tailieunhanh - The Complete IS-IS Routing Protocol- Part 6

The Complete IS-IS Routing Protocol- P6: 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. | Common Properties of Command Line Interfaces 37 And for IOS the prompt would look like this London What you will always see is the hostname the name of the router followed by the sign. In JUNOS you also see the username followed by the @ sign before the hostname. Now you can issue commands to the router. The commands are organized in a hierarchical fashion as shown in Figure . The more arguments a command has the more specific the command gets. For instance a show isis database London just shows a single link-state database LSDB entry while show isis database shows all LSDB entries. hannes@Frankfurt show isis database London IS-IS level 2 link-state database LSP ID 1 LSPs Sequence 0x1af Checksum 0xa977 Lifetime 25314 Attributes L1 L2 hannes@Frankfurt show isis database IS-IS level 1 link-state database IS-IS level 2 link-state database LSP ID Sequence Checksum Lifetime Attributes 0x1af 0xa977 25314 L1 L2 0x1a7 0x3dd0 31088 L1 L2 0x1a2 0x16f5 46510 L1 L2 0x19a 0x3ec 5184 L1 L2 408 LSPs The arguments for a command are separated by a simple blank. Sometimes the router has too few arguments and this forms an unambiguous command. Typically routers complain about an ambiguous command with a prompt hannes@Frankfurt show isis syntax error expecting command . Figure . The command line space is organized in a hierarchical fashion 38 3. Introduction to the IOS and JUNOS Command Line Interface This is from a router running JUNOS and Munich show isis Incomplete command. is from an IOS-based router. However there is an easy way to discover what kinds of commands the router gives you context-sensitive help. Context-sensitive Help At any time you can enter a question mark at the user prompt which makes the CLI display all the options that are available at this point in the command-line hierarchy hannes@Frankfurt show isis Possible completions adjacency database hostname interface route spf .