After configuring the interface command on routers, the interface stays in the up/down or down/down status, depending on the platform. 03-08-2019 Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Keepalives take longer to report a problem than the inherent SONET alarm structure. On some CatOS platforms, this feature can be disabled in order to allow redundancy in special scenarios. Our interfaces of course! In the question, the interface is layer-1, and the line protocol is layer-2. Interface link parameters must match at both ends of the link. Here is why: Hi, your lessons are very interesting. This document describes how to troubleshoot interfaces that are down on router ethernet links. FWD to BLK) ? This is fixed through bug ID CSCdt75094 (registered customers only) in 6.2.2 , 6.3.1 and later releases. sometimes is the encapsulation mismatch. This problem is resolved in Cisco IOS Software Release 12.0(19)S under Cisco bug ID CSCdt43759 (registered customers only) . Since the only port (3/1) is diabled, !--- the line protocol for interface VLAN 151 is down. - edited Additionally, you should keep the following in mind when troubleshooting fibre based interfaces: Hi Laz, 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. Hi, can you provide the configs of 3 switches? Its also possible to use usernames/passwords instead: What main items check when troubleshooting fiber based interface. Why does the line protocol for this specific VLAN sometimes go up/down ? Click here for a complete list of PPP protocol field values . Change the cables and SFP. Check the status of port 3/1 assigned to VLAN 15. 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. FastEthernet 0/1 is showing down. The output of various debug privileged EXEC commands provides diagnostic information related to protocol status and network activity for many internetworking events. An access switch is connected to a core switch with an access port in the VLAN 2. (refer to bug ID CSCdr80722 (registered customers only) for more information). If the Ping fails, it points to a cable or SFP problem. At least one L2 (access port or trunk) port is in spanning-tree forwarding state on the VLAN. However, although closely related, PPP and HDLC are not the same, and different debug commands are used to troubleshoot line protocol problems. I can put some really messed up layer-3 addressing on the interfaces to the point that layer-3 doesn't work, but that doesn't do anything to bring down layer-1 or layer-2. rev2023.3.1.43268. If it does, check the equipment on the other end. This may have solved the problem but it doesn't give us any details to start any troubleshooting process. Lets check if all interfaces are up: This is what we are looking for. Thus, packet over SONET is more accurately PPP over SONET or HDLC over SONET. whick menas that keepalives will not be receiver on the far end. I think this is because they use a lower priority than our core switches ("0" I guess because our core switches have 4096). Lets try a ping: Unfortunately our pings are not working. VLAN interface exists on the router and is not administratively down. 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. I miss the valuable information because at that time i have panic and directly t restart my router, btw thanks for your advice. Refer to Understanding Loopback Modes on Cisco Routers for guidance. When a higher priority router preempts a lower priority router, the router sends a Coup message. Priority is determined first by the configured priority value, and then by the IP address. Find answers to your questions by entering keywords or phrases in the Search bar above. As you can see, the line protocol on interface VLAN 151 is still down. Keep in mind that a Gigabit interface doesnt support half-duplex. 542), How Intuit democratizes AI development across teams through reusability, We've added a "Necessary cookies only" option to the cookie consent popup. Is the Dragonborn's Breath Weapon from Fizban's Treasury of Dragons an attack? Use syslog to implement centralized logging. POS interfaces support multiple encapsulations - HDLC, PPP and Frame Relay. There are many reasons why an interface does not come up on a cisco router. If the router and port ASICs are properly initialised the interface must come up and self ping must work. 09:23 AM. Configure the interface in local loopback. from 2960 to 3750 to Core ? In redundant dual MSFC configuration mode, it may be useful to disable the autostate feature. Possible triggers include loss of carrier, authentication failure, link quality failure, the expiration of idle-period timer, or the administrative closing of the link. I configured port security in the example above, so it only allows MAC address aaaa.bbbb.cccc. The interface will be in up/down state? On reception, the Identifier field of the Echo-Request is copied into the Identifier field of the Echo-Reply packet. Try moving the connection to a different switch port to see whether the problem follows the move. Lets walk through a couple of scenarios. At least one L2 (access port or trunk) port exists and has a link up on this VLAN. As a result, our Cisco switch will learn the MAC address of H1 and H2 on its FastEthernet 0/1 interface. Its telling me port-security is the reason. Also, is there any history somewhere that records the changes of states of the ports (ie. PPP is not aware of APS. 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? 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. Thestandby preemptcommand enables the Hot Standby Router Protocol (HSRP) router with the highest priority to immediately become the active router. 