Find answers to your questions by entering keywords or phrases in the Search bar above. 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). How can I explain to my manager that a project he wishes to undertake cannot be performed by the team? When a higher priority router preempts a lower priority router, the router sends a Coup message. 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. This sample output captures the LCP link configuration stage on a POS interface: Note:A POS interface configured with PPP encapsulation continually tries to establish a PPP session. The number of distinct words in a sentence. Start by replacing the cable connected to the port with a new one. Is variance swap long volatility of volatility? In my case, use different prefix length can cause this problem. is there a chinese version of ex. If your network is live, ensure that you understand the potential impact of any command. is cable that connected to the local interface, but not connected to the far end switch, will cause that situation? Is quantile regression a maximum likelihood method? Line protocol on Interface GigabitEthernet1/0/1, changed state to down, The open-source game engine youve been waiting for: Godot (Ep. 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. 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. As a result, our Cisco switch will learn the MAC address of H1 and H2 on its FastEthernet 0/1 interface. This should ring a couple of alarm bells (at least it means we are onto something). And if the cable is bad? Side A would be admin down, and side B would be down/down. Instead of reading 1253 pdfs from Cisco in 10min everything was understood with simple and interesting examples. 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. %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to down. Perform a local loop test first, and then a remote test. Initially, both the interfaces are up and the HSRP priority of the interface is 120, as in the show standby command output: This reduces the HSRP priority by 10from 120 to a value of 110. 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 Session into the MSFC and verify the status of the VLAN interface again. Does Cast a Spell make you a spellcaster? This is sample output from the debug serial interface command for an HDLC connection when keepalives are received properly by both ends. 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 . When a router is rebooted the valuable information found in the "sh logs" command is erased. Thats looking better! Note:The autostate feature enhancement for multi-RSM scenarios in one chassis is enhanced in 6.1.2. When an external event, such as carrier detection or network administrator configuration, indicates that the physical layer is ready to be used, PPP proceeds to the link establishment phase. Thus, clocking is set to internal on one side and to default to line on the other end. Lets check it out: We can look at the port security configuration and we see that only 1 MAC address is allowed. Ping from one VRF to the other VRF. The router is now looped back to itself. I have checked the spanning-tree configuration and found out something abnormal. Why was the nose gear of Concorde located so far aft? As you can see, L2 ports 3/1 and 15/1(MSFC) are assigned to VLAN 151. The documentation set for this product strives to use bias-free language. A statement without backup is typically suspect. Is the Dragonborn's Breath Weapon from Fizban's Treasury of Dragons an attack? Issue the following commands to check the status of all conditions during troubleshooting: sh int mod/port trunk (if L2 port is trunk). *Mar 1 01:54:39.699: %LINEPROTO-5-UPDOWN: Line protocol on Interface Tunnel0, changed state to up. Provide frame delineation, which defines for a receiver exactly where a packet and frame begins and ends. 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. The end of the field is indicated by the Length. We have a security violation, and as a result, the port goes in err-disable state. In any case, the layer-3 addressing doesn't do anything to the layer-1 and layer-2 on the interface. My router is a FRITZ!Box 6690 Cable with four LAN ports. Click here for a complete list of PPP protocol field values . A VLAN interface will be brought up after the L2 port has had time to converge (that is, transition from listening-learning to forwarding). If the problem persists, check other hardware components. If you're seeing up / down, the most likely causes are: I haven't seen that recently. In the question, the interface is layer-1, and the line protocol is layer-2. One function is determination when a link is functioning properly and when it is failing. POS interfaces support PPP in High-Level Data Link Control (HDLC)-like framing, as specified in RFC 1662 , for data encapsulation at Layer 2. Can you post the configuration and spanning-tree config ? Other than quotes and umlaut, does " mean anything special? Check the status of port 3/1 assigned to VLAN 15. Consider this sample topology: This sample log output was captured after the fiber cabling on GSRb's POS 1/0 interface was removed. 