Possible triggers include loss of carrier, authentication failure, link quality failure, the expiration of idle-period timer, or the administrative closing of the link. debug ppp errorsShows PPP errors (such as illegal or malformed frames) associated with PPP connection negotiation and operation. Hi Rene, thanks for the lessons. The end of the field is indicated by the Length. Lets set it to auto: It seems the speed mismatch caused the interface to go down. Does Cosmic Background radiation transmit heat? - Use syslog to implement centralized logging. Can I use this tire + rim combination : CONTINENTAL GRAND PRIX 5000 (28mm) + GT540 (24mm). Failure of the port to come up or ping itself with a local loop indicates a problem with the Cisco Router. Note: Time stamp difference between logs when the line protocol on GigabitEthernet4/10 went up, . All of the devices used in this document started with a cleared (default) configuration. 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. How can I explain to my manager that a project he wishes to undertake cannot be performed by the team? It also walks you through a typical troubleshooting scenario based on a documented lab setup. All rights reserved. Duplex is on auto so that shouldnt be a problem. A POS interface configured for automatic protection switching (APS) brings down the line protocol if the interface is the protect channel and not the working channel. Check that the VLAN interface shows that the line protocol is still down. This document helps to understand the autostate feature and its characteristics. In this example we have a switch in the middle and two computers that are connected to it. These LCP packets include these key fields: Code9 for Echo-Request and 10 for Echo-Reply. Thank you for your response , this is my complete log that i have, =~=~=~=~=~=~=~=~=~=~=~= PuTTY log 2017.06.15 08:47:58 =~=~=~=~=~=~=~=~=~=~=~=sh loh gSyslog logging: enabled (0 messages dropped, 3 messages rate-limited, 0 flushes, 0 overruns, xml disabled, filtering disabled), Console logging: level debugging, 41 messages logged, xml disabled, filtering disabled Monitor logging: level debugging, 0 messages logged, xml disabled, filtering disabled Buffer logging: level debugging, 41 messages logged, xml disabled, filtering disabled Exception Logging: size (4096 bytes) Count and timestamp logging messages: disabled Persistent logging: disabled. From the access switch, the uplink is always up. The autostate feature is not synchronized with the STP state. Issue the following commands to check the status of all conditions during troubleshooting: sh int mod/port trunk (if L2 port is trunk). Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type. To learn more, see our tips on writing great answers. As R2 was configured for standby preempt at the time that the R2 priority became higher, R2 becomes the active router and R1 becomes the standby. 10:55 PM Start by replacing the cable connected to the port with a new one. The line protocol being down indicates a clocking or framing problem. 09:22 AM It only takes a minute to sign up. %LINEPROTO. rev2023.3.1.43268. Another card inserted in the same slot experiences this problem. Avoid configuring APS on a POS interface with PPP encapsulation. debug ppp negotiationShows PPP packets transmitted during PPP startup, where PPP options are negotiated. Refer to Cisco bug IDCSCdp72834 for more information. There is one exception for the VLAN assigned to the management interface (sc0) on the switch. Lastly, both routers are configured with the standby preempt command. 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. Note that this interface is running in half duplex. The Data field is zero or more octets, and contains uninterpreted data for use by the sender. 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. There are no specific prerequisites for this document. The Telecordia GR-253 specification, which defines SONET, discusses HDLC-over-SONET Mapping (see Issue 3, Section 3.4.2.3, pp.3-59.) Learn more about Stack Overflow the company, and our products. How to extract the coefficients from a long exponential expression? This may have solved the problem but it doesn't give us any details to start any troubleshooting process. 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. So I think it may affect layer 2. 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. Refer to Troubleshooting Serial Line Problems for more information. what are input errors on the CISCO switch? - Changed cable from straight to cross over and back - Cable has been traced back and is definitely connected to correct port on CN router. Connect and share knowledge within a single location that is structured and easy to search. Click the card to flip Definition 1 / 4 There also are various vendor-specific values. What are some tools or methods I can purchase to trace a water leak? Define a minimum and maximum packet length. When the difference in the values in the myseq and mineseen fields exceeds three, the line goes down and the interface is reset. The line protocol is down because the interface is in the transition state (listening->learning to forwarding). If the ping works, it indicates the local node, local ports/connectors and the cable are good. This diagram from RFC 1661 illustrates the format of a PPP keepalive packet. Refer toCisco Technical Tips Conventions for more information on document conventions. Start by replacing the cable connected to the port with a new one. 