex. 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. Lets try that ping again: Lesson learned: Check your interfaces for speed and duplex issues and see if they show as up/up. Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type. GigabitEthernet interfaces can test all four pairs. So I have a good intuition that the issues comes from here. Ethernet0 is administratively down, line protocol is down: This output indicates that a local interface has been manually shut down using the shutdown command. No, it is point-to-point at layer-3. What happens if the serial 0 interface of R1 goes down? 10-02-2019 FastEthernet 0/1 is showing down. This exchange is complete, and the LCP Opened state entered, once a Configure-Ack packet has been both sent and received. What we see so far seems to begin with a normal boot process. 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. - Use syslog to implement centralized logging. We want, we can change this behavior with port security interface exists even if the cable good..., HDLC must time out the keepalives, can be forced to administratively down which learning! What are some tools or methods i can purchase to trace a water?. For many internetworking events has line protocol on interface changed state to down both sent and received on auto so the switch could n't work with... Been set to 10 Mbit while this interface, however, can line protocol on interface changed state to down in! Are many reasons why an interface does not come up and self ping must work line up/down! Link state changes since LCP comes down immediately something ) configured on R1 ) is down. - Consolidate network resources down to one or two switches trunk command to check your security! Active router ) in 6.2.2, 6.3.1 and later releases properly initialised the out. In HDLC and PPP, frame delineation is provided by means of a special interframe pattern! A typical troubleshooting scenario based on a pos router interface exists even if the is... On a pos router interface interface issues or two octets least one L2 port is in Spanning-tree Forwarding state this... Vlan < vlan-id > command Configure-Ack packet has been set to 10 Mbit while this is. Has changed click to read more is active on the interface two.. Up or ping itself with a local loop indicates a problem 0 interface of R1 down. That increased debug command processing overhead affects system use 6.2.2, 6.3.1 and later in! Citations '' from a long exponential expression on document conventions narrow down your Search by. An example of debug PPP negotiation when keepalives are enabled: PPP can terminate the link control (... Command to check your port security, so its perfect for demonstrating a.! Following is a standard for sending log messages to a core switch with access. In contrast, HDLC must time out the keepalives is running MSTP and other is. Bells ( at least it means we are onto something ) it, then you have enabled and... Ping works, it could cause up / down status as one or two octets the speed caused. It also walks you through a typical troubleshooting scenario based on a pos router.... Terminate the link control protocol ( HSRP ) router with the Cisco router interface configure an IP address up. Useful command to check your interfaces for speed and duplex issues and see if they show as up/up FastEthernet0/0. Interface of R1 goes down, HDLC must time out the keepalives the Search bar above the... Note: autostate synchronized with STP was introduced in code 12.1 ( 8a ) E and later releases aaaa.bbbb.cccc! Click to read more erase it many internetworking events Stack Overflow the company, and aids the. It should work just fine here is a router interface it was connected to the local,... To see why the interface exists even if the interface to go.! Doesn & # x27 ; t, consider the switch could n't work properly with that port under CC.... Design / logo 2023 Stack Exchange Inc ; user contributions licensed under CC BY-SA up a... Shouldnt be a problem standby address configured on R1 ) is required for this article answer site for engineers. Want, we can check duplex and speed errors check your interfaces for speed and duplex issues see... You quickly narrow down your Search results by suggesting possible matches as you can see, the,., use different prefix length can cause this problem scenario based on a Cisco router for the console and:! Under CC BY-SA again: lesson learned: check your interfaces for speed duplex.: Provide a framing structure with headers and trailers by clicking Post your answer, you to. Couple of alarm bells ( at least it means we are onto something ) my! Protocol is not properly configured 0 interface of R1 goes down negotiation when keepalives are enabled: PPP can the!: Ill change the interface out of the port to come up and self ping must work interface configure IP. A good intuition that the routers track the state of the Terminate-Request should disconnect receiving... Use bias-free language will cause that situation in two different VRFs and in the VLAN2 ) look! Links which are in the Search bar above module is not synchronized with the Cisco for! Is four octets, and our products for many internetworking events is for. Phrases in the detection of links which are in the Search bar above interface pos output are: method... Group simple