H3C Technologies H3C S12500 Series Switches - Manual (Page 17)

9
Table 2 SPBM multicast address fields
Field Description
M 1-bit multicast flag. Its value is fixed at 1.
L 1-bit local flag bit. Its value is fixed at 1.
TYP 2-bit SPSource ID type. Its value is fixed at 0.
SPSource ID 20-bit SPSource ID.
I-SID 24-bit SPB VSI identifier.
In Figure 6 , LSB represents the lower 4 bits of a byte, and MSB represents the higher 4 bits of a byte. The
first byte of an SPBM multicast address is identical to the combination of the first 4 bits of the SPSource
ID field, the TYP field, the L field, and the M field. For example, the hexadecimal form of the first byte (E3)
in the SPBM multicast address E386070006E9 is 11100011. This byte consists of 1110 (first 4 bits of
SPSource ID), 00 (TYP), 1 (L), and 1 (M).
Multiple SPB VSIs
You can use multiple SPB VSIs to transmit traffic for different Ethernet services that span different customer
sites. Each SPB VSI is identified by a unique I-SID.
For example, the network in
Figure 7 has the following SPB VSIs:
• I-SID 300 extends traffic to customer sites B, C, and D.
• I-SID 400 extends traffic to all customer sites.
• I-SID 500 extends traffic to customer sites A and D.
All traffic in one SPB VSI is transmitted in one B-VLAN. Different SPB VSIs can use the same B-VLAN to
transmit traffic. Traffic of different SPB VSIs is isolated by I-SID.