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. No, it is point-to-point at layer-3. You should see a path alarm indication signal (P-AIS) on router 7507a and a path remote defect indication (P-RDI) on 7507b. 3750 switch connect to each Core for the uplink, 2960 access switch connected to 3750 ? What are some tools or methods I can purchase to trace a water leak? *Aug 8 11:18:12.081: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down What facility generated this message? 2023 Cisco and/or its affiliates. This also helps in scenarios where a loopback plug is not available for test. In any case, the layer-3 addressing doesn't do anything to the layer-1 and layer-2 on the interface. The VLAN must be allowed on the router trunk. Can you confirm that at least some of the interfaces are connected to devices that are powered up and attempting to connect to the router? Provide frame delineation, which defines for a receiver exactly where a packet and frame begins and ends. is there a chinese version of ex. Probable reasons for this are encapsulation and clock rate mismatches. 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. Configure the two ports/interfaces in two different VRFs and in the same subnet. Ping from one VRF to the other VRF. Then, PPP must send network control protocol (NCP) packets to choose and configure one or more network-layer protocols. What are some tools or methods I can purchase to trace a water leak? Well start by checking the interfaces: FastEthernet 0/3 is looking fine but something is wrong with FastEthernet 0/1. this can only confirm based on some more inputs. The examples are pulled for an ethernet link on ASR1000 router. The value in this field identifies the datagram encapsulated in the Information field of the packet. The trailer provides error checking. On these switches, the autostate feature is enabled by default and can be disabled. DataThe Data field is zero or more octets, and contains uninterpreted data for use by the sender. I have configured port security, so only one MAC address is allowed. If the Ping fails, it points to a cable or SFP problem. debug ppp packetShows PPP packets being sent and received. Was Galileo expecting to see so many stars? There also are various vendor-specific values. yourseenReflects the value of the myseq sequence number the router has received in a keepalive packet from the remote router. You need to investigate why this line protocol is not up. R2 is the standby router and tracks the R2 Serial 1 interface state. The autostate feature is synchronized with the STP state. Learn more about how Cisco is using Inclusive Language. This diagram shows an example that uses the standby preempt command in conjunction with the standby track command. The next issue is about port-security, well use the same topology: Same topology but theres a different problem here. 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). CN router also shows the interface going up/down when disconnected and reconnected When both these tracked serial interfaces (serial 0 and serial 1) go down, the resultant priority is 100. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. If an interface is up/down because of APS deselection, PPP tries resetting the interface and continuously transmits PPP negotiation packets. All rights reserved. - VLAN exists in the vlan db and is active, - An access port is inside this VLAN and its status is always connected, - There is not entries regarding STP in the syslog, - There's no error (input, CRC, etc) when checking the interface counters. Try moving the connection to a different switch port to see whether the problem follows the move. My switch is permanently changing the state of port GigabitEthernet1/0/1 from up to down and from down to up. Are there conventions to indicate a new item in a list? What can cause "FastEthernet is up, line protocol is down" on a Cisco Switch? 15 more replies! 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 HDLC and PPP, frame delineation is provided by means of a special interframe fill pattern or idle pattern. During this time, you monitored log messages from your router and switch directly from each device's console. The latest implementation of the autostate feature allows synchronization to Spanning-Tree Protocol (STP) port status. 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! For these switches, the autostate feature is enabled by default. 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. This diagram illustrates the protocol stack used on a POS interface. 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. 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. 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). Note:The autostate feature enhancement for multi-RSM scenarios in one chassis is enhanced in 6.1.2. There is one exception for the VLAN assigned to the management interface (sc0) on the switch. This document helps to understand the autostate feature and its characteristics. Maybe the Rapid-PVST+ wanted to be the root for the CST? Spanning-tree port status is in listening yet. 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. In addition, disable keepalives to avoid unnecessary line protocol flaps. 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. The end of the field is indicated by the Length. Note: FastEthernet interfaces by-definition can only test two of the four pairs. On MSFC, issue the show int vlan command. 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. For the purposes of document, the output of show interface pos is as this output shows. The end of the field is indicated by the Length. This output illustrates the packet exchange captured with debug ppp packet while a link is being established. How to test layer 2 connectivity on Cisco Switch? You can use this to only allow specific MAC addresses. It uses these configurations: Note:These debugs were captured on two routers in a back-to-back lab setup. @RonMaupin But, when I config ip address with /31 mask, it become a real p2p link. 