Network Engineering Stack Exchange is a question and answer site for network engineers. How is "He who Remains" different from "Kang the Conqueror"? This diagram shows an example that uses the standby preempt command in conjunction with the standby track command. 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). When a higher priority router preempts a lower priority router, the router sends a Coup message. The autostate feature is not synchronized with the STP state. There are no specific prerequisites for this document. POS interfaces support PPP in High-Level Data Link Control (HDLC)-like framing, as specified in RFC 1662 , for data encapsulation at Layer 2. A transition to this phase produces an UP event to the link control protocol (LCP), which provides several functions. Alternately, when performing this test, execute the show controller pos command, which displays SONET alarms. Glad to hear it was useful to you. Here is why: Hi, your lessons are very interesting. 15 more replies! If your switch is running MSTP and other switch is running Rapid-PVST+ (for example) it should work just fine. If an interface is up/down because of APS deselection, PPP tries resetting the interface and continuously transmits PPP negotiation packets. The last MAC address seen on the interface is 000c.2928.5c6c. Note: Time stamp difference between logs when the line protocol on GigabitEthernet4/10 went up, . I ran the command keep alive on that interface and the state changed to up/up.. Did any answer help you? This document helps to understand the autostate feature and its characteristics. This output illustrates the packet exchange captured with debug ppp negotiation during LCP's link establishment phase. Let's take a closer look at port security: SW1#show interfaces fa0/1 FastEthernet0/1 is down, line protocol is down (notconnect) Hardware is Fast Ethernet, address is 0011.bb0b.3603 (bia 0011.bb0b.3603) MTU 1900 bytes, BW 100000 Kbit, . The best answers are voted up and rise to the top, Not the answer you're looking for? Configure the interface in local loopback. This means that another HSRP router with higher priority can become the active router if that router has the standby preempt enabled. 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. (Refer to the APS Technology Support Page for more information.). 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. 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 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. 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. 10-02-2019 On IOS based switches, this feature cannot be disabled. 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. This document describes how to troubleshoot interfaces that are down on router ethernet links. Click here for a complete list of PPP protocol field values . Only registered Cisco users can access internal bug information. My switch is permanently changing the state of port GigabitEthernet1/0/1 from up to down and from down to up. whick menas that keepalives will not be receiver on the far end. Asking for help, clarification, or responding to other answers. To use this feature, autostate must be enabled. What happens if the serial 0 interface of R1 goes down? Keepalives are disabled automatically on most POS router hardware. 2023 Cisco and/or its affiliates. debug ppp negotiationShows PPP packets transmitted during PPP startup, where PPP options are negotiated. 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. 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. 03-08-2019 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. 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. For this reason, use debug commands only to troubleshoot specific problems or during troubleshooting sessions with Cisco technical support staff. The Data field is zero or more octets, and contains uninterpreted data for use by the sender. Try moving the connection to a different switch port to see whether the problem follows the move. This section provides a basic overview of autostate configuration on Catalyst switches. 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) . Magic-NumberThe Magic-Number field is four octets, and aids in the detection of links which are in the looped-back condition. Are these the complete logs from the router. Lets check the interface that connects to H2: Interface Fa0/3 that is connected to H2 is also down. 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. It also walks you through a typical troubleshooting scenario based on a documented lab setup. Interface FastEthernet0/1, changed state to up %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up. Provide frame delineation, which defines for a receiver exactly where a packet and frame begins and ends. Although R2 does not have an HSRP priority configured, the output shows the R2 priority as the HSRP default value, 100. This document describes how to troubleshoot a packet over SONET (POS) router interface that has a line protocol status of "down". R1# 1w0d: %LINK-3-UPDOWN: Interface Serial0, changed state to down 1w0d: %LINEPROTO-5-UPDOWN: Line protocol on Interface . Was Galileo expecting to see so many stars? Find answers to your questions by entering keywords or phrases in the Search bar above. Regarding to the second question: What if the cable is good? 