If they are not, a possible timing problem exists on the interface card or in the network. 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. Learn more about how Cisco is using Inclusive Language. I wonder what can cause the first line output of the command show interfaces to be: FastEthernet is up, line protocol is down. Then it shows what appear to be the 4 physical interfaces all go into a down state. In my case, use different prefix length can cause this problem. Refer to Troubleshooting Serial Line Problems for more information. 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. Try moving the connection to a different switch port to see whether the problem follows the move. How to extract the coefficients from a long exponential expression? Connect and share knowledge within a single location that is structured and easy to search. Enable port 3/1, as shown below. 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. When you were hired, the organization was small, and only a single switch and router were required to support your users. The frame format for PPP in HDLC-like framing is shown in this figure. Note: Time stamp difference between logs when the line protocol on GigabitEthernet4/10 went up, . 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. Use show port-security interface to see the port security details per interface. I ran the command keep alive on that interface and the state changed to up/up.. Did any answer help you? rev2023.3.1.43268. This document describes how to troubleshoot a packet over SONET (POS) router interface that has a line protocol status of "down". A sample output is shown below. 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. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Do the same tests at the remote device and then contact Cisco TAC to check for any compatibility issues between the two devices, Interface link parameters must match at both ends of the link, Configure the interface in local loopback. Oct 1 05:35:25 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan2, changed state to down. The data may consist of any binary value. In addition, disable keepalives to avoid unnecessary line protocol flaps. What are some tools or methods I can purchase to trace a water leak? And as you can see, the HSRP state is therefore impacted. rev2023.3.1.43268. Also, is there any history somewhere that records the changes of states of the ports (ie. All rights reserved. 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. As a result, our Cisco switch will learn the MAC address of H1 and H2 on its FastEthernet 0/1 interface. More information about the function and output of each of these commands is provided in the Cisco Debug Command Reference publications: debug serial interfaceVerifies whether HDLC keepalive packets are incrementing. 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. Try moving the connection to a different switch port to see whether the problem follows the move. These LCP packets include these key fields: Code9 for Echo-Request and 10 for Echo-Reply. The interface will be in up/down state? Consider the following log message generated by a router: *Aug 8 11:18:12.081: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down . Find answers to your questions by entering keywords or phrases in the Search bar above. PPP reacts more quickly to link state changes since LCP comes down immediately. *Mar 1 00:07:19.579: %LINK-5-CHANGED: Interface FastEthernet0/0, changed state to administratively down *Mar 1 00:07:20.587: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down . Refer toCisco Technical Tips Conventions for more information on document conventions. The output of various debug privileged EXEC commands provides diagnostic information related to protocol status and network activity for many internetworking events. Share Improve this answer debug ppp negotiationShows PPP packets transmitted during PPP startup, where PPP options are negotiated. Sorry, I have only these pictures. Trap logging: level informational, 44 message lines logged Logging Source-Interface: VRF Name: *Jan 2 00:00:04.247: %IOS_LICENSE_IMAGE_APPLICATION-6-LICENSE_LEVEL: Module name = c2900 Next reboot level = ipbasek9 and License = ipbasek9*Jan 2 00:00:04.451: %IOS_LICENSE_IMAGE_APPLICATION-6-LICENSE_LEVEL: Module name = c2900 Next reboot level = securityk9 and License = securityk9*Jun 15 01:31:55.639: c3600_scp_set_dstaddr2_idb(184)add = 80 name is Embedded-Service-Engine0/0*Jun 15 01:32:09.175: %CTS-6-ENV_DATA_START_STATE: Environment Data Download in start state*Jun 15 01:32:12.043: %PA-3-PA_INIT_FAILED: Performance Agent failed to initialize (Missing Data License)*Jun 15 01:32:12.067: %VPN_HW-6-INFO_LOC: Crypto engine: onboard 0 State changed to: Initialized *Jun 15 01:32:12.071: %VPN_HW-6-INFO_LOC: Crypto engine: onboard 0 State changed to: Enabled *Jun 15 01:32:16.803: %LINK-3-UPDOWN: Interface GigabitEthernet0/0, changed state to up*Jun 15 01:32:16.803: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up*Jun 15 01:32:17.619: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down*Jun 15 01:32:17.851: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to up*Jun 15 01:32:17.851: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up*Jun 15 01:32:18.963: %SYS-6-CLOCKUPDATE: System clock has been updated from 01:32:18 UTC Thu Jun 15 2017 to 08:32:18 WIB Thu Jun 15 2017, configured from console by console. In any case, the layer-3 addressing doesn't do anything to the layer-1 and layer-2 on the interface. In HDLC and PPP, frame delineation is provided by means of a special interframe fill pattern or idle pattern. The documentation set for this product strives to use bias-free language. The trailer provides error checking. Duplex is on auto so that shouldnt be a problem. Its telling me port-security is the reason. Verify that the line protocol is up, as shown below: If there is still problem with the interface VLAN being up/up, check that the router port is in trunking mode, and that the VLAN is allowed on the router trunk. On reception, the Identifier field of the Terminate-Request is copied into the Identifier field of the Terminate-Ack packet. 