H3C Technologies H3C SR8800 - Manual (Page 158)

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Figure 54 PDU common header format
• Intradomain Routing Protocol Discriminator—Set to 0x83.
• Length Indicator—Length of the PDU header in bytes, including both common and specific headers.
• Version/Protocol ID Extension—Set to 1(0x01).
• ID Length—Length of the NSAP address and NET ID.
• R(Reserved)—Set to 0.
• PDU Type—For detailed information, see Table 2 .
• Version—Set to 1(0x01).
• Maximum Area Address—Maximum number of area addresses supported.
Table 2 PDU type
Type PDU Type Acronym
15 Level-1 LAN IS-IS hello PDU L1 LAN IIH
16 Level-2 LAN IS-IS hello PDU L2 LAN IIH
17 Point-to-Point IS-IS hello PDU P2P IIH
18 Level-1 Link State PDU L1 LSP
20 Level-2 Link State PDU L2 LSP
24 Level-1 Complete Sequence Numbers PDU L1 CSNP
25 Level-2 Complete Sequence Numbers PDU L2 CSNP
26 Level-1 Partial Sequence Numbers PDU L1 PSNP
27 Level-2 Partial Sequence Numbers PDU L2 PSNP
Hello PDU
Hello packets are used by routers to establish and maintain neighbor relationships. A hello packet is also
an IS-to-IS hello PDU (IIH). For broadcast networks, the Level-1 routers use the Level-1 LAN IIHs; and the
Level-2 routers use the Level-2 LAN IIHs. The P2P IIHs are used on point-to-point networks.
Figure 55 illustrates the hello packet format in broadcast networks, where the blue fields are the common
header.
Intradomain routing protocol discriminator
Reserved
Version
R
ID length
Version/Protocol ID extension
Length indicator
Maximum area address
R R PDU type
No. of Octets
1
1
1
1
1
1
1
1