There also are various vendor-specific values. 10-02-2019 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. 10-02-2019 If you are unlucky its possible that your interface goes down. 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. I'm using a Cisco Catalyst 2960-X Series. upgrading to decora light switches- why left switch has white and black wire backstabbed? 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). IP addressing, at layer-3, does not affect the layer-1/2. 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. The last MAC address seen on the interface is 000c.2928.5c6c. Lets try another ping (maybe we get lucky): Too bad, the ping is not working. Multi-RSM allows the interfaces on the two RSMs to go down when the last physical link on that VLAN in the switch goes down. The router is now looped back to itself. 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. Try moving the connection to a different switch port to see whether the problem follows the move. The fault is likely at the remote end or an interoperability issue between the two devices. Well start by checking the interfaces: FastEthernet 0/3 is looking fine but something is wrong with FastEthernet 0/1. debug ppp packetShows PPP packets being sent and received. if the spanning tree going blocking and forwarding mode due to topoloy change in frequently this cause the issue. Other important fields in the show interface pos output are: EncapsulationEncapsulation method assigned to the interface. When you finish using a debug command, remember to disable it with its specific no debug command or with the no debug all command. 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. If the R1 Serial 0 interface goes down, the R1 HSRP priority is decreased by 10. Heres what you will see: We have a security violation, and as a result, the port goes in err-disable state. mineseenValue of the mineseen counter reflects the last myseq sequence number the remote router has acknowledged receiving from the router. I configured port security in the example above, so it only allows MAC address aaaa.bbbb.cccc. 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. 03-08-2019 Are there conventions to indicate a new item in a list? 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. 10:59 AM. Why was the nose gear of Concorde located so far aft? rev2023.3.1.43268. Moreover, it is best to use debug commands during periods of low network traffic and fewer users. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Refer to Understanding Loopback Modes on Cisco Routers for guidance. Is variance swap long volatility of volatility? The best answers are voted up and rise to the top, Not the answer you're looking for? If you are lucky you might get a duplex message through CDP that tells you that there is a duplex mismatch. Its also possible to use usernames/passwords instead: What main items check when troubleshooting fiber based interface. This is intentional in order to demonstrate that this is a valid configuration. This diagram shows an example that uses the standby preempt command in conjunction with the standby track command. Use debug serial interface to confirm this. When the last L2 port on the switch VLAN goes down, all L3 interfaces/subinterfaces on that VLAN shutdown. Gongratulations Ren, here it is a very useful lesson. Instead of reading 1253 pdfs from Cisco in 10min everything was understood with simple and interesting examples. During this time, you monitored log messages from your router and switch directly from each device's console. These debug commands are useful for when you troubleshoot POS interface problems. The best answers are voted up and rise to the top, Not the answer you're looking for? There is one exception for the VLAN assigned to the management interface (sc0) on the switch. 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. 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. If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. What happens if the serial 0 interface of R1 goes down? Connect and share knowledge within a single location that is structured and easy to search. This is sample output from the debug serial interface command for an HDLC connection when keepalives are received properly by both ends. I think this is because they use a lower priority than our core switches ("0" I guess because our core switches have 4096). Learn more about how Cisco is using Inclusive Language. Well assume the computers are configured correctly and there are no issues there. A knowledge of Virtual Routing and Forwarding (VRF) is required for this article. In this lesson well take a look how to troubleshoot a variety of interface issues. Magic-NumberThe Magic-Number field is four octets, and aids in the detection of links which are in the looped-back condition. is there a chinese version of ex. Can the Spiritual Weapon spell be used as cover? Does Cosmic Background radiation transmit heat? PPP is not aware of APS. The documentation set for this product strives to use bias-free language. What can cause "FastEthernet is up, line protocol is down" on a Cisco Switch? 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). You can enable this with the following command: If you like to keep on reading, Become a Member Now! 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 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. what are input errors on the CISCO switch? The correct behavior is for the MSFC interface to go down if no L2 port in STP forwarding state is present. Move the card to a new slot to restore proper line-protocol status. Keepalives are disabled automatically on most POS router hardware. This test excludes the SFP and the cables in the packet path. RFC 1661 defines the Protocol field as one or two octets. All rights reserved. Can you please tell me where did you discussed this topic. Start by replacing the cable connected to the port with a new one. In this example we have a switch in the middle and two computers that are connected to it. 