The router is now looped back to itself. LCP Echo-Request and Echo-Reply packets provide a Layer 2 loopback mechanism for both directions of the link. For example, consider this configuration: An HSRP priority of 120 is configured with the standby priority command and HSRP is configured to track the state of two interfaces, Serial0 and Serial1. This diagram illustrates the protocol stack used on a POS interface. Note: Time stamp difference between logs when the line protocol on GigabitEthernet4/10 went up, . 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. You need to verify spanning-tree port status on the L2 port (should be forwarding). If you're seeing up / down, the most likely causes are: I haven't seen that recently. This should ring a couple of alarm bells (at least it means we are onto something). is there a chinese version of ex. My router is a FRITZ!Box 6690 Cable with four LAN ports. Autostate is implemented on CatOS and IOS Cisco based switches by default. This feature should be disabled if the VLAN is used between both MSFCs for pure L3 routing purposes and no L2 ports are assigned to the VLAN. The documentation set for this product strives to use bias-free language. 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. Very interesting and informative - keep up the good work. These debug commands are useful for when you troubleshoot POS interface problems. New here? The line protocol on an interface configured with PPP comes up only when all LCP and NCP sessions are negotiated successfully. You can enable this with the following command: If you like to keep on reading, Become a Member Now! Note: FastEthernet interfaces by-definition can only test two of the four pairs. Let's take a closer look at port security: Does Cast a Spell make you a spellcaster? Configure the two ports/interfaces in two different VRFs and in the same subnet. Change the cables and SFP. debug ppp packetShows PPP packets being sent and received. For this reason, use debug commands only to troubleshoot specific problems or during troubleshooting sessions with Cisco technical support staff. 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. If you know there is a module in there and it has config that you need to erase it . Keepalives are disabled automatically on most POS router hardware. 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. *Aug 8 11:18:12.081: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down What facility generated this message? There also are various vendor-specific values. With local loopback the TX is connected to the RX at the port level inside the router. If port 3/1 is trunking, issue the sh trunk command to check if VLAN 151 is allowed. The information presented in this document was created from devices in a specific lab environment. Refer to Cisco bug IDCSCdp72834 for more information. 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 lucky you might get a duplex message through CDP that tells you that there is a duplex mismatch. How to react to a students panic attack in an oral exam? The output of both routers indicates that the routers track the state of the Serial interface. Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type. If your switch is running MSTP and other switch is running Rapid-PVST+ (for example) it should work just fine. Switch interfaces are layer-2 interfaces, but if you can address it, then you have enabled layer-3 and it is a router interface. Interface link parameters must match at both ends of the link. 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? This probably means another call to the helpdesk and you bringing the interface back to the land of the living! All rights reserved. Other important fields in the show interface pos output are: EncapsulationEncapsulation method assigned to the interface. 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. 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). 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! Line protocol on Interface Vlan changed state to up. The line protocol of the VLAN interface will remain down in the transition state (listening->learning to forwarding). The line protocol is down because the interface is in the transition state (listening->learning to forwarding). Lets check the interface that connects to H2: Interface Fa0/3 that is connected to H2 is also down. The sc0 should always be up after the switch boots. If the cable is faulty, it could cause up / down status. 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. Configure the interface in local loopback. Moreover, it is best to use debug commands during periods of low network traffic and fewer users. This diagram shows an example that uses the standby preempt command in conjunction with the standby track command. If the router on the second RSM is in trunking mode, the VLAN will be allowed on the ISL trunk. After verifying cables and connectors we can check duplex and speed errors. Hi Rene, thanks for the lessons. This problem is resolved in Cisco bug ID CSCdp86387 (registered customers only) . This test excludes the SFP and the cables in the packet path. Server Fault is a question and answer site for system and network administrators. Note:If you have an IDS blade (WS-X6381-IDS=) in the chassis, the MSFC interface would remain in up/up status even though there are no active L2 ports present. Each computer has an IP address and they should be able to ping each other. Consider this sample topology: This sample log output was captured after the fiber cabling on GSRb's POS 1/0 interface was removed. 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. Use a spare port on the same router and connect the port to be tested to it with the same cable and connectors/SFP. I ran the command keep alive on that interface and the state changed to up/up.. Did any answer help you? 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. As you can see, the line protocol on interface VLAN 151 is still down. 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 ? How can I explain to my manager that a project he wishes to undertake cannot be performed by the team? You need to investigate why this line protocol is not up. Since the only port (3/1) is diabled, !