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). Find answers to your questions by entering keywords or phrases in the Search bar above. If the problem persists, check other hardware components. The open-source game engine youve been waiting for: Godot (Ep. 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. It might be easier if the interface could recover itself after a certain time. Lets set it to auto: It seems the speed mismatch caused the interface to go down. 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. Does Cast a Spell make you a spellcaster? - Use syslog to implement centralized logging. 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 Changing it to auto-speed brings back the interface to the land of the living. Check the status of interface gig 4/10 assigned to VLAN 151. 2023 Cisco and/or its affiliates. Speed mismatch (I personally haven't seen a duplex mismatch bring an intf up / down). The correct behavior is for the MSFC interface to go down if no L2 port in STP forwarding state is present. Refer to bug ID CSCdu07244 (registered customers only) for more information. 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. One of these is for a 2.5Gbps link that the switch was plugged into. What we see so far seems to begin with a normal boot process. 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. Learn more about Stack Overflow the company, and our products. 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. Here is an example of debug ppp negotiation when keepalives are enabled: PPP can terminate the link at any time. 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. Now, if the R1 serial 0 interface comes back up, the R1 priority is 105, again. 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. This problem is resolved in Cisco bug ID CSCdp86387 (registered customers only) . Change the cables and SFP. This diagram from RFC 1661 illustrates the format of a PPP keepalive packet. 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. 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. This exchange is complete, and the LCP Opened state entered, once a Configure-Ack packet has been both sent and received. So I think it may affect layer 2. PPP reacts more quickly to link state changes since LCP comes down immediately. Is the Dragonborn's Breath Weapon from Fizban's Treasury of Dragons an attack? How to troubleshoot? When bringing up a point to point link, PPP goes through several distinct phases that can be drawn in a state diagram. 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. If the router on the second RSM is in trunking mode, the VLAN will be allowed on the ISL trunk. Another card inserted in the same slot experiences this problem. When R1 and R2 exchange HSRP hellos, R2 learns the standby IP address from R1. How to react to a students panic attack in an oral exam? Lets take a closer look at port security: Here is a useful command to check your port security configuration. For more information on document conventions, see the Cisco Technical Tips Conventions. The protocol line state for the VLAN interfaces will come up when the first L2 port belonging to the corresponding VLAN link comes up. 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. Other important fields in the show interface pos output are: EncapsulationEncapsulation method assigned to the interface. 06-14-2017 Instead R1 would have remained the active router. How can I explain to my manager that a project he wishes to undertake cannot be performed by the team? Is lock-free synchronization always superior to synchronization using locks? Does Cosmic Background radiation transmit heat? This is intentional in order to demonstrate that this is a valid configuration. If not, what would cause an interface to be in an up,down state? The interfaces that Im working with are both showing up/up. 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. New here? LCP uses Terminate packets to close the link. Thanks, 66 more replies! This is the symptom of a VLAN interface being in up/down status. On IOS based switches, this feature cannot be disabled. Make sure by checking the switch, as shown below. Instead of reading 1253 pdfs from Cisco in 10min everything was understood with simple and interesting examples. Older switches don't have a tdr function you'd have to test the cabling manually. The reason for the line protocol of interface VLAN 151 being down is because GigabitEthernet4/10 link is not connected, as seen from the interface status. The documentation set for this product strives to use bias-free language. GigabitEthernet interfaces can test all four pairs. However, when two router POS interfaces connect across a Telco cloud with SONET/SDH equipment, Layer 1 loss information is not propagated to the remote end. According to point 3 as I understand Ping from one VRF to the other VRF. POS interfaces support PPP in High-Level Data Link Control (HDLC)-like framing, as specified in RFC 1662 , for data encapsulation at Layer 2. Switch interfaces are layer-2 interfaces, but if you can address it, then you have enabled layer-3 and it is a router interface. The Spanning-tree port status is LRN, which means learning state. If port 3/1 is trunking, issue the sh trunk command to check if VLAN 151 is allowed. For example, on switch interface configure an IP address 192.0.2.0/31 and on server interface configure 192.0.2.1/24. Can the Spiritual Weapon spell be used as cover? Terminate LCP packets include these key fields: Code5 for Terminate-Request and 6 for Terminate-Ack. And besides, please elaborate when you mean "router totally down". Use the switchport port-security mac-address command to define the MAC address that you want to allow. For retransmissions, the Identifier can remain unchanged. 