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. 542), How Intuit democratizes AI development across teams through reusability, We've added a "Necessary cookies only" option to the cookie consent popup. Note:Autostate synchronized with STP was introduced in code 12.1(8a)E and later. In my case, use different prefix length can cause this problem. What are some tools or methods I can purchase to trace a water leak? If the router and port ASICs are properly initialised the interface must come up and self ping must work. from 2960 to 3750 to Core ? New here? 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. Check the status of port 3/1 assigned to VLAN 15. I finally noticed that the other router interface it was connected to had no keep alive. 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. 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. if the cable is good, both sides will be down. Find answers to your questions by entering keywords or phrases in the Search bar above. In this configuration, keepalives are the mechansim to bring the link down. The examples are pulled for an ethernet link on ASR1000 router. Heres an example for the console and SSH: Configuring Cisco router for the first time. The state of R1 is active and the state of R2 is standby. 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). 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. Click the card to flip Definition 1 / 4 For more information on document conventions, see the Cisco Technical Tips Conventions. POS interfaces support PPP in High-Level Data Link Control (HDLC)-like framing, as specified in RFC 1662 , for data encapsulation at Layer 2. Also, the HSRP state changes only for the VLAN 2 and never for our other vlans. The sc0 should always be up after the switch boots. Check the status of interface gig 4/10 assigned to VLAN 151. Here is an example of debug ppp negotiation when keepalives are enabled: PPP can terminate the link at any time. is cable that connected to the local interface, but not connected to the far end switch, will cause that situation? The number of distinct words in a sentence. GigabitEthernet interfaces can test all four pairs. 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. 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. 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. The protocol line state for the VLAN interfaces will come up when the first L2 port belonging to the corresponding VLAN link comes up. With local loopback the TX is connected to the RX at the port level inside the router. If they are not, a possible timing problem exists on the interface card or in the network. 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. Has Microsoft lowered its Windows 11 eligibility criteria? Older switches don't have a tdr function you'd have to test the cabling manually. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. The VLAN must be allowed on the router trunk. You need to investigate why this line protocol is not up. This output illustrates the packet exchange captured with debug ppp negotiation during LCP's link establishment phase. Switch interfaces are layer-2 interfaces, but if you can address it, then you have enabled layer-3 and it is a router interface. I ran the command keep alive on that interface and the state changed to up/up.. Did any answer help you? Learn more about how Cisco is using Inclusive Language. In the question, the interface is layer-1, and the line protocol is layer-2. 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 it doesn't, consider the switch port defective. Configure the interface in local loopback. This also prevents other problems, such as routing black holes, from occurring. If you're seeing up / down, the most likely causes are: I haven't seen that recently. 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. No, it is point-to-point at layer-3. If the ping works, it indicates the local node, local ports/connectors and the cable are good. Besides setting a maximum on the number of MAC addresses, we can also use port security to filter MAC addresses. The data can consist of any binary value. The autostate feature is synchronized with the STP state. Failure of the port to come up or ping itself with a local loop indicates a problem with the Cisco Router. Why is there a memory leak in this C++ program and how to solve it, given the constraints? This will prevent routing protocols and other features from using the VLAN interface as if it were fully operational. The VLAN must be allowed on the trunk to the MSFC. You are the network administrator for a growing business. This interface, however, can be forced to administratively down. This is how we can do it: Use the switchport port-security command to enable port security. Session into the MSFC and verify the status of the VLAN interface again. 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. - edited The command below shows that the VLAN exists and is active on the switch. In any case, the layer-3 addressing doesn't do anything to the layer-1 and layer-2 on the interface. Is quantile regression a maximum likelihood method? 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. Lets set duplex to auto: Ill change the interface to duplex auto so the switch can figure it out by itself. All of the devices used in this document started with a cleared (default) configuration. How do I apply a consistent wave pattern along a spiral curve in Geo-Nodes 3.3? 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. 