H3C S7500 Series Operation Manual

Also see for S7500 Series: Operation manual Operation manual Operation manual Command manual Command manual

Contents

H3C S7500 Series Operation Manual Manual pdf 353 page image

Operation Manual – Routing ProtocolH3C S7500 Series Ethernet Switches Chapter 5 IS-IS Configuration5-4Area 1L2Area 3Area 2L1L1 L1/L2L2L1/L2L1Area 4Figure 5-2 An example of the IS-IS topology IINote:The IS-IS backbone does not need to be a particular Area.In IS-IS, SPF algorithm is used to generate the shortest path tree (SPT) regardless ofthe Level-1 or Level-2 router.5.1.3 IS-IS Address StructureI. Address structure1) NSAPThe ISO uses the NSAP address format shown in Figure 5-3. The NSAP addressconsists of the initial domain part (IDP) and the domain specific part (DSP). The IDPequals to the network id field in the IP address, and the DSP equals to the subnet andhost id field.The IDP, defined by OSI, includes the authority and format identifier (AFI) and theinitial domain identifier (IDI).The DSP includes the high order DSP (HODSP), the System ID and SEL, where theHODSP identifies the area, the System ID identifies the host, and the SEL indicatesthe type of service.The length of IDP and DSP is variable. The maximum length of the NSAP address is20 bytes.