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. Define a minimum and maximum packet length. Help me understand the context behind the "It's okay to be white" question in a recent Rasmussen Poll, and what if anything might these results show? I found the problem! (Refer to the APS Technology Support Page for more information.). In this lesson well take a look how to troubleshoot a variety of interface issues. 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. 2023 Cisco and/or its affiliates. 10:55 PM 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 autostate feature is not synchronized with the STP state. Ethernet0 is administratively down, line protocol is down: This output indicates that a local interface has been manually shut down using the shutdown command. rev2023.3.1.43268. 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). Refer to Cisco Technical Tips Conventions for more information on document conventions. Well assume the computers are configured correctly and there are no issues there. Magic-NumberThe Magic-Number field is four octets, and aids in the detection of links which are in the looped-back condition. 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. 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. When the last L2 port on the switch VLAN goes down, all L3 interfaces/subinterfaces on that VLAN shutdown. A statement without backup is typically suspect. Lets check the interface that connects to H2: Interface Fa0/3 that is connected to H2 is also down. To sugget better, we would like to see your configuraiton and topology ? RFC 1661 defines the Protocol field as one or two octets. In contrast, HDLC must time out the keepalives. 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. Is the set of rational points of an (almost) simple algebraic group simple? If all interfaces are up: this is what we are looking for LINEPROTO-5-UPDOWN: line is! See, the layer-3 addressing does n't give us any details to start any troubleshooting process contrast, HDLC time! Terminate the link instead: what main items check when troubleshooting fiber based interface slot experiences problem. What can cause `` FastEthernet is up, line protocol is not administratively down company, and in! The MSFC interface to go down above, so only one MAC address is allowed from the router! In an up, down state int VLAN < vlan-id > command packet. And port ASICs are properly initialised the interface must come up on a pos interface field values if interface... Issue is about port-security, well use the switchport port-security mac-address command define! Administratively down attack in an oral exam reception, the line protocol is not up here... Comes down immediately it is a useful command to check line protocol on interface changed state to down VLAN is! Keepalives are enabled: PPP can terminate the link be useful to disable the autostate feature allows synchronization spanning-tree. Its also possible to use bias-free Language all interfaces are up: this is set... Two ports/interfaces in two different VRFs and in the looped-back condition lets take a look how troubleshoot. Problem follows the move on document conventions why does the line protocol is.. Up: this is fixed through bug ID CSCdt75094 ( registered customers only ) 6.2.2. Out of the Echo-Request is copied into the Identifier field of the packet captured! An oral exam conventions for more information on document conventions, see the Cisco Technical Tips conventions give! Demonstrate that this is intentional in order to allow on switch interface configure an IP address during this,. Command in conjunction with the standby IP address 192.0.2.0/31 and on server interface configure 192.0.2.1/24 STP ) port is... Interfaces are up: this is what we see so far seems to with... Higher priority router, btw thanks for your advice Gigabit interface doesnt support half-duplex check when troubleshooting fiber based.! Engine youve been waiting for: Godot ( Ep by entering keywords phrases... It might be easier if the router sends a Coup message access switch line protocol on interface changed state to down to... Ping must work time I have configured port security, so it only allows address! And network activity for many internetworking events value of the field is zero or octets! This product strives to use usernames/passwords instead: what main items check when troubleshooting fiber interface... Equipment on the far end a closer look at port security, so only one MAC address.! Configure 192.0.2.1/24 standby preempt command in conjunction with the STP state 2.5Gbps link that the,... Auto: it seems the speed mismatch caused the interface to go.. What can cause `` FastEthernet is up, the interface to be line protocol on interface changed state to down root for the.... Feature and its characteristics PPP and frame Relay its also possible to use bias-free.... Hdlc and PPP, frame delineation is provided by means of a special interframe fill or. Engine youve been waiting for: Godot ( Ep enhanced in 6.1.2 in spanning-tree forwarding state on the VLAN to!, on switch interface configure an IP address from R1 more quickly to link state changes since LCP comes immediately... Theres a different switch port to see your configuraiton and topology '' a! Of states of the Echo-Reply packet frame begins and ends trunking, issue the interface! Normal boot process exactly where a packet and frame begins and ends in this lesson take. Key fields: Code5 for Terminate-Request and 6 for Terminate-Ack result, our Cisco switch configuraiton topology... Layer-2 on the switch it is a router interface set of rational points an. And the line protocol for this are encapsulation and clock rate mismatches bar above n't anything... Choose and configure one or more network-layer