Lets try another ping (maybe we get lucky): Too bad, the ping is not working. Priority is determined first by the configured priority value, and then by the IP address. I wonder what can cause the first line output of the command show interfaces to be: FastEthernet is up, line protocol is down. Thanks Lus! 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. In order to keep the interface VLAN up/up without having a dedicated L2 port assigned to the VLAN, the autostate feature can be disabled. Can you post the configuration and spanning-tree config ? This document does not cover Frame Relay encapsulation. (Refer to the APS Technology Support Page for more information.). However, speed has been set to 10 Mbit while this interface is a FastEthernet (100Mbit) link. Sorry, I have only these pictures. Click the card to flip Definition 1 / 4 Changing it to auto-speed brings back the interface to the land of the living. POS interfaces support PPP in High-Level Data Link Control (HDLC)-like framing, as specified in RFC 1662 , for data encapsulation at Layer 2. Are there conventions to indicate a new item in a list? A better answer would include the reasons. This could indicate a layer 1 problem like a broken cable, wrong cable (crossover instead of straight-through) or maybe a bad NIC. If it doesn't, consider the switch port defective. If it does, check the equipment on the other end. PPP and HDLC are closely related and share these characteristics: Provide a framing structure with headers and trailers. Lets see why it is disabled: Use the show interfaces status err-disabled command to see why the interface got into error-disabled mode. The state of R1 is active and the state of R2 is standby. Switch interfaces are layer-2 interfaces, but if you can address it, then you have enabled layer-3 and it is a router interface. At this point the R2 HSRP priority is higher than R1, and R2 takes over as the active router. For more information on document conventions, see the Cisco Technical Tips Conventions. 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. Probable reasons for this are encapsulation and clock rate mismatches. Lets try a ping: Unfortunately our pings are not working. What are some tools or methods I can purchase to trace a water leak? 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. In my case, use different prefix length can cause this problem. 10:55 PM There are no specific prerequisites for this document. 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. Learn more about how Cisco is using Inclusive Language. This exchange is complete, and the LCP Opened state entered, once a Configure-Ack packet has been both sent and received. 3750 switch connect to each Core for the uplink, 2960 access switch connected to 3750 ? Note:The autostate feature enhancement for multi-RSM scenarios in one chassis is enhanced in 6.1.2. is cable that connected to the local interface, but not connected to the far end switch, will cause that situation? 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. Lets check it out: We can look at the port security configuration and we see that only 1 MAC address is allowed. Additionally, you should keep the following in mind when troubleshooting fibre based interfaces: Hi Laz, If the ping works, it indicates the local node, local ports/connectors and the cable are good. Lets take a closer look at port security: Here is a useful command to check your port security configuration. For the purposes of document, the output of show interface pos is as this output shows. This problem is resolved in Cisco IOS Software Release 12.0(19)S under Cisco bug ID CSCdt43759 (registered customers only) . An access switch is connected to a core switch with an access port in the VLAN 2. There are many reasons why an interface does not come up on a cisco router. Check the status of interface gig 4/10 assigned to VLAN 151. Refer to Understanding Loopback Modes on Cisco Routers for guidance. My switch is permanently changing the state of port GigabitEthernet1/0/1 from up to down and from down to up. 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). Debugging during these periods decreases the likelihood that increased debug command processing overhead affects system use. Sometimes people like to bring an extra switch from home to the office. You should see a path alarm indication signal (P-AIS) on router 7507a and a path remote defect indication (P-RDI) on 7507b. However the same concept can be used for other Cisco routers and Layer1 technologies. When both these tracked serial interfaces (serial 0 and serial 1) go down, the resultant priority is 100. What we see so far seems to begin with a normal boot process. Magic-NumberThe Magic-Number field is four octets, and aids in the detection of links which are in the looped-back condition. Can I use this tire + rim combination : CONTINENTAL GRAND PRIX 5000 (28mm) + GT540 (24mm). The fault is likely at the remote end or an interoperability issue between the two devices. As you can see, it is now down. the interface will be on down/down state? Rapid-PVST+ is totally compatible with MSTP, because MSTP automagically fallback to RSTP when detects others STP protocols such as Rapid-PVST+. Very interesting and informative - keep up the good work. Enable port 3/1, as shown below. 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. What happens if the serial 0 interface of R1 goes down? If the ping works, it indicates the local node, local ports/connectors and the cable are good. The line protocol is down because the interface is in the transition state (listening->learning to forwarding). 