The Complete IS-IS Routing Protocol- P3:IS-IS has always been my favourite Interior Gateway Protocol. Its elegant simplicity, its well-structured data formats, its flexibility and easy extensibility are all appealing – IS-IS epitomizes link-state routing. Whether for this reason or others, IS-IS is the IGP of choice in some of the world’s largest networks. Thus, if one is at all interested in routing, it is well worth the time and effort to learn IS-IS. | Cisco Systems IOS CLI 47 412058846 packets input 4066852672395 bytes 0 no buffer Received 0 broadcasts 0 runts 0 giants 0 throttles 0 parity 1 input errors 1 CRC 0 frame 0 overrun 0 ignored 0 abort 627685025 packets output 4025356699702 bytes 0 underruns 0 output errors 0 applique 4 interface resets 0 output buffer failures 0 output buffers swapped out 3 carrier transitions The output contains information about the Layer-2 encapsulation maximum transmission unit MTU the current forwarding rate expressed in packets and bytes plus counters for the aggregate number of bytes and packets that have been processed through this interface. For IS-IS-related purposes you will often see the interface names for example in commands like show clns neighbor London show clns neighbor System Id Interface SNPA State Holdtime Type Protocol Frankfurt PO3 0 PPP Up 22 L2 IS-IS Munich PO4 1 PPP Up 20 L2 IS-IS Changing Router Configuration In IOS you tell the router to take configuration input and to transfer it to the central configuration file using the configure command. The standalone configure command will prompt you to enter the way that you want to input the configuration file London coni igure Configuring from terminal memory or network terminal Enter configuration commands one per line. End with CNTL Z. London config The memory option lets you source the configuration file from a memory storage device inside the router such as flash-disks or the NVRAM. But a more typical way is from the network or from the terminal. From the network means that you have to specify a trivial FTP TFTP server and a filename and the router will then attempt to pull down the file using the TFTP protocol. London conf network Address or name of remote host Source filename London-confg Configure using tftp London-confg confirm The most common way is to put the router into configuration mode and then enter the configuration statements manually from the .