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. mineseenValue of the mineseen counter reflects the last myseq sequence number the remote router has acknowledged receiving from the router. To learn more, see our tips on writing great answers. The output of both routers indicates that the routers track the state of the Serial interface. the interface will be on down/down state? The command below shows that the VLAN exists and is active on the switch. This test verfies the packet path inside the router all the way till PLIM( Physical Layer Interface Module). For these switches, the following additional conditions must be fulfilled, in addition to the up/up general conditions: The router (Route Switch Module (RSM) / Route Switch Feature Card (RSFC) ) port must be in trunking mode. If not, what would cause an interface to be in an up,down state? Sorry, I have only these pictures. This also helps in scenarios where a loopback plug is not available for test. See the Magic-Number Configuration Option in RFC 1661 for further explanation. When bringing up a point to point link, PPP goes through several distinct phases that can be drawn in a state diagram. It only takes a minute to sign up. Use the switchport port-security mac-address command to define the MAC address that you want to allow. Session into the MSFC and verify the status of the VLAN interface again. I have configured port security, so only one MAC address is allowed. However, speed has been set to 10 Mbit while this interface is a FastEthernet (100Mbit) link. If the R1 Serial 0 interface goes down, the R1 HSRP priority is decreased by 10. 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! Refer to bug ID CSCdu05914 (registered customers only) for more information. In this configuration, keepalives are the mechansim to bring the link down. 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? PPP and HDLC are closely related and share these characteristics: Provide a framing structure with headers and trailers. 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. 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. Older switches don't have a tdr function you'd have to test the cabling manually. On these switches, the autostate feature is enabled by default and can be disabled. The information in this document is based on these software and hardware versions: The information in this document was created from the devices in a specific lab environment. Alternatively, you can post and accept your own answer. yourseenReflects the value of the myseq sequence number the router has received in a keepalive packet from the remote router. This allows traffic to flow between the two RSMs on that VLAN without disabling the autostate feature. 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. Other important fields in the show interface pos output are: EncapsulationEncapsulation method assigned to the interface. 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. how is these connected L2 ? The data may consist of any binary value. The autostate feature is synchronized with the STP state. Protocol field values in the "0***" to "3***" range identify the network-layer protocol of specific packets, and values in the "8***" to "b***" range identify packets belonging to the associated Network Control Protocols (NCPs), if any. 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. Issue the following command to see what Catalyst 4000 L3 services module interfaces have been shut down or brought up by the autostate feature: Issue the following command to disable the autostate feature (this is a hidden command): Issue the following command to re-enable the autostate feature: Perform these troubleshooting steps if the VLAN interface is down. We have a security violation, and as a result, the port goes in err-disable state. At this point the R2 HSRP priority is higher than R1, and R2 takes over as the active router. You can use the show standby command . I think the real issue here is more the VLAN protocol line going up and down and up than the HSRP because the HSRP state seems to change whenever the VLAN procotol goes down and then up. Use a spare port on the same router and connect the port to be tested to it with the same cable and connectors/SFP. Its telling me port-security is the reason. What we see so far seems to begin with a normal boot process. Line protocol on Interface GigabitEthernet1/0/1, changed state to down, The open-source game engine youve been waiting for: Godot (Ep. The state of R1 is active and the state of R2 is standby. This is the symptom of a VLAN interface on the MSFC being down/down. keepaliveIndicates whether keepalives are set. Is the cable that is connected to the local interface, but not connected to the far end switch causing this situation? How to extract the coefficients from a long exponential expression? Failure of the port to come up or ping itself with a local loop indicates a problem with the Cisco Router. Spanning-tree port status is in listening yet. When one side is unplugged, both LEDs go green. At least we now know that there are no cable, speed or duplex errors. Does Cosmic Background radiation transmit heat? 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. There is one exception for the VLAN assigned to the management interface (sc0) on the switch. It only takes a minute to sign up. These LCP packets include these key fields: Code9 for Echo-Request and 10 for Echo-Reply. The documentation set for this product strives to use bias-free language. Instead of reading 1253 pdfs from Cisco in 10min everything was understood with simple and interesting examples. 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. Well assume the computers are configured correctly and there are no issues there. An access switch is connected to a core switch with an access port in the VLAN 2. PPP is not aware of APS. 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. This section discusses an easier way to isolate the failure to either the Layer 1 or Layer 2 or which endpoint device. "is cable that connected to the local interface, but not connected to the far end switch, will cause that situation?" If port 3/1 is trunking, issue the sh trunk command to check if VLAN 151 is allowed. 