Which Cisco command will provide information about the status of all interfaces including the number of Giants runts and collisions on the interface?
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One of the most useful and popular commands used on Cisco devices is the “show interface” command.  It can be very useful at troubleshooting connectivity issues and physical port issues, check the status of physical ports, watch how much traffic is passing through the interface, which IP address is assigned to the interface (for Layer3 interfaces) etc. This command works on both Cisco Switches and Cisco Routers and has the same functionality on both types of devices. In this article we will discuss and explain the “show interface” command on both routers and switches, so let’s get started. Topology DiagramHere is the topology used to gather the various output data for each device in this article: On a Layer 2 switch we can check the status and various other counters and metrics for each physical ethernet interface or for every interface on the device. I usually start first with the following command: Switch0# show interfaces status Port Name Status Vlan Duplex Speed Type Fa0/1
connected 1 auto auto 10/100BaseTX The above gives me a quick status update of each available interface on the switch, on which VLAN it belongs, speed settings etc. Now if you want to dive deeper in the counters for each physical interface, we can be more specific as shown below: Switch0# show interfaces FastEthernet 0/1 FastEthernet0/1 is up, line protocol is up (connected) The “Show Interface” command above which includes the specific interface number (FastEthernet 0/1), shows much more information. The most important data you need to take into consideration are the following: FastEthernet0/1 is up, line protocol is up (connected): This shows that the specific interface is connected (both physical access and line protocol are up), so it is ready to pass traffic. Hardware is Lance, address is 000b.be66.0b01 (bia 000b.be66.0b01):Here you can see the MAC (hardware) address of the interface. reliability 255/255: If you have reliability 255/255 it means that there are no input and output errors on the interface. If you have interface errors the reliability factor will decrease. 5 minute input rate 0 bits/sec, 0 packets/sec The above counters are useful to check how much traffic has passed through the interface the last 5 minutes. 2357
packets output, 263570 bytes, 0 underruns The above counters are also useful to watch how much traffic has passed through the interface, if there were any errors or frame collisions, buffer failures etc. NOTE: The number of errors shown on each interface is a cumulative number which shows statistics (input/output errors etc) from the time the device was booted up. If you see a small number of errors among millions of packets, then you don’t need to worry. However, if the total number of errors is a big percentage compared to the number of packets, then you should investigate for possible interface problems. Let’s now see another useful show interface command on switches: Switch0# show interfaces trunk Port Mode Encapsulation Status Native vlan If you want to see which interfaces are configured as “Trunk” ports, the above command will show you just this. As shown above, port Fa0/3 is configured as 802.1q Trunk which means it is connected to another switch in order to pass VLANs from one switch to another. As you can see, VLANs 1-1005 are allowed to pass through the trunk connection. Show Interface on Cisco RoutersOn a Layer 3 router, the show interface command is equally important to obtain crucial information about each interface for various purposes. Let’s see three cases of the command: Router0# show ip interface brief Interface IP-Address OK? Method Status
Protocol I always start by getting a brief high-level picture of all interfaces with the “show ip interface brief” command. As shown above, this shows me the IP address assigned to each physical interface, if the port is UP, if the protocol is UP etc. For example, one interface might be connected to a Frame Relay connection. The physical port might be UP but the protocol might show Down. Now, if you want to get more IP details and other statistics for a specific interface, run the following: Router0# show ip interface GigabitEthernet 0/0 GigabitEthernet0/0 is up, line protocol is up (connected) The command above shows statistics up to Layer 3 of the OSI model (Physical, Data Link and Network Layers). It shows the IP address configured and also if there are any Access Control Lists (ACL) applied to the specific interface with the below fields: Outgoing access list is not set An ACL is a packet filtering mechanism which controls IP packets passing through the interface (block or allow) based on IP address and port numbers. Now let’s see the generic show command which we described also on the switch section above: Router0# show interfaces GigabitEthernet 0/0 GigabitEthernet0/0 is up, line protocol is up (connected) Just like the command executed on a switch, the same command on a Cisco router displays similar statistics such as:
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Which command will provide information about the status of all interfaces including the number of Giants runts and collisions on the interface *?Which command will provide information about the status of all interfaces including the number of giants, runts, and collisions on the interface? Explanation: The show interfaces command is the most comprehensive in providing information about interfaces.
What is command to verify status of all interfaces?The netstat command generates displays that show network status and protocol statistics. You can display the status of TCP, SCTP, and UDP endpoints in table format. You can also display routing table information and interface information.
How do you display the status of the connected interfaces on the switch Cisco?To display summary details of the system interfaces, use the show interface summary command. This command has no arguments or keywords. To display details of the system interfaces, use the show interface command. Displays detailed redundancy management interface information.
What is the command used in Cisco router to quickly reveal the status of all interfaces on the router briefly?Router#show interfaces
This command shows the status and configuration of interfaces. By default it will display all interfaces.
Which command shows the status of the switch interfaces?The show IP interface brief command gives you the answers to these questions and is the best summary of the status, protocol and IP addresses of your interfaces. This command can be used in both User EXEC and Privileged EXEC mode.
What is runts in Cisco interface?Runt packets are packets that are less than the minimum packet size (64 bytes for Ethernet). They often occur due to collisions on the line. On switches the cause is usually a mis-matched duplex problem (full on one end and half on the other) caused by bad autodetection of a device.
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