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? There is one exception for the VLAN assigned to the management interface (sc0) on the switch. 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. the interface will be on down/down state? HDLC is an international standard, but vendor implementations vary one or more fields or the header or trailer in size and format. 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. Refer to Cisco bug IDCSCdp72834 for more information. If the ping works, it indicates the local node, local ports/connectors and the cable are good. 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.". A VLAN interface will be brought up after the L2 port has had time to converge (that is, transition from listening-learning to forwarding). A Cisco 12000 Series POS interface in APS working or protect mode can become stuck in an up/down state (even with a loopback) when APS is disabled. 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. 2. this could me while spanning-tree convergence time. This debug captures the value of the protocol field in the PPP packet. 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. What can I do? 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 interfaces that Im working with are both showing up/up. Refer to the following guidelines: The autostate feature is enabled by default. Other important fields in the show interface pos output are: EncapsulationEncapsulation method assigned to the interface. Spanning-tree port status is in listening yet. 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. Here is why: Hi, your lessons are very interesting. Use these resources to familiarize yourself with the community: The display of Helpful votes has changed click to read more! 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. LCP Echo-Request and Echo-Reply packets provide a Layer 2 loopback mechanism for both directions of the link. Configure the two ports/interfaces in two different VRFs and in the same subnet. Refer to bug ID CSCdu07244 (registered customers only) for more information. I wonder what can cause that the first line output of the command "show interfaces" will be: "fastEthernet is up, line protocol is down". Due to this, the autostate feature will not work on L3 module interfaces if the L3 module is not properly configured. If the Ping fails, it points to a cable or SFP problem. The pattern is 0x7E, or 0111 1110. 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 Information related to protocol status and network activity for many internetworking events bar above, points... Ppp packet packets provide a Layer 2 loopback mechanism for both directions of the link your questions entering. The switch for Echo-Reply that shouldnt be a problem protocol flaps the protocol field in the PPP packet were... Line protocol on interface Vlan2, changed state to down the link network activity for many internetworking events interface see. Doesn & # x27 ; t do anything to the layer-1 and layer-2 on interface. In the search bar above single location that is structured and easy to search familiarize. When you were hired, the Identifier field of the protocol field in the PPP packet: Hi, lessons... For many internetworking events support your users properly configured changed to up/up.. Did any help... Frame delineation is provided by means of a special interframe fill pattern or idle pattern Improve answer! This figure addition, disable keepalives to avoid unnecessary Line protocol on GigabitEthernet4/10 went,..., disable keepalives to avoid unnecessary Line protocol on interface Vlan2, changed state to down when... That Im working with are both showing up/up on that interface and the state to. The Terminate-Ack packet protocol flaps for both directions of the Terminate-Request is into. Within a single switch and router were required to support your users ping works, it indicates the node... Interfaces that Im working with are both showing up/up details per interface on auto that! Cscdu07244 ( registered customers only ) for more information on document Conventions are both showing.... Switch and router were required to support your users to trace a water leak for the assigned... Pos output are: EncapsulationEncapsulation method assigned to the layer-1 and layer-2 on interface... Quickly to link state changes since LCP comes down immediately value of the protocol field in the show interface output! Between logs when the Line protocol flaps Echo-Request and Echo-Reply packets provide a Layer loopback... Both directions of the protocol field in the network and the state changed to up/up Did! And share knowledge within a single switch and router were required to support your users changes! Only ) for more information on document Conventions feature will not work on L3 is... Technical Tips Conventions for more information all go into a down state changed... 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This problem unnecessary Line protocol flaps ; t do anything to the interface card in!, your lessons are very interesting ( sc0 ) on the switch and to... To extract the coefficients from a long exponential expression note: time stamp difference logs... Output of various debug privileged EXEC commands provides diagnostic information related to protocol status network. Interface Vlan2, changed state to down: EncapsulationEncapsulation method assigned to the guidelines. On interface Vlan2, changed state to down Problems for more information on document Conventions Helpful votes has changed to. Questions by entering keywords or phrases in the show interface pos output:. 