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. GigabitEthernet interfaces can test all four pairs. Spanning-tree port status is in listening yet. There are no specific prerequisites for this document. This is not the MAC address of my computer, so its perfect for demonstrating a violation. This is the symptom of a VLAN interface being in up/down status. With local loopback the TX is connected to the RX at the port level inside the router. Troubleshoot. These LCP packets include these key fields: Code9 for Echo-Request and 10 for Echo-Reply. 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. Is the set of rational points of an (almost) simple algebraic group simple? 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. 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. The data may consist of any binary value. If port 3/1 is trunking, issue the sh trunk command to check if VLAN 151 is allowed. R1# 1w0d: %LINK-3-UPDOWN: Interface Serial0, changed state to down 1w0d: %LINEPROTO-5-UPDOWN: Line protocol on Interface . Is quantile regression a maximum likelihood method? from 2960 to 3750 to Core ? Here is why: Hi, your lessons are very interesting. *Jun 15 01:32:19.759: %SYS-5-CONFIG_I: Configured from memory by console*Jun 15 01:32:20.179: %LINEPROTO-5-UPDOWN: Line protocol on Interface NVI0, changed state to up*Jun 15 01:32:20.723: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan613, changed state to down*Jun 15 01:32:21.115: %LINK-5-CHANGED: Interface Embedded-Service-Engine0/0, changed state to administratively down*Jun 15 01:32:22.147: %LINEPROTO-5-UPDOWN: Line protocol on Interface Embedded-Service-Engine0/0, changed state to down*Jun 15 01:32:22.919: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/0, changed state to down*Jun 15 01:32:22.919: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/1, changed state to down*Jun 15 01:32:22.919: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/2, changed state to down*Jun 15 01:32:22.919: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/3, changed state to down, did you check the show version before it was rebooted to see what it provided or take a show tech before it was rebooted , rebooting it would have cleared the errors and reset the logs , do you have syslog in place on the router so the logs went to any other server. Configure the two ports/interfaces in two different VRFs and in the same subnet. This section discusses an easier way to isolate the failure to either the Layer 1 or Layer 2 or which endpoint device. 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. how is these connected L2 ? As you can see, it is now down. Avoid configuring APS on a POS interface with PPP encapsulation. 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. The line protocol on an interface configured with PPP comes up only when all LCP and NCP sessions are negotiated successfully. POS interfaces support multiple encapsulations - HDLC, PPP and Frame Relay. PPP is not aware of APS. There is one exception for the VLAN assigned to the management interface (sc0) on the switch. Is lock-free synchronization always superior to synchronization using locks? whick menas that keepalives will not be receiver on the far end. Terminate LCP packets include these key fields: Code5 for Terminate-Request and 6 for Terminate-Ack. When both these tracked serial interfaces (serial 0 and serial 1) go down, the resultant priority is 100. 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.". Possible triggers include loss of carrier, authentication failure, link quality failure, the expiration of idle-period timer, or the administrative closing of the link. Thus, packet over SONET is more accurately PPP over SONET or HDLC over SONET. 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. The protocol line state for the management interface VLAN on the MSFC will always be up. RFC 1661 defines PPP as a protocol. Ethernet0 is administratively down, line protocol is down: This output indicates that a local interface has been manually shut down using the shutdown command. Glad to hear it was useful to you. DataThe Data field is zero or more octets, and contains uninterpreted data for use by the sender. The line protocol being down indicates a clocking or framing problem. - Use syslog to implement centralized logging. Line Protocol Is Down With PPP RFC 1661 defines PPP as a protocol. Lets try a ping: Unfortunately our pings are not working. Change the cables and SFP. Also, the HSRP state changes only for the VLAN 2 and never for our other vlans. Asking for help, clarification, or responding to other answers. Lets walk through a couple of scenarios. The interface will be in up/down state? This is the configuration for each router: Note: R2 does not have a standby IP address configured. Lets see why it is disabled: Use the show interfaces status err-disabled command to see why the interface got into error-disabled mode. New here? Yes, the 2960 is connected to the CORE2 with a L2 link (access port in the VLAN2). 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, . Ill show you what happens in a bit. Suspicious referee report, are "suggested citations" from a paper mill? Lets set duplex to auto: Ill change the interface to duplex auto so the switch can figure it out by itself. 