3Com Switch 4800G 24-Port Configuration Manual page 332

332 C 29: IS-IS C
HAPTER ONFIGURATION
Figure 104 PDU common header format
Intradomain routing protocol discriminator
Length indicator
Version/Protocol ID extension
ID length
R R R
Version
Reserved
Maximum area address
Intra-domain Routing Protocol Discriminator: Set to 0x83.
■
Length Indicator: The length of the PDU header, including both common and
■
specific headers, present in bytes.
Version/Protocol ID Extension: Set to 1(0x01).
■
ID Length: The length of the NSAP address and NET ID.
■
R (Reserved): Set to 0.
■
PDU Type: For detail information, refer to Table 44.
■
Version: Set to 1(0x01).
■
Maximum Area Address: Maximum number of area addresses supported.
■
Table 44 PDU type
Type PDU Type
15 Level-1 LAN IS-IS hello PDU
16 Level-2 LAN IS-IS hello PDU
17 Point-to-Point IS-IS hello PDU
18 Level-1 Link State PDU
20 Level-2 Link State PDU
24 Level-1 Complete Sequence Numbers PDU
25 Level-2 Complete Sequence Numbers PDU
26 Level-1 Partial Sequence Numbers PDU
27 Level-2 Partial Sequence Numbers PDU
Hello
The hello packet is used by routers to establish and maintain the neighbor
relationship. It is also called IS-to-IS hello PDU (IIH). For broadcast network, the
Level-1 router uses the Level-1 LAN IIH; and the Level-2 router uses the Level-2
LAN IIH. The P2P IIH is used on point-to-point network.
Figure 105 illustrates the hello packet format in broadcast networks, where the
blue fields are the common header.
No. of Octets
1
1
1
1
PDU type 1
1
1
1
Acronym
L1 LAN IIH
L2 LAN IIH
P2P IIH
L1 LSP
L2 LSP
L1 CSNP
L2 CSNP
L1 PSNP
L2 PSNP