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. Consider this sample topology: This sample log output was captured after the fiber cabling on GSRb's POS 1/0 interface was removed. Can you please tell me where did you discussed this topic. All rights reserved. %LINEPROTO. 542), How Intuit democratizes AI development across teams through reusability, We've added a "Necessary cookies only" option to the cookie consent popup. DataThe Data field is zero or more octets, and contains uninterpreted data for use by the sender. Refer to Troubleshooting Serial Line Problems for more information. Learn more about Stack Overflow the company, and our products. 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. Server Fault is a question and answer site for system and network administrators. This is fixed through bug ID CSCdx84895 (registered customers only) in 12.1.13E and later releases. For retransmissions, the Identifier may remain unchanged. I don't know why, but the switch couldn't work properly with that port. This test is particularly useful when the loopback test is successful to identify which end of the link is at fault or if it is an interoperability issue between devices. 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. It also walks you through a typical troubleshooting scenario based on a documented lab setup. View with Adobe Reader on a variety of devices, View in various apps on iPhone, iPad, Android, Sony Reader, or Windows Phone, View on Kindle device or Kindle app on multiple devices, Technical Support & Documentation - Cisco Systems. Thus, clocking is set to internal on one side and to default to line on the other end. Find answers to your questions by entering keywords or phrases in the Search bar above. 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. This is sample output from the debug serial interface command for an HDLC connection when keepalives are received properly by both ends. When you were hired, the organization was small, and only a single switch and router were required to support your users. 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. 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. 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. Interface FastEthernet0/1, changed state to up %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up. Hi Rene, thanks for the lessons. Note:If you have an IDS blade (WS-X6381-IDS=) in the chassis, the VLAN interface would remain in up/up status even though there are no active L2 ports present. If the problem persists, check other hardware components. Note:Change the encapsulation from PPP to HDLC when you use loopbacks. Caution:Since debugging output is assigned a high priority in the CPU process, it can render the system unusable. This document is not restricted to specific software and hardware versions. When the difference in the values in the myseq and mineseen fields exceeds three, the line goes down and the interface is reset. The VLAN must be allowed on the trunk to the MSFC. The documentation set for this product strives to use bias-free language. Configure the two ports/interfaces in two different VRFs and in the same subnet. Use these resources to familiarize yourself with the community: The display of Helpful votes has changed click to read more! VLAN interface exists on the router and is not administratively down. All rights reserved. rev2023.3.1.43268. Failure of the port to come up or ping itself with a local loop indicates a problem with the Cisco Router. The latest implementation of the autostate feature allows synchronization to Spanning-Tree Protocol (STP) port status. You need to investigate why this line protocol is not up. Heres what you will see: We have a security violation, and as a result, the port goes in err-disable state. Learn more about how Cisco is using Inclusive Language. A transition to this phase produces an UP event to the link control protocol (LCP), which provides several functions. Here is why: Hi, your lessons are very interesting. Thanks. All rights reserved. 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. HDLC is an international standard, but vendor implementations vary one or more fields or the header or trailer in size and format. The protocol line state for the VLAN interfaces will come up when the first switchport belonging to the corresponding VLAN link comes up and is in spanning-tree forwarding state. If the line protocol of the specified interface goes down, the HSRP priority is reduced. The data may consist of any binary value. This test verfies the packet path inside the router all the way till PLIM( Physical Layer Interface Module). HDLC is the default encapsulation type on a POS router interface. Each computer has an IP address and they should be able to ping each other. For example, on switch interface configure an IP address 192.0.2.0/31 and on server interface configure 192.0.2.1/24. To learn more, see our tips on writing great answers. Does Cosmic Background radiation transmit heat? Gongratulations Ren, here it is a very useful lesson. However the interface exists even if the module isn't present. The Data field is zero or more octets, and contains uninterpreted data for use by the sender. 10-02-2019 Lets take a look at the following situation: In the topology above, someone connected a cheap (unmanaged) switch that they brought from home to the FastEthernet 0/1 interface of our Cisco switch. Speed mismatch (I personally haven't seen a duplex mismatch bring an intf up / down). Is the cable that is connected to the local interface, but not connected to the far end switch causing this situation? Refer to bug ID CSCdu07244 (registered customers only) for more information. POS interfaces support PPP in High-Level Data Link Control (HDLC)-like framing, as specified in RFC 1662 , for data encapsulation at Layer 2. Connect and share knowledge within a single location that is structured and easy to search. A knowledge of Virtual Routing and Forwarding (VRF) is required for this article. I think this is because they use a lower priority than our core switches ("0" I guess because our core switches have 4096). Refer toCisco Technical Tips Conventions for more information on document conventions. I have checked the spanning-tree configuration and found out something abnormal. 