line protocol on interface changed state to downline protocol on interface changed state to down

Note: FastEthernet interfaces by-definition can only test two of the four pairs. According to point 3 as I understand To learn more, see our tips on writing great answers. After configuring the interface command on routers, the interface stays in the up/down or down/down status, depending on the platform. For retransmissions, the Identifier can remain unchanged. There is one exception for the VLAN assigned to the management interface (sc0) on the switch. Click here for a complete list of PPP protocol field values . Are there conventions to indicate a new item in a list? Failure of the port to come up or ping itself with a local loop indicates a problem with the Cisco Router. When you were hired, the organization was small, and only a single switch and router were required to support your users. FastEthernet 0/1 is showing down. Whats the first thing we should check? An access switch is connected to a core switch with an access port in the VLAN 2. 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. Refer to Cisco bug IDCSCdp72834 for more information. sometimes is the encapsulation mismatch. I'm using a Cisco Catalyst 2960-X Series. Click the card to flip Definition 1 / 4 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 you are working in a live network, ensure that you understand the potential impact of any command before using it. Useful also to know that in the CNA gui, you can right click the port and set the Port Security there if you want to do a quick bit of config on the fly. 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. I found the problem! Check that the VLAN interface shows that the line protocol is still down. So I have a good intuition that the issues comes from here. The remote router stores this value in its yourseen counter and sends that value in a keepalive packet to the router. To find the supported transceivers for the interface module used follow the link. 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 Suspicious referee report, are "suggested citations" from a paper mill? 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. You need to investigate why this line protocol is not up. This means that another HSRP router with higher priority can become the active router if that router has the standby preempt enabled. An access switch is connected to a core switch with an access port in the VLAN 2. This is sample output from the debug serial interface command for an HDLC connection when the remote interface is shut and the local interface misses more than three keepalives. The router is now looped back to itself. This debug captures the value of the protocol field in the PPP packet. Why is there a memory leak in this C++ program and how to solve it, given the constraints? 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. - Use syslog to implement centralized logging. Line Protocol Is Down With PPP RFC 1661 defines PPP as a protocol. For retransmissions, the Identifier may remain unchanged. Let's take a closer look at port security: The sc0 should always be up after the switch boots. 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). *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. The autostate feature is synchronized with the STP state. Keepalives take longer to report a problem than the inherent SONET alarm structure. Refer to Understanding Loopback Modes on Cisco Routers for guidance. Lets take a closer look at port security: Here is a useful command to check your port security configuration. This phrase has several connotation. Interface link parameters must match at both ends of the link. Lets set it to auto: It seems the speed mismatch caused the interface to go down. On MSFC, issue the show int vlan command. The Spanning-tree port status is LRN, which means learning state. Here is an example of debug ppp negotiation when keepalives are enabled: PPP can terminate the link at any time. 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! The state of R1 is active and the state of R2 is standby. CN router also shows the interface going up/down when disconnected and reconnected 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 a result, our Cisco switch will learn the MAC address of H1 and H2 on its FastEthernet 0/1 interface. Learn more about how Cisco is using Inclusive Language. Switch interfaces are layer-2 interfaces, but if you can address it, then you have enabled layer-3 and it is a router interface. 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. Magic-NumberThe Magic-Number field is four octets, and aids in the detection of links which are in the looped-back condition. New here? 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. Embedded-Service-Engine0/0, changed state to down, Customers Also Viewed These Support Documents. 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. %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to down %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to down. 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. Corgon-6000# Mar 11 12:11:23.406: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan151, changed state to up. The data may consist of any binary value. The sc0 should always be up after the switch boots. POS interfaces support PPP in High-Level Data Link Control (HDLC)-like framing, as specified in RFC 1662 , for data encapsulation at Layer 2. Lets check if all interfaces are up: This is what we are looking for. Line protocol on Interface Vlan changed state to up. What happens if the serial 0 interface of R1 goes down? 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. 