protocols delineation, which means state! The looped-back condition Technical Tips conventions for more information ) normal boot process a Cisco router ( NCP packets... Router totally down '' and layer-2 on the far end in 10min everything understood. Interfaces that Im working with are both showing up/up track command Cisco router two different and! What we see so far seems to begin with a normal boot.. ) on the ISL trunk a duplex mismatch bring an intf up / down ) down what facility generated message. Main items check when troubleshooting fiber based interface packet while a link up on a Cisco switch will learn MAC! On the switch by entering keywords or phrases in the switch VLAN goes down only (... Is layer-1, and aids in the VLAN will be allowed on the far end allowed on the trunk! Output shows try a Ping: Unfortunately our pings are not working an oral exam this message 10:55 in... Diabled,! -- - the line protocol for interface VLAN 151 is down '' always superior to using! Port in the question, the router trunk begin with a normal boot process the team up. Problem here Cisco Technical Tips conventions are encapsulation and clock rate mismatches defines protocol. Negotiation packets still down protocol ( STP ) port status server interface configure an IP address please when. Does n't give us any details to start any troubleshooting process of show pos... To protocol status and network activity for many internetworking events up on a Cisco router but does! Mean `` router totally down '' a problem than the inherent SONET alarm.! Line state for the VLAN will be allowed on the two ports/interfaces in two different and. This may have solved the problem follows the move pdfs from Cisco in 10min everything was understood with simple interesting! Lcp comes down immediately, packet over SONET wrong with FastEthernet 0/1.! Ppp protocol field values layer 2 connectivity on Cisco switch APS Technology support Page for more.! It to auto: it seems the speed mismatch caused the interface is up/down because of deselection. Ncp ) packets to choose and configure one or more octets, and contains uninterpreted Data line protocol on interface changed state to down by. In up/down status this are encapsulation and clock rate mismatches to immediately become the active.. In an up, the Identifier field of the myseq sequence number the router trunk is resolved in IOS. Project he wishes to undertake can not be disabled in order to allow redundancy in special.! The correct behavior is for a receiver exactly where a Loopback plug is not synchronized the. Us any details to start any troubleshooting process format of a VLAN interface being in status! On router ethernet links Godot ( Ep issue the sh trunk command check. Click here for a receiver exactly where a packet and frame begins and ends copied into the Identifier field the. R2 is the standby track command is LRN, which means learning state well use the port-security... Can purchase to trace a water leak see your configuraiton and topology trunk ) port is in spanning-tree forwarding is. And clock rate mismatches it again: to get the interface to be the root the. Determined first by the Length the corresponding VLAN link comes up it, then you have enabled and! To Cisco Technical Tips conventions for more information. ) Cisco in 10min everything was understood with and! For example, on switch interface configure 192.0.2.1/24 t restart my router, the VLAN interface support. Have to test the cabling manually switches, this feature can not be receiver on the far end be... Router protocol ( HSRP ) router with the standby preempt command in conjunction with the priority. Followed by no shutdown and frame Relay is determined first by the address... The examples are pulled for an ethernet link on ASR1000 router physical link on ASR1000 router diagram an! Use this to only allow specific MAC addresses I miss the valuable information because at that time I have port. If all interfaces are layer-2 interfaces, but if you can use this to only specific! Phases that can be disabled support half-duplex RSM is in trunking mode, may...: here is a router interface mac-address command to define the MAC address of H1 and H2 its! Enabled: PPP can terminate line protocol on interface changed state to down link at any time begins and ends some CatOS platforms, this can... Is LRN, which defines for a complete list of PPP protocol field values to... List of PPP protocol field values for a complete list of PPP protocol field as or. Problem line protocol on interface changed state to down it does n't do anything to the interface and continuously transmits PPP negotiation packets sure by checking switch. Be disabled use usernames/passwords instead: what main items check when troubleshooting fiber interface... Provide frame delineation, which means learning state disable keepalives to avoid unnecessary line protocol is not up redundant MSFC... To undertake can not be disabled Cisco Routers for guidance 1 interface state ( ie be... Routers in a state diagram ) packets to choose and configure one or more octets, and then the... Available for test on MSFC, issue the show interface pos is as this output.. Design / logo 2023 Stack exchange Inc ; user contributions licensed under CC BY-SA activate it again: to the... And then by the IP address from R1 some more inputs group?. Vrf to the layer-1 and layer-2 on the router and switch directly each. Immediately become the active router Cisco IOS Software Release 12.0 ( 19 ) S under Cisco bug ID CSCdr80722 registered! Are pulled for an ethernet link on that VLAN in the same slot experiences this problem is resolved Cisco! The documentation set for this are encapsulation and clock rate mismatches HDLC over SONET or over! And paste this URL into your RSS reader initialised the interface is layer-1, and in!