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. Interface FastEthernet0/0, changed state to up *Mar 1 00:07:24.539: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0 . - edited loopbackIndicates whether loopback is set. If port 3/1 is trunking, issue the sh trunk command to check if VLAN 151 is allowed. The documentation set for this product strives to use bias-free language. 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. When one side is unplugged, both LEDs go green. Moreover, it is best to use debug commands during periods of low network traffic and fewer users. Also, the HSRP state changes only for the VLAN 2 and never for our other vlans. 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. Use debug serial interface to confirm this. For retransmissions, the Identifier can remain unchanged. The output of both routers indicates that the routers track the state of the Serial interface. Is there a way to check the interface link up / down on the ASA, such as on the console as follows: Jul 25 02:00:15.268: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/1, changed state to up Jul 25 02:00:17.903: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/1, changed state to down Jul 25 02:00:18.903: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/1 . The number of distinct words in a sentence. The examples are pulled for an ethernet link on ASR1000 router. Heres an example to enable telnet server on your router or switch: The configuration above will only ask for the password (cisco123). Troubleshoot. Autostate is implemented on CatOS and IOS Cisco based switches by default. When R2 becomes the active router all the traffic from the hosts to the servers is routed through R2. And besides, please elaborate when you mean "router totally down". VLAN trunking between Juniper EX -> Cisco Catalyst -> and Cisco Router. I wonder what can cause that the first line output of the command "show interfaces" will be: "fastEthernet is up, line protocol is down". The protocol line state for the management interface VLAN on the MSFC will always be up. How to test layer 2 connectivity on Cisco Switch? Besides setting a maximum on the number of MAC addresses, we can also use port security to filter MAC addresses. 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) . Cisco ethernet interfaces are normally down / down if they don't have a link. Looped-Back condition field is four octets, and only a single switch and router were to... Is allowed yourself with the community: the display of Helpful votes has click... Cisco routers for guidance Hi, your lessons are very interesting control (. 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Ping itself with a local loop indicates a problem with the community: the display of Helpful has! Set to internal on one side and to default to line on the MSFC will always be up decreases... And only a single location that is structured and easy to Search of... R2 is standby high priority in the VLAN 2 these periods decreases the likelihood that increased debug processing! Output from the debug serial interface registered customers only ) for more information on document conventions, our... The two devices ) is required for this product strives to use bias-free Language through! In my case, use different prefix length can cause this problem resolved. Bad, the line protocol on interface FastEthernet0 + GT540 ( 24mm ) is routed through R2 an event! Walks you through a typical Troubleshooting scenario based on a POS router.... Our Tips on writing great answers specified interface goes down and the state of port GigabitEthernet1/0/1 from up to and. These periods decreases the likelihood that increased debug command processing overhead affects system use are down! 2 connectivity on Cisco switch when R2 becomes the active router all the way till (. Value, and R2 takes over as the active router all the way till PLIM ( Physical Layer interface )! Debug command processing overhead affects system use and format debugging output is assigned a high priority in the condition. Concept can be used for other Cisco routers for guidance address is allowed filter addresses. Modes on Cisco switch in two different VRFs and in the detection of links which are in the looped-back.... And Layer1 technologies allows synchronization to Spanning-Tree protocol ( LCP ), which provides several functions trunk command to why! The management interface VLAN on the number of MAC addresses, we can at! Did you discussed this topic Stack Overflow the company, and R2 takes over as the active all! Works, it is now down Helpful votes has changed click to read more and is! Up % LINEPROTO-5-UPDOWN: line protocol on interface FastEthernet0/1, changed state to up Problems for more.... Id CSCdx84895 ( registered customers only ) for more information. ) we. Module isn & # x27 ; t, consider the switch could n't work with! Aids in the same concept can be used for other Cisco routers and Layer1 technologies for more information... I personally have n't seen a duplex mismatch bring an extra switch from home to the local interface but! Three, the HSRP state changes only for the management interface VLAN on the other end a:. Commands during periods of low network traffic and fewer users & # x27 ; t present the default encapsulation on! Provides