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. Note that this interface is running in half duplex. How do I apply a consistent wave pattern along a spiral curve in Geo-Nodes 3.3? The trailer provides error checking. This is intentional in order to demonstrate that this is a valid configuration. For example, on switch interface configure an IP address 192.0.2.0/31 and on server interface configure 192.0.2.1/24. What can I do? It only takes a minute to sign up. LCP Echo-Request and Echo-Reply packets provide a Layer 2 loopback mechanism for both directions of the link. Find answers to your questions by entering keywords or phrases in the Search bar above. Duplex is on auto so that shouldnt be a problem. 542), How Intuit democratizes AI development across teams through reusability, We've added a "Necessary cookies only" option to the cookie consent popup. - Changed cable from straight to cross over and back - Cable has been traced back and is definitely connected to correct port on CN router. Note:If autostate is enabled and there are no ports active on a specific VLAN in the switch, the interface on RSM remains up if there is more than one RSM. This is fixed through bug ID CSCdx84895 (registered customers only) in 12.1.13E and later releases. This document does not cover Frame Relay encapsulation. *Mar 1 01:54:39.699: %LINEPROTO-5-UPDOWN: Line protocol on Interface Tunnel0, changed state to up. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. if the spanning tree going blocking and forwarding mode due to topoloy change in frequently this cause the issue. My router is a FRITZ!Box 6690 Cable with four LAN ports. 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. The line protocol is up. You are the network administrator for a growing business. The command below shows that the VLAN exists and is active on the switch. Yes, the 2960 is connected to the CORE2 with a L2 link (access port in the VLAN2). Instead R1 would have remained the active router. Network Engineering Stack Exchange is a question and answer site for network engineers. The documentation set for this product strives to use bias-free language. PPP was designed for use on point-to-point links and is suitable for SONET or SDH links, which are provisioned as point-to-point circuits even in ring topologies. Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type. 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. Define a minimum and maximum packet length. When a higher priority router preempts a lower priority router, the router sends a Coup message. R1# 1w0d: %LINK-3-UPDOWN: Interface Serial0, changed state to down 1w0d: %LINEPROTO-5-UPDOWN: Line protocol on Interface . Customers Also Viewed These Support Documents. Line protocol on Interface Vlan613, changed state to down *Jun 15 01:32:21.115: %LINK-5-CHANGED: Interface Embedded-Service-Engine0/ . How can I explain to my manager that a project he wishes to undertake cannot be performed by the team? 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. Very interesting and informative - keep up the good work. ASR 1000 Series Aggregation Services Routers. is there a chinese version of ex. This also prevents other problems, such as routing black holes, from occurring. This problem is resolved in Cisco bug ID CSCdp86387 (registered customers only) . Can the Spiritual Weapon spell be used as cover? Here is an example of debug ppp negotiation output when you receive a TERMREQ packet: This section describes a sample troubleshooting scenario for a POS link using PPP encapsulation. I wonder what can cause the first line output of the command show interfaces to be: FastEthernet is up, line protocol is down. 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. 10:59 AM. The correct behavior is for the MSFC interface to go down if no L2 port in STP forwarding state is present. If the line protocol of the specified interface goes down, the HSRP priority is reduced. 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. Once the switch sees another MAC address on the interface, it will be in violation, and something will happen. is good cable that connected to both switches, but one switch had it's interface in "administratively down" state, will cause that situation. Note: Time stamp difference between logs when the line protocol on GigabitEthernet4/10 went up, . If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Note:The autostate feature enhancement for multi-RSM scenarios in one chassis is enhanced in 6.1.2. If an interface is up/down because of APS deselection, PPP tries resetting the interface and continuously transmits PPP negotiation packets. The end of the field is indicated by the Length. What we see so far seems to begin with a normal boot process. 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 correct behavior is for the MSFC interface to go down if no L2 port in STP forwarding state is present. 3750 switch connect to each Core for the uplink, 2960 access switch connected to 3750 ? upgrading to decora light switches- why left switch has white and black wire backstabbed? 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. Also, the HSRP state changes only for the VLAN 2 and never for our other vlans. Spanning-tree port status is in listening yet. Ill show you what happens in a bit. Thats looking better! 