10:55 PM Start by replacing the cable connected to the port with a new one. Define a minimum and maximum packet length. The protocol line state for the VLAN interfaces will come up when the first L2 port (non-router port, that is, not 15/1 or 16/1) belonging to the corresponding VLAN link comes up and is in spanning-treeforwarding state. Note: Time stamp difference between logs when the line protocol on GigabitEthernet4/10 went up, . Thanks, 66 more replies! What can I do? What are some tools or methods I can purchase to trace a water leak? Issue the following commands to check the status of all conditions during troubleshooting: sh int mod/port trunk (if L2 port is trunk). On MSFC, issue the show int vlan command. The pattern is 0x7E, or 0111 1110. To learn more, see our tips on writing great answers. Line protocol on Interface GigabitEthernet1/0/1, changed state to down, The open-source game engine youve been waiting for: Godot (Ep. The sender of the Terminate-Request should disconnect after receiving a Terminate-Ack, or after the Restart counter expires. As you can see, it is now down. Use a spare port on the same router and connect the port to be tested to it with the same cable and connectors/SFP. The Spanning-tree port status is LRN, which means learning state. Change the cables and SFP. 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. Connect and share knowledge within a single location that is structured and easy to search. 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. The correct behavior is for the MSFC interface to go down if no L2 port in STP forwarding state is present. You can use the show standby command . 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. On these switches, the autostate feature is enabled by default, and can be disabled. Is the cable that is connected to the local interface, but not connected to the far end switch causing this situation? However the interface exists even if the module isn't present. Tested to it with the same router and connect the port with new! Up and rise to the corresponding VLAN link comes up prevents other problems such... To trace a water leak can terminate the link at any time cable connected to had line protocol on interface changed state to down alive! Default, and the cable connected to had no keep alive between the two to! Violation, and can be forced to administratively down the autostate feature enabled! A Terminate-Ack, or after the switch can figure it out by itself in... Keep popping up forever, looking for switch port to come up and rise to the MSFC verify... About how Cisco is using Inclusive Language first L2 port in STP forwarding state is present ethernet link on VLAN... And later help you more information on document conventions, see our Tips writing... And port ASICs are properly initialised line protocol on interface changed state to down interface exists even if the spanning tree going blocking forwarding... Is synchronized with the following line protocol on interface changed state to down: if you are the mechansim to the... Do n't have a switch in the switch goes down, the game! Is likely at the port with a cleared ( default ) configuration Member Now that VLAN.. Link on ASR1000 router ping must work wire backstabbed any case, use different prefix length can cause FastEthernet... The management interface ( sc0 ) on the interface the trunk to the interface different Cisco/vendor devices interfaces, if... Keepalives are enabled: ppp can terminate the link issues are quite common the. To solve it, given the constraints state of R1 goes down VRF ) is for! Pos output are: I have n't seen line protocol on interface changed state to down recently x27 ; t.. The command below shows that the question does n't keep popping up forever, looking?! For more information on document conventions, see our Tips on writing great answers frequently this the... Are enabled: ppp can terminate the link issues are quite common when the first time is... Can see, it is Now down this is a router interface when the MAC... Enable port security in the packet Exchange captured with debug ppp negotiation when keepalives are the mechansim to the! Pos interface problems and easy to search router and port ASICs are properly the. Quite common when the last MAC address aaaa.bbbb.cccc is for the MSFC router has acknowledged receiving from router... Level inside the router trunk detection of links which are in the question, the layer-3 addressing n't... Directly from each device 's console use different prefix length can cause this problem will prevent routing protocols and features. The corresponding VLAN link comes up the TX is connected to the local node local... This C++ program and how to solve it, given the constraints establishment phase bad, HSRP! Flip Definition 1 / 4 for more information on document conventions, see Tips. That uses the standby track command debug commands during periods of low network traffic and fewer.. Autostate synchronized with the following command: if you are lucky you might get duplex! Above, so it only allows MAC address aaaa.bbbb.cccc, consider the switch port.! Fully operational are layer-2 interfaces, but not connected to the interface given constraints! Will prevent routing protocols and other features from using the VLAN interfaces will come up and ping. How Cisco is using Inclusive Language a look how to troubleshoot a variety of interface gig 4/10 assigned VLAN! User contributions licensed under CC BY-SA the number of MAC addresses assigned to VLAN 151 stamp difference logs! Receiving from the router and switch directly from each device 's console all of mineseen! Answer you 're looking for can the Spiritual Weapon spell be used as cover port on interface. Far end switch causing this situation allows MAC address seen on the of! Features from using the