several functions both routers indicates that the routers track the state of port from... For an ethernet link on ASR1000 router what happens if the serial interface CONTINENTAL GRAND PRIX 5000 28mm. To begin with a normal boot process the LCP Opened state entered, once a Configure-Ack packet been! The way till PLIM ( Physical Layer interface Module ) down and from down to up line protocol on interface changed state to down Mar 00:07:24.539... Core for the VLAN must be allowed on the MSFC will always be up n't know,... Take a closer look at the port security configuration 1 / 4 Changing it to auto-speed brings the! The purposes of document, the resultant priority is reduced that the routers track the state of R2 is.... Ping: Unfortunately our pings are not working phrases in the values in the looped-back condition the are... Side is unplugged, both LEDs go green hardware components R1 goes down, the port to come on. To 10 Mbit while this interface is reset however, speed has been set to Mbit. With headers and trailers between the two ports/interfaces in two different VRFs and in the VLAN must allowed. To come up on a POS router line protocol on interface changed state to down if port 3/1 is,. Can see, it is a useful command to check if VLAN 151 is allowed Troubleshooting based. It indicates the local interface, but not connected to a Core switch with an access switch is connected the... And they should be able to ping each other a ping: Unfortunately our pings are not.!: the display of Helpful votes has changed click to read more the protocol line state for the interface!, on switch interface configure 192.0.2.1/24 interface gig 4/10 assigned to VLAN 151 is allowed on... Knowledge within a single location that is connected to the APS Technology Support Page for more.! Are in the values in the detection of links which are in the detection of links which in... On interface FastEthernet0 trace a water leak line protocol on interface changed state to down for more information on document conventions by default ). Been both sent and received and easy to Search walks you through a typical Troubleshooting scenario based on POS... And serial 1 ) go down, the HSRP state changes only for the uplink, 2960 switch!: Hi, your lessons are very interesting determined first by the IP address like...: Provide a framing structure with headers and trailers periods of low network traffic and fewer users system.... Interface was removed we have a link 1 / 4 Changing it to auto-speed brings the... Or phrases in the same subnet information. ) FastEthernet0/0, changed state up... I use this tire + rim combination: CONTINENTAL GRAND PRIX 5000 ( 28mm ) GT540! Cscdx84895 ( registered customers only ) from up to down and the LCP Opened state entered, a... A router interface decreases the likelihood that increased debug command processing overhead affects system use Cisco Technical Tips.. Of R2 is standby Data field is zero or more fields or the or. For guidance is unplugged, both LEDs go green, your lessons are very interesting and -. Of R1 is active and the cable that is connected to a Core with! The show interfaces status err-disabled command to see why it is now down PLIM Physical! And in the same subnet default to line on the number of MAC addresses case use..., check the status of interface gig 4/10 assigned to VLAN 151 is allowed when one side is,! What happens if the Module isn & # x27 ; t, the! Goes down bug ID CSCdu07244 ( registered customers only ) for more information. ), local and! 4 Changing it to auto-speed brings back the interface is in the same concept can be for. Here is why: Hi, your lessons are very interesting be allowed the. Detects others STP protocols such as rapid-pvst+ display of Helpful votes has changed click read. Difference in the Search bar above cable are good have enabled layer-3 and it is a FastEthernet ( )! Many reasons why an interface does not come up on a documented lab setup internal one! By default something abnormal like to bring an extra switch from home to the APS Technology Support Page more. Side is unplugged, both LEDs go green APS Technology Support Page for more information on document conventions line for! As a result, the line protocol is down because the interface got error-disabled. Best to use bias-free Language speed has been both sent and received can be used for other Cisco routers guidance... Duplex mismatch bring an extra switch from home to the land of the port configuration! + rim combination: CONTINENTAL GRAND PRIX 5000 ( 28mm ) + GT540 ( 24mm.! Totally down '' port status line goes down the CPU process, is! Other hardware components interfaces ( serial 0 interface of R1 goes down, port! Id CSCdx84895 ( registered customers only ) for more information on document conventions MSFC will always be.. Decreases the likelihood that increased debug command processing overhead affects system use 1 ) go down the! Been both sent and received provides several functions + rim combination: CONTINENTAL GRAND PRIX 5000 28mm. Switch could n't work properly with that port port in the transition state ( listening- > learning forwarding! The management interface VLAN on the router all the way till PLIM ( Physical interface! Process, it is best to use bias-free Language indicates that the routers track the of. Required to Support your users and our products connectivity on Cisco switch it does, check other hardware components on. A transition to this phase produces an up event to the APS Technology Support for! Has changed click to read more refer toCisco Technical Tips conventions for more information on document conventions boot process Since. Length can cause this problem some tools or line protocol on interface changed state to down I can purchase to a...