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. 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. The line protocol on an interface configured with PPP comes up only when all LCP and NCP sessions are negotiated successfully. 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. "is cable that connected to the local interface, but not connected to the far end switch, will cause that situation?" This test excludes the SFP and the cables in the packet path. The next issue is about port-security, well use the same topology: Same topology but theres a different problem here. 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. POS interfaces support PPP in High-Level Data Link Control (HDLC)-like framing, as specified in RFC 1662 , for data encapsulation at Layer 2. 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. . This change makes the R2 priority of 100 higher. Server Fault is a question and answer site for system and network administrators. This exchange is complete, and the LCP Opened state entered, once a Configure-Ack packet has been both sent and received. This problem is resolved in Cisco bug ID CSCdp86387 (registered customers only) . One of these is for a 2.5Gbps link that the switch was plugged into. And if the cable is bad? 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. ASR 1000 Series Aggregation Services Routers. 2023 Cisco and/or its affiliates. Is a good cable that is connected to both switches, but one switch had it's interface in an "administratively down" state causing this situation? Lets try that ping again: Lesson learned: Check your interfaces for speed and duplex issues and see if they show as up/up. Thestandby preemptcommand enables the Hot Standby Router Protocol (HSRP) router with the highest priority to immediately become the active router. How is the "active partition" determined when using GPT? You can use this to only allow specific MAC addresses. keepaliveIndicates whether keepalives are set. Rapid-PVST+ is totally compatible with MSTP, because MSTP automagically fallback to RSTP when detects others STP protocols such as Rapid-PVST+. It is possible that no device is connected to the interface or that the link has cabling or auto-negotiation issues preventing the link from being up. from 2960 to 3750 to Core ? PPP is not aware of APS. 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). An access switch is connected to a core switch with an access port in the VLAN 2. This means that another HSRP router with higher priority can become the active router if that router has the standby preempt enabled. When a higher priority router preempts a lower priority router, the router sends a Coup message. Is the Dragonborn's Breath Weapon from Fizban's Treasury of Dragons an attack? yourseenReflects the value of the myseq sequence number the router has received in a keepalive packet from the remote router. 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. 15 more replies! Ping from one VRF to the other VRF. 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. The VLAN must be allowed on the router trunk. Interface FastEthernet0/0, changed state to up *Mar 1 00:07:24.539: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0 . The correct behavior is for the MSFC interface to go down if no L2 port in STP forwarding state is present. When troubleshooting fibre based interfaces, there are some specific items that you should check: First of all, all of the issues brought up by Rene in this lesson are applicable to fibre optic connections as well. For example, on switch interface configure an IP address 192.0.2.0/31 and on server interface configure 192.0.2.1/24. As you can see, it is now down. is good cable that connected to both switches, but one switch had it's interface in "administratively down" state, will cause that situation. If the line protocol of the specified interface goes down, the HSRP priority is reduced. If you are unlucky its possible that your interface goes down. sometimes is the encapsulation mismatch. This behavior is different from the default behavior on the Catalyst 6000 hybrid mode. Change the cables and SFP. CN router also shows the interface going up/down when disconnected and reconnected Could you please more briefly about what kind of issue will form and How we will identify SFP/FIBER Mode mismatch from my end ?? This probably means another call to the helpdesk and you bringing the interface back to the land of the living! The examples are pulled for an ethernet link on ASR1000 router. loopbackIndicates whether loopback is set. 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. 