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. Cisco ASR 1000 Series Aggregation Services Routers, 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, There are many reasons why an interface does not come up on a cisco router. The best answers are voted up and rise to the top, Not the answer you're looking for? Probable reasons for this are encapsulation and clock rate mismatches. Changing it to auto-speed brings back the interface to the land of the living. Enable port 3/1, as shown below. If the R1 Serial 0 interface goes down, the R1 HSRP priority is decreased by 10. 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. PPP and HDLC are closely related and share these characteristics: Provide a framing structure with headers and trailers. 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). On some CatOS platforms, this feature can be disabled in order to allow redundancy in special scenarios. This probably means another call to the helpdesk and you bringing the interface back to the land of the living! This problem is resolved in Cisco bug ID CSCdp86387 (registered customers only) . You need to investigate why this line protocol is not up. How to test layer 2 connectivity on Cisco Switch? How is the "active partition" determined when using GPT? However, although closely related, PPP and HDLC are not the same, and different debug commands are used to troubleshoot line protocol problems. This test verfies the packet path inside the router all the way till PLIM( Physical Layer Interface Module). According to point 3 as I understand Refer toCisco Technical Tips Conventions for more information on document conventions. Sorry, I have only these pictures. Here is a conceptual diagram of the switches involved into this situation : CORE SWITCH 1 [HSRP active] (3750X) <------ trunk link with many vlans ------>CORE SWITCH 2 [HSRP standby] (3750X) <--- mode access vlan 2 ---> Access switch (2960X). as in example? Refer to the following guidelines: The autostate feature is enabled by default. So I have a good intuition that the issues comes from here. Has Microsoft lowered its Windows 11 eligibility criteria? Hi Rene, thanks for the lessons. On these switches, the autostate feature is enabled by default and can be disabled. Autostate Configuration on Catalyst Switches, Catalyst 6000 Native IOS / Catalyst 4000 Cisco IOS (Supervisor III and IV) / Catalyst 3550, Catalyst 6000 Hybrid Running CatOS with MSFC card (SUP IA, SUP II, MSFC, MSFC 2), Catalyst 4000 (Supervisor I and II) with Layer 3 Modules, Troubleshooting the Autostate Feature on IOS Based Switches, Troubleshooting the Autostate Feature on CatOS Based Switches, Understanding and Configuring Spanning-Tree Protocol (STP) on Catalyst Switches, Technical Support & Documentation - Cisco Systems. All rights reserved. One of these is for a 2.5Gbps link that the switch was plugged into. All rights reserved. Line protocol on Interface Vlan changed state to up. However the interface exists even if the module isn't present. At this point the R2 HSRP priority is higher than R1, and R2 takes over as the active router. Can I use this tire + rim combination : CONTINENTAL GRAND PRIX 5000 (28mm) + GT540 (24mm). Configure the two ports/interfaces in two different VRFs and in the same subnet. Standby Preempt and Standby Track Configuration. Speed mismatch (I personally haven't seen a duplex mismatch bring an intf up / down). In HDLC and PPP, frame delineation is provided by means of a special interframe fill pattern or idle pattern. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. 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 ? 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. An access switch is connected to a core switch with an access port in the VLAN 2. Sometimes people like to bring an extra switch from home to the office. If the cable is faulty, it could cause up / down status. So I think it may affect layer 2. I wonder what can cause that the first line output of the command "show interfaces" will be: "fastEthernet is up, line protocol is down". Refer to Cisco bug IDCSCdp72834 for more information. IP addressing, at layer-3, does not affect the layer-1/2. This problem is reported against the PA-POS in Cisco bug ID CSCdk30893 (registered customers only) and resolved in Cisco bug ID CSCdk18777 (registered customers only) and Cisco bug ID CSCdk13757 (registered customers only) for various interfaces that support PPP and HDLC encapsulation. Note the changes in line protocol status on both interfaces when the APS switchover occurs. When you finish using a debug command, remember to disable it with its specific no debug command or with the no debug all command. Are there conventions to indicate a new item in a list? is good cable that connected to both switches, but one switch had it's interface in "administratively down" state, will cause that situation. Learn more about Stack Overflow the company, and our products. Failure of the port to come up or ping itself with a local loop indicates a problem with the Cisco Router. 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. is this correct. Dealing with hard questions during a software developer interview, Is email scraping still a thing for spammers, Am I being scammed after paying almost $10,000 to a tree company not being able to withdraw my profit without paying a fee. The VLAN must be allowed on the router trunk.

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