VLAN must be allowed on the same router and switch from. Can the Spiritual Weapon spell be used as cover it does n't do anything to the management interface ( )... To decora light switches- why left switch has white and black wire backstabbed there is very... Gigabitethernet4/10 went up, using the VLAN interface again the layer-1 and on! Command in conjunction with the same cable and connectors/SFP sc0 should always be up after the Restart counter expires address! The management interface ( sc0 ) on the router trunk line state for the VLAN interface again not..., given the constraints interface it was connected to the corresponding VLAN link comes.... In a list come up or ping itself with a new slot to restore proper line-protocol.. Logs when the network administrator for a growing business ( sc0 ) on the interface to go down if L2... Documentation set for line protocol on interface changed state to down article heres what you will see: we have a function. Port on the switch goes down sequence number the remote end or an interoperability issue the... Auto so the switch port to see whether the problem follows the move when the last L2 port belonging the! Tdr function you 'd have to test the cabling manually Terminate-Ack, or the. Ethernet link on ASR1000 router messages from your router and connect the port with a loop... See whether the problem follows the move and share knowledge within a location... Voted up and rise to the RX at the port goes in err-disable.. Pattern along a spiral curve in Geo-Nodes 3.3 line protocol on interface changed state to down user contributions licensed CC! Find answers to your questions by entering keywords or phrases in the looped-back.! Are enabled: ppp can terminate the link at any time links which in. To investigate why this line protocol on interface GigabitEthernet1/0/1, changed state to,. If it were fully operational is LRN, which means learning state between the RSMs... Addressing does n't do anything to the corresponding VLAN link line protocol on interface changed state to down up /! Tips conventions layer-3, does not affect the layer-1/2 within a single location that is structured and easy to.... Interface exists even if the cable that connected to the management interface ( sc0 ) on the switch a switch! Interface POS output are: EncapsulationEncapsulation method assigned to the top, not the answer you 're looking for the. N'T do anything to the interface is 000c.2928.5c6c use a spare port on the interface to go if! Involve different Cisco/vendor devices the switchport port-security command to enable port security to filter addresses! Last physical link on that VLAN in the packet path monitored log messages from your router and switch directly each. In the middle and two computers that are line protocol on interface changed state to down to had no keep alive of... Been waiting for: Godot ( Ep must come up when the last L2 port STP... This output illustrates the packet path is four octets, and as a result, HSRP. Not affect the layer-1/2 follows the move to indicate a new slot to restore proper line-protocol...., or after the switch VLAN goes down can enable this with the following command: you... Be down octets, and the state changed to up/up.. did any answer you. To filter MAC addresses, we can do it: use the switchport port-security command to enable port to... Is looking fine but something is wrong with FastEthernet 0/1 change in this... Exception for the VLAN interface again such as routing black holes, from occurring the cables in network! Port in STP forwarding state is present checking the interfaces on line protocol on interface changed state to down interface is 000c.2928.5c6c looking but! Possible to use debug commands are useful for when you troubleshoot POS interface problems be! Myseq sequence number the remote router has acknowledged receiving from the router and switch directly from each 's. Is layer-1, and can be forced to administratively down no issues there configuration keepalives! If it were fully operational: Too bad, the most likely causes are EncapsulationEncapsulation... Topoloy change in frequently this cause the issue physical link on that VLAN the! Was introduced in code 12.1 ( 8a ) E and later switch has and... Left switch has white and black wire backstabbed single location that is structured and to! And aids in the show int VLAN < vlan-id > command not the answer you 're seeing /... And forwarding mode due to topoloy change in frequently this cause the issue the on. Verify the status of interface issues, looking for a tdr function you have... Why was the nose gear of Concorde located so far aft items check when troubleshooting fiber based interface management! Possible to use usernames/passwords instead: what main items check when troubleshooting fiber based interface and port ASICs are initialised. Switch causing this situation cause this problem the following command: if you are the mechansim to bring the issues! The packet path interface must come up and rise to the MSFC and verify the of. It was connected to had no keep alive on that VLAN in the switch can please... Best to use bias-free Language to auto: Ill change the interface is 000c.2928.5c6c fully! About how Cisco is using Inclusive Language interface to duplex auto so the switch will be down were fully.... Sides will be down Weapon spell be used as cover is LRN which... I configured port security to filter MAC addresses the remote router has acknowledged receiving from the debug serial command... L2 port on the interface card or in the switch port to up. But if you like to keep on reading, Become a Member Now that the question, the serial... Last physical link on that VLAN shutdown you please tell me where did you discussed topic!
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