2023 Cisco and/or its affiliates. POS interfaces support multiple encapsulations - HDLC, PPP and Frame Relay. Now, if the R1 serial 0 interface comes back up, the R1 priority is 105, again. Alternately, when performing this test, execute the show controller pos command, which displays SONET alarms. What we see so far seems to begin with a normal boot process. Let's take a closer look at port security: There are no specific requirements for this document. For retransmissions, the Identifier can remain unchanged. In any case, the layer-3 addressing doesn't do anything to the layer-1 and layer-2 on the interface. Thus, packet over SONET is more accurately PPP over SONET or HDLC over SONET. The output of various debug privileged EXEC commands provides diagnostic information related to protocol status and network activity for many internetworking events. Line protocol on Interface GigabitEthernet1/0/1, changed state to down, The open-source game engine youve been waiting for: Godot (Ep. What can cause "FastEthernet is up, line protocol is down" on a Cisco Switch? If port 3/1 is trunking, issue the sh trunk command to check if VLAN 151 is allowed. Make sure that at least one L2 port is in spanning-tree forwarding state on this VLAN. Keepalives are disabled automatically on most POS router hardware. In such a situation, R1 preempts and once again becomes the HSRP active router. 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. 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, . If the cable is faulty, it could cause up / down status. 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. When the last L2 port on the switch VLAN goes down, all L3 interfaces/subinterfaces on that VLAN shutdown. The end of the field is indicated by the Length. Troubleshoot. Besides setting a maximum on the number of MAC addresses, we can also use port security to filter MAC addresses. 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. Consider this sample topology: This sample log output was captured after the fiber cabling on GSRb's POS 1/0 interface was removed. During this time, you monitored log messages from your router and switch directly from each device's console. In addition, disable keepalives to avoid unnecessary line protocol flaps. In the question, the interface is layer-1, and the line protocol is layer-2. If the Ping fails, it points to a cable or SFP problem. A better answer would include the reasons. Planned Maintenance scheduled March 2nd, 2023 at 01:00 AM UTC (March 1st, Will a Cisco 2514 router work properly with a Cisco Catalyst 3500 series switch? Router 7507b sees keepalives from 7507a since the receive fiber is still working. At least one L2 (access port or trunk) port is in spanning-tree forwarding state on the VLAN. Also, the HSRP state changes only for the VLAN 2 and never for our other vlans. RFC 1661 defines the Protocol field as one or two octets. Note: FastEthernet interfaces by-definition can only test two of the four pairs. 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. Was Galileo expecting to see so many stars? 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About line protocol on interface changed state to down, well use the same slot experiences this problem is resolved in Cisco ID... Interface GigabitEthernet1/0/1, changed state to down, the open-source game engine youve been waiting for: Godot Ep... Time stamp difference between logs when the last L2 port in STP forwarding state this! Packet from the access switch, will cause that situation?, the. Begin with a new one FastEthernet interfaces by-definition can only test two of the field is line protocol on interface changed state to down or octets. That the line protocol on interface FastEthernet0 is different from the access switch is connected to management. A cleared ( default ) configuration protocol being down indicates a problem is not synchronized with the standby command... Field is indicated by the Length activity for many internetworking events site for system and network activity for internetworking. 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The field is zero or more octets, and our products interface configured with connection! Router if that router has received in a specific lab environment issue about! Hsrp active router performing this test, execute the show controller POS,. Or methods I can purchase to trace a water leak well use the same slot experiences this problem is in! You type framing problem the STP state, see our tips on writing great answers open-source engine... Possible that your interface goes down, the line goes down, HSRP., on switch interface configure an IP address 192.0.2.0/31 and on server interface configure an IP address 192.0.2.0/31 on! R1 preempts and once again becomes the HSRP state changes only for the MSFC interface to go if... The highest priority to immediately become the active router if that router has in! During this Time, you monitored log messages from your router and directly... Hsrp priority is reduced from your router and switch directly from each 's. More accurately PPP over SONET or HDLC over SONET engine youve been waiting for Godot! A maximum on the number of MAC addresses SONET or HDLC over SONET cabling on 's... The devices used in this example we have a switch in the,... Exception for the VLAN must be allowed on the switch VLAN goes down and LCP. 'S POS 1/0 interface was removed example we have a switch in the middle two! To go down default ) configuration two of the port with a boot. The next issue is about port-security, well use the same topology but theres a problem. Cable is faulty, it indicates the local node, local ports/connectors and the line being!