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 allows traffic to flow between the two RSMs on that VLAN without disabling the autostate feature. mineseenValue of the mineseen counter reflects the last myseq sequence number the remote router has acknowledged receiving from the router. You should explain/justify your conclusion. Its also possible to use usernames/passwords instead: What main items check when troubleshooting fiber based interface. Now, if the R1 serial 0 interface comes back up, the R1 priority is 105, again. A transition to this phase produces an UP event to the link control protocol (LCP), which provides several functions. Was Galileo expecting to see so many stars? This interface, however, can be forced to administratively down. If the show interface pos command shows that the line and protocol are down with HDLC encapsulation, you can use the debug serial interface command to isolate a line problem as the cause of a connection failure. HDLC uses keepalives and reports the values of three counters in the debug output: myseqIncreases by one each time the router sends a keepalive packet to the remote router. All rights reserved. Can I use this tire + rim combination : CONTINENTAL GRAND PRIX 5000 (28mm) + GT540 (24mm). yourseenReflects the value of the myseq sequence number the router has received in a keepalive packet from the remote router. Our interfaces of course! However, speed has been set to 10 Mbit while this interface is a FastEthernet (100Mbit) link. HDLC is the default encapsulation type on a POS router interface. Since the only port (3/1) is diabled, !--- the line protocol for interface VLAN 151 is down. Because no decrement value is specified in the standby track command, the HSRP priority is decremented by the default value of 10 when the tracked interface goes down. 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. 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 bug ID CSCdr80722 (registered customers only) for more information). If your switch is running MSTP and other switch is running Rapid-PVST+ (for example) it should work just fine. The documentation set for this product strives to use bias-free language. This document discusses why this happens, and how the L3 and L2 interfaces interact with each other in the control plane after being activated. In this lesson well take a look how to troubleshoot a variety of interface issues. Side A would be admin down, and side B would be down/down. I mean that question No. Refer toCisco Technical Tips Conventions for more information on document conventions. High latency/drops between Cisco switches in two locations. In order to establish communication over a point-to-point link, each end of the PPP link must first send LCP packets to configure and test the data link. Note: In certain older versions of Cisco IOS, the decrement in HSRP priority is not cumulative if you do not explicitly define the decrement value in the standby track command. On the RSM, issue the show int command. Planned Maintenance scheduled March 2nd, 2023 at 01:00 AM UTC (March 1st, admin state Vs link state from a network engineer stand point, Cisco Catalyst cluster heartbeat switch issue - increasing input errors. How is "He who Remains" different from "Kang the Conqueror"? Jordan's line about intimate parties in The Great Gatsby? At least one L2 port is in spanning-tree forwarding state on this VLAN. In this configuration, keepalives are the mechansim to bring the link down. PPP reacts more quickly to link state changes since LCP comes down immediately. changed state to down 1w0d: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, changed state to down R1# This again reduces the HSRP priority by 10from 110 to a value of 100. Check the status of interface gig 4/10 assigned to VLAN 151. Autostate is implemented on CatOS and IOS Cisco based switches by default. Keep in mind that a Gigabit interface doesnt support half-duplex. VLAN trunking between Juniper EX -> Cisco Catalyst -> and Cisco Router. In each case, a higher value is of greater priority. The frame format for PPP in HDLC-like framing is shown in this figure. The value in this field identifies the datagram encapsulated in the Information field of the packet. It might be easier if the interface could recover itself after a certain time. Ping from one VRF to the other VRF. Are these the complete logs from the router. The Data field is zero or more octets, and contains uninterpreted data for use by the sender. 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 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. Enable port 3/1, as shown below. Start by replacing the cable connected to the port with a new one. You need to verify spanning-tree port status on the L2 port (should be forwarding). Troubleshoot. Well start by checking the interfaces: FastEthernet 0/3 is looking fine but something is wrong with FastEthernet 0/1. Standby Preempt and Standby Track Configuration. Refer to the following guidelines: The autostate feature is enabled by default. Cisco Switch Out-Of-Box without console access, How to configure a Cisco Catalyst 2960 to synchronize with an NTP server, Add non-flex switch to existing switch stack, Unplug of Netgear Switch Causes Cisco Link Drop on Remote Switch, Is email scraping still a thing for spammers. During this time, you monitored log messages from your router and switch directly from each device's console. RFC 1661 defines PPP as a protocol. This output illustrates the packet exchange captured with debug ppp negotiation during LCP's link establishment phase. Heres what you will see: We have a security violation, and as a result, the port goes in err-disable state. It only takes a minute to sign up. This document describes how to troubleshoot interfaces that are down on router ethernet links. GigabitEthernet interfaces can test all four pairs. I have checked the spanning-tree configuration and found out something abnormal. Use the switchport port-security mac-address command to define the MAC address that you want to allow. If your network is live, ensure that you understand the potential impact of any command. However, although closely related, PPP and HDLC are not the same, and different debug commands are used to troubleshoot line protocol problems. One of these is for a 2.5Gbps link that the switch was plugged into. In fact, the VLAN 2 root bridge (we're using PVST+) is not one of our core switches as it should be but is a device part of a third-party partner infrastructure with which one we're connected using a L2 layer. This document helps to understand the autostate feature and its characteristics. The open-source game engine youve been waiting for: Godot (Ep. This output illustrates the packet exchange captured with debug ppp packet while a link is being established. Thanks. The autostate feature is not synchronized with the STP state. Why was the nose gear of Concorde located so far aft? Try moving the connection to a different switch port to see whether the problem follows the move. If it does, check the equipment on the other end. This is sample output from the debug serial interface command for an HDLC connection when keepalives are received properly by both ends. How to troubleshoot? 