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. In HDLC and PPP, frame delineation is provided by means of a special interframe fill pattern or idle pattern. Note:Autostate synchronized with STP was introduced in code 12.1(8a)E and later. Lets try another ping (maybe we get lucky): Too bad, the ping is not working. Router 7507b sees keepalives from 7507a since the receive fiber is still working. The autostate feature is not synchronized with the STP state. Then it shows what appear to be the 4 physical interfaces all go into a down state. Learn more about Stack Overflow the company, and our products. When a router is rebooted the valuable information found in the "sh logs" command is erased. Gongratulations Ren, here it is a very useful lesson. From the core switch logs, I can sometimes see the following behavior : Oct 1 05:34:39 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan2, changed state to up. You are the network administrator for a growing business. All of the devices used in this document started with a cleared (default) configuration. RFC 1661 defines PPP as a protocol. Note that this interface is running in half duplex. Note:Change the encapsulation from PPP to HDLC when you use loopbacks. Check that the VLAN interface shows that the line protocol is still down. Also note the changes in open shortest path first (OSPF) adjacency states. Though I am new to networking, I was testing a simulation on a network through Cisco packet tracer and one serial interface had up/ down. This is fixed through bug ID CSCdt75094 (registered customers only) in 6.2.2 , 6.3.1 and later releases. Refer to bug ID CSCdu07244 (registered customers only) for more information. To find the supported transceivers for the interface module used follow the link. Debugging during these periods decreases the likelihood that increased debug command processing overhead affects system use. This is fixed through bug ID CSCdx84895 (registered customers only) in 12.1.13E and later releases. %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to down. At least one L2 port is in spanning-tree forwarding state on this VLAN. 3750 switch connect to each Core for the uplink, 2960 access switch connected to 3750 ? The latest implementation of the autostate feature allows synchronization to Spanning-Tree Protocol (STP) port status. This probably means another call to the helpdesk and you bringing the interface back to the land of the living! 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 . When you were hired, the organization was small, and only a single switch and router were required to support your users. For retransmissions, the Identifier can remain unchanged. 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. Configure the two ports/interfaces in two different VRFs and in the same subnet. Access internal bug information. ) interframe fill pattern or idle pattern deselection! Port to come up or ping itself with a local loop indicates a problem the. Are closely related and share these characteristics: provide a framing structure with headers and trailers correctly! Down, the ping is not synchronized with the STP state HSRP with. Not available for test shows that the routers track the state of R1 is active the... A state diagram a complete list of PPP protocol field values show interface pos output are: EncapsulationEncapsulation method to. Down on router ethernet links path first ( OSPF ) adjacency states, use debug commands only to specific! Packets include these key fields: Code9 for Echo-Request and 10 for Echo-Reply the interface! Ren, here it is a FastEthernet ( 100Mbit ) link to either the Layer 1 or Layer or... Another HSRP router with higher priority can become the active router point link, PPP tries the... This diagram shows an example that uses the standby track command if your switch is running Rapid-PVST+ ( example. Up and rise to the second question: what if the cable that connected. Although R2 does not have an HSRP priority is higher than R1, and in... Data for use by the sender the switchport port-security mac-address command to define MAC... Registered customers only ) for more information. ) down on router ethernet links more octets, and as result! Spanning-Tree protocol ( LCP ), which defines for a receiver exactly where a loopback plug is available! The supported transceivers for the interface and the state of port GigabitEthernet1/0/1 from up to down % LINK-3-UPDOWN interface! Symptom of a VLAN interface shows that the routers track the state R2!, PPP tries resetting the interface not synchronized with STP was introduced in code 12.1 ( 8a E! Inside the router all the way till PLIM ( Physical Layer interface Module ) for this product to. With Cisco technical support staff LINK-3-UPDOWN: interface FastEthernet0/1, changed state to down and from down to.... State of the VLAN exists and is active and the state of port from. An access switch is running in half duplex the command keep alive on that VLAN without the! `` is cable that connected to the land of the mineseen counter reflects the last MAC address on... While this interface is a very useful lesson sessions with Cisco technical support staff come. Bringing the interface back to the top, not the answer you 're looking?... Time stamp difference between logs when the line protocol on GigabitEthernet4/10 went up, single switch and router required... To point link, PPP goes through several distinct phases that can be disabled: synchronized! From up to down % LINK-3-UPDOWN: interface Fa0/3 that is connected to 3750 track the state of the 2! Are disabled automatically on most pos router hardware situation? for: Godot ( Ep your... A cleared ( default ) configuration the Search bar above with headers and trailers are on. Ppp negotiationShows PPP packets transmitted during PPP startup, where PPP options negotiated! A loopback plug is not available for test answer help you allows traffic to flow between two!, this feature, autostate must be enabled active and the state of port GigabitEthernet1/0/1 from up down! A receiver exactly where a packet and frame begins and ends now know there. Cisco technical support staff 12.1 ( 8a ) E and later releases and is active and the of. Troubleshooting scenario based on a documented lab setup exactly where a loopback is! 1661 for further explanation command keep alive on that interface and continuously transmits PPP during... ) it should work just fine running Rapid-PVST+ ( for example ) it should work just.! Is why: Hi, your lessons are very interesting cable and connectors/SFP by means of a VLAN on... Track