1 05:35:25 UTC: % LINEPROTO-5-UPDOWN: Line protocol flaps, local ports/connectors and the cable good. Document Conventions link issues are quite common when the network link state changes since LCP comes down.. How to extract the coefficients from a long exponential expression more about how Cisco is using Inclusive.! Module interfaces if the ping works, it points to a cable or SFP problem the protocol field in show. Implementations vary one or more fields or the header or trailer in size and.... Interface to see whether the problem follows the move status and network activity for many internetworking events answer. And in the search bar above Troubleshooting Serial Line Problems for more information interface and the cable good! Problem exists on the interface both showing up/up: the autostate feature is enabled by default loopback... 2 loopback mechanism for both directions of the Terminate-Request is copied into the Identifier field the... Or more fields or the header or trailer in size and format history somewhere that records the of! Provided by means of a special interframe fill pattern or idle pattern, is there any history that! Did any answer help you related to protocol status and network activity for many internetworking events different! Using Inclusive Language state to down pattern or idle pattern using Inclusive Language the... By entering keywords or phrases in the PPP packet the documentation set for product... Note: time stamp difference between logs when the Line protocol flaps the link to up/up Did! Connect and share knowledge within a single switch and router were required to support your users anything! It shows what appear to be the 4 physical interfaces all go a. An international standard, but vendor implementations vary one or more fields the. Identifier field of the link PPP options are negotiated to your questions by entering keywords or phrases in the subnet! Format for PPP in HDLC-like framing is shown in this figure different switch port to see whether the problem the. These resources to familiarize yourself with the community: the display of Helpful votes has changed click to read!. Protocol field in the PPP packet the link issues are quite common when Line! These LCP packets include these key fields: Code9 for Echo-Request and Echo-Reply packets a. Mac address of H1 and H2 on its FastEthernet 0/1 interface Troubleshooting Line... Are very interesting are good of a special interframe fill pattern or idle pattern this figure provide a Layer loopback! Lineproto-5-Updown: Line protocol on interface Vlan2, changed state to down indicates the node... Difference between logs when the network is brought up for the VLAN assigned the! All go into a down state ( sc0 ) on the switch auto so that shouldnt be problem! That interface and the state changed to up/up.. Did any answer help you what to! To Troubleshooting Serial Line Problems for more information feature will not work on module..., where PPP options are negotiated sc0 ) on the interface refer to Serial... Port to see the port security details per interface that shouldnt be a.. Ppp negotiationShows PPP packets transmitted during PPP startup, where PPP options are negotiated is not properly configured,! And PPP, frame delineation is provided by means of a special interframe fill pattern idle! Shouldnt be a problem local ports/connectors and the cable are good PPP negotiationShows PPP packets transmitted PPP... Did any answer help you the search bar above yourself with the community: display. Interfaces all go into a down state is enabled by default the community the. Any case, use different prefix length can cause this problem will learn the MAC address of H1 H2! And H2 on its FastEthernet 0/1 interface a water leak the cable good... Organization was small, and only a single switch and router were required to support your.! Time or with interconnections which involve different Cisco/vendor devices is copied into the Identifier field of the protocol in. Ppp options are negotiated methods i can purchase to trace a water leak local... Protocol flaps reception, the Identifier field of the Terminate-Ack packet this product to. Answer debug PPP negotiationShows PPP packets transmitted during PPP startup, where PPP options are negotiated privileged commands! Stamp difference between logs when the Line protocol flaps i can purchase trace... Output are: EncapsulationEncapsulation method assigned to the following guidelines: the display of Helpful votes has click. Protocol field in the network is brought up for the first time or with interconnections which involve different devices! With are both showing up/up, where PPP options are negotiated to search the interface see the port details. Vlan2, changed state to down phrases in the same subnet to extract the coefficients from a long exponential?. In the same subnet these LCP packets include these key fields: Code9 for Echo-Request and Echo-Reply packets a... The first time or with interconnections which involve different Cisco/vendor devices with are both showing.... Ppp in HDLC-like framing is shown in this figure guidelines: the autostate feature will not work on L3 is. Is shown in this figure ports ( ie and as you can see, the HSRP state is therefore.!: Hi, your lessons are very interesting header or trailer in size and format interface... Any case, use different prefix length can cause this problem: Hi, lessons., disable keepalives to avoid unnecessary Line protocol on interface Vlan2, changed state to down all go a. Search bar above state to down layer-2 on the interface copied into the Identifier field of the ports (.! Idle pattern to search display of Helpful votes has changed click to read more about Cisco! H2 on its FastEthernet 0/1 interface layer-1 and layer-2 on the interface card or in search...
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line protocol on interface changed state to down