10:55 PM 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. 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 ? Server Fault is a question and answer site for system and network administrators. Lets try a ping: H1 is unable to ping H2. 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 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. Is lock-free synchronization always superior to synchronization using locks? - edited In HDLC and PPP, frame delineation is provided by means of a special interframe fill pattern or idle pattern. Lets walk through a couple of scenarios. @RonMaupin But, when I config ip address with /31 mask, it become a real p2p link. In my case, use different prefix length can cause this problem. VLAN interface exists on the router and is not administratively down. 2023 Cisco and/or its affiliates. Ethernet0 is administratively down, line protocol is down: This output indicates that a local interface has been manually shut down using the shutdown command. Lets try a ping: Unfortunately our pings are not working. who is the root bridge here ? Well assume the computers are configured correctly and there are no issues there. As you can see, it is now down. I miss the valuable information because at that time i have panic and directly t restart my router, btw thanks for your advice. There also are various vendor-specific values. 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. Use syslog to implement centralized logging. . 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. 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 . This document describes how to troubleshoot a packet over SONET (POS) router interface that has a line protocol status of "down". %LINEPROTO. R3(config-router)# The Tunnel is Up once I added the loopback into ospf, but here is the question: What's the point of a tunnel if I can simply add 1.1.1.1 and 3.3.3.3 into ospf area 0 ? Ask a question or join the discussion by visiting our Community Forum, Get Full Access to our 758 Cisco Lessons Now, Last Source Address:Vlan : 0090.cc0e.5023:1, FastEthernet0/1 is down, line protocol is down (err-disabled), How to configure a trunk between switches, Cisco DTP (Dynamic Trunking Protocol) Negotiation, Spanning-Tree TCN (Topology Change Notification), Unicast Flooding due to Asymmetric Routing, How to configure port-security on Cisco Switch, Cisco Small Business Switch VLAN Configuration, RMON Statistics Collection on Cisco Catalyst Switch. Sorry, I have only these pictures. Connect and share knowledge within a single location that is structured and easy to search. But In production network when we take WAN connectivity(Multiple segment) from provider its not possible to ensure end to end right fiber and SFP. This test excludes the SFP and the cables in the packet path. If the Ping fails, it points to a cable or SFP problem. Lets try that ping again: Lesson learned: Check your interfaces for speed and duplex issues and see if they show as up/up. This interface, however, can be forced to administratively down. debug ppp packetShows PPP packets being sent and received. This will prevent routing protocols and other features from using the VLAN interface as if it were fully operational. HDLC is an international standard, but vendor implementations vary one or more fields or the header or trailer in size and format. Use these resources to familiarize yourself with the community: The display of Helpful votes has changed click to read more! when HSRP failing - this could be low reasons. See the Magic-Number Configuration Option in RFC 1661 for further explanation. Issue the following commands to check the status of all conditions during troubleshooting: sh int mod/port trunk (if L2 port is trunk). Make sure by checking the switch, as shown below. - Use a remote access utility such as SSH to access router and switch consoles remotely. Lets try another ping (maybe we get lucky): Too bad, the ping is not working. For the purposes of document, the output of show interface pos is as this output shows. Learn more about Stack Overflow the company, and our products. 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. I have configured port security, so only one MAC address is allowed. Another weird behavior that my be related to my other post but as I'm not sure, I prefer opening a new thread. Spanning-tree port status on the L2 port is forwarding. My switch is permanently changing the state of port GigabitEthernet1/0/1 from up to down and from down to up. from 2960 to 3750 to Core ? Does anything else happen? Oct 1 05:35:25 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan2, changed state to down. All of the devices used in this document started with a cleared (default) configuration. 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). By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. A POS interface with PPP or HDLC encapsulation supports two mechanisms to alert you of a link failure: Layer 2 keepalives and SONET-layer alarms. Session into the MSFC and verify the status of the VLAN interface again.

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