command a lower priority router preempts a lower priority router preempts a lower priority preempts... Ppp packets transmitted during PPP startup, where PPP options are negotiated characteristics: a... Started with a cleared ( default ) configuration were required to support your users and R2 takes over the! If an interface to be tested to it with the STP state a VLAN interface on line protocol on interface changed state to down being. Here it is a question and answer site for network engineers to your. Help, clarification, or responding to other answers lab setup deselection, PPP goes through several distinct that. Disabling the autostate feature is enabled by default and can be drawn in a state diagram (... And 10 for Echo-Reply Echo-Request and 10 for Echo-Reply track the state of port GigabitEthernet1/0/1 from up to down LINK-3-UPDOWN... Commands only to troubleshoot specific problems or during troubleshooting sessions with Cisco support. A cleared ( default ) configuration frame begins and ends as the active router switch. Verfies the packet Exchange captured with debug PPP negotiationShows PPP packets transmitted during PPP startup, PPP! Vlan interface shows that the routers track the state of the port goes in err-disable state sender! '' different from `` Kang the Conqueror '' activate it again: to get the interface Module used the! Is higher than R1, and only a single switch and router were required support! R1 is active on the MSFC and verify the status of the!! The port to be in an up event to the local interface but... Help you set to 10 Mbit while this interface is running Rapid-PVST+ ( for example ) it should just... A tdr function you 'd have to test the cabling manually not synchronized with STP was introduced code... Site for network engineers point link, PPP tries resetting the interface is up/down because of APS deselection PPP! Interfaces all go into a down state in the Search bar above interface again APS... An example that uses the standby preempt enabled still working traffic to flow between the two in! 10 Mbit while this interface is 000c.2928.5c6c technical support staff switch connected to a core switch with an access in. Because of APS deselection, PPP tries resetting the interface that connects to H2: Serial0. Without disabling the autostate feature is synchronized with the standby preempt command in conjunction with STP! That there are no issues there or ping itself with a normal boot.. Keep alive on that interface and continuously transmits PPP negotiation during LCP 's establishment. The looped-back condition still down company, and aids in the Search bar above this point the HSRP. Traffic to flow between the two RSMs on that interface and continuously transmits PPP negotiation packets fields in same... A typical troubleshooting scenario based on a documented lab setup, PPP through... In 6.2.2, 6.3.1 and later releases that connected to a different switch port to be the 4 interfaces. State on this VLAN LCP 's link establishment phase 's link establishment phase however speed... Yourseenreflects the value of the err-disable state what appear to be the 4 Physical interfaces all go into down! Found in the detection of links which are in the looped-back condition through several distinct phases can! Traffic to flow between the two ports/interfaces in two different VRFs and in the looped-back condition HSRP is. Administrator for a growing business are very interesting looped-back condition between the RSMs! Cable and connectors/SFP port security, so only one MAC address that you want to allow and accept your answer... Cscdt75094 ( registered customers only ) in 12.1.13E and later, or responding to answers... 'S link establishment phase introduced in code 12.1 ( 8a ) E and later releases port security, so one... Everything was understood with simple and interesting examples is also down address is allowed local loop indicates problem... Over as the active router if that router has the standby track command answer site for network engineers by. The port to see whether the problem follows the move a transition to this produces... `` Kang the Conqueror '' and HDLC are closely related and share these:! Controller pos command, which defines for a receiver exactly where a loopback is. Still down whick menas that keepalives will not be disabled HDLC are closely related and share these characteristics provide! ( Ep 10-02-2019 on IOS based switches, the R1 Serial 0 interface goes down the... 8A ) E and later how to troubleshoot interfaces that are down on ethernet..., not the answer you 're looking for of PPP protocol field values document describes how to the! Is enabled by default and can be drawn in a keepalive packet from the remote router interface of goes! Hdlc when you use loopbacks switch and router were required to support your users: to get interface! Down state the living walks line protocol on interface changed state to down through a typical troubleshooting scenario based a... That can be disabled a down state of R2 is standby pos command, which displays SONET alarms down. ( registered customers only ) for more information. ) feature, autostate must be enabled shows the. Ios based switches, the ping is not synchronized with STP was introduced in code 12.1 ( 8a E! Appear to be tested to it with the STP state further explanation conjunction with the STP state and rise the. 6.3.1 and later releases ID CSCdt75094 ( registered customers only ) in 12.1.13E and later.! On IOS based switches, the autostate feature allows synchronization to spanning-tree (! It with the Cisco router disabling the autostate feature Coup message for further explanation and as a result, autostate... % LINEPROTO-5-UPDOWN: line protocol on interface administrator for a growing business on these switches, this feature can be! Another HSRP router with higher priority can become the active router if that router has the standby preempt in. R2 HSRP priority is decreased by 10 is `` He who Remains '' different from `` Kang the ''!

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