Configuring Integrated Is-Is - 3Com 8807 Configuration Manual

IS-IS Routing Protocol
Packets
Configuring
Integrated IS-IS
NET
Network Entity Title (NET) indicates the network layer information, which contains
no transfer layer information (SEL=0). You can regard it as a special NSAP.
In general, you can configure a NET for a router. If you will redivide an area
(combine multiple areas or divide an area into multiple areas), you can configure
multiple NETs to ensure correct routes in the case of reconfiguration. Because you
can configure up to three area addresses, you can only configure up to three NETs.
For example, there is a NET 47.0001.aaaa.bbbb.cccc.00, in which,
Area=47.0001, System ID=aaaa.bbbb.cccc, SEL=00.
For example, there is a NET 01.1111.2222.4444.00, in which,
Area=01, System ID=1111.2222.4444, and SEL=00.
IS-IS packets are directly encapsulated in the data link frames and mainly divided
into 3 kinds, Hello, LSP and SNP.
Hello packets
Hello packets, which is also called IIH (IS-to-IS Hello PDUs), can establish and
maintain neighbor relations. The Level-1 router in a broadcast LAN forwards
Level-1 LAN IIH; the Level-2 router in a broadcast LAN forwards Level-2 LAN IIH;
non-broadcast network forwards Point-to-Point IIH.
LSP
Link state packet (LSP) can switch link state information. LSP can be divided into
Level-1 LSP and Level-2 LSP. Level-2 routers transmit Level-2 LSPs; Level-1 routers
transmit Level-1 LSPs; Level-1-2 routers transmit both Level-2 LSPs and Level-1
LSPs.
SNP
Sequence Number Packet (SNP) can confirm the LSPs last received from neighbors.
SNPs function as acknowledge packets, but SNPs function more validly. SNP
includes complete SNP (CSNP) and partial SNP (PSNP). SNP can be further divided
into Level-1 CSNP, Level-2 CSNP, Level-1 PSNP and Level-2 PSNP.
PSNP only lists one or more last received LSP sequence numbers, and confirms
multiple LSPs. When detecting asynchronous LSDBs, the system asks neighbors to
send new LSPs by PSNPs.
CSNP contains all LSP digest information in a LSDB, synchronizing LSDBs for
neighbor routers. On a broadcast network, a DIS sends CSNPs periodically (the
default sending period is 10 seconds). On the point-to-point line, a DIS sends
CSNPs only when the neighbors are established for the first time.
Among the following configurations, the configuration of enabling integrated
IS-IS is required, while other configurations are optional.

Configuring Integrated IS-IS

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