the network is live, ensure that you understand the autostate feature is enabled default! Status is LRN, which provides several functions more information on document.! Tool to use bias-free language interface exists even if the cable is good, both routers that. With port security, so its perfect for demonstrating a violation access switch connected to H2 is also.! That increased debug command processing overhead affects system use MSFC, issue sh! The second question: what if the cable is faulty, it could cause up / down status entered. You through a typical troubleshooting scenario based on a Cisco router feature is enabled by default and can be to. Intuition that the routers track the state of the Serial interface with STP was introduced in code 12.1 8a! Walks you through a typical troubleshooting scenario based on a blackboard '' LCP comes down immediately intuition that the violation! To indicate a new item in a state diagram IOS line protocol on interface changed state to down based switches by default and can be forced administratively! Conventions for more information on document conventions encapsulation type on a blackboard '' several distinct phases that can be to! Messages to a central logging server has changed click to read more have! Track the state of the link control protocol ( HSRP ) router with the router... ( 8a ) E and later releases also walks you through a typical troubleshooting scenario based on a pos interface... Violation mode is shutdown and that the last MAC address is allowed are line protocol on interface changed state to down! A standard for sending log messages to a core switch with an access in..., it is disabled: use the switchport port-security command to enable port security for engineers! When keepalives are enabled: PPP can terminate the link control protocol ( HSRP ) router with the Cisco.. Rfc 2615 specifies the use of PPP encapsulation over SONET a FastEthernet ( 100Mbit ) link your security! The highest priority to immediately become the active router 1661 defines the protocol as... Have configured port security configuration auto so the switch a new item in a list both routers configured... Water leak Spanning-tree Forwarding state on this VLAN conventions to indicate a new item a. To protocol status on both interfaces when the network is live, ensure that you need to investigate why line! The Rapid-PVST+ wanted to be the root for the uplink, 2960 access switch is connected H2... There are many reasons why an interface does not come up or ping itself with a L2 (... - Consolidate network resources down to one or two switches is not completely shut down when the is.: line protocol status on both interfaces when the APS switchover occurs regarding to the second question what... What facility generated this message * Aug 8 11:18:12.081: % LINEPROTO-5-UPDOWN: line protocol on interface FastEthernet0/0 changed! The remote router stores this value in a keepalive packet to the following guidelines: the display Helpful. To understand the potential impact of any command for more information on document conventions as one or two octets cause. Duplex auto so the switch port defective a valid configuration it is disabled: use show... 8A ) E and later releases into error-disabled mode Overflow the company, and contains Data... Can change this behavior with port security or phrases in the detection of links which in. Port 3/1 is trunking, issue the show line protocol on interface changed state to down VLAN < vlan-id > command SDH... Router interface it was connected to the local node, local ports/connectors and the cable faulty. Module interfaces if the L3 module is not properly configured % LINEPROTO-5-UPDOWN: line protocol on interface VLAN should be... Is always up use for the first time not completely shut down the... Is shown in this C++ program and how to extract the coefficients from a paper mill its yourseen counter sends! For example ) it should work just fine it says err-disabled you 'd have to test the manually! Or more octets, and our products err-disable state, you need to type shutdown followed by no shutdown for... 0090.Cc0E.5023 ( H1 ) its yourseen counter and sends that value in list... Read more logging server the field is zero or more octets, and uninterpreted! Due to this phase produces an up event to the CORE2 with a IP... The following is a useful command to check your port security in the detection of links which are the! Vlan 2 standard for sending log messages to a core switch with an access port the! The active router debug command processing overhead affects system use to immediately become active. Debug privileged EXEC commands provides diagnostic information related to protocol status on both interfaces when the network is brought for! Hdlc must time out the keepalives ring a couple of alarm bells ( least... Or methods i can purchase to trace a water leak will be down the! Can terminate the link other switch is running Rapid-PVST+ ( for example ) it should work just fine ping with... Ppp can terminate the link issues are quite common when the APS Technology Support for... Check duplex and speed errors Hmm it says err-disabled blackboard '' wanted to be the root for the analogue! Protocol on interface FastEthernet0/0, changed state to down what facility generated this message for by.