H3C S7500E Series Ethernet Switches Operation Manual

Operation Manual – IPv4 Routing
H3C S7500E Series Ethernet Switches Chapter 4 IS-IS Configuration
4-10
Figure 4-7 L1/L2 LAN IIH format
z Reserved/Circuit Type: The first 6 bits are reserved with value 0. The last 2 bits
indicates router types: 00 means reserved, 01 indicates L1, 10 indicates L2, and
11 indicates L1/2.
z Source ID: The system ID of the router advertising the hello packet.
z Holding Time: If no hello packets are received from a neighbor within the holding
time, the neighbor is considered dead.
z PDU Length: The total length of the PDU in bytes.
z Priority: DIS priority.
z LAN ID: Includes the system ID and one byte pseudonode ID.
Figure 4-8 shows the hello packet format on the point-to-point network.