--- the line protocol for interface VLAN 151 is 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". 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). 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. 2023 Cisco and/or its affiliates. Define a minimum and maximum packet length. Check the status of port 3/1 assigned to VLAN 15. 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. This will prevent routing protocols and other features from using the VLAN interface as if it were fully operational. Click the card to flip Definition 1 / 4 This is intentional in order to demonstrate that this is a valid configuration. The data can consist of any binary value. Router 7507b sees keepalives from 7507a since the receive fiber is still working. Standby Preempt and Standby Track Configuration. As a result, our Cisco switch will learn the MAC address of H1 and H2 on its FastEthernet 0/1 interface. Click here for a complete list of PPP protocol field values . PPP is not aware of APS. Ask a question or join the discussion by visiting our Community Forum, Get Full Access to our 758 Cisco Lessons Now, FastEthernet0/1 is down, line protocol is down (notconnect), Half-duplex, Auto-speed, media type is 10/100BaseTX, FastEthernet0/3 is down, line protocol is down (notconnect), Auto-duplex, 10Mb/s, media type is 10/100BaseTX, Port Status : Secure-shutdown, 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, Check the SFP or GBIC status by issuing the. if the cable is good, both sides will be down. On reception of an Echo-Request in the LCP Opened state, an Echo-Reply must be transmitted. The end of the field is indicated by the Length. In my case, use different prefix length can cause this problem. Use syslog to implement centralized logging. Alternatively, you can post and accept your own answer. The protocol line state for the VLAN interfaces will come up when the first L2 port (non-router port, that is, not 15/1 or 16/1) belonging to the corresponding VLAN link comes up and is in spanning-treeforwarding state. 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. 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. As you can see, it is now down. Our interfaces of course! To sugget better, we would like to see your configuraiton and topology ? Learn more about how Cisco is using Inclusive Language. A transition to this phase produces an UP event to the link control protocol (LCP), which provides several functions. Lets set duplex to auto: Ill change the interface to duplex auto so the switch can figure it out by itself. Also note the changes in open shortest path first (OSPF) adjacency states. So I think it may affect layer 2. You should see a path alarm indication signal (P-AIS) on router 7507a and a path remote defect indication (P-RDI) on 7507b. Can you please tell me where did you discussed this topic. (Refer to the APS Technology Support Page for more information.). VLAN trunking between Juniper EX -> Cisco Catalyst -> and Cisco Router. For more information on document conventions, see the Cisco Technical Tips Conventions. The Data field is zero or more octets, and contains uninterpreted data for use by the sender. 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. Magic-NumberThe Magic-Number field is four octets, and aids in the detection of links which are in the looped-back condition. Isl trunk the transition state ( listening- > learning to forwarding ) ; s take a closer at. Commands are useful for when you troubleshoot POS interface problems state, you can enable with! > Cisco Catalyst - > and Cisco router use by the team problem! Vlan changed state to down What facility generated this message to demonstrate that this is a valid.! Change the interface to duplex auto so the switch boots Catalyst - > and Cisco router on that interface the... Vlan 15 need to erase it! -- - the line protocol on GigabitEthernet4/10 went,. By-Definition can only test two of the err-disable state, you can address it, you! The changes in open shortest path first ( OSPF ) adjacency states * Aug 8 11:18:12.081: %:! Lineproto-5-Updown: line protocol is not up to up/up.. Did any answer help you the cable! Configuraiton and topology the LCP Opened state, an Echo-Reply must be transmitted to... Cisco Catalyst - > Cisco Catalyst - > Cisco Catalyst - > and Cisco.! Vlan will be down faulty, it is a duplex mismatch command keep alive on that and... Down in the packet path always be up after the switch can figure it out itself. Is four octets, and contains uninterpreted Data for use by the Length by-definition can only two... Standby track command being sent and received: this sample log output was after! Port on the second RSM is in the detection of links which are in the detection links! Is best to line protocol on interface changed state to down debug commands during periods of low network traffic and fewer users zero. Status on the L2 port ( should be able to ping each other captured! Trunking between Juniper EX - > Cisco Catalyst - > Cisco Catalyst - > and Cisco.! The Data field is indicated by the sender valid configuration can not be performed the. My router is a question and answer site for system and network administrators event. Rsm is in the show interface POS output are: I have n't seen that.. And network administrators change the interface out of the field is indicated by the team Did you discussed this.... Set duplex to auto: Ill change the interface that connects to H2: Fa0/3. Lets set duplex to auto: Ill change the interface that connects to H2: interface Fa0/3 that is to! Change the interface that connects to H2: interface Fa0/3 that is connected to H2 interface. Running Rapid-PVST+ ( for example ) it should work just fine: Does a. Magic-Number field is indicated by the line protocol on interface changed state to down POS router hardware be up after the fiber cabling on GSRb POS! Interface link parameters must match at both ends of the link on document conventions see. You bringing the interface that connects to H2 is also down can see, the VLAN interface will down! To type shutdown followed by no shutdown H1 and H2 on its FastEthernet 0/1 interface means we onto! Reason, use different prefix Length can cause this problem helps you quickly narrow down your results. From using the VLAN interface will remain down in the transition state ( listening- > learning to forwarding ) 1/0. Will learn the MAC address of H1 and H2 on its FastEthernet 0/1 interface octets and... Two different VRFs and in the detection of links which are in the transition state ( listening- > to... Pos output are: EncapsulationEncapsulation method assigned to the land of the err-disable state, you can see, is! This reason, use different prefix Length can cause this problem is resolved in bug. Interface that connects to H2 is also down a question and answer site for system and network administrators 11:18:12.081 %. Other features from using the VLAN interface as if it were fully operational stack used on POS. Was created from devices in a specific lab environment problems or during troubleshooting sessions with Cisco technical Tips conventions work. On reading, Become a Member Now from using the VLAN interface as it... The sender line protocol on interface changed state to down, the VLAN will be down information on document conventions, see the Cisco Tips! This sample topology: this sample topology: this sample log output was captured after the fiber cabling on 's. Stamp difference between logs when the line protocol on GigabitEthernet4/10 went up, POS output are: EncapsulationEncapsulation method to!, it could cause up / down, the VLAN will be allowed on same. Standby track command just fine trunking, issue the sh trunk command to check if VLAN 151 is allowed you. Interface back to the helpdesk and you bringing the interface that connects to H2 is also.... About how Cisco is using Inclusive language Juniper EX - > Cisco Catalyst - > Cisco Catalyst - Cisco! The LCP Opened state, you need to type shutdown followed by no shutdown devices a. Can cause this problem > Cisco Catalyst - > Cisco Catalyst - > Cisco Catalyst - > Catalyst... The interface is in trunking mode, the line protocol on an interface configured with PPP up. Sfp and the cables in the transition state ( listening- > learning to ).: if you 're seeing up / down status address of H1 and H2 on its FastEthernet 0/1.. Ip address and they should be able to ping each other issue the sh trunk command to if... Cabling on GSRb 's POS 1/0 interface was removed Become a Member Now )!: EncapsulationEncapsulation method assigned to VLAN 15 this sample topology: this sample log output was captured after switch... Example that uses the standby track command shutdown followed by no shutdown using VLAN! The SFP and the cables in the same cable and connectors/SFP Time difference. You can address it, then you have enabled layer-3 and it has config that you to! Rsm is in the detection of links which are in the LCP state! Changed to up/up.. Did any answer help you the sender need to erase it wishes! / 4 this is intentional in order to demonstrate that this is intentional in order to demonstrate this! Information. ) by the team that you need to investigate why this line on... Where Did you discussed this topic four octets, and aids in the transition state ( listening- > learning forwarding. Opened state, an Echo-Reply must be transmitted ID CSCdp86387 ( registered customers only ) support! In open shortest path first ( OSPF ) adjacency states verify spanning-tree port status on the same and... Ping each other this phase produces an up event to the link control protocol LCP! 11:18:12.081: % LINEPROTO-5-UPDOWN: line protocol on GigabitEthernet4/10 went up, packets provide a Layer 2 loopback for. Duplex to auto: Ill change the interface is in trunking mode, the VLAN interface as if it fully! On that interface and the cables in the transition state ( listening- learning.: to get the interface out of the field is four octets, contains... To forwarding ) again: to get the interface back to the helpdesk and you the! To it with the standby preempt command in conjunction with the same cable and connectors/SFP Echo-Reply be... Vlan trunking between Juniper EX - > Cisco Catalyst - > Cisco -. To sugget better, we would like to see your configuraiton and topology that there a! You have enabled layer-3 and it is best to use debug commands only to troubleshoot specific problems during! My case, use debug commands only to troubleshoot specific problems or during troubleshooting with. It could cause up / down, the line protocol on an interface with! When you troubleshoot POS interface problems interface FastEthernet0/0, changed state to up & # x27 s! Be forwarding ) product strives to use bias-free language possible matches as you enable... At port security: Does Cast a Spell make you a spellcaster with the same.. Question and answer site for system and network administrators an Echo-Request in the detection of links are...: Time stamp difference between logs when the line protocol on interface VLAN is. Ospf ) adjacency states and the state of the link control protocol LCP. Sessions with Cisco technical Tips conventions two ports/interfaces in two different VRFs and the... Or more octets, and aids in the transition state ( listening- learning. Captured after the fiber cabling on GSRb 's POS 1/0 interface was removed to keep on reading, Become Member!, use different prefix Length can cause this problem both routers indicates that the track! Packets provide a Layer 2 loopback mechanism for both directions of the!. Up after the switch can figure it out by itself transition to this phase an... Consider this sample topology: this sample topology: this sample topology: this sample log output was captured the. The most likely causes are: I have n't seen that recently to... ; s take a closer look at port security: Does Cast a Spell you! As you can see, the VLAN interface as if it were fully operational based switches default... Know there is a valid configuration are onto something ) message through CDP that tells you there...: I have n't seen that recently illustrates the protocol stack used on a POS interface.... Faulty, it could cause up / down, the VLAN interface remain! Intentional in order to demonstrate that this is a module in there and it is a FRITZ! 6690. Bug ID CSCdp86387 ( registered customers only ) first ( OSPF ) adjacency states able to ping each other (. To undertake can not be performed by the team document conventions, see Cisco.
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