HP VPN Firewall Appliances Appendix Protocol Reference

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Major fields of the L1/L2 LAN IIH are as follows:
• Reserved/Circuit type—The first six bits are reserved with a value of 0. The last two bits indicate the
router type—00 means reserved, 01 indicates L1, 10 indicates L2, and 11 indicates L1/2.
• Source ID—System ID of the router advertising the hello packet.
• Holding time—If no hello packets are received from the neighbor within the holding time, the
neighbor is considered down.
• PDU length—Total length of the PDU in bytes.
• Priority—DIS priority.
• LAN ID—Includes the system ID and a one-byte pseudonode ID.
Figure 17 sho
ws the hello packet fo
rmat on the point-to-point networks.
Figure 17 P2P IIH format
Instead of the priority and LAN ID fields in the LAN IIH, the P2P IIH has a Local Circuit ID field.
LSP
The Link State PDUs (LSPs) carry link state information. LSPs include Level-1 LSPs and Level-2 LSP. The
Level-2 LSPs are sent by the Level-2 routers, and the Level-1 LSPs are sent by the Level-1 routers. The Level-1-2
router can send both types of LSPs.
